How to Save Money Using Heat Pumps

How to buy, use and maintain heat pumps of all sizes to heat and cool your home with less electricity, to save money using heat pumps. How they work and when they are better than other ways of heating and cooling your home. ssssssssssssssssss sssssssssss ssssssssssss ssssssssssss sssssssssssss sssssssssss ssssssssss sssssssssss ssssssss 

Heat pumps move heat from the outside air into the home in the heating season. They cool the home by transferring heat from inside the home to outside, like air conditioners. They cool the home using basically the same technology as air conditioners. Simply put, they heat the home by operating in reverse. Freon is pumped in one direction when cooling and in the opposite direction when heating.


In the winter you can save money using a heat pump on days that aren’t too cold. In summer, heat pumps cool the home at a cost similar to central air conditioning. They are normally a good investment in moderate climates. There are many energy tips which can help you lower your electric bills when using a heat pump of any size or type.

There are heat pump systems that transfer heat to and from a body of water such as a pond, and systems that transfer heat from the ground. Some heat pumps can dehumidify the home. The main disadvantage to heat pumps is that they can only be used on days when the outdoor temperature is not too cold and not too hot. See,  How Do Heat Pumps Work?

Your yearly energy cost will depend on how many energy-saving features are on the model and whether use the heat pump efficiently. Some of these features are explained in  Energy Tips for Buying a Whole House Heat Pump . Heat pumps don’t burn fuel to create heat, so there is no risk of carbon monoxide poisoning and there is no flame to worry about.

If you must replace both your air conditioning and your heating equipment, installing a whole house heat pump or a mini split heat pump system is much less expensive than buying conventional air conditioning and heating systems. A mini split system has the heating/cooling units mounted to exterior walls and have no HVAC ducts. They can be used to heat and cool a small house or a section of a house. This is explained in the section in  Mini Split Heat Pumps.

When heating a home on a day that is not very cold, transferring heat energy from outside to inside costs less than generating energy in a furnace or other heating unit by burning fuel or using resistance electric heat. In climates that are occasionally too cold for a heat pump, whole house heat pump systems have supplemental electric heaters. In the summer, using a heat pump can cost about the same as using an air conditioner, because their components are similar and they both use the refrigeration cycle.

Conventional whole house heat pumps, mini split heat pumps, and portable heat pumps are “air-source heat pumps” because they transfer energy with the outside air. “Water-source” and “ground-source” heat pumps transfer heat energy with the earth or a with a nearby body of water. These are described below in the section  Water-Source and Ground-Source Heat Pump Systems   

Is a Heat Pump Right for You?

If your climate is moderate and you heat your home more days than you cool it, a heat pump is probably a good investment. However, if you live in a very hot or very cold climate, a heat pump will be less efficient and not as good of an investment. If you must replace your central heating system and whole house air conditioner, you may be able to save money by replacing them both with a heat pump system in place of buying both sets of equipment.

There are too many factors to estimate how much you would save; there are only rules of thumb. Twelve of the factors are given below. Also, heat pumps have a few problems of their own. See, Some   Problems with Heat Pumps that Air Conditioners Don’t Have.

Whole house heat pumps normally heat a home more economically than other types of central heating systems down to temperatures of around 25 to 30 degrees, depending on the model. At that point, either a gas furnace or an air handler with supplemental electric heat must be used to create extra heat.

Heat pumps use electricity to transfer heat from outside to inside your home in winter, so the colder it is outside the less heat is in the air and the more electricity it takes to make your home warm. This is also true in cooling the home in the summer but air conditioners are similar to heat pumps operating in their cooling mode, and will probably use a similar amount of electricity.

Many factors determine how much it would cost to buy, install and use a heat pump. They are true for all types of heat pumps:

Some Problems Heat Pumps Have That Air Conditioners Don’t Have

  • Some models can ice up on very cold, snowy winter days.
  • Water dripping from gutters can turn to ice. They are inefficient when covered by ice and can suffer damage. They normally go into defrost mode to melt the ice, but this may not always be sufficient.
  • On very cold and windy days they may not heat the home sufficiently because they may have little or no extra heating capacity for strong wind.
  • In some small towns, there are no well-qualified heat pump technicians. Consequently, air conditioning technicians must do the repairs.
  • Basically, they are probably not as reliable as gas furnaces at heating the home, because their condenser unit is outdoors so there are more possible problems.

How Do Heat Pumps Work?

“How does a heat pump transfer heat from outdoors to indoors on a cold day to heat a home?” Explained simply, Freon transfers heat by being pumped through tubes from inside the home to outside and back to the inside. Freon is a gas at higher temperatures and lower pressures, and a liquid at lower temperatures and higher pressures.

In winter, it is pumped outside in liquid form. The tube expands, causing the pressure to become lower so the Freon becomes a gas. As the tube becomes wider the pressure becomes very low so the gas becomes very cold, colder than the surrounding air. Since heat flows from hot to cold, heat energy from the outside air flows into the Freon.

The Freon is pumped through the compressor which compresses it to make it a hot liquid, which is pumped into the house. In the house it expands to become a hot gas, which flows through coils. Air is blown past the coils, which heats it, and it is then blown into every room of the house.

To cool the home in summer, a heat pump transfers heat energy from inside the house to the outside by pumping the Freon through the same tubes but in the opposite direction. All of the same components are used. This is called the “refrigeration cycle” which air conditioners use.nnnnnnnnnnnnnnnn

Conventional Whole House Heat Pumps

“How does a heat pump transfer heat from outdoors to indoors on a cold day to heat a home?” Explained simply, Freon transfers heat by being pumped through tubes from inside the home to outside and back to the inside. Freon is a gas at higher temperatures and lower pressures, and a liquid at lower temperatures and higher pressures.

In winter, it is pumped outside in liquid form. The tube expands, causing the pressure to become lower so the Freon becomes a gas. As the tube becomes wider the pressure becomes very low so the gas becomes very cold, colder than the surrounding air. Since heat flows from hot to cold, heat energy from the outside air flows into the Freon.

In the past, air-source heat pumps were only appropriate for warmer climates, but in recent years the technology has improved. They’re now cost-effective in some colder regions, such as the upper parts of the Northeast and Midwest. However, an auxiliary heating system is necessary where temperatures drop below 10 degrees F to 25 degrees F, depending on your system’s size.

To The Freon is pumped through the compressor which compresses it to make it a hot liquid, which is pumped into the house. In the house it expands to become a hot gas, which flows through coils. Air is blown past the coils, which heats it, and it is then blown into every room of the house.


To cool the home in summer, a heat pump transfers heat energy from inside the house to the outside by pumping the Freon through the same tubes but in the opposite direction. All of the same components are used. This is called the “refrigeration cycle” which air conditioners use. Conventional whole house heat pump systems are also called “split-system heat pumps”. These are “air-source” because they transfer heat between the house and the outside air. They are called “split-system because some of their components are outside in the yard or on the roof and some are inside. The compressor, fan and outdoor coil is outside, housed in the “outdoor unit” and the indoor coil and blower are inside. They transfer heated or cooled air directly to rooms through HVAC ducts with a register in the wall or ceiling of each room. 

New whole house heat pumps can reduce your heating costs greatly over electric furnaces and baseboard heaters and they dehumidify better than standard central air conditioners, so your home will be more comfortable in warmer, muggier months.

They are more energy efficient when the outdoor air is warmer because they draw energy from outdoor to heat the home. Also, they cannot heat the home when the outside air temperature is too low, for some models this is about 35°F. Most have electric resistance heating strips to heat your home on very cold days. They release energy into the outdoor air when they cool the home, so the hotter it is outside the more energy they use to cool the home.

If you presently heat your home with electric heat and your climate is moderate, installing a whole house heat pump system could lower your heating costs by up to 50 percent. In addition, they dehumidify better than standard central air conditioners. The technology is improving, and consequently the range of temperatures for which they can heat the home efficiently has been increasing. They are now used in relatively cold regions, but back-up electric heat must be used when the temperature is too cold.

Whole house heat pumps can have a significant problem. Models that are not equipped with “ultraviolet C” (UVC) lights often emit odors. The residents may not realize that the odors are caused by fungus, mold, and bacteria on the coils of the heat pump. When not controlled by UVC, the fungus, mold, and bacteria can spread throughout HVAC ducts. In addition to emitting unpleasant smells, they can create health problems and cause a reduction in heat pump efficiency.

Mini Split Heat Pumps

Mini split heat pumps, also called “ductless heat pumps” have the basic components of conventional whole house heat pumps. Like whole house heat pumps, they transfer heat energy from the outside to the inside of the house in the winter, and from the inside to the outside in the summer. As a result, they are very expensive to use and not very effective in areas of the country where it is often very cold.

These systems have indoor units mounted high on the walls of one or more of rooms that will be heated and cooled. These “air handlers” create warm and cool air from hot or cold Freon that is pumped in through the wall where they are mounted. There is one outdoor unit for the house, which heats and cools the Freon and pumps it into each of the air handlers. The outdoor unit may be called “compressor/condenser”.

Air handlers draw in air to heat and cool through thin vents at the bottom, and blow it out the top through two registers which are similar to heating registers. Inside the cover is a heat exchanger which looks like a car radiator rolled into a large cylinder. This heat exchanger transfers energy into or out of the Freon into the air.

Their outside unit contains a fan, a compressor and an outdoor coil, as do conventional heat pumps. Refrigerant is heated or cooled in the outdoor unit and pumped through small tubes to the indoor units. The indoor units have tubes running through the wall to drain the condensation water. A mini split heat pump system can have from 0ne to five indoor units. An indoor unit can be installed in a room that is not on an exterior wall.

To install these systems, the installer must cut a 3” diameter hole through the wall of the house behind each unit mounted to the wall. The conduit houses a power cable, refrigerant (Freon) tubing, suction tubing, and a condensate drain tube.

Most models require that a 240v circuit be installed. A cable must be run from the main circuit panel to the outdoor unit, so the cost depends on the distance the cable must run. Also, if your home does not have 200 amps, you may need to do a “heavy-up” to increase its electrical capacity to 200 amps. Models that operate on a 120v circuit are available, but these are less efficient.

The best mini split systems have higher heating and cooling efficiencies, and have many energy-saving features. See Energy Tips for Buying and Using Mini Split Heat Pumps.

Mini split heat pumps are often used when a new room is added to a house that has forced air heating and cooling, and the climate is moderate. They normally use less electricity when heating the room than heating it with space heaters. They may cost about the same to use as cooling with window unit air conditioners, but these block the view through a window.

For maximum efficiency, they should be installed by a heating and cooling technician who can determine the proper size and right product for your home and climate. See Energy Tips for Buying and Using Mini Split Heat Pumps.

The cost of installing a mini split heat pump system is higher than installing other appliances that heat orcool individual rooms, but there may be federal and state tax credits to offset the initial installation cost. 

Like conventional whole house heat pumps, they use energy taken from the outdoor air to heat the home, so the warmer the outdoor temperature the more energy efficient they are. Also, they cannot heat the home when the outside air temperature is below about 35°F, depending on the model. Most have electric resistance heating strips for very cold days. When cooling the home, they release energy into the outdoor air, so the hotter it is outdoors, the more electricity they use to cool the home.

They are often chosen because not all of the rooms in the home need to be cooled, or because they can be turned off in rooms when they are not occupied. They do not have the energy loss associated with HVAC ducts, and this loss is very significant in some homes, especially if the ductwork was designed for forced air heat. However, an air handler does not heat and cool a room as efficiently as a whole house heat pump system.

Mini split heat pump systems are now a popular heating and air conditioning choice; mainly to heat and cool a few rooms in homes with no HVAC ducts. They can heat and cool an entire house if the house is relatively small and the climate is moderate. Each indoor unit has its own thermostat, so different rooms can be set at different temperatures and the units can be turned off for periods of the day to save energy. A possible problem is that in some places there are no qualified installers or repair persons. 

Their energy efficiency ratings for cooling and heating can be as high as those of whole house heat pumps. These ratings indicate how much hot or cold air is created by how many kilowatt-hrs of electricity.

To install these systems, the installer must cut a 3” diameter hole through the wall of the house behind each unit mounted to the wall. The conduit houses a power cable, refrigerant (Freon) tubing, suction tubing, and a condensate drain tube.

Mini Split Heat Pumps Compared to Conventional Whole House Heat Pumps 

If your home is small and you are considering installing a whole house heat pump system with new HVAC ducts, installing a mini split system may be a better choice. It’s cost could be lower and you will have no ducts taking up space all over the house.

If your home has HVAC ducts, a whole house heat pump system should cost less to install, because the mini split systems would have about four inside units, and require that a new circuit be installed to the outside unit. A mini split system could cost much less to operate, however, if you reduce the heating and cooling in areas of the house that aren’t occupied.

If you are considering installing a heat pump system with new HVAC ducts which would run through your attic, ask the contractor to estimate how much energy you would lose through the attic ducts in the cooling season. This could be a significant expense if you live in a hot climate and tip the scale in favor of installing a mini split system. Another factor that could tip the scale is that there may be no qualified mini split installers or repair persons in your area.

Portable Heat Pumps

Portable heat pumps have the basic components of whole house and mini split heat pumps combined in one unit. They are on wheels, and can be rolled from room to room, drawing in and exhausting air through the lower sash of a double-hung window or through a horizontally sliding window. They can save electricity very well if you turn off the central air conditioning and only cool one or two rooms which are occupied. 

The largest models are designed to heat and cool one large room. Some models have dehumidifier and fan functions. They begin heating the room quickly, unlike oil-filled electric space heaters, and they cool as quickly as window air conditioners. Unlike window air conditioners, they allow an open view through the window. At least one brand can be used as an HEPA Air Purifier instead of a heat pump, which is useful when the pollen count is high. 

The most efficient portable heat pumps are similar in their cooling efficiencies to the most efficient window unit air conditioners. This is because a heat pump operating in the cooling mode is mechanically similar to an air conditioner. Heat pumps cost much more to buy than window unit air conditioners, so they are only a good investment if they will be used mainly for heating, and only if your outdoor temperature is moderate, so they can be energy efficient.

Their costs range from about $300 to about $1000. Some portable heat pumps are called, “heat pump portable air conditioners”, but these are the same. Heating efficiencies are not often given because a model’s heating efficiency is similar to its cooling efficiency. One high capacity portable heat pump with a dehumidifier function has these technical specifications.

Technical Specifications for a Typical High Capacity Portable Heat Pump

Cooling Capacity13,000 Btu
Heating Capacity12,500 Btu
Power Supply115v (60 Hz)
Cooling Input12A (1350W)
Heating Input11A (1180W)
Dehumidifier60 pints/day
Sound Level47 dB (A) Max
Airflow225 CFM
Product Size18.875" wide x 17.125" deep x 32" high
Weight88 lbs.

Before buying a portable heat pump, determine if the electrical circuit it would use has enough extra capacity; most circuits do not. An electrical circuit is the wiring that provides power for all of the outlets and lights protected by one circuit breaker or fuse.

To check which outlets and lights are on a circuit, turn off its circuit breaker or remove its fuse. The lights and outlets that don’t operate are on that circuit. Normally, all of the lights and outlets on a circuit are relatively close together on the same floor, but there is an exception. A basement outlet may be on almost any circuit in the house because it was added by tapping into a cable that runs through the basement to another part of the house.

A typical portable heat pump requires about 12 amps, and most of the circuits in your home are probably 15-amp circuits, so they would not have enough extra capacity unless they are used for almost nothing else. Most kitchens have outlets on 20-amp circuits, so you could use a 14 gage extension cord from a kitchen circuit.

If an outside circuit is a 20-amp circuit you could run a 14 gage extension cord out the window to it. It is best to hire an electrician to install a 20 amp circuit with an outlet near the window where the heat pump will be used.

A portable heat pump’s efficiency may be given either as an EER value or an SEER value. The EER (Energy Efficiency Ratio) is the ratio of cooling (in Btu/hr) to electrical power (in watts), at 95° outside and 80° inside, with 50% relative humidity. The SEER (Seasonal Energy Efficiency Ratio) is similar except it is calculated for a typical year’s weather (temperatures and humidities) in a typical location.

The EER for a heat pump is about 87% of it’s SEER. Do not compare the estimated cost of operating a portable heat pump with that of operating a mini-split heat pump by comparing their EER’s or SEER’s because mini-split heat pumps have larger fans. Their fans blow the heated and cooled air farther into the room. The EPA does not rate portable heat pumps for efficiency or award them an ENERGY STAR® designation.

To help you to buy a model of the right size, to operate the portable heat pump with maximum efficiency, there may be a “sizing guide” printed on the box or in the user’s manual on the website. One manufacturer gives the sizing guide shown below for its products. It is for a room with an average number of sun-exposed windows. If a room has few windows or no sun-exposed windows you could buy a heat pump with a lower cooling capacity.

Sizing Guide for Portable Heat Pumps

Room Size (sq. ft.)Cooling Capacity (Btu/hr)
150-2005000
200-2506000
250-3007000
300-3508000
350-4009000

Dual Hose Models Compared with Single Hose Models

Portable heat pumps are either “single hose” or “dual hose”. A dual hose heat pump draws air into the house through one hose, the air is passed through a heat exchanger and blown out through a separate hose. In the winter, this outside air heats cold refrigerant flowing through the heat exchanger. In the summer, it cools hot refrigerant. These cost more but save electricity compared to single hose heat pumps. 

A single hose heat pump blows air from the house through a heat exchanger to outside the house, in all seasons of the year. It is air that has leaked into the house through doors and windows. In summer, the air transfers heat from the heat exchanger to the outside air. In winter the air leaves the house as cold air after transferring its heat to air that passes through the heat pump into the house. A single hose heat pump is much less effective and much less efficient.

Dual hose models have cooling efficiencies in the range of 9 to 10 EER, according to their manufacturers. This is about 10.5 to 11.5 SEER. Dual hose and single hose models are compared below. The best portable heat pumps have several energy-saving features: self-evaporation technology, dual hose design, 3-speed fans, energy-saving thermostats, and dual motor design. A dual hose portable heat pump can be used at a conventional double hung window or at a window with sliding sashes.

You must change the filters regularly to have your portable heat pump to operate efficiently. It will use much more electricity when the filters are dirty. In addition, you should vacuum it inside by following the instructions given in the Use and Care manual. 

Water-Source and Ground-Source Heat Pump Systems 

Water-source and ground-source heat pump systems are called “geothermal” heat pump systems. They can reduce your home’s energy use and control humidity, while providing they are quiet, long lasting service with little maintenance. A ground-source system has long loops of piping buried in the ground through which refrigerant is pumped. The temperature deep in the ground is between 50º and 60º depending on the season and region of the country.

In these systems, the refrigerant is pumped through the piping and enters the evaporator of the heat pump in the house at the temperature under the ground. The refrigerant in the piping absorbs heat in the winter and releases heat in the summer. The technology is similar to that of conventional air-source heat pump systems but use much less electricity to deliver the same heating and cooling because the ground holds more energy per cubic ft. and energy transfers more easily from the ground to coolant than from air to coolant.

Since their installation requires much digging, the cost is very high and is seldom used in homes. However, their high efficiency can make ground-source heat pump systems suitable for very large homes. 

A water-source heat pump system can be a “lake loop system” or a “well system” (open loop system). A lake loop system has long loops of piping that run along the bottom of a lake or pond and have refrigerant pumped through them.

In a well system, water is pumped from a well or lake through a heat exchanger to absorb energy or add energy to it, then discharges it into a different well or lake. The temperature at the bottom of a deep lake or pond is much cooler than the outside air in the summer and is warmer than the outside air in the winter, so the refrigerant in the piping absorbs heat in the winter and releases heat in the summer.

As with ground source heat pumps, the technology used in water-source heat pump systems is similar to that of conventional air-source heat pump systems but uses much less electricity to deliver the same heating and cooling because heat transfers more easily from water to coolant than from air to coolant. Both types of water-source systems can be good investments if a body of water is close to your house and the climate is moderate.

Geothermal heat pump systems are not practical for small lots or for certain soil conditions, and installation is costly, especially for ground-source systems. However, federal and local incentives can drop the initial cost considerably, and the maintenance and repair costs are much lower than conventional air-source systems. 

Whole House Heat Pump Energy Tips

  • If you are heating and cooling your home with a whole house heat pump, hire an HVAC contractor to do a tune-up and inspection every one or two years. The key components of your system are checked and adjustments are made to keep the system operating efficiently and to extend its life. A very thorough tune-up and inspection should include:
  • Check carbon monoxide emission
  • Inspect tubes for refrigerant leaks
  • Check if the system has lost refrigerant. If refrigerant is lost the heat pump will be less efficient.
  • Inspect visible ductwork and flue pipe for air leaks. Air leaks in the ductwork reduce the unit’s efficiency.
  • Inspect the indoor blower wheel and motor and recording amp draw (how much electricity the motor uses). If it is too high the motor is wasting electricity.
  • Check for noise that indicates the motor bearings are worn.
  • Inspect unit wiring and electrical disconnect.
  • Calibrate the thermostat.
  • If the outdoor unit is closely surrounded by shrubbery, replant the shrubbery 2 to 3 feet away. Shrubbery traps heat, decreasing the coils’ ability to dissipate heat in the cooling season.

    Also, leaves could be drawn into the unit by the fan. This could cause the fan to create a vacuum back pressure that could shorten the life of the unit.
  • Buy a programmable thermostat designed for heat pumps and use it to set back the temperature when heating (not cooling). All other programmable thermostats can cause the unit to operate inefficiently, canceling out any savings achieved by lowering the temperature setting. Programmable thermostats designed for heat pumps are available at home centers.
  • Do not set back the temperature at night in the heating season unless you have a thermostat designed for heat pump set-back, such as a programmable heat pump thermostat. The electric resistance backup heat would engage when the thermostat is raised in the morning, resulting in higher energy consumption.
  • Check that the outdoor unit is level. It must be level for maximum efficiency. If not, there could be problems with drainage and premature wear.  If the concrete slab is very old, one side may have sunk into the ground. If not level, adjust the leveling feet or shim the feet with slate shingles or cedar shims.
  • If high winds are common, plant shrubbery to block the unit from wind. High winds can reduce efficiency by allowing frost to form because the defrost cycles may be unable to melt it in high winds.
  • Check if your heat pump cycles too often in the cooling season. If it cycles too often it is wasting energy. They normally cycle about three times per hour when the outdoor temperature is 95° to 105°. If yours cycles more than this your thermostat may not be working correctly or the filter is clogged or the blower is malfunctioning. Replace the filter, and if this doesn’t help you should call an HVAC technician.
  • Do not allow run-off from the roof to fall on the outdoor unit. This could cause ice buildup.
  • Do not set back the temperature at night in the heating season unless you have a thermostat designed for heat pump set-back, such as a programmable heat pump thermostat. The electric resistance backup heat would engage when the thermostat is raised in the morning, resulting in higher energy consumption.
  • Check that the outdoor unit is level. It must be level for maximum efficiency. If not, there could be problems with drainage and premature wear.  If the concrete slab is very old, one side may have sunk into the ground. If not level, adjust the leveling feet or shim the feet with slate shingles or cedar shims.
  • If high winds are common, plant shrubbery to block the unit from wind. High winds can reduce efficiency by allowing frost to form because the defrost cycles may be unable to melt it in high winds.
  • Check if your heat pump cycles too often in the cooling season. If it cycles too often it is wasting energy. They normally cycle about three times per hour when the outdoor temperature is 95° to 105°. If yours cycles more than this your thermostat may not be working correctly or the filter is clogged or the blower is malfunctioning. Replace the filter, and if this doesn’t help you should call an HVAC technician.
  • Do not allow run-off from the roof to fall on the outdoor unit. This could cause ice buildup.
  • Never use a weather cover over the outdoor unit. This will trap moisture, causing rust and damage to electrical parts.
  • If the outdoor unit is exposed to summer sun, build a plywood roof for it to give it shade and increase its efficiency at cooling. The refrigerant releases its heat energy at the coils through radiation, allowing it to condense from hot gas to liquid. When radiation from the sun heats the coils, the refrigerant enters the house at a higher temperature, making the heat pump less efficient.  See How to Build a Roof for a Heat Pump Condenser Unit
  • If a large room or a small area in your  home has no HVAC ducts leading to it for heating and cooling and you must use electric space heaters and window unit air conditioners there, install a mini-split heat pump. This is common where a room that was formerly a porch has been converted into a room. It could be a poor investment to buy and operate if you use it while heating and cooling the rest of the home, but it would allow you to turn off the central heating and air conditioning  when using only that room.
  • If you have freezing weather, do not install a condenser unit under a gutter that overflows when it isn’t cleaned. If water drips onto the unit and freezes, the coils could become covered with ice.
  • Post this list of energy tips on the wall next to the heat pump:
  • Change the filter the first week of each month.
  • If your thermostat is not designed for heat pump set-back, write, “Do not set back the temperature in the heating season”
  • If you do not have a variable-speed fan, do not run the fan continuously, except on “auto” fan setting on thermostat.
  • Call a service technician if you see excess ice buildup or hear excess noise.
  • If the indicator light shows that resistance heat is being used and the outdoor temperature is moderate, call a service technician.

Energy Tips for Buying a Whole House Heat Pump

If you plan to buy a heat pump, there are too many factors to accurately estimate how much electricity you would save. Many of the factors are listed above in Is a Heat Pump Right for You? Some heat pump manufacturers have a “Savings Estimator” on their websites, but this may give exaggerated savings.

A whole house heat pump or mini split heat pump would probably be a good investment if your heating bills are high and your climate is moderate because your air conditioning costs may remain about the same with a heat pump. Your savings from buying a mini-split heat pump would of course be high if you turn off the units in rooms when they are not occupied.

  • Heat pump manufacturers and retailers give descriptions such as, “12,000 BTU, 13-SEER mini-split ductless heat pump”, and “One ton, 18-SEER mini-split heat pump”. A ton is 12,000 BTU’s/hr. Describing its capacity in BTU’s is incorrect because it is actually BTU’s/hr.

    Normally, the Btu’s/hr for cooling is given but not the Btu’s/hr for heating because they are close. The specification table will give them both. The SEER, which is the cooling efficiency, is given, but the heating efficiency, the HSPF, is not given because the SEER is sufficient to describe the efficiency of the equipment.

    Furthermore, the HSPF is more complicated than the SEER rating because it takes into account supplemental heating needs, i.e., using electric heat when the temperature is too cold for the heat pump, and the energy used to defrost the unit.

    This energy use depends, of course, on how often there is freezing temperature. A rule of thumb is that in warmer climates, a higher SEER is more important, and in colder climates, a higher HSPF is better.
  • For better energy efficiency in the heating season, choose a heat pump with a high HSPF. For units with comparable HSPF ratings, check their steady-state rating at -8.3°C, the low temperature setting. The unit with the higher rating will be more efficient.

    The cooling efficiency may be given as the SEER or EER. The EER (Energy Efficiency Ratio) is the ratio of output cooling (in Btu/hr) to input electrical power (in watts), at 95° outside and 80° inside, with 50% relative humidity.

    The SEER (Seasonal Energy Efficiency Ratio) is similar except it is calculated for a typical year’s weather (temperatures and humidities) in a typical location. The EER for a heat pump (or any other cooling device) is about 87% of it’s SEER.
  • A heat pump system must be sized and installed properly for maximum energy efficiency, so hire a well-qualified HVAC contractor. Heat pumps are sized for either the heating demand or the cooling demand, depending on which is greater.

    If it is too large it will cycle on and off more than necessary, wasting energy. This may shorten it’s life by putting more stress on the equipment. If it is too small, it will cost slightly less to operate on most days but on the coldest days the supplemental electric heat will be used more often, wasting electricity.

    An HVAC professional is trained to determine the home’s heating and cooling requirements, but these are difficult to estimate accurately, so many HVAC contractors tend to size the system larger than necessary to be safe. You may tell the contractor that it is better to install a unit that is too small than too large, to avoid any chance of installing a system that is too large and wastes electricity.
  • If your climate is almost too cold for a heat pump, the electric heat would be used often, so consider using some other type of auxiliary heat source than electric resistance heating. Electric resistance heat is used in the large majority of heat pump systems because the equipment costs much less to buy. It is simply large heating coils in the HVAC supply duct.

    Consider adapting your gas or oil furnace that you were planning to remove, to create auxiliary heat. Your local utility company may have information on how to do this. Some manufacturers of heat pumps offer a “hybrid” system. This is a conventional gas or oil furnace heats the home on colder days and the home is heated by the heat pump on moderate days.

    An “intelligent controller” can be used to determine which heat source is most energy efficient from hour to hour. This system is  expensive to buy, but may be a good investment for a large house in a cold climate. The combustion fuel could be propane, natural gas, oil, or even coal and wood.
  • Heat pump systems require larger duct sizes than central heating systems to achieve their maximum efficiency. Hence, the efficiency claimed by the manufacturer could only be achieved if the ducts were larger than those in your home. However, it is not a good investment to replace all of your ductwork when installing a heat pump system.  
  • As mentioned above, whole house heat pumps that do not have ultraviolet C (UVC) lights often emit odors due to fungus, mold, and bacteria on the coils. This can create health problems and cause a reduction in heat pump efficiency. Thus, buy a heat pump with ultraviolet C lights.
  • Fans and compressors can be noisy, so they should not be located outside of bedroom windows if possible. This is  especially true if you have single-pane windows. You can reduce this noise by choosing relatively quiet equipment or by mounting the unit on a noise-absorbing base.
  • Heat pumps have many feature options designed for increased energy efficiency. The efficiencies, HSPF and SEER, basically reflect how many energy-saving options the heat pump has. These include:
  • Dual-mode (two-stage) compressors and motors that save energy by adjusting up or down according to the level of heating or cooling needed.
  • Scroll compressors. These are quieter, more energy efficient and last longer than other compressors.
  • Two-speed and variable-speed blowers. The control system determines when less air than normal should cross the coils, to use only the energy that is needed. The least expensive heat pumps have only one speed.
  • Defrost Mode. Frost can form on the outdoor coils, which is insulation, making the heat pump less efficient. Heat pumps with defrost mode have sensors that determine when there is frost. Heat is then sent back outdoors to melt the ice. Conventional heat pumps do this on a time and temperature basis, wasting energy.
  • A desuperheater. This is a small heat exchanger that transfers heat in the heat pump, which would be wasted, into your water heater. This allows the water heater to use less energy.

Energy Tips for Buying and Using Mini Split Heat Pumps

Energy Tips for Using Mini Split Heat Pumps

  • Check the outside cabinet periodically for airflow obstructions such as leaves, ice and snow.
  • Hire an HVAC contractor to do a tune-up and inspection. Only a technician trained in ductless heat pumps {mini split heat pumps) should inspect and test it’s components. A very thorough tune-up and inspection will include:
  • Clean or replace the air filter in each indoor unit (air handler) monthly. a dirty filter blocks airflow and increases energy bills.
  • Use the “Auto” setting on the remote controls if your system has them. In that zone (the area heated and cooled by that indoor unit), the temperature you select will be maintained and the most energy efficient fan speed will automatically be chosen.
  • Check if the temperature setting you enter is the same as the temperature where you normally sit. If you are cooling the room and it is 2 or 3 degrees cooler where you sit, you are paying for 2 or 3 degrees you don’t want.

    The temperatures will normally be different, because the system will maintain the temperature you entered at the inside unit, where it is higher. Also, if you are cooling the room, the air near the wall may be warmer than in the rest of the room if the sun is shining on that wall.

    When you heat the room in the winter, the area near the air handler may be cooler when wind is blowing on it. As a result, you would over-heat the room. Set a thermometer next to where you normally sit to compare the temperatures.
  • If a room with an air handler is kept cooler than other rooms in the cooling season, mount a door sweep or weatherizing door bottom to the bottom of the room’s door. This will prevent the cooler air that settles to the bottom from flowing out from under the door.
  • If the outdoor unit is closely surrounded by shrubbery, replant the shrubbery  2 to 3 feet away. Shrubbery traps heat, decreasing the coils’ ability to dissipate heat in the cooling season. Also, leaves could be drawn into the unit by the fan. This could cause the fan to create a vacuum back pressure that could shorten the life of the unit.
  • Avoid frequently turning the system on and off. Some homeowners try to conserve energy by turning their systems off when they aren’t home, but this usually doesn’t save energy. Mini split systems use less energy when they run continuously.

    You can use less electricity by setting the temperature down to about 60 degrees in the heating season when you will be away all day. You can set it up 5 or 10 degrees in the cooling season.
  • If high winds are common, plant shrubbery to block the outdoor unit from wind. High winds can reduce efficiency by allowing frost to form because the defrost cycles may be unable to melt it in high winds.
  • If you have freezing weather, do not locate an outside unit under a gutter that overflows when it isn’t cleaned. If water drips onto the unit and freezes, the coils could become covered with ice.
  • Mount one or two outdoor thermometers where you can see them looking out the the windows, to quickly check the outdoor temperature in the cooling season. When it is cooler outside than indoors, run the indoor units at fan mode. At this setting the unit may use about one-tenth of the electricity.
  • If your home has forced air heating or cooling (with registers), and you turn it off and use a mini split heat pump to condition one or more rooms on some days, close the registers in those rooms.
  • In the indoor units, if there is a gap between the casing and the wall, caulk it with interior/exterior caulk.
  • Close the blinds and curtains on hot, sunny days in rooms cooled by the indoor units. The outdoor heat and ultraviolet radiation causes the heat pumps to run more each day.
  • If there is occasional heavy snowfall where you live, you could mount the outdoor unit to the side of your house, at 2 feet above the ground. They are not designed to be mounted to a wall, you must build a stand for it to rest on. Reducing the days it is buried in snow will allow it to run more efficiently.
  • Do not cover the outside unit with a weather cover to protect it from snow. This will trap moisture, causing rust and damage to electrical parts.

Energy Tips for Buying Mini Split Heat Pumps

  • Choose a mini split heat pump system with a cooling capacity at the low end of the recommended range. It will use less electricity each day, but this area of your home may not be quite cool enough on the hottest days and may not be quite warm enough on the coldest days.

    For example, if the contractor tells you that the total area you need to heat and cool requires a system that creates between 25,000 and 35,000 Btu cooling capacity, choose a system that creates 25,000 Btu for greater energy efficiency. Heat pump systems are normally chosen for their cooling capacities, not heating capacities.
  • Buy a system with high energy efficiency. ENERGYSTAR models all have high energy efficiencies. Normally, the EER (Energy Efficiency Ratio) is given, to indicate the system’s efficiency. This is its cooling efficiency and not its heating efficiency. Only the EER is given because it is sufficient to describe the efficiency of the equipment.

    Mini split heat pump efficiencies range from 11 EER to 15 EER. A few manufactures report efficiencies as SEER (Seasonal Energy Efficiency Ratio). These range from about 17 SEER to about 38 SEER.

    EER is the ratio of output cooling energy (in Btu’s) to input electrical energy (in watt-hours) at a given operating point. It is generally calculated using a 95 °F (35 °C) outside temperature and an inside temperature of 80 °F (27 °C) and 50% relative humidity. SEER is similar, but represents the expected overall performance for a typical year’s weather in a given location.
  • Buy a system with many energy saving features, such as:
  • The option to select “Auto” for temperature and fan settings. This automatically maintains the temperature you selected and chooses the most energy efficient fan speed.
  • Remote control for each indoor unit. Almost all models have these.
  • Wi-Fi. This allows you to control the temperature of all the inside units from a smart phone or other device from anywhere in the home or away from home. You can conveniently raise the cooling temperature and lower the heating temperature to save energy. As explained above, it is better not to turn off the system.
  • Relative Humidity Sensor. This allows you to raise the cooling temperature on dry days, saving energy.
  • Occupancy Sensor. On indoor units, these detect when someone is in the room and direct cooled air toward them. This could allow you to use less air conditioning by setting it at a slightly higher temperature.
  • Coating on indoor units designed to prevent dust and dirt from accumulating. The surfaces transfer energy more efficiently when clean. It can be applied to the heat exchanger, vanes and blower wheel.

Create a Zoned HVAC System for Energy Savings

To save more energy using a heat pump, you could hire an HVAC contractor to install flow control valves, called “dampers” in the HVAC ducts. These allow you to reduce or shut off the heated and cooled air to individual areas of your home. For example, you could shut off the hot or cold air to the second floor during the day and to the first floor at night.

A typical home has two or three branches, often one for each floor. Each branch has an HVAC duct that feeds smaller HVAC ducts, often leading to individual rooms. In a zoned HVAC system, the duct for each branch has a damper to control the airflow going through it. A separate thermostat is installed for each damper, allowing the residents to control that zone (area of the house).

A typical home has two or three branches, often one for each floor. Each branch has an HVAC duct that feeds smaller HVAC ducts, often leading to individual rooms. In a zoned HVAC system, the duct for each branch has a damper to control the airflow going through it. A separate thermostat is installed for each damper, allowing the residents to control that zone (area of the house).

It will cost a few thousand dollars to install dampers throughout your house to create a zoned HVAC system, but you can, of course, spend much less by installing them only in one or two ducts leading to areas where you use less heating and cooling. 

A damper is are normally installed to control the airflow through a branch, not an individual room. Installing a damper on a duct that feeds only one room may not lower your energy bills. When it shuts off the airflow to that room, the other registers on that branch would have more air flowing out of them.   

Maintenance You Can Do Yourself to Improve the Efficiency of Your Whole House Heat Pump

You can save more energy and lower your utility bills more using your heat pump if you do some simple maintenance that is often recommended for homeowners to do.

  • Clean the outdoor coil. Dirt on the coils insulates them, reducing the heat pump’s efficiency. They are in the outdoor unit in the yard or on the roof.
  1. You must first shut off the power to the heat pump at its electrical disconnect switch. This is outside in a weatherproof metal box, mounted on the wall of the house near the heat pump. 

    Also, turn off the circuit breaker for the unit in the main electrical service panel. Then, wait a few minutes to allow any stored electrical charge in the unit’s capacitors to dissipate. ssssss ssssss
  2. Remove the cover on top of the and the protective side grille. Be careful not to break any wires. sssssssss sssssss sssssss  
  3. Remove any leaves or pieces of debris from the outside of the coils. Vacuum the coils, being careful not to bend them. Spraying it with a garden hose could bend the coils. ssssss ssssssss sss sssss sssssss 
  4. From inside the outdoor unit, spray water through the coils through to the outside to remove debris. ssssssssss sssssssss s
  5. If your owner’s manual recommends that you oil the fan motor bearings, do this also.

While the cover and side grille are removed, straighten any bent fins in the outdoor unit. Bent fins restrict air flow, causing the unit run harder, decreasing its energy efficiency so it uses more electricity. Fins are made from delicate thin metal and can be damaged by sticks falling from a tree, hail, or power washing.

A fin comb is used to straighten bent fins in a condensing unit. Both air conditioners and heat pumps have them. These tools may come with single, multiple or interchangeable heads that have different fin comb sizes and counts to best match the coil fin size of the repaired unit.

Some six sided head models will work for 8, 9, 10, 12, 14 and 15 fins per inch coils. The comb is carefully drawn across the bent coil fins straightening them out in the process. They are sold at plumbing stores and can be ordered at some home centers.

  • Inside your home, periodically clean or replace the filter in the duct. Do this every 6 months, or more frequently if it becomes clogged with dust in less than 6 months. The filter is located where the return duct meets the heat pump, in the duct or in the heat pump. It will be either disposable or washable—this should be marked on the filter’s edge,
  • Inside your home, clean and lubricate the fan motor, but only if your owner’s manual includes this among the maintenance procedures that homeowners can do. Check for a loose fan belt.
  • Clean the indoor heat exchanger coils with a vacuum cleaner.
  • Inside the home, adjust the blower unit and the drive belts if instructions for this are given in the manufacturer’s instruction booklet. This will improve the efficiency of the heat pump.

How to Build a Roof to Shade Your Heat Pump Condenser Unit 

TOOLS:

  • Sledgehammer
  • Hacksaw
  • Drill
  • Hammer
  • Framing Square
  • Saw
  • Tape Measure

MATERIALS:

  • 1/2″ pressure treated plywood or nominal 1″ thick pine boards
  • Seven 8′ long 2×4’s
  • 12d galvanized nails or 3″ deck screws
  • Package of shingles
  • 3/4″ roofing nails
  • 8d nails or 2″ deck screws
  • 4′ of 1/2″ EMT piping (sold in electrical departments)

STEPS:

  1. Cut the pieces of the frame from 2×4’s. The top should have a slight slope and be a foot above the condenser (so heat isn’t trapped) and be large enough to shade the condenser throughout the day. If the condenser is east or west of the house, then the roof should be large enough to shade the condenser when the sun is low. ssssssss ssssssss sssssssssss sssssssssss      
  2. Use 3” deck screws or 12d nails to build the top of the frame and mount the legs. Nail or screw on a piece of 2×4 as a diagonal (not shown on dwg). Place it over the condenser. Drill two ¾” holes through each piece of the frame that rests on the ground, and nail or screw these to the legs (see drawing).sssss  ssss sssssssssss ss s sssssssssssssssssssss ssssssssss ssssssssss
  3. Cut ½” EMT pipe into four 12” pieces to use as stakes, with one end of each cut to 45º to penetrate the ground. Flatten 1” of the other end with a sledgehammer and bend it over. This end will hold down the board. Pound the stakes through the holes until the ends rest on the boards. sssssssssss ssss ss ssssssssss sssssss
  4. Using 1/2” plywood or 1” boards, cut the wood for the roof. Fasten it to the frame using 8d nails or 2” screws. sssssssssssssssss sssssssss sssssssssss ssssssssss sssssssss
  5. Cut the shingles with a utility knife and nail them to the roof with ¾” roofing nails.


Heat pumps are complicated, but in simple terms, they move heat energy from outside to inside in winter and from inside to the outside in summer, lowering your utility bills. Buy a whole house heat pump or a smaller model if your climate is moderate and use these energy tips and you will save money using a heat pump.  

Heat pumps move heat from the outside air into the home in the heating season. They cool the home by transferring heat from inside the home to outside, like air conditioners. They cool the home using basically the same technology as air conditioners. Simply put, they heat the home by operating in reverse. Freon is pumped in one direction when cooling and in the opposite direction when heating.

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