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Furnaces

Keep your home warm

Burgeson's can keep your family warm and help you save money and energy by replacing your outdated furnace. Look into our list of Lennox equipment including high efficiency, variable capacity gas furnaces as well as other home heating systems.

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HERE'S WHAT OUR CUSTOMERS HAVE TO SAY

Between the technician and the people I spoke with over the phone, I received very friendly and professional service. The technician had my furnace up and running in no time, and had no qualms about crawling into my rather unpleasant crawlspace while there was snow on the ground. I'll certainly be using Burgeson's again if the need arises.
Travis C.

Furnaces and Boilers 

Most U.S. homes are heated with either furnaces or boilers. Furnaces heat air and distribute the heated air through the house using ducts; boilers heat water, providing either hot water or steam for heating. Steam is distributed via pipes to steam radiators, and hot water can be distributed via baseboard radiators or radiant floor systems, or can heat air via a coil. Steam boilers operate at a higher temperature than hot water boilers, and are inherently less efficient, but high-efficiency versions of all types of furnaces and boilers are currently available.

  • Understanding the Efficiency Rating of Furnaces and Boilers
  • Retrofitting Your Furnace or Boiler
  • Replacing Your Furnace or Boiler
  • Maintaining Furnaces and Boilers
  • Maintaining Proper Ventilation for Combustion Systems
  • A New Furnace Can Reduce Heating Costs

Understanding The Efficiency Rating Of Furnaces And Boilers

A central furnace or boiler's efficiency is measured by annual fuel utilization efficiency (AFUE). The Federal Trade Commission requires new furnaces or boilers to display their AFUE so consumers can compare heating efficiencies of various models. AFUE is a measure of how efficient the appliance is in the energy in its fuel over the course of a typical year.

Specifically, AFUE is the ratio of heat output of the furnace or boiler compared to the total energy consumed by a furnace or boiler. An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere. AFUE doesn't include the heat losses of the duct system or piping, which can be as much as 35% of the energy for output of the furnace when ducts are located in the attic.

An all-electric furnace or boiler has no flue loss through a chimney. The AFUE rating for an all-electric furnace or boiler is between 95% and 100%. The lower values are for units installed outdoors because they have greater jacket heat loss. However, despite their high efficiency, the higher cost of electricity in most parts of the country makes all-electric furnaces or boilers an uneconomic choice. If you are interested in electric heating, consider installing a heat pump system.

The minimum allowed AFUE rating for a non-condensing fossil-fueled, warm-air furnace is 78%; the minimum rating for a fossil-fueled boiler is 80%; and the minimum rating for a gas-fueled steam boiler is 75%. A condensing furnace or boiler condenses the water vapor produced in the combustion process and uses the heat from this condensation. The AFUE rating for a condensing unit can be much higher (by more than 10 percentage points) than a non-condensing furnace. Although condensing units cost more than non-condensing units, the condensing unit can save you money in fuel costs over the 15- to 20-year life of the unit, and is a particularly wise investment in cold climates.

You can identify and compare a system's efficiency by not only its AFUE but also by its equipment features, listed below.

 Old, low-efficiency heating systems:

  • Natural draft that creates a flow of combustion gases
  • Continuous pilot light
  • Heavy heat exchanger
  • 68%–72% AFUE

Mid-efficiency heating systems:

  • Exhaust fan controls the flow of combustion air and combustion gases more precisely
  • Electronic ignition (no pilot light)
  • Compact size and lighter weight to reduce cycling losses
  • Small-diameter flue pipe
  • 80%–83% AFUE

High-efficiency heating systems:

  • Condensing flue gases in a second heat exchanger for extra efficiency
  • Sealed combustion
  • 90%–97% AFUE

 Retrofitting Your Furnace Or Boiler

Furnaces and boilers can be retrofitted to increase their efficiency. These upgrades improve the safety and efficiency of otherwise sound, older systems. The costs of retrofits should be carefully weighed against the cost of a new boiler or furnace, especially if replacement is likely within a few years or if you wish to switch to a different system for other reasons, such as adding air conditioning (see the section on choosing heating and cooling systems). If you choose to replace your gas heating system, you'll have the opportunity to install equipment that incorporates the most energy-efficient heating technologies available. Since retrofits are fuel-specific, see the following sections for retrofit information:

Other retrofitting options that can improve a system's energy efficiency include installing programmable thermostatsupgrading ductwork in forced-air systems, and adding zone control for hot-water systems, an option discussed in the Heat Distribution Systems section.

 Replacing Your Furnace or Boiler

Although older furnace and boiler systems had efficiencies in the range of 56%–70%, modern conventional heating systems can achieve efficiencies as high as 97%, converting nearly all the fuel to useful heat for your home. Energy efficiency upgrades and a new high-efficiency heating system can often cut your fuel bills and your furnace's pollution output in half. Upgrading your furnace or boiler from 56% to 90% efficiency in an average cold-climate house will save 1.5 tons of carbon dioxide emissions each year if you heat with gas, or 2.5 tons if you heat with oil.

If your furnace or boiler is old, worn out, inefficient, or significantly oversized, the simplest solution is to replace it with a modern high-efficiency model. Old coal burners that were switched over to oil or gas are prime candidates for replacement, as well as gas furnaces with pilot lights rather than electronic ignitions. Newer systems may be more efficient but are still likely to be oversized, and can often be modified to lower their operating capacity.

Before buying a new furnace or boiler or modifying your existing unit, first make every effort to improve the energy efficiency of your home, then have a heating contractor size your furnace. Energy-efficiency improvements will save money on a new furnace, because you will need a smaller furnace. A properly sized furnace will also operate most efficiently. You'll also want to look for a dependable unit and compare the warranties of each furnace or boiler under consideration.

When shopping for high-efficiency furnaces and boilers, look for the ENERGY STAR label. If you live in a cold climate, it usually makes sense to invest in the highest-efficiency system. In milder climates with lower annual heating costs, the extra investment required to go from 80% to 90%-95% efficiency may be hard to justify.

You can estimate the annual savings from heating system replacements by using Table 1. The table assumes that both furnaces have the same heat output. However, most older systems are oversized, and will be particularly oversized if you significantly improve the energy efficiency of your home. Because of this additional benefit, your actual savings in upgrading to a new system could be much higher than indicated in the table.

Specify a sealed combustion furnace or boiler, which will bring outside air directly into the burner and exhaust flue gases (combustion products) directly to the outside, without the need for a draft hood or damper. Furnaces and boilers that are not sealed-combustion units draw heated air into the unit for combustion and then send that air up the chimney, wasting the energy that was used to heat the air. Sealed-combustion units avoid that problem and also pose no risk of introducing dangerous combustion gases into your house. In furnaces that are not sealed-combustion units, backdrafting of combustion gases can be a big problem.

High-efficiency sealed-combustion units generally produce an acidic exhaust gas that is not suitable for old, unlined chimneys, so the exhaust gas should either be vented through a new duct or the chimney should be lined to accommodate the acidic gas (see the section on maintaining proper ventilation, below).

 

Table 1. Annual Estimated Savings for Every $100 of Fuel Costs by Increasing Your Heating Equipment Efficiency*

Existing System AFUE

New/Upgraded System AFUE

55%

60%

65%

70%

75%

80%

85%

90%

95%

50%

$9.09

$16.76

$23.07

$28.57

$33.33

$37.50

$41.24

$44.24

$47.36

55%

----

$8.33

$15.38

$21.42

$26.66

$31.20

$35.29

$38.88

$42.10

60%

----

----

$7.69

$14.28

$20.00

$25.00

$29.41

$33.33

$37.80

65%

----

----

----

$7.14

$13.33

$18.75

$23.52

$27.77

$31.57

70%

----

----

----

----

$6.66

$12.50

$17.64

$22.22

$26.32

75%

----

----

----

----

----

$6.50

$11.76

$16.66

$21.10

80%

----

----

----

----

----

----

$5.88

$11.11

$15.80

85%

----

----

----

----

----

----

----

$5.55

$10.50

90%

----

----

----

----

----

----

----

----

$5.30

*Assuming the same heat output

Maintaining Furnaces And Boilers

The following maintenance should be provided by a heating system professional.

All systems:

  • Check the condition of your vent connection pipe and chimney. Parts of the venting system may have deteriorated over time. Chimney problems can be expensive to repair, and may help justify installing new heating equipment that won't use the existing chimney.
  • Check the physical integrity of the heat exchanger. Leaky boiler heat exchangers leak water and are easy to spot. Furnace heat exchangers mix combustion gases with house air when they leak—an important safety reason to have them inspected.
  • Adjust the controls on the boiler or furnace to provide optimum water and air temperature settings for both efficiency and comfort.
  • If you're considering replacing or retrofitting your existing heating system, have the technician perform a combustion-efficiency test.

Forced-air Systems:

  • Check the combustion chamber for cracks
  • Test for carbon monoxide (CO) and remedy if found
  • Adjust blower control and supply-air temperature
  • Clean and oil the blower
  • Remove dirt, soot, or corrosion from the furnace or boiler
  • Check fuel input and flame characteristics, and adjust if necessary
  • Seal connections between the furnace and main ducts.

Hot-water Systems:

  • Test pressure-relief valve
  • Test high-limit control
  • Inspect pressure tank, which should be filled with air, to verify that it's not filled with water
  • Clean the heat exchanger.

Steam Systems:

  • Drain some water from the boiler to remove sediments. This improves the heat exchange efficiency
  • Test low-water cutoff safety control and high-limit safety control
  • Drain the float chamber to remove sediments. This prevents the low-water cutoff control from sediment clogs
  • Analyze boiler water and add chemicals as needed to control deposits and corrosion
  • Clean the heat exchanger
  • See also the section on 

Maintaining Proper Ventilation For Combustion Systems

Anytime you maintain, retrofit, or replace a gas heating system you also need to be concerned with air quality. Combustion air is needed by all oil and gas heating systems to support the combustion process. This air is provided in some homes by unintentional air leaks, or by air ducts that connect to the outdoors. The combustion process creates several byproducts that are potentially hazardous to human health and can cause deterioration in your home. You can protect yourself from these hazards, as well as maintain energy efficiency, by ensuring that your chimney system functions properly and that your gas heating system is properly ventilated. In some cases, installing a sealed-combustion furnace or boiler can also help.

Chimneys

Properly functioning chimney systems will carry combustion byproducts out of the home. Therefore, chimney problems put you at risk of having these byproducts, such as carbon monoxide, spill into your home.

Most older gas furnaces and boilers have naturally drafting chimneys. The combustion gases exit the home through the chimney using only their buoyancy combined with the chimney's height. Naturally drafting chimneys often have problems exhausting the combustion gases because of chimney blockage, wind or pressures inside the home that overcome the buoyancy of the gases.

Atmospheric, open-combustion furnaces and boilers, as well as fan-assisted furnaces and boilers, should be vented into masonry chimneys, metal double-wall chimneys, or another type of manufactured chimney. Masonry chimneys should have a fireclay, masonry liner or a retrofitted metal flue liner.

Many older chimneys have deteriorated liners or no liners at all and must be relined during furnace or boiler replacement. A chimney should be relined when any of the following changes are made to the combustion heating system:

  • When you replace an older furnace or boiler with a newer one that has an AFUE of 80% or more. These mid-efficiency appliances have a greater risk of depositing acidic condensation droplets in chimneys, and the chimneys must be prepared to handle this corrosive threat. The new chimney liner should be sized to accommodate both the new heating appliance and the combustion water heater by the installer.
  • When you replace an older furnace or boiler with a new 90+ AFUE appliance or a heat pump. In this case, the heating appliance will no longer vent into the old chimney, and the combustion water heater will now vent through an oversized chimney. This oversized chimney can lead to condensation and inadequate draft. The new chimney liner should be sized for the water heater alone, or the water heater in some cases can be vented directly through the wall.

Other Ventilation Concerns

Some fan-assisted, non-condensing furnaces and boilers, installed between 1987 and 1993, may be vented horizontally through high-temperature plastic vent pipe (not PVC pipe, which is safely used in condensing furnaces). This type of venting has been recalled and should be replaced by stainless steel vent pipe. If horizontal venting was used, an additional draft-inducing fan may be needed near the vent outlet to create adequate draft. Floor furnaces may have special venting problems because their vent connector exits the furnace close to the floor and may travel 10 to 30 feet before reaching a chimney. Check to see if this type of venting or the floor furnace itself needs replacement. If you smell gases, you have a venting problem that could affect your health. Contact your local utility or heating contractor to have this venting problem repaired immediately.

A New Furnace Can Reduce Heating Costs

Heating bills across the country are the highest they have ever been, with out any relief in sight. Even if your older furnace runs, from an economic standpoint it would be wise to replace it. With the proper furnace selection, your central air-conditioning bills can be lower too.

Compared with a 17-year-old furnace, a new furnace can save the typical family hundreds of dollars per year. Based on the efficiency of your old furnace, probably 60% at best, a new furnace can cut your utility bills by 40%. You can do the arithmetic to determine your annual savings.

Not only will you have lower utility bills, but the comfort and quiet operation of a new system will surprise you. The contractor should install a computerized thermostat with it. This thermostat, coupled with the electronic controls in the new furnace, will maintain even room temperatures.

You can choose from two basic designs of furnaces: condensing and non-condensing. The condensing models (this refers to the type of heat exchanger used) are the most efficient and the best choice for most homeowners. The efficiencies of condensing models range from about 90% to over 95%.

These models are very efficient, and so little heat is lost in the flue gases that a chimney is not needed. The gases are exhausted by a 2-inch-diameter plastic pipe through an outdoor wall. With no need for a new chimney liner, a condensing furnace is often cheaper to install.

 Some models also offer sealed combustion for better efficiency. The combustion air is drawn in from outdoors through another plastic pipe instead of being drawn from inside your house. Being sealed, there are fewer indoor drafts, less noise and less chance of hazardous back drafting.

 For the ultimate in comfort and efficiency, but at a higher initial cost, is a two-stage heat output furnace with a variable-speed blower. This type of blower is needed if you want the best central air-conditioning.

 In all but the coldest weather, the gas burners operate at a low heat level. This allows the furnace to run more continuously with fewer uncomfortable on/off cycles. The blower also runs slower and quieter at this low level. During very cold weather, it automatically switches to high heat.

 If your budget allows, also install a quality air cleaner. Since a two-stage unit runs more, the air cleaner is more effective for allergy sufferers.

 

Electric Resistance HeatinG

 Electric resistance heating converts nearly 100% of the energy in the electricity to heat. However, most electricity is produced from oil, gas, or coal generators that convert only about 30% of the fuel's energy into electricity. Because of electricity generation and transmission losses, electric heat is often more expensive than heat produced in the home or business using combustion appliances, such as natural gas, propane, and oil furnaces.

 If electricity is the only choice, heat pumps are preferable in most climates, as they easily cut electricity use by 50% when compared with electric resistance heating. The exception is in dry climates with either hot or mixed (hot and cold) temperatures (these climates are found in the non-coastal part of California; the southern tip of Nevada; the southwest corner of Utah; southern and western Arizona; southern and eastern New Mexico; the southeast corner of Colorado; and western Texas). For these dry climates, there are so few heating days that the high cost of heating is not economically significant.

Electric resistance heating may also make sense for a home addition if it is not practical to extend the existing heating system to supply heat to the new addition.

 Types Of Electric Resistance Heaters

Electric resistance heat can be supplied by centralized forced-air electric furnaces or by heaters in each room. Room heaters can consist of electric baseboard heaters, electric wall heaters, electric radiant heat, or electric space heaters. To learn about electric radiant heat and electric space heaters, see the radiant heating and small space heaters sections. It is also possible to use electric thermal storage systems to avoid heating during times of peak power demand.

 Electric Furnaces

Electric furnaces are more expensive to operate than other electric resistance systems because of their duct heat losses and the extra energy required to distribute the heated air throughout your home. Heated air is delivered throughout the home through supply ducts and returned to the furnace through return ducts. If these ducts run through unheated areas, they lose some of their heat through air leakage as well as heat radiation and convection from the duct's surface.

Blowers (large fans) in electric furnaces move air over a group of three to seven electric resistance coils, called elements, each of which are typically rated at five kilowatts. The furnace's heating elements activate in stages to avoid overloading the home's electrical system. A built-in thermostat called a limit controller prevents overheating. This limit controller may shut the furnace off if the blower fails or if a dirty filter is blocking the airflow.

 As with any furnace, it's important to clean or replace the furnace filters as recommended by the manufacturer, in order to keep the system operating at its top efficiency.

 Electric Baseboard Heaters

Electric baseboard heaters are zonal heaters controlled by thermostats located within each room. Baseboard heaters contain electric heating elements encased in metal pipes. The pipes, surrounded by aluminum fins to aid heat transfer, run the length of the baseboard heater's housing, or cabinet. As air within the heater is warmed, it rises into the room, and cooler air is drawn into the bottom of the heater. Some heat is also radiated from the pipe, fins, and housing.

 Baseboard heaters are usually installed underneath windows. There, the heater's rising warm air counteracts falling cool air from the cold window glass. Baseboard heaters are seldom located on interior walls because standard heating practice is to supply heat at the home's perimeter, where the greatest heat loss occurs.

Baseboard heaters should sit at least three-quarters of an inch (1.9 centimeters) above the floor or carpet. This is to allow the cooler air on the floor to flow under and through the radiator fins so it can be heated. The heater should also fit tightly to the wall to prevent the warm air from convecting behind it and streaking the wall with dust particles.

 The quality of baseboard heaters varies considerably. Cheaper models can be noisy and often give poor temperature control. Look for labels from Underwriter's Laboratories (UL) and the National Electrical Manufacturer's Association (NEMA). Compare warranties of the different models you are considering.

 Electric Wall Heaters

Electric wall heaters consist of an electric element with a reflector behind it to reflect heat into the room and usually a fan to move air through the heater. They are usually installed on interior walls because installing them in an exterior wall makes that wall difficult to insulate.

 Electric Thermal Storage

Some electric utilities structure their rates in a way similar to telephone companies and charge more for electricity during the day and less at night. They do this in an attempt to reduce their "peak" demand.

 If you are a customer of such a utility, you may be able to benefit from a heating system that stores electric heat during nighttime hours when rates are lower. This is called an electric thermal storage heater, and while it does not save energy, it can save you money because you can take advantage of these lower rates.

The most common type of electric thermal storage heater is a resistance heater with elements encased in heat-storing ceramic. Central furnaces incorporating ceramic block are also available, although they are not as common as room heaters. Storing electrically heated hot water in an insulated storage tank is another thermal storage option.

 Some storage systems attempt to use the ground underneath homes for thermal storage of heat from electric resistance cables. However, this requires painstaking installation of insulation underneath concrete slabs and all around the heating elements to minimize major heat losses to the earth. Ground storage also makes it difficult for thermostats to control indoor temperatures.

 Any type of energy storage systems suffers some energy loss. If you intend to pursue an electric thermal storage system, it would be best for the system to be located within the conditioned space of your home, so that any heat lost from the system actually heats your home, rather than escaping to the outdoors. It would also be best to know how quickly heat will escape from the system. A system that leaks too much heat could cause control problems, such as the accidental overheating of your home.

 Control Systems

All types of electric resistance heating are controlled through some type of thermostat: baseboard heaters often use a line-voltage thermostat (the thermostat directly controls the power supplied to the heating device), while other devices use low-voltage thermostats (the thermostat uses a relay to turn the device on and off). Line-voltage thermostats can be built into the baseboard heater, but then they often don't sense the room temperature accurately. It's best to instead use a remote line-voltage or low-voltage thermostat installed on an interior wall. Both line-voltage and low-voltage thermostats are available as programmable thermostats for automatically setting back the temperature at night or while you're away.

 Since baseboard heaters supply heat to each room individually, they are ideally suited to zone heating, which involves heating the occupied rooms in your home while allowing unoccupied sections (such as empty guest rooms or seldom-used rooms) to remain cooler. Zone heating can produce energy savings of more than 20% compared to heating both occupied and unoccupied areas of your house.

Zone heating is most effective when the cooler portions of your home are insulated from the heated portions, allowing the different zones to truly operate independently. Note that the cooler parts of your home still need to be heated to well above freezing to avoid freezing pipes.

 Radiant Heating

Radiant heating systems involve supplying heat directly to the floor or to panels in the wall or ceiling of a house. The systems depend largely on radiant heat transfer: the delivery of heat directly from the hot surface to the people and objects in the room via the radiation of heat, which is also called infrared radiation. Radiant heating is the effect you feel when you can feel the warmth of a hot stovetop element from across the room. When radiant heating is located in the floor, it is often called radiant floor heating or simply floor heating.

 Radiant heating has a number of advantages: it is more efficient than baseboard heating and usually more efficient than forced-air heating because no energy is lost through ducts. The lack of moving air can also be advantageous to people with severe allergies. Hydronic (liquid-based) systems use little electricity, a benefit for homes off the power grid or in areas with high electricity prices. The hydronic systems can also be heated with a wide variety of energy sources, including standard gas- or oil-fired boilers, wood-fired boilers, solar water heaters, or some combination of these heat sources.

 Despite their name, radiant floor heating systems also depend heavily on convection, the natural circulation of heat within a room, caused by heat rising from the floor. Radiant floor heating systems are significantly different than the radiant panels used in walls and ceilings. For this reason, the following sections discuss radiant floor heat and radiant panels separately.

 Radiant Floor Heat

There are three types of radiant floor heat: radiant air floors (air is the heat-carrying medium); electric radiant floors; and hot water (hydronic) radiant floors. All three types can be further subdivided by the type of installation: those that make use of the large thermal mass of a concrete slab floor or lightweight concrete over a wooden subfloor (these are called "wet installations"); and those in which the installer "sandwiches" the radiant floor tubing between two layers of plywood or attaches the tubing under the finished floor or subfloor ("dry installations").

 Types of Radiant Floor Heat

 Air-Heated Radiant Floors

Because air cannot hold large amounts of heat, radiant air floors are not cost-effective in residential applications, and are seldom installed. Although they can be combined with solar air heating systems, those systems suffer from the obvious drawback of only being available in the daytime, when heating loads are generally lower. Because of the inefficiency of trying to heat a home with a conventional furnace by pumping air through the floors, the benefits of using solar heat during the day are outweighed by the disadvantages of using the conventional system at night. Although some early solar air heating systems used rocks as a heat-storage medium, this approach is not recommended.

 Electric Radiant Floors

Electric radiant floors typically consist of electric cables built into the floor. Systems that feature mats of electrically conductive plastic are also available, and are mounted onto the subfloor below a floor covering such as tile.

Because of the relatively high cost of electricity, electric radiant floors are usually only cost-effective if they include a significant thermal mass, such as a thick concrete floor, and your electric utility company offers time-of-use rates. Time-of-use rates allow you to "charge" the concrete floor with heat during off-peak hours (approximately 9 p.m. to 6 a.m.). If the floor's thermal mass is large enough, the heat stored in it will keep the house comfortable for eight to ten hours, without any further electrical input (particularly when daytime temperatures are significantly warmer than nighttime temperatures). This saves a considerable number of energy dollars compared to heating at peak electric rates during the day.

 Electric radiant floors may also make sense for additions onto homes for which it would be impractical to extend the heating system into the addition. However, homeowners should examine other options, such as mini-split heat pumps, which operate more efficiently and have the advantage of also providing cooling

Hydronic Radiant Floors

Hydronic (liquid) systems are the most popular and cost-effective radiant heating systems for heating-dominated climates. Hydronic radiant floor systems pump heated water from a boiler through tubing laid in a pattern underneath the floor. In some systems, the temperature in each room is controlled by regulating the flow of hot water through each tubing loop. This is done by a system of zoning valves or pumps and thermostats. The cost of installing a hydronic radiant floor varies by location and also depends on the size of the home, the type of installation, the floor covering, remoteness of the site, and the cost of labor.

 Types Of Floor Installations 

Whether cables or tubing, the methods of installing electric and hydronic radiant systems in floors is about the same.

So-called "wet" installations embed the cables or tubing within a solid floor and are the oldest form of modern radiant floor systems. The tubing or cable can be embedded in a thick concrete foundation slab (commonly used in "slab" ranch houses that don't have basements) or in a thin layer of concrete, gypsum, or other material installed on top of a subfloor. If concrete is used and the new floor is not on solid earth, additional floor support may be necessary because of the added weight. You should consult a professional engineer to determine the floor's carrying capacity.

 Thick concrete slab systems have high heat capacity and are ideal for storing heat from solar energy systems, which have a fluctuating heat output. The downside of the thick slabs is their slow thermal response time, which makes strategies such as night or daytime setbacks difficult if not impossible. Most experts recommend maintaining a constant temperature in homes with these heating systems.

 Due to recent innovations in floor technology, so-called "dry" floors, in which the cables or tubing run in an air space beneath the floor, have been gaining in popularity, mainly because a dry floor is faster and less expensive to build. But because dry floors involve heating an air space, the radiant heating system needs to operate at a higher temperature.

 Some dry installations involve suspending the tubing or cables underneath the subfloor between the joists. This method usually requires drilling through the floor joists in order to install the tubing. Reflective insulation must also be installed under the tubes to direct the heat upward. Tubing or cables may also be installed from above the floor, between two layers of subfloor. In these instances, liquid tubing is often fitted into aluminum diffusers that spread the water's heat across the floor in order to heat the floor more evenly. The tubing and heat diffusers are secured between furring strips (sleepers), which carry the weight of the new subfloor and finished floor surface.

 At least one company has improved on this idea by making a plywood subfloor material manufactured with tubing grooves and aluminum heat diffuser plates built into them. The manufacturer claims that this product makes a radiant floor system (for new construction) considerably less expensive to install and faster to react to room temperature changes. Such products also allow for the use of half as much tubing or cabling since the heat transfer of the floor is greatly improved over more traditional dry or wet floors.

 Floor Coverings

Ceramic tile is the most common and effective floor covering for radiant floor heating, as it conducts heat well from the floor and adds thermal storage because of its high heat capacity. Common floor coverings like vinyl and linoleum sheet goods, carpeting, or wood can also be used, but any covering that helps to insulate the floor from the room will decrease the efficiency of the system.

If you want carpeting, use a thin carpet with dense padding and install as little carpeting as possible. If some rooms, but not all, will have a floor covering, then those rooms should have a separate tubing loop to make the system heat these spaces more efficiently. This is because the water flowing under the covered floor will need to be hotter to compensate for the floor covering. Wood flooring should be laminated wood flooring instead of solid wood. This reduces the possibility of the wood shrinking and cracking from the drying effects of the heat.

 Radiant Panels

Wall- and ceiling-mounted radiant panels are usually made of aluminum and can be heated with either electricity or with tubing that carries hot water, although the latter creates concerns about leakage in wall- or ceiling-mounted systems. The majority of commercially available radiant panels for homes are electrically heated.

 Like any type of electric heat, radiant panels can be expensive to operate, but they can provide supplemental heating in some rooms or can provide heat to a home addition when extending the conventional heating system is impractical.

Unlike other types of radiant heating systems, radiant panels have very low heat capacity and have the quickest response time of any heating technology.

 Because the panels can be individually controlled for each room, the quick response feature can potentially result in cost and energy savings compared to other systems when rooms are infrequently occupied: when entering a room, the occupant can increase the temperature setting and reach a comfortable level within minutes. But as with any system, the thermostat must be maintained at a minimum temperature that will prevent pipes from freezing.

 Radiant heating panels operate on a line-of-site basis: you'll be most comfortable if you're close to the panel. Some people find the ceiling-mounted systems uncomfortable, since the panels heat the top of their heads and shoulders more effectively than the rest of their body. 

 

Portable Heaters

Small space heaters are typically used when the main heating system is inadequate or when central heating is too costly to install or operate. In some cases, small space heaters can be less expensive to use if you only want to heat one room or supplement inadequate heating in one room. They can also boost the temperature of rooms used by individuals who are sensitive to cold, especially elderly persons, without overheating your entire home.

Space heater capacities generally range between 10,000 Btu to 40,000 Btu per hour. Common fuels used for this purpose are: electricity, propane, natural gas, and kerosene.

 Although most space heaters rely on convection (the circulation of air in a room) to heat a room, some rely on radiant heating; that is, they emit infrared radiation that directly heats up objects and people that are within their line of sight. Radiant heaters are a more efficient choice when you will be in a room for only a few hours, if you can remain within the line of sight of the heater. They can be more efficient when using a room for a short period because they avoid the energy needed to heat the entire room by instead directly heating the occupant of the room and the occupant's immediate surroundings.

 Safety is a top consideration when using space heaters. The U.S. Consumer Product Safety Commission estimates that more than 25,000 residential fires every year are associated with the use of space heaters, causing more than 300 deaths. An estimated 6,000 persons receive hospital emergency room care for burn injuries associated with contacting hot surfaces of room heaters, mostly in non-fire situations.

 When buying and installing a small space heater, follow these guidelines:

  • Only purchase newer model heaters that have all of the current safety features.
    • Make sure the heater has the Underwriter's Laboratory (UL) label attached to it.
  • Choose a thermostatically controlled heaters, since they avoid the energy waste of overheating a room.
  • Select a heater of the proper size for the room you wish to heat.
    • Do not purchase oversized heaters. Most heaters come with a general sizing table.
  • Locate the heater on a level surface away from foot traffic.
    • Be especially careful to keep children and pets away from the heater.

 Vented and Unvented Combustion Space Heaters

Space heaters are classified as vented and unvented, or "vent free." Unvented combustion units are not recommended for use inside your home, as they introduce unwanted combustion products into the living space, including nitrogen oxides, carbon monoxide, and water vapor. The units also deplete the air in the space where they are located. Most states have banned unvented kerosene heaters for use in the home and at least five have banned the use of unvented natural gas heaters.

 Vented units are designed to be permanently located next to an outside wall, so that the flue gas vent can be installed through a ceiling or directly through the wall to the outside. Look for sealed combustion or "100% outdoor air" units, which have a duct to bring outside into the combustion chamber. Sealed combustion heaters are much safer to operate than other types of space heaters, and operate more efficiently because they do not draw in the heated air from the room and exhaust it to the outdoors. They are also less likely to backdraft and adversely affect indoor air quality.

 Less expensive (and less efficient) units use the room air for combustion. They do not have a sealed glass front to keep room air away from the fire and should not be confused with a sealed combustion heater.

In addition to the manufacturer's installation and operating instructions, you should follow these general safety guidelines for operating any combustion space heater:

 For liquid-fueled heaters, use only the approved fuel. Never use gasoline! Follow the manufacturer's fueling instructions. Never fill a heater that is still hot. Do not overfill the heater; you must allow for the expansion of the liquid. Only use approved containers clearly marked for that particular fuel, and store them outdoors. Have vented space heaters professionally inspected every year. If the heater is not vented properly, not vented at all, or if the vent is blocked, separated, rusted, or corroded, dangerous levels of carbon monoxide can enter the home causing sickness and death. CO also can be produced if the heater is not properly set up and adjusted for the type of gas used and the altitude at which it is installed.

 Electric Space Heaters

Electric space heaters are generally more expensive to operate than combustion space heaters, but they are the only unvented space heaters that are safe to operate inside your home. Although electric space heaters avoid indoor air quality concerns, they still carry hazards of potential burns and fires, and should be used with caution.

 For convection (non-radiant) space heaters, the best types incorporate a heat transfer liquid, such as oil, that is heated by the electric element. The heat transfer fluid provides some heat storage, allowing the heater to cycle less and to provide a more constant heat source.

 When buying and installing an electric space heater, you should follow these general safety guidelines:

 Electric heaters should be plugged directly into the wall outlet. If an extension cord is necessary, use a heavy-duty cord of 14-gauge wire or larger.

For portable electric heaters, buy a unit with a tip-over safety switch, which automatically shuts off the heater if the unit is tipped over.

 

Heat Distribution SystemS

Heat is distributed through your home through a variety of ways. Forced-air systems use ducts. Likewise, unique heat distribution systems are employed for radiant heating and are discussed in that section. That leaves two systems that apply broadly to heating systems: steam radiators and hot water radiators.

 Steam Radiators

Steam heating is one of the oldest heating technologies, but the process of boiling and condensing water is inherently less efficient than more modern systems, plus it typically suffers from significant lag times between the boiler turning on and the heat arriving in the radiators. As a result, steam systems make it difficult to implement control strategies such as a night setback system.

The first central heating systems for buildings used steam distribution because steam moves itself through piping without the use of pumps. Non-insulated steam pipes often deliver unwanted heat in unfinished areas. Therefore, pipe insulation in these areas is usually very cost effective. Care should be used to install fiberglass pipe insulation that can withstand the high temperatures of these delivery pipes.

 Regular maintenance for steam radiators depends on whether the radiator is a one-pipe system (the pipe that supplies steam also returns condensate) or a two-pipe system (a separate pipe returns condensate). One-pipe systems use automatic air vents on each radiator, which bleed air as steam fills the system and then shut automatically when steam reaches the vent. A clogged air vent will keep a steam radiator from heating up. Air vents can sometimes be cleaned by boiling them in a water and vinegar solution, but usually need to be replaced.

Steam radiators can also warp the floor they are sitting on and their thermal expansion and contraction over time can dig ruts into the floor. Both of these effects can cause the radiator to tilt, preventing water from properly draining from the radiator when it cools. This will cause banging noises when the radiator is heating up. Shims should be inserted under radiators to pitch them slightly toward the pipe in a one-pipe system or toward the steam trap in a two-pipe system.

 In two-pipe systems, older steam traps often stick in either the open or closed position, throwing off the balance in the system. If you seem to have problems with some radiators providing too much heat and others providing too little, this might be the cause. The best approach is often to simply replace all the steam traps in the system.

 Steam radiators located on exterior walls can cause heat loss by radiating heat through the wall to the outdoors. To prevent such heat loss, you can install heat reflectors behind these radiators. You can make your own reflector from foil-covered cardboard, available from many building supply stores, or by mounting foil onto a foam board or other similar insulating surface. The foil should face away from the wall, and the reflector should be the same size or slightly larger than the radiator. Periodically clean the reflectors to maintain maximum heat reflection.

 Hot Water Radiators

Hot-water radiators are one of the most common heat distribution systems in newer homes, second only to forced-air systems. They may be a baseboard-type radiator or may be of an upright design that resembles steam radiators. The most common problem in hot-water systems is unwanted air in the system. At the start of each heating season, while the system is running, go from radiator to radiator and open each bleed valve slightly, then close it when water starts to escape through the valve. For multi-level homes, start at the top floor and work your way down.

 One way to save energy in hot-water systems is to retrofit them to provide separate zone control for different areas of large homes. Zone control is most effective when large areas of the home are not used often or are used on a different schedule than other parts of the home. A heating professional can install automatic valves on the hot-water radiators, controlled by thermostats in each zone of the house. Using programmable thermostats will allow you to automatically heat and cool off portions of your home to match your usage patterns.

 Zone control works best in homes designed to operate in different heating zones, with each zone insulated from the others. In homes not designed for zone control, leaving one section at a lower temperature could cause comfort problems in adjacent rooms because they will lose heat to the cooler parts of the home.

 Zone control will also work best when the cooler sections of the home can be isolated from the others by closing doors. In some cases, new doors may be needed to isolate one area from another. Cooler parts of the home should be kept around 50°F to prevent water pipes from freezing; never shut off heat entirely in an unused part of your home.