Heat Pumps Not As Mysterious As Most Homeowners Think

When it comes to home comfort, many homeowners know that heat pumps are the most advanced, energy-efficient heating and cooling systems they can purchase.

According to the Trane Home Comfort Institute, however, there are just as many homeowners who are badly misinformed about heat pumps and their operation.

To help ensure that you're not one of the latter, the Trane Home Comfort Institute offers the following list of common heat pump misconceptions and their realities:

Misconception #1: Heat pumps are effective only in milder climates.
At one time that may have been true, but not any more.

During the seventies, when they first came into prominence, many heat pumps were installed in the southern sections of the country. The reason was that during the heating season, a heat pump's efficiency increases on mild days and decreases on cold days. The efficiency rating or Heating Seasonal Performance Factor ( HSPF ) is therefore higher in a mild climate than in a region where winters are severe.

Through the years, however, improvements in design have broadened the geographical range of heat pumps to almost every section of the country. Today, you'll find heat pumps in Augusta, Maine, as well as Augusta, Georgia.

Misconception #2: The quality of heating from a heat pump is different from that of other heating systems.
Not in terms of the end result, which is a warm, comfortable home.

In its heating mode, the temperature of the air supplied by a heat pump is not as hot as the air supplied by a furnace. Air entering a room from a heat pump is normally about 100 degrees Fahrenheit compared to about 120 to 130 degrees F from a furnace.

Thus, a heat pump warms a room gradually and more uniformly than a furnace. It's similar to slowly warming your bath water by turning the hot water faucet to a moderately warm setting rather than turning the faucet all the way to maximum hot and then turning if off and having water cool down.

Misconception #3: Heat pumps only heat your home.
Judging by their name, you might think that's the case. However, heat pumps got their name because they pump heat into your home in winter and out of your home in summer. Thus, they function like a furnace during the winter and a central air conditioner during the summer. This ability to both heat and cool makes them very economical and efficient home comfort systems. Misconception #4: Heat pumps are only meant for new homes.

Definitely not. Heat pumps can also be installed in older, existing homes, especially if they already have a forced-air heating system, suitable ductwork and adequate insulation.

In these cases, all that's required is the addition of an indoor coil on the furnace, refrigerant lines and the proper thermostat. In addition, heat pumps can work with any forced-air heating system ... gas, oil, propane or electric.

If you're still uncertain about heat pumps and their operation, the Trane Home Comfort Institute recommends you contact your local heating and cooling contractor. He can help dispel any other misconceptions you have and recommend the best system for you.

Ever since their introduction in the late fifties, heat pumps seem to be a mystery to most homeowners.

To help you better understand these remarkable devices, the Trane Home Comfort Institute has compiled the most frequently asked questions about heat pumps and their answers.

What is a heat pump?

A heat pump is essentially a central air conditioning system that also has the ability to heat your home during cold weather months.

It's called a "heat pump" because it pumps heat into your home in winter, and pumps heat out of your home in summer. Its ability to both heat and cool makes it a very economical and efficient home comfort system.

How does a heat pump work?

In summer, it functions exactly like a standard central air conditioning system, pulling the heat out of your home and releasing it outside.

In winter, it simply reverses the process, extracting the heat that's present in outdoor air and pumping it into your home.

How can a heat pump obtain heat from cold winter air?

As strange as it may seem, heat is present in all air, even air that's well below freezing. Think of the way your refrigerator removes unwanted heat that accumulates when you open the door and place warm food inside. You can feel that heat coming back into your kitchen from the refrigerator's exhaust fan.

In a similar way, heat pumps remove heat from cold outdoor air and deliver it to your home to keep you warm and comfortable.

What does a heat pump look like?

A typical heat pump installation consists of two parts: an outdoor unit that contains the outdoor coil, compressor, reversing valve, and fan; and an indoor unit that contains the indoor coil, supplemental heater and fan.

The outdoor unit looks exactly like a central air conditioner in both size and appearance. The indoor unit is called an air handler and looks similar to a gas furnace.

Where is the furnace?

There isn't any. The heat pumps takes its place. Because a heat pump simply moves heat from one place to another, there is no burning of fuel to make heat, no smoke and no fumes.

Do heat pumps have efficiency ratings?

Yes. In fact, they have two, one for heating and one for cooling. The heating rating is called the Heating Seasonal Performance Factor ( HSPF ), the cooling rating is called the Seasonal Energy Efficiency Ratio ( SEER ). In both cases, the higher the number, the greater the efficiency and the lower the operating costs.

When comparing ratings, remember that they are based on the total system, meaning the combination of the outdoor unit and the indoor unit.

Why is a heat pump so economical?

Because during the heating season, a heat pump simply has to move heat instead of making it. Unlike a furnace that must turn fossil fuel or electricity into heat, the heat pump simply collects heat that already exists in the outdoor air and pumps it into your home.

Why do heat pumps have supplemental heaters?

Heat naturally migrates from warmer to colder areas through windows, doors, ceilings and walls. Insulation, weather-stripping and caulk slow down this heat loss, but cannot totally eliminate it. The colder it becomes, the faster a home loses heat.

The supplemental heater helps the heat pump during weather extremes when a home may lose heat faster than the heat pump can replace it. Electric heating elements in the indoor unit turn on automatically to make up the difference.

Can heat pumps be installed in existing homes?

Yes, especially if you already have a forced-air heating system, suitable ductwork and adequate insulation. Heat pumps can work with any forced air heating system ... gas, oil, propane or electric.

Let's face it, central air conditioning has become an integral part of the American homeowner's lifestyle.

A recent study shows that seven out of every ten new homes built today include central air conditioning as a standard feature.

Thousands of other homeowners are adding central air to their existing homes.

Yet, how many owners or prospective owners of central air conditioners know how the system works?

According to a recent study by the Trane Home Comfort Institute, not that many.

To help you understand how this integral part of your home operates, the Trane Home Comfort Institute offers this simplified explanation:

A central air conditioning system essentially consists of two parts: the coil, which extracts unwanted heat and humidity from your home, and the condenser, which discharges the unwanted heat to the outdoors.

Most residential air conditioners are split systems, meaning that the coil is located indoors and the condenser, outdoors. When the coil and the condenser are both located outdoors in the same unit, the system is called a packaged system.

In a split system, two copper tubes called refrigerant lines connect the indoor coil and the outdoor condenser. The smaller of the lines is called the liquid line; the larger, the suction line.

The lines are filled with a chemical refrigerant which has a boiling point low enough that it evaporates at relatively low temperatures and takes heat and moisture out of the air as it passes through the coil. The refrigerant travels in a closed loop between the coil and the condenser.

The loop begins as the liquid refrigerant passes through the coil, which is a network of tubes located on top of the furnace.

As the refrigerant travels through the coil, it evaporates from a liquid to a vapor, absorbing heat by cooling the air passing around the coil. The furnace blower distributes the cooled air through ducts into the interior of the house.

Meanwhile, the vaporized refrigerant moves through the suction lines to a compressor in the outdoor unit. The compressor compacts the vapor and then moves the hot refrigerant gas under high pressure through the condenser, which is a network of tubes exposed to outdoor air. As the refrigerant travels through these tubes, it cools and turns back into a liquid. The heat released during this condensation process is dispersed into the outdoor air by a fan.

The refrigerant then flows through the liquid lines from the condenser back to the coil inside the house and the cycle begins again.

The compressor is considered "the heart of the system" because it is the pump that circulates the refrigerant through the loop. Because of its importance, experts at the Trane Home Comfort Institute recommend that you look carefully at the compressor's reputation and warranty when selecting a system.

They also recommend checking the SEER or Seasonal Energy Efficiency Rating, which is an indication of a unit's efficiency. The higher the SEER, the higher the efficiency. The higher the efficiency, the less electricity needed to cool your home.

In addition, it's important to note that an outdoor condenser can be combined with dozens of different indoor coils. To obtain the rated efficiency, make sure the capacity and SEER of the indoor unit matches that of the outdoor unit.

Finally, you want your new central air conditioning system to operate for a long time, so compare the reliability and durability features of the equipment you select to get the most for your money.