Total System Services Heating & Cooling

Heating Basics

The majority of American homes are heated with a forced-air furnace, most commonly fueled by natural gas, but also by electricity, liquid propane or fuel oil.

How a Furnace Works

A furnace works by drawing air inside a heat exchanger, where it is warmed with a flame of natural gas, propane or fuel oil, or with heated electric coils. A blower sends the warmed air through the house via metal ducts; it enters the room through a register or grill in the floor or wall. Indoor air is circulated continuously through the system, so a furnace filter is used to contain dust, pollen and other airborne particles.

An older home might have a boiler, fueled by natural gas, liquid propane or fuel oil. A boiler works by heating water and circulating is through pipes to radiators, where it warms the surrounding air. Unlike a furnace, a boiler doesn't circulate air throughout the house, which is why the air in a boiler-heated home might seem "stuffier."

Electric Heat Pumps

Another home heating option is an electric heat pump. This unit works by moving existing heat from one area to another in one of three ways:

Air-to-air: An condenser absorbs heat from the outdoor air (even the coldest air contains some heat) and transfers it to an indoor heat exchanger inside the home. Indoor air is warmed in the heat exchanger and circulated throughout the home. During the summer, the process is reversed to cool and dehumidify the home.
W ater-to-air: Instead of extracting heat from outside air, this type of pump absorbs heat from ground water or surface water, such as a farm pond.
Ground-to-air: Also known as a geothermal system, this type of heat pump uses underground loops to absorb heat from the earth. Geothermal systems are usually installed in newly-built homes, but can also be used in existing home.

One advantage of a heat pump is that it provides both heating and cooling capabilities in one unit. Electric heat pumps are usually supplemented with a backup system, such as radiant floor heaters or baseboard units (see below), in case of ex tended periods of extreme temperatures. Heat pumps also use filters to reduce airborne particles and keep the unit clean.

Electric Resistant Heating

Electric resistance heating, usually found in the form of baseboard heaters, was popular during the 1940s and 1950s, and is often used in multi-family dwelling like apartment houses. A baseboard unit has an electric heating element encased in metal pipe. Air warmed by the heating unit rises to the top of the room, and cooler air is drawn into the bottom of the heater. Each unit has a separate thermostat to allow for different temperatures in each room.

Radiant Heating

Radiant heating is making a comeback in many new homes. Instead of circulating heat by moving the air in the room, a radiant system heats objects - including people. The most common form is radiant floor heating, which uses electric cables or small tubes of hot water embedded in a concrete floor or under a tiled floor. During the height of its popularity during the '40s and 50s, radiant heating was also installed in wall or ceiling panels.

Homeowners in the Midwest usually use radiant heating as a supplement to a primary heating system. It's most often installed under the floor in uncarpeted areas such as kitchens, bathrooms, laundry rooms and garages. For added luxury, radiant heating cables can be embedded in a driveway - no more shoveling!

Although older forced-air and hot water boiler s ystems had efficiencies in the range of 56% to 70%, modern heating systems can achieve efficiencies as high as 97%, converting nearly all the fuel to useful heat for the home.

Conservation efforts 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.

Replacing your Furnace Can Be The Best Solution

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.

Before buying your new furnace or boiler, first make every effort to improve the energy efficiency of your home, then have a heating contractor run a heat-loss calculation to size your new furnace. Energy-efficiency improvements will save money on the furnace, because your home will need a smaller furnace. A properly sized furnace will also operate most efficiently.

Effieciency Rating

If you live in a cold climate, it usually makes sense to invest in the highest-efficiency system available. 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. When shopping for high-efficiency furnaces and boilers, look for dependability, and look for the ENERGY STAR® label. Buy a system with a good warranty and a reputable company to back it up.

When buying gas and oil systems, specify sealed combustion. Sealed-combustion furnaces 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. They generally burn more efficiently and pose no risk of introducing dangerous combustion gases into your house. In furnaces that are not sealed-combustion units, back-drafting of combustion gases can be a big problem.

For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners.

Like your refrigerator, heat pumps use electricity to move heat from a cool space into a warm place (heat pumps powered by natural gas are also commercially available now). During the heating season, heat pumps move heat from the cool outdoors into your warm house; during the cooling season, heat pumps move heat from your cool house into the warm outdoors.

Using a Heat Pump to Heat And Cool Your Home

Because they move heat rather than generating heat, heat pumps can provide up to 4 times the amount of energy they consume. If you heat with electricity, a heat pump can trim the amount of electricity you use for heating by as much as 30% to 40%. High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months.

If your home lacks a ductwork system, you would need to add one to convert to a heat pump system. Even if your house has ducts, you may need to modify them, as heat pump systems generally require larger duct sizes than other central heating systems. For proper heat pump operation, air flow should be 50 to 60 liters per second per kilowatt-hour or 400 to 500 cubic foot per minute per ton of cooling capacity. Consult a local heating and cooling contractor to assure that your ductwork is sized properly.

The "conventional" model of heat pump is the air-source heat pump, which transfers heat between your house and the outside air. Although air-source heat pumps can be used in nearly all parts of the United States, they do not perform well over extended periods of sub-freezing temperatures. In regions with sub-freezing winter temperatures, it may not be cost effective to meet all your heating needs with an air-source heat pump.

Higher efficiencies are achieved with ground-source (or geothermal) heat pumps, which transfer heat between your house and the ground. Although they cost more to install, geothermal heat pumps have low operating costs because they take advantage of relatively constant ground temperatures. However, the installation depends on the size of your lot, the subsoil and landscape. If your house is located near a body of water, such as a pond or lake, water-source heat pumps offer similar advantages. Ground-source or water-source heat pumps can be used in more extreme climatic conditions than air-source heat pumps, and customer satisfaction with the systems is very high.

Another consideration for heating your home is where you want the warmed air to go. Heating systems can be grouped into one of two categories: central and zoned.

Central Heating Systems

Central heating systems, which include furnaces, boilers and electric heat pumps, use a blower and ductwork to circulate air throughout your entire home. Every room in the home is heated to the same temperature, which is controlled by a single thermostat. The presence of ductwork allows for the added comfort of a central air conditioning system as well.

Zoned Systems

In contrast, a zoned system has multiple thermostats spaced throughout the home, allowing you to adjust the temperatures in different area. Electric baseboard heaters and radiant heating panels are examples of zoned heating. Traditional zoned systems like these have the disadvantage of having no ductwork, and therefore no capability to use central air conditioning.

Choosing a System

The type that's best for you depends on the size and age of your home, as well as your lifestyle. If you have a large home with rooms you rarely use, such as guest bedrooms, a zoned system will allow you to shut off the heat in that area - a practice not recommended for central heating systems. Zoned heating is also a plus if you and other family members disagree about the most comfortable temperature.

If you'd like the versatility of a zoned system with the energy efficiency and year-round comfort of a central system, ask your dealer about the new zoned systems for forced-air furnaces and heat pumps. Different areas of your home, such as the kitchen and family room, bedrooms and basement, are designated as individual zones with dedicated thermostats. The furnace will be specially designed and sized to accommodate the temperature changes in each area. Adding a zoned thermostat system to a high-efficiency natural gas furnace can help your save an additional 10-15 percent on your heating costs.

A central furnace or boiler's efficiency is measured by annual fuel utilization efficiency (AFUE).

AFUE is a measure of how efficient the appliance is in using electricity or fossil fuels (oil or gas) over the course of a typical year.

AFUE Ratings

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, you might consider installing a heat-pump system.

The minimum allowed AFUE rating for a noncondensing 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 p oints) than a noncondensing furnace. Although a condensing unit costs more than a noncondensing unit, the condensing unit can save you money in fuel costs over the 15 to 20-year life of the unit

When was the last time you changed or cleaned your furnace filter? Failing to replace or clean the filter regularly can be costly!

Dust and dirt can work their way into the blower and coil assemblies, reducing the furnace's operating efficiency and eventually causing damage to the motor. Heating professionals say simple dust and dirt are the cause of almost half of their service calls; most manufacturers recommend changing or cleaning filters at least every other month (once a month is best).

Get An Annual Service Check Up

An annual service checkup by a heating professional is usually a good idea. The technician will check the flues and temperature settings, examine the heat exchanger for cracks, and check the safety mechanisms on natural gas units. A $50-100 annual tune-up can reduce your heating unit's operating cost by three to four percent.

Oil burning equipment is in need of regular maintenance, far more so than gas burning equipment. Oil burners flames tend to be dirtier than gas burners and combustion chambers in oil-fired equipment can rapidly build up so much debris that draft can be significantly reduced, resulting in a spillage of combustion products into the home. Note that oil-burning boilers are supposed to be cleaned every year at the interior, but only rarely is this done. Most boiler service technicians appear only to change the burner nozzle regularly. Allowing de bris to build up on the interior of the boiler can result in a loss of up to 10% of fuel efficiency.

What to Expect

During your annual fall check, your technician should:

Look at the burner and pilot assembles
Check the heat exchanger for cracks
Look at the pilot thermocouple
Examine the filter
Check vent piping
Test gas piping for leaks
Test the electronic ignition
Test the fan
Adjust the burner for efficiency
Test the limit switch
Measure the manifold gas pressure
Measure the temperature rise
Check for carbon monoxide
Set the heat anticipator
Check belt/tension
Examine the draft diverter and lubricate the fan motor

Keep in mind, that just like your car, your heating system needs regular care and maintenance. And just like having a good mechanic for your car, you should have a good technician for your heating system.



	Heating Basics The majority of American homes are heated with a forced-air furnace, most commonly fueled by natural gas, but also by electricity, liquid propane or fuel oil. How a Furnace Works A furnace works by drawing air inside a heat exchanger, where it is warmed with a flame of natural gas, propane or fuel oil, or with heated electric coils. A blower sends the warmed air through the house via metal ducts; it enters the room through a register or grill in the floor or wall. Indoor air is circulated continuously through the system, so a furnace filter is used to contain dust, pollen and other airborne particles. An older home might have a boiler, fueled by natural gas, liquid propane or fuel oil. A boiler works by heating water and circulating is through pipes to radiators, where it warms the surrounding air. Unlike a furnace, a boiler doesn't circulate air throughout the house, which is why the air in a boiler-heated home might seem "stuffier." Electric Heat Pumps Another home heating option is an electric heat pump. This unit works by moving existing heat from one area to another in one of three ways: Air-to-air: An condenser absorbs heat from the outdoor air (even the coldest air contains some heat) and transfers it to an indoor heat exchanger inside the home. Indoor air is warmed in the heat exchanger and circulated throughout the home. During the summer, the process is reversed to cool and dehumidify the home. W ater-to-air: Instead of extracting heat from outside air, this type of pump absorbs heat from ground water or surface water, such as a farm pond. Ground-to-air: Also known as a geothermal system, this type of heat pump uses underground loops to absorb heat from the earth. Geothermal systems are usually installed in newly-built homes, but can also be used in existing home. One advantage of a heat pump is that it provides both heating and cooling capabilities in one unit. Electric heat pumps are usually supplemented with a backup system, such as radiant floor heaters or baseboard units (see below), in case of ex tended periods of extreme temperatures. Heat pumps also use filters to reduce airborne particles and keep the unit clean. Electric Resistant Heating Electric resistance heating, usually found in the form of baseboard heaters, was popular during the 1940s and 1950s, and is often used in multi-family dwelling like apartment houses. A baseboard unit has an electric heating element encased in metal pipe. Air warmed by the heating unit rises to the top of the room, and cooler air is drawn into the bottom of the heater. Each unit has a separate thermostat to allow for different temperatures in each room. Radiant Heating Radiant heating is making a comeback in many new homes. Instead of circulating heat by moving the air in the room, a radiant system heats objects - including people. The most common form is radiant floor heating, which uses electric cables or small tubes of hot water embedded in a concrete floor or under a tiled floor. During the height of its popularity during the '40s and 50s, radiant heating was also installed in wall or ceiling panels. Homeowners in the Midwest usually use radiant heating as a supplement to a primary heating system. It's most often installed under the floor in uncarpeted areas such as kitchens, bathrooms, laundry rooms and garages. For added luxury, radiant heating cables can be embedded in a driveway - no more shoveling! Although older forced-air and hot water boiler s ystems had efficiencies in the range of 56% to 70%, modern heating systems can achieve efficiencies as high as 97%, converting nearly all the fuel to useful heat for the home. Conservation efforts 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. Replacing your Furnace Can Be The Best Solution 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. Before buying your new furnace or boiler, first make every effort to improve the energy efficiency of your home, then have a heating contractor run a heat-loss calculation to size your new furnace. Energy-efficiency improvements will save money on the furnace, because your home will need a smaller furnace. A properly sized furnace will also operate most efficiently. Effieciency Rating If you live in a cold climate, it usually makes sense to invest in the highest-efficiency system available. 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. When shopping for high-efficiency furnaces and boilers, look for dependability, and look for the ENERGY STAR® label. Buy a system with a good warranty and a reputable company to back it up. When buying gas and oil systems, specify sealed combustion. Sealed-combustion furnaces 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. They generally burn more efficiently and pose no risk of introducing dangerous combustion gases into your house. In furnaces that are not sealed-combustion units, back-drafting of combustion gases can be a big problem. For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners. Like your refrigerator, heat pumps use electricity to move heat from a cool space into a warm place (heat pumps powered by natural gas are also commercially available now). During the heating season, heat pumps move heat from the cool outdoors into your warm house; during the cooling season, heat pumps move heat from your cool house into the warm outdoors. Using a Heat Pump to Heat And Cool Your Home Because they move heat rather than generating heat, heat pumps can provide up to 4 times the amount of energy they consume. If you heat with electricity, a heat pump can trim the amount of electricity you use for heating by as much as 30% to 40%. High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. If your home lacks a ductwork system, you would need to add one to convert to a heat pump system. Even if your house has ducts, you may need to modify them, as heat pump systems generally require larger duct sizes than other central heating systems. For proper heat pump operation, air flow should be 50 to 60 liters per second per kilowatt-hour or 400 to 500 cubic foot per minute per ton of cooling capacity. Consult a local heating and cooling contractor to assure that your ductwork is sized properly. The "conventional" model of heat pump is the air-source heat pump, which transfers heat between your house and the outside air. Although air-source heat pumps can be used in nearly all parts of the United States, they do not perform well over extended periods of sub-freezing temperatures. In regions with sub-freezing winter temperatures, it may not be cost effective to meet all your heating needs with an air-source heat pump. Higher efficiencies are achieved with ground-source (or geothermal) heat pumps, which transfer heat between your house and the ground. Although they cost more to install, geothermal heat pumps have low operating costs because they take advantage of relatively constant ground temperatures. However, the installation depends on the size of your lot, the subsoil and landscape. If your house is located near a body of water, such as a pond or lake, water-source heat pumps offer similar advantages. Ground-source or water-source heat pumps can be used in more extreme climatic conditions than air-source heat pumps, and customer satisfaction with the systems is very high. Another consideration for heating your home is where you want the warmed air to go. Heating systems can be grouped into one of two categories: central and zoned. Central Heating Systems Central heating systems, which include furnaces, boilers and electric heat pumps, use a blower and ductwork to circulate air throughout your entire home. Every room in the home is heated to the same temperature, which is controlled by a single thermostat. The presence of ductwork allows for the added comfort of a central air conditioning system as well. Zoned Systems In contrast, a zoned system has multiple thermostats spaced throughout the home, allowing you to adjust the temperatures in different area. Electric baseboard heaters and radiant heating panels are examples of zoned heating. Traditional zoned systems like these have the disadvantage of having no ductwork, and therefore no capability to use central air conditioning. Choosing a System The type that's best for you depends on the size and age of your home, as well as your lifestyle. If you have a large home with rooms you rarely use, such as guest bedrooms, a zoned system will allow you to shut off the heat in that area - a practice not recommended for central heating systems. Zoned heating is also a plus if you and other family members disagree about the most comfortable temperature. If you'd like the versatility of a zoned system with the energy efficiency and year-round comfort of a central system, ask your dealer about the new zoned systems for forced-air furnaces and heat pumps. Different areas of your home, such as the kitchen and family room, bedrooms and basement, are designated as individual zones with dedicated thermostats. The furnace will be specially designed and sized to accommodate the temperature changes in each area. Adding a zoned thermostat system to a high-efficiency natural gas furnace can help your save an additional 10-15 percent on your heating costs. A central furnace or boiler's efficiency is measured by annual fuel utilization efficiency (AFUE). AFUE is a measure of how efficient the appliance is in using electricity or fossil fuels (oil or gas) over the course of a typical year. AFUE Ratings 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, you might consider installing a heat-pump system. The minimum allowed AFUE rating for a noncondensing 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 p oints) than a noncondensing furnace. Although a condensing unit costs more than a noncondensing unit, the condensing unit can save you money in fuel costs over the 15 to 20-year life of the unit When was the last time you changed or cleaned your furnace filter? Failing to replace or clean the filter regularly can be costly! Dust and dirt can work their way into the blower and coil assemblies, reducing the furnace's operating efficiency and eventually causing damage to the motor. Heating professionals say simple dust and dirt are the cause of almost half of their service calls; most manufacturers recommend changing or cleaning filters at least every other month (once a month is best). Get An Annual Service Check Up An annual service checkup by a heating professional is usually a good idea. The technician will check the flues and temperature settings, examine the heat exchanger for cracks, and check the safety mechanisms on natural gas units. A $50-100 annual tune-up can reduce your heating unit's operating cost by three to four percent. Oil burning equipment is in need of regular maintenance, far more so than gas burning equipment. Oil burners flames tend to be dirtier than gas burners and combustion chambers in oil-fired equipment can rapidly build up so much debris that draft can be significantly reduced, resulting in a spillage of combustion products into the home. Note that oil-burning boilers are supposed to be cleaned every year at the interior, but only rarely is this done. Most boiler service technicians appear only to change the burner nozzle regularly. Allowing de bris to build up on the interior of the boiler can result in a loss of up to 10% of fuel efficiency. What to Expect During your annual fall check, your technician should: Look at the burner and pilot assembles Check the heat exchanger for cracks Look at the pilot thermocouple Examine the filter Check vent piping Test gas piping for leaks Test the electronic ignition Test the fan Adjust the burner for efficiency Test the limit switch Measure the manifold gas pressure Measure the temperature rise Check for carbon monoxide Set the heat anticipator Check belt/tension Examine the draft diverter and lubricate the fan motor Keep in mind, that just like your car, your heating system needs regular care and maintenance. And just like having a good mechanic for your car, you should have a good technician for your heating system.
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