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- If you have a masonry log-burning fireplace and you don’t want to burn logs, there are many other fuels you could use. As explained in Appendix A, “Fireplace Inserts” a
fireplace can be converted for use with a different fuel. Log fireplaces are most often converted to natural gas. If you would like to use natural gas but your home does not have natural gas service, you can convert your fireplace to propane if there is propane service in your area. Using these two fuels is explained in Appendix C, “Gas Fireplaces”. Fireplaces that use electric resistance heating are the least expensive to use if you use a fireplace only for the beauty of a fire, because of these most have a “flame only setting”. In this setting, a realistic-looking flame is created using light bulbs, and no heat is generated. If you use an electric fireplace for supplemental heat it may be more expensive than the other types. Electric fireplaces are explained in Appendix D, “Electric Fireplaces”. Gel fireplaces are fueled by “gel fuel”, also called “gel alcohol fuel”, which is sold in small cans. It is designed to smell, and even sound like wood burning. It is also an expensive way to create heat. Ethanol is a liquid or gel fireplace fuel derived from corn. It is alcohol with some impurities. It has the advantages of not producing smoke and producing very little carbon dioxide. It can be used in a free standing fireplace (no chimney or vent) because it requires no fuel lines. It is explained in Appendix E, “Ethanol fireplaces”. A fireplace may also be converted for use with coal or with wood pellets. Wood pellet fireplaces automatically feed the fire with small pieces of wood, allowing you to enjoy a wood fire without the work of a log fire.
If you burn logs in your fireplace, you can burn them more efficiently, which is basically at a higher temperature, if you follow these rules:
Cut plenty of kindling. Using much kindling lets you make a very hot fire to put the logs in.
Don’t cut the logs too large
Allow the logs to dry out thoroughly. This may take six months. They burn the hottest if dried for over 12 months.
Separate the logs
Check the chimney for smoke. There should be almost no smoke. If there is, the fire is burning poorly.
If your fireplace has a chimney, check if the damper closes tightly. If you have one directly above the fireplace and another at the top of the chimney, the damper at the top was probably installed because the other was not air-tight. The damper at the top is a “top-seal damper” and it will probably be relatively new. If unsure if the damper leaks, tape a very thin plastic sheet across the chimney on a very cold day. It will billow in if the damper leaks, especially when the wind blows. Old, cast iron dampers were not designed to be completely airtight, so the plastic sheet will billow slightly if the damper is operating as designed and this may be acceptable, unless your climate is very cold. Some newer steel dampers can become significantly warped. Many top seal dampers are not designed to be air-tight. If the draft up the chimney seems too great, you may be able to repair the damper by removing debris around it. If not, mount a top-seal damper to the top of the chimney. This is closed by a chain or cable that drops down into the fireplace. A do-it-yourselfer can install one.
Most top-seal dampers are mounted with screws to the top of the flue tile. Some have a chimney cap and side screening to keep out rain and pests when the damper is open.
- If you have a masonry chimney and your home is at least a few decades old, with no damper door and no “top-seal damper”, replace the door or install a top-seal damper. Until recent decades, most, if not all masonry chimneys had cast iron dampers, with cast iron hinges that could break. These dampers cannot be repaired because they were “bricked in” when the chimney was built. It may be possible, but very unlikely, to buy a new or used damper plate that fits perfectly. Ask a chimney sweep or check at a chimney store. if you can’t buy it mount an air-tight top-seal damper to the top of the chimney. See measure above.
If you have a fireplace with a chimney or flue, do not use it while your central heating system is on, except with closed fireplace doors. More heat will escape up the chimney than is created by the fire.
You can use your fireplace with your central heating system on, and watch the fire and receive much of its heat if there are closed glass fireplace doors and a grate heater or a fireplace blower. These are both heat exchangers that deliver heat from the fire into the room. See, Appendix G, “Grate Heaters”. Fireplace blowers are accessories that are available when you install a fireplace as an insert. They are explained in Appendix A, “Fireplace inserts”.
- If you use your fireplace without closing the fireplace doors and with your central heating on, there are ways to reduce the heat that will be lost from your home by going up the chimney.
- Close the doors to that room and close any registers. Open a window in the room by one or two inches. The flame will draw air in through that window in place of drawing in heated air from throughout the house.
- Close the fireplace doors immediately after the fire goes out, to block warm air from leaving the house.
- Install an outdoor air intake to the fireplace. This is a short piece of pipe that goes through the exterior wall and enters the side or rear of the fireplace. There are do-it-yourself web sites and books that show how to install one.
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- If have a log fireplace and no fireplace doors, and you leave the damper open all night after putting out a fire to prevent smoke from entering your home, install fireplace doors. You can leave the damper open all night with them closed, and block warm air from leaving your house. Attractive doors will also increase the value of your home. See Appendix H, “Fireplace Doors”
- If you have a gas fireplace and enough free logs are available for firewood, consider converting your fireplace to a log fireplace. This is not always possible because the flue may not be large enough. A National Fireplace Institute safety inspector should be able to come to your home and tell you if your fireplace can be safely converted to a log fireplace. There are other advantages to using logs as fuel beyond saving fuel costs. A log flame is more charming; people like its appearance, its crackling sound and the smell of burning wood. The contractor who converts it could leave in the fuel line so you can convert it back to gas when you don’t have any logs. He can show you how you can easily do this. Leaving in the fuel line may also help to protect your home’s property value because gas fireplaces are more desirable than log fireplaces.
- To change the fuel you use in your fireplace, you may be able to install a “fireplace insert”. This is basically a steel or cast iron box that contains the fire. Many are designed for a specific fuel.
With some fuels the chimney can be closed while the fire is burning, allowing much more heat energy to enter your home. These are called, “ventless fireplaces”. Natural gas fireplace inserts are by far the most common, and are permitted to be ventless in all but a few states. Appendices A, B, C and D explain fireplace inserts, ventless fireplaces, electric fireplaces”, and “ethanol fireplaces”.
- If you have a masonry fireplace that is not a fireplace insert and does not use natural gas or propane, set a stainless steel fireback in it. This will reflect the heat to increase the efficiency of the fireplace. Firebacks should not be used in natural gas or propane fireplaces because they could cause the gas shut-off valve to be damaged by the higher temperature.
A stainless steel fireback is made of one or three panels of mirror-polished stainless steel. You simply set it behind the fire. Its second purpose is to protect the fireplace wall from decay. Single-panel stainless steel firebacks cost between $75 and $100. The most effective models have three panels.
Stainless steel firebacks are very difficult to find in stores, since there are now very few fireplace stores. To buy one, use a Web search engine and enter the phrase, “fireplace heat reflectors”.
Stainless steel fireback with 3 panels
They are available in many heights and widths, so you can buy the largest size that will fit into your fireplace. If your fireplace is designed for a type of fuel other than logs or natural gas, ask the dealer if their product would be suitable.
Cast iron firebacks are popular, but they reflect very little heat. They are decorative and they protect the rear fireplace wall from the heat of the fire. They absorb heat energy and radiate some of it into the room, but not enough to justify their cost, which is high. Some homeowners buy them to make their fireplaces burn more efficiently because they have been mislead by false claims.
Cast iron fireback
- If you are considering installing an ethanol fireplace, see Appendix E, “Ethanol Fireplaces”. They may be the most expensive fireplaces to operate and they have other disadvantages.
- If your fireplace is not a fireplace insert (these are explained in Appendix A) or a free standing fireplace, you may be able to install a grate heater. These make a fireplace more efficient by transferring into the room. The two main styles are shown below. See Appendix G, “Grate Heaters”.
Conventional grater heater for wood burning fireplace
Tubular grate heater for log fireplace
- If you burn logs and you close your fireplace doors when using the fireplace to prevent sparks from entering your home, install a mesh curtain (mesh screen), and close this instead of the door. These are chain link curtains designed to block sparks and hot embers but let air flow through. They should only be used while someone is in the room with the fire; the doors should be closed whenever the fire is unattended.
- If you use a log-burning fireplace, buy a grate made from “C-shaped” pipes, or buy a “high efficiency grate”. Both of these grates allow the logs to radiate more heat as they burn. High efficiency grates as shown below, radiate heat from a large area that faces the room. Grates made from C-shaped pipes are designed to burn the logs more efficiently. They have “deep-bed construction” to keep the logs closer together for burning, and they have a larger area facing the outside of the fireplace for greater radiation.
Grate made from C-shaped pipes
“High efficiency” grate
- If you have a gas or propane fireplace, there are many maintenance measures you could do to keep your fireplace operating efficiently. They are listed in your Use and Care Manual. Many of these you can do yourself. The measures below will improve the efficiency, but there are others in the manuals, for cleaning, safe operation, etc.
- Clean the gas pilots and burners
- Check that that the gas pilot safety system is working properly
- Check if the chimney draw is correct
- Make sure that the ignition and combustion are working as designed
- Inspect the door gaskets.
- Check that the blower is operating properly.
- If your chimney has a cast iron damper, check for a gap between the bricks and the steel frame that holds the damper. There may be a gap if the bricks are not well-aligned. To caulk a gap here, first clean both surfaces carefully, wearing goggles. Use a “high temperature silicone sealant”. These sealants are designed for fireplaces and other high temperature locations.
Cast iron damper
- If you have a masonry fireplace that is never used, check if the damper seals tightly. As explained above, most do not, mainly because they were not designed to. To check it, on a cold day cover the fireplace with a thin plastic sheet and check for billowing, or hold a burning candle and check if the smoke goes toward the fireplace. If the damper does not seal tightly, seal the gap around the damper with a removable material. A good material for this is “duct seal”, the putty used by electricians to seal the gap around the main electrical cable where it enters the house. Clean both surfaces carefully, wearing goggles, before applying the material.
- Check on the fireplace floor and walls for a small sliding door for an outside air vent-it may be there and you didn’t see it. Outside air vents let in outside air so the fire draws in less heated air from the house. If your fireplace has one, open it when using the fireplace on a cold day and keep it closed at other times.
- Post a small sign on the chimney to remind the members of your household what to do after using the fireplace, to prevent air from escaping up the chimney. The sign could say, PLEASE CLOSE FIREPLACE DOORS AS FIRE DIES DOWN. CLOSE DAMPER AND VENT DOOR ON FLOOR WHEN SMOKE STOPS.
- If your fireplace is in a room with a very high ceiling and there is a ceiling fan, turn on the ceiling fan when using the chimney. In these rooms the air can be a few degrees higher at the ceiling, but not in rooms with lower ceilings. The fan must be set to rotate in the opposite direction as in the summer.
Check if the flame appears to be burning well. If not, your chimney probably has poor draft. The flame isn’t receiving enough oxygen, so the fuel is burning inefficiently. Many of the possible causes of poor draft, and back draft, in which smoke enters the home, are given below, some with their solutions.
1. The furnace vents into the chimney flue, and the flue isn’t large enough for both. Normally, you would not use them at the same time.
2. The flue pipe isn’t large enough in diameter. It is probably not possible to increase the size of the flue pipe.
3. The chimney is partially blocked by soot. To check for this, look into the chimney from the roof using a 100-watt trouble light. If it is partially blocked, hire a chimney sweep to clean it.
4. It is an old, masonry chimney with no lining, and there are holes between the bricks. Air is drawn into the chimney through the holes, which reduces the flow of air from the fireplace. Hire a chimney specialist to repair the holes.
5. The cleanout door on the chimney floor is poorly fitting. It may only need cleaning.
6. A steep nearby hill, a large tree, or a large adjacent building can cause wind to blow slightly downward onto your house. A strong wind may even cause smoke to blow into the home (wind induced downdraft). If your chimney has no chimney cap, installing one may help, at least a little. If your chimney has a cap, the problem can be reduced by installing a “draft increasing chimney cap”. These use the wind to create a stronger draft, so they increase the draw only when necessary. They have blades that are rotated by the wind, and the rotation draws air up the chimney.
Draft increasing chimney cap
7. The draft may be poor because your house is unusually air-tight. Test for this by cracking open a window. If you must leave the window cracked open to improve the combustion efficiency, the cold air that enters would offset the energy savings. A better solution would be to install an outdoor air intake to the fireplace. This is a short piece of pipe that goes through the exterior wall and enters the side or rear of the fireplace. There are do-it-yourself web sites and books that show how to install one.
8.Smoke from the chimney could occasionally blow into a house which has no large trees, large buildings, or nearby hills . This is caused by, “dynamic wind loading”. When the wind is blowing very strongly and you open a door or window on a wall not facing the wind, the wind will draw some air out of the house. Air will enter the house through the chimney to make up for it. One solution is to “crack open” a window on the side of the house facing the wind. A less effective solution is to install a draft increasing chimney cap.
- If you have air-tight fireplace doors, check for gaps between the doors’ frame and the masonry wall and around the edges of the doors. Sealing the gaps will block air from escaping from the house when the fireplace is not in use. If there are gaps around the edges of the doors due to deteriorated gaskets, order replacement gaskets from the manufacturer. If there are gaps between the frame and a masonry wall, caulk them with high temperature silicone caulk. Do not use weather strip for homes because it cannot withstand high temperatures.
- If your climate is very cold and you don’t have air-tight fireplace doors, build a fireplace cover to seal the fireplace, and use it on the coldest days of the year. If your damper is not air-tight, and many are not, a cover will prevent warm air from escaping up the chimney. If you mount an air-tight top seal damper (explained above) onto the top of the chimney, your home will not be insulated from the cold air inside the fireplace. This air can be cold because the back wall of a masonry fireplace is built from bricks, which are poor insulation. To determine if a cover would save much energy, check if the back wall is cold to the touch on a very cold day.
The cover could be cut from ¾” plywood. Thinner plywood may warp. It could also be made from thick Styrofoam rigid insulation. This insulates much better than plywood, and it can be cut with a knife. It could also be built from 1” x 10” boards, cut with a hand saw. Make the cover two boards thick with the front boards vertical and the rear boards horizontal. Cut it to fit tightly into the fireplace opening. Styrofoam rigid insulation is sold only in 4’x8’ pieces, so if you cut it poorly you can cut another from the same piece. If you use ¾” plywood, first cut a piece of cardboard to size to check your measurements.
Wrap fabric around the cover to make it more attractive. The fabric can be stapled to wood with ¼” staples, but must be glued to Styrofoam. Staple ¾” x ¾” foam weather strip to the back side, around all four edges, to extend slightly beyond the plywood to seal the gaps. If Styrofoam is used, the weather strip must be glued to the fabric, but staples could be used to hold it in place until the glue dries. Mount two cabinet handles to the cover.
Nail several 1” hard cut nails into the left and right sides of the fireplace walls (if the walls are brick), for the cover to rest against. To hold the cover in place, drill a ¼” hole on the left side and one on the right side and push in ¼” nails.
- Adjust your damper for optimum efficiency. When a damper is fully open, air passes through the fireplace most rapidly, so the air in the fireplace does not become as hot is if it were flowing slower. Thus, less heat radiates into the house. Your damper should be open just enough that the smoke flows freely up the chimney. To adjust your damper:
- At a time that is not windy, start a fire in your fireplace. Leave the fireplace doors open for the test, so smoke will enter the room if the damper is not open enough. If it is windy during your test, you may choose a damper setting that does not allow enough air to flow up the chimney when there is no wind. This is because wind draws air up the chimney. Record the outside temperature. The ideal setting is slightly different at a different temperature.
- Set the damper at different positions, at different stages of the fire: when it is newly lit, when it has been burning for a while, and when the fire has a thick bed of coals. The ideal setting could be different for each. At each stage of the fire, close the damper as much as possible without causing smoke to enter the room. Record these damper settings.
- Repeat the test when it is much warmer or colder outside and there is no wind. Record this temperature and the ideal damper settings at different stages of the fire. After recording the ideal damper settings at two temperatures you could estimate what the settings would be at a few higher and lower temperatures, and make a table that includes these estimates settings.
- If your home has no fireplace and you wish to add a log burning fireplace, you may be able to install a prefabricated (factory built) fireplace or construct a more expensive conventional fireplace. Prefabricated fireplaces can be made of steel or light weight masonry. They can be installed in almost any home, regardless of its age. In many areas, local code regulations prohibit the installation of conventional fireplaces in older homes. A building inspector must approve the installation of either type of fireplace. Adding a fireplace would not pay for itself in energy savings but may pay for itself in increasing the value of your home, so ask a realtor to estimate how much value it would add. If most potential buyers wouldn’t like it, it would be a poor investment.
A fireplace of either type is much less expensive to install and more effective if located away from a wall. Located here, the heat will radiate in all directions.
Prefabricated fireplace in center of room
- If you use your fireplace while heating your home with central heating without closing the fireplace doors, you may be able to install a fireplace vent in the floor to supply the fire with outside air. The flame will draw outside air into the house through the duct. This will reduce the heat lost from warm air in your home escaping up the chimney. This is a do-it-yourself project and may not be a good investment if a contractor is hired. Cut a 4” by 10” opening in the floor in front of the fireplace and mount a 4”x10” floor register which has a closing mechanism. Mount a 4” or 6” diameter flexible metal duct to it from under the floor. Connect the metal duct to the register using a, “register vent boot”.
4”x10” decorative floor register Register vent boot
Run the duct to the nearest basement window. Hang it from the ceiling with plastic hanger strap. If your basement ceiling is unfinished or has removable tiles you may be able to run the duct between the floor joists for part of the run. Register vent boots and flexible metal ducts are available in home centers and plumbing stores.
At the window, replace one glass pane with a PlexiglasTM pane. This is sold in a thickness close to that of window glass, so it can be mounted in the same way. Cut a 4” hole through it with a jig saw, and mount an aluminum or plastic hood to it. These have dampers that open when air leaves the house, so you must remove the damper. Mount on a piece of metal lath or heavy wire screen to prevent rodents from entering. Nail the sash shut to prevent an intruder from reaching through the hole and un-latching the sash.
Keep the register grille closed when not using your fireplace. They are not very air-tight, so if you feel cold air entering the room through it you could cover it with a small rug. Hoods are sold at home centers and hardware stores.
Appendix A Fireplace Inserts
A fireplace insert is inserted into an existing fireplace. It has a firebox to contain the fire. They are normally designed to convert the fireplace for use with a different fuel. Homeowners with inefficient log fireplaces may install a log fireplace insert with a fireplace blower, to make their fireplace burn logs efficiently. Fireplace inserts have a steel or cast iron box to contain the fire, glass doors, and normally a fireplace blower to transfer some of the heat into the room. There are fireplace inserts designed for logs or coal, wood pellets, natural gas, propane, ethanol, and gel fuel. There are also “electric fireplace” models, which generate heat by electric resistance heat.
Fireplace inserts are expensive. A good fireplace insert will cost in the range of $1500 to $2500, plus the cost of the fireplace blower. They must be professionally installed, and this will likely cost between $500 and $2000 depending on your home design. If you are converting your fireplace to natural gas you must pay for a gas line, which may not be expensive, and if you are converting to propane there will be a charge for the tank. You will probably need to install a chimney liner in the chimney if you wish to make the fireplace energy efficient. This is a stainless steel or aluminum tube that is sized to give the fireplace insert its maximum efficiency. You can buy a used, professionally-refurbished fireplace insert. These were most often sold to fireplace insert dealers by homeowners who converted their fireplaces back to log fireplaces or converted it to a different fuel.
In spite of the high cost of a fireplace insert, it could have a reasonable payback period if you install a gas or log fireplace insert and it allows you to turn off your central heating on mild days. The other fuels are relatively expensive, and are normally selected to enjoy having a fire in a fireplace, not for supplemental heat. Converting a log fireplace to a gas fireplace should increase the value of your home because gas fireplaces are more desirable than log fireplaces. Converting a log or gas fireplace for use with another fuel would probably decrease your home’s value.
Most fireplace inserts are installed with fireplace blowers as accessories. These draw in air from the room, blow it up, behind the firebox and back into the room at a higher temperature. The walls of the firebox radiate heat energy into it. Air is drawn in under the firebox by a long, thin, squirrel cage blower.
Fireplace insert with blower
Squirrel cage blower
If you have a log fireplace that you use often to help heat your home, it may be a good investment to install log fireplace insert with a fireplace blower. These are carefully designed to burn the wood efficiently, so you get the maximum energy from each log. Masonry log fireplaces on older homes are not efficient because the chimney is wider than it needs to be. As a result, the air flows too fast past the burning logs and doesn’t become as hot as it could. However, as mentioned above, you can slow the airflow to the optimum speed if you set the damper at the optimum setting, but few people do this. The optimum setting depends on the size of the fire, the outside temperature and wind conditions, and whether the fire is burning strongly or beginning to die down. Log-burning inserts that protrude into the hearth are generally more efficient because they provide more radiant heat. All log-burning inserts must be EPA certified, which means they must meet the EPA’s high standards for efficiency.
If you install a log fireplace insert, have it inspected periodically by a National Fireplace Institute safety inspector to guarantee that it operates safely and efficiently. Also, follow the maintenance routine given by the manufacturer to keep it operating at maximum efficiency.
A fireplace insert of any type should only be installed by a certified installer. These persons receive their certifications from the National Fireplace Institute.
Log-burning fireplace insert with blower, with doors closed
Appendix B Ventless Fireplaces
Ventless fireplaces create heat by burning a fuel or through electric resistance heating, and do not exhaust the by-products of combustion from the house. They are preferred by some homeowners because they burn nearly 100% efficiently, because no heat leaves the house. Also, they can be located where there is no chimney, such as in the center of a room. Some free standing units are designed to be beautiful architectural features of the home.
There are ventless fireplaces, including ventless fireplace inserts, designed for every fireplace fuel except logs, wood pellets and coal. All electric fireplaces are ventless, and most, if not all ethanol and gel fuel fireplaces are as well. Free standing gas ventless fireplaces require a fuel line, which will enter through the floor.
Free standing ventless fireplaces as architectural features
Ventless fireplaces have many advantages over vented fireplaces.
You can heat your home with central heating while using the fireplace without losing heated air from the house.
They can be installed in many locations in the home, but a concealed fuel supply line must be installed for a gas fireplace.
There are many beautiful designs.
They are less expensive to install than a vented fireplace because there is no vent.
Ventless fireplaces have the disadvantage of creating water vapor, which can lead to mold growth and some moisture-related building problems in humid climates. Mold can also be a serious health hazard for at-risk individuals. However, the humidity in a home is lowest when the outdoor temperature is cold, when a fireplace is normally used.
There is some risk in using ventless gas fireplaces. They can cause carbon monoxide poisoning and physical sickness. To minimize the risk you should have it installed by professionals. To lower the risk of carbon monoxide poisoning, manufacturers instruct customers to keep a window open while ventless fireplaces are in operation, but doing this would make it a poor source of supplemental heat. Many manufacturers install an oxygen-detection sensor that shuts off the flame if oxygen level in the home becomes too low, but this is not 100% fail-safe. Since there is some risk in using gas ventless fireplaces, some states have outlawed them. It is possible that some states have, or will outlaw ventless fireplaces that use other fuels also.
Some homeowners install fireplace blowers in ventless fireplaces. These are probably a poor investment, in the cost of the blower and in the cost of electricity because ventless fireplaces transfer all of the heat into the room.
Appendix C Gas Fireplaces
A gas fireplace can use either propane or natural gas, but adjustments must me made to convert from one fuel to the other. Installing a gas fireplace allows you to enjoy most of the features of a log fireplace without having most of its disadvantages. It is the only popular alternative to a log fireplace, largely because it also can produce much heat. Coal is the only other fuel used in fireplaces that produces as much heat as logs, but it is not a popular source of fuel for fireplaces.
Natural gas is less expensive than propane, so if your home has natural gas service it is better to use it than use propane. Propane can only be used if your home is in the delivery area of a propane dealer. The propane dealer must install a large tank outside of the home and refill it periodically. The fuel is fed to the fireplace from the tank through copper tubing. Before buying a propane fireplace, ask the propane dealer where he must put the tank to have an acceptable path from it to the fireplace. You may not want the tank there, and choose a different fireplace fuel.
Gas fireplaces have the disadvantage that they require either a pilot light or an igniter. The pilot light consumes gas all of the time, which is wasteful. The igniter must be replaced periodically, requiring expensive service calls, unless you can repair it yourself.
Gas fireplaces have many advantages over log fireplaces:
A constant fuel supply. Log fireplace users can run out of logs or the logs may be soaked by rain.
No ashes to remove.
Some people leave the fireplace doors open with a gas fireplace, but would close them if they had a log fireplace, for safety and to prevent smoke from entering. If the doors are left open there is a better view of the fire and more heat enters the home.
Can be turned on and off with a switch on the wall or by a hand held remote switch.
No fumes or particles are released into the air or in your home. This can occur with a log fireplace when a strong wind causes a back draft.
There are beautiful designs and styles of gas fireplaces.
No states have banned vented gas fireplaces. Some states have banned log fireplaces due to environmental concerns.
Less expensive to install than a log fireplace if the gas fireplace has a flue in place of a chimney. Those that are direct vent cost even less because the vent passes through the wall behind them, and ventless gas fireplaces cost the least.
None of the problems associated with storing logs.
No need to hire a chimney sweep.
Gas fireplaces are available in a range of fuel efficiencies. You should be able to obtain information from the manufacturers about rated fuel efficiencies (thermal efficiencies). If a manufacturer does not offer this, the fireplace is likely to be relatively inefficient. Some ventless models have efficiency ratings of over 99%. Most vented models have fuel efficiencies in the 70% to 80% range. Direct vent models, which vent through a nearby wall, have somewhat higher fuel efficiencies; most are probably over 80% efficient.
If you install a gas fireplace insert that will use your existing masonry chimney but without installing a flue that is sized for the new insert, the efficiency will be lower than the rated value. The correct flue will be smaller in diameter to allow better draft and thus, better combustion. A flue of the correct size will also prevent condensation, which can damage the chimney.
There are several energy-saving features available in gas fireplaces:
An igniter in place of a continuously-burning pilot light. This will save gas, but may not save you money. The igniter must be replaced occasionally, and the service call is expensive. An igniter is more likely to be a good investment if you will seldom use your fireplace, or if you can replace it yourself.
A fireplace blower. This transfers heat from the fire into the room. See Appendix A, “Fireplace Inserts”.
Variable setting control. These allow you to regulate gas consumption by setting the flame temperature. Some fireplaces can be turned down to 20 percent while others can only be adjusted to 70 percent.
Appendix D Electric Fireplaces
Electric fireplaces use resistance heating to create heat, as do toasters and electric ranges. Their heating elements are metal tubes with coiled wires running through them; the wires are heated by electric current and transfer heat to the tubes. Air is blown over the tubes to become warm, and then enters the room. Most are designed to create a realistic-looking flame using light bulbs and refracting the light. The light creates the illusion of a dancing flame. Electric fireplaces are an expensive way to heat a home with a fireplace, but they can operate on a “flame only setting”, giving the appearance of flames but no heat, allowing you to use only a fraction of the energy. They are the only type of fireplace that creates heat with no fire, and some homeowners favor them for this reason.
They are available as fireplace inserts to install in an existing fireplace. There may be some danger of fire if drapery or upholstered furniture is too close.
Their advantages and disadvantages include:
They can operate on a “flame only setting”, giving the appearance of flames but no heat, to save energy.
Installation of an electric fireplace insert is easy if there is an outlet close by, and if there is enough extra electric capacity on that circuit. There would only be enough extra electric capacity if you are using the circuit for very little, such as only room lighting. If the circuit does not have enough extra capacity you must install a circuit. This may or may not be costly; if the basement ceiling below is un-finished, a cable can be run from the circuit panel to the fireplace at low cost.
A stand-alone electric fireplace can easily be moved to any location where the nearby outlet can provide enough power.
A disadvantage is that they cannot be used as a backup heat source if your home loses power.
Their flame is less realistic looking than that of other types of fireplaces.
Electric fireplaces typically consume 1.4 to 1.6 kilowatts; 1.4 kilowatts is 1400 watts, and 11.7 amps; 1.6 kilowatts is 1600 watts and 13.3 amps. The circuits in a house are 15-amp or 20-amp, except those used for electric clothes driers, electric ranges and whole house air conditioners, which are larger. The amperage of every circuit is printed on its circuit breaker or fuse. A 20-amp circuit provides up to 2.4 kilowatts and a 15 amp circuit provides up to 1.8 kilowatts. Thus, very little else could be used on a circuit that an electric fireplace is plugged into.
An electric fireplace that uses 1.5 kW, used 4 hrs every day for one month will consume 180 kilowatt-hours of electricity each month it is used. If the electric rate is 12 cents/kWh the cost would be $21.60/month. Of course, using the fireplace could allow you to turn off the central heating on some days to save energy, or to turn the heat down to 60 degrees if you will be in that room.
Appendix E Ethanol Fireplaces
Ethanol is a liquid or gel fuel that can be derived from corn, sugar cane or potatoes. It is alcohol with impurities in it, and it is also known as grain alcohol. Ethanol for fireplace fuel is sold as a liquid in small bottles and as a gel. When burned in a fireplace, it produces no smoke, very little carbon dioxide, and no odor.
There are two types of ethanol burners. In one type the fuel is absorbed in a porous material, and the fire appears more similar to a log fire. This type is the safest because the fuel cannot spill. It also burns more efficiently. The other type has small containers in which you pour the fuel.
There are portable ethanol fireplaces of all sizes. Permanently-mounted ethanol fireplaces are larger and should be properly ventilated, according to most, but not all people. According to some experts, burning ethanol (or natural gas) in an unventilated room can be hazardous because partially-burned ethanol emits carbon monoxide.
Ethanol can cost ten times as much for the heat produced as any other fireplace fuel, not including electric heat. The heat produced per volume varies significantly, based mainly on its country of origin. The cost per volume varies greatly because it costs more in smaller quantities, and because it can be ordered from discount suppliers.
Ethanol is often favored by people who are environmentally conscious, in spite of its being the most expensive fuel for fireplaces. It is a source of renewable energy because the crops it is derived from are re-planted each year.
An ethanol fireplace has many advantages:
It can be burned in a fireplace with no chimney or flue.
It releases no smoke, and very little CO2
It requires no fuel line. This allows you to locate it in many rooms of your house. You should, however locate it in a room with a window you can crack open. You may use it to heat your bedroom in the winter and move it to the living room in other seasons.
It is relatively inexpensive to buy, and does not require the cost of installing a fuel line. This may make it less expensive to buy and use if you seldom use it. The fuel is much more expensive so under normal use it will be more expensive in the long run.
The flame is attractive and you can watch it with the fireplace doors open.
It requires almost no maintenance
It can be easily inserted into a masonry fireplace, and no permit is required. It can be used in a fireplace that is in disrepair that could not be used for a log fire.
It also has many disadvantages:
Ethanol is much more costly than any other fuel. A typical ethanol fireplace will cost over $2 per hour to use.
It is highly flammable liquid; refueling while the fireplace is very hot could cause a fire.
If the fuel does not burn completely, carbon monoxide will be released into the room.
The nearest store that carries it may be far away.
Some water vapor is released, which is negligible unless you have a humidity problem. A dehumidifier can be used but these are expensive to operate. Most homes do not have a humidity problem in the coldest months of the year when the fireplace would be used.
Ethanol gives off odor when you refuel and when you light the fire, which some people dislike.
There is a lack of manufacturing standards for ethanol fireplaces, and some substandard models are sold.
As a free standing fireplace, as with all other free standing fireplaces, it could possibly be knocked over while a fire is burning. Some homeowners lay a fireproof material under it.
Appendix F Direct Vent Gas Fireplaces
Direct vent fireplace with combustion air inlet
Direct vent gas fireplaces normally use natural gas or propane as fuel, and vent the by-products of combustion through a relatively small metal duct. They are most often mounted against an exterior wall or built into the wall, and vented directly through that wall. Due to their venting they are a little more efficient, and may be safer than conventional fireplaces. Unlike most masonry fireplaces, combustion air is normally drawn in from outside, to avoid exhausting the heated air in the house. This allows you to use the fireplace while heating the home with central heating, which you normally would not do with a fireplace that has a chimney or is vented through the roof. They have become very popular, partly because there are many attractive designs to choose from. Some homeowners use sealed glass doors to prevent any exhaust gas from entering the home, but this greatly reduces the fireplace’s, heating ability. If sealed glass doors are used, a grate heater is often used to transfer some of the heat into the room, but a fireplace blower may be used instead. As explained above, fireplace blowers use a fan to draw in air below the firebox, and blow it back, from above the firebox, at a higher temperature.
Direct vent fireplaces that use natural gas or propane are normally highly efficient; up to 78% of the energy generated by the fireplace enters the home if there are no glass doors.
A skilled do-it-yourselfer can install a direct vent gas fireplace. The units come with manufacturers’ installation instructions. Be careful to follow any state or community regulations.
Appendix G Grate Heaters
A grate heater transfers heat from the fire to the room by forcing air through pipes in the frame of the grate, where it absorbs heat from the fire. A grate is the rack the logs rest on. Fireplaces that use other fuels normally have artificial logs that rest on a grate, so grate heaters can be used with these as well. There are several types of grate heaters, but they each transfer heat by passing air through pipes in their frames. Most models have a blower that forces the air through the grate, but one type, the “tubular grate heater”, uses only convection, and is not electric. “Hearth heaters” and “fireplace heat exchangers” are two other terms for grate heaters. Grate heaters that use blowers may be called “fireplace blowers”, but this term is also used to describe the accessory that is sold with fireplace inserts.
As a general rule, a grate heater is much more effective when the fireplace doors are closed than when they are open, because the grate heater saves much of the heat that would have been lost up the chimney. It may not even be worth its cost if it will be used with the doors open. Most brands add significantly to the heat output of the fireplaces, but there are brands that are not very effective.
Grate heaters that can be used with the fireplace doors closed cannot be installed with your existing doors: the doors must be shorter to allow space for the grate heater. Thus, when you buy doors or buy a fireplace insert is your opportunity to buy and install a grate heater. Below, left is shown a grate heater with a blower, for use in a log fireplace. Its frame is made from hollow square pipes. The pipes become very hot and air is forced through them to enter the room at a higher temperature. Below, right is this grate heater installed in a fireplace, with the doors closed. This is a popular type for log fireplaces, and there is one other popular type for log fireplaces, which is called a “tubular grate heater” or a “tubular fireplace blower”. This is built from “C-shaped” large-diameter hollow pipes. The air in them becomes hot and is blown out into the room. They are only used in fireplaces that have no doors.
Grate heater for log fireplace designed for use with doors closed
Tubular grate heater (tubular fireplace blower) for log fireplaces
There are also tubular grate heaters that have no blowers. These rely on convection to move air in and out of the fireplace. The pipes above the fire become extremely hot, heating the air inside of them. The colder air in the pipes below the fire forces out the warmer air by the force of convection. Users have reported that they feel hot air coming from the pipes, but for less than an hour. Eventually the pipes become hot everywhere and the convection stops. There are advertisements for these grate heaters that make much exaggerated claims. They cost in the vicinity of $300, and are probably a very poor investment.
Tubular grate heater with no blower
There are grate heaters designed for vented gas fireplaces. These fireplaces use artificial logs, and the grate heater holds the logs. These grate heaters are also made from hollow square pipes, which the air is blown through to transfer heat to the room. Most buyers of gas fireplaces with fireplace doors buy a grate heater as an accessory.
Grate heater for vented gas fireplace
Most grate heaters cost between $400 and $500, and in addition to this you may need to hire an electrician to install an outlet nearby. Some types have advertisers who make much exaggerated claims about how much heat they deliver.
Grate heaters used in log fireplaces can get clogged with soot, so they may need to be cleaned often to maintain their effectiveness. Some users have reported that their grate heaters have blown smoke into the room. This is likely a result of very poor draft or an occasional down draft caused by a strong wind.
Appendix H Fireplace Doors
Fireplace doors close off the fireplace while allowing you to safely watch the fire burn. They also allow you to leave the damper open for hours after putting out a fire, allowing the smoke to escape, while preventing warm air in the home from escaping. They all have clear, unbreakable glass. They are installed to prevent floating embers and sparks from entering the room, to protect small children from the fire, and to prevent smoke and soot from entering the home when wind causes a back draft. Air-tight fireplace doors block warm air in the house from escaping up the chimney while a fire is burning, but most are not designed to be air-tight. Mesh screens are also designed to prevent floating embers and sparks from entering the room but if the fire is unattended or if it is out but embers are still burning, it is safer to have closed glass doors. The doors fit in a metal frame, which has small vents at the bottom to allow in air to feed the fire. You should close the vents when not using the fireplace.
Air-tight fireplace doors will prevent warm air in the house from escaping up the chimney when there is no fire. Most dampers will not prevent warm air from escaping because they were not designed to be air-tight. Older homes have cast iron dampers, and probably none of these are air-tight. Air-tight fireplace doors are sold as, “air sealed fireplace doors” or “air tight fireplace doors”.
When fireplace doors are closed, the fire heats the home much less efficiently. They can only help you use your fireplace more efficiently if you leave them open while the fire is burning, and then immediately close them when the fire is out, preventing warm air from escaping from your home. If you have a log fireplace you can close a “mesh screen” (mesh curtain) while burning logs with the doors open. These are designed to prevent sparks and embers from entering your home, but if you leave the room while the fire is burning you should close the fireplace doors.
If you plan to buy fireplace doors only to block sparks and embers from entering your home, it would be much less costly to buy a fireplace mesh screen. These normally cost from $30 to $60, but fireplace doors cost hundreds of dollars. They also allow warm air to flow through, so the fire delivers more heat, but they don’t allow you to watch the fire as well.
If you close your fireplace doors while the fire is burning, most of the heat is lost up the chimney, but using a grate heater or a fireplace blower will transfer much of it into the room. Both of these use a blower to draw in air from the room and blow it back out at a warmer temperature. As explained in Appendices A and G, fireplace blowers are used with fireplace inserts, and grate heaters are used in conventional masonry fireplaces. If you would like to install a grate heater you must buy doors that are slightly smaller to allow space for it. See Appendix G.
Most glass fireplace doors cost between $200 and $500. They are expensive, but all but the least expensive of them last almost indefinitely. They add beauty to the room, especially if they match the room’s décor. Their installation is fairly simple and the instructions are given in the package. Some models require you to drill holes in the sides of the fireplace. Fireplace doors may be called glass fireplace doors, but all fireplace doors are glass. Thin glass is no better than thick glass for allowing heat from the fire to pass through because virtually all of the resistance to heat flow is at the inner and outer surfaces.