As energy costs increase, adding a new heat pump to your furnace may yield good returns for home heating and cooling.

With the new minimum energy-efficiency requirements for 2006, there have been improvements in heat pumps that make them an excellent choice for almost any home. The price of fuels such as natural gas, oil and propane are at record highs, so using a heat pump may be least expensive for home heating and cooling options.

Heat pump efficiency in the cooling mode is rated by a SEER (seasonal energy efficiency rating), similar to a central air conditioner. In the heating mode, the efficiency is rated by the HSPF (heating seasonal performance factor). Generally, the ones that are most efficient at cooling your home are also the most efficient at heating. If you now have an old heat pump with a SEER in the 8.0 range, installing one of the most efficient (SEER of 19) new ones could cut your utility bills by more than 50 percent.

Many HVAC (heating, ventilation, air conditioning) manufacturers are starting to recommend hybrid heating, even in colder northern climates. Hybrid heating refers to installing a heat pump, instead of just a central air conditioner, along with a fossil fuel furnace.

In mild weather, the heat pump can be less expensive to operate than the most efficient fossil fuel furnace. When the outdoor temperature drops, the furnace takes over. A heat pump of the same capacity, efficiency and features may cost only about $400 to $500 more than an equivalent (cooling only) central air conditioner.

As a brief background, a heat pump is basically a central air conditioner with a reversing valve. When switching from the cooling to heating mode, the valve reverses the direction of the refrigerant. The hot gases flow through the indoor blower coil to heat the air inside your home. The wall thermostat takes care of automatically switching the reversing valve, depending upon whether you need heating or cooling.

A two-stage heat pump is your most efficient option and provides the best comfort. The heat pump has two different output levels when heating and cooling. This allows the heat pump to be sized to handle some of the coldest or hottest days, yet be effective during milder weather. Depending on the compressor design, the heat pump’s lower-output level will be from 50 percent to 67 percent of the maximum higher-output level. A third stage is the backup electric-resistance, or gas or oil furnace.

This is a big advantage, because the heat pump runs in longer, more efficient cycles when it is operating in the lower-output level. Even though it is running longer, the compressor is using less electricity at this level, so the overall electricity usage is reduced. By running longer and slower, there is less indoor blower and air flow sound, and indoor temperatures remain more constant.

The majority of HVAC manufacturers have switched to using a two-stage scroll compressor with R410A refrigerant, instead of R-22 (commonly called Freon). R410A is much more environmentally friendly and operates at slightly higher pressures. This requires stouter tubing, so the noise level from the outdoor unit is less noticeable. By 2010, manufacturers will no longer be allowed to produce units using R-22.

Over the past several years, there has been quite a design push to make the outdoor unit quieter. This is accomplished by insulating the compressor motors, using more sound-damping mounts and redesigning the fins, fan blades and housing for quieter air flow. Most of the manufacturers can provide you with sound level ratings for their models. Sound level does vary by size and compressor type.

Most two-stage heat pumps use a General Electric® variable-speed blower motor in the indoor air handler. This efficient motor varies its speed depending upon the heat pump stage currently running and the air flow resistance in the ductwork. Heat pump efficiency and indoor comfort depends upon matching the outdoor unit, the indoor coil and the blower speed (air flow).

One of the key advantages of the variable-speed blower, when used with the proper thermostat, is in controlling the indoor humidity level. This affects comfort and common allergens such as mold spores and dust mites. By varying the indoor air flow, the ratio of cooling to dehumidification can be controlled. This is ideal for humid climates.

Write for, or instantly download, www.dulley.com) Update Bulletin No. 763 – a buyer’s guide of the 21 most efficient, comfortable heat pumps listing number of stages, efficiency, compressor, refrigerant, size, blower speeds, and a savings/payback chart. Please include $3 and a business-size SASE. Send inquiries to James Dulley, Michigan Country Lines, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com.