How to Choose the Correct Air-Source Heat Pump Furnace for Winter

Unlike ornate cast-iron stoves, heat pumps are not designed to be pieces of living room furniture. It is not the external appearance but the performance that counts. You can easily judge a heat pump's performance by checking the efficiency ratings.

The heating efficiency for air-source heat pumps is indicated by the heating season performance factor (HSPF), which is the ratio of the seasonal heating output (in Btu) divided by the seasonal power consumption (in watts). The simplest approach is to look for an Energy Star label, which is awarded to units with an SEER of 12 or greater and an HSPF of 7 or greater.

If you live in a warm climate, you should give more importance to the cooling efficiency rating. If you live in a cooler climate, the heating efficiency rating is more important. It is also helpful to know that some models of heat pumps are specifically designed for colder climates while the others are optimized for warmer regions.

Another important factor while selecting the air-source heat pumps is noise. The operating sounds from the outdoor unit of some heat pumps are annoyingly loud. There is a problem if the unit is located under your neighbor's bedroom window. All heat pumps have sound ratings, which are expressed in units of bels.

Sizing an air-source heat pump to match the heating requirements of your home is extremely important. Installing an oversize unit will result in excess energy consumption, inferior humidity control and shorter equipment life due to short cycling.

Another important factor is the balancing point. As outside temperature drops during the winter, so does the capacity of the air-source heat pump to absorb outdoor heat. This can lead to problems if the outdoor temperature drops too far. At the balance point, the heat pump's capacity is equal to the heat loss of your house. Typical balance point temperatures fall between 27 and 35 degrees Fahrenheit.

Air source heat pumps are particularly well suited to new construction, because you can plan in advance for the various system elements. Replacement or add on systems are also possible in most situations. The outdoor unit should be placed on a stand that is anchored to a concrete pad.

The concrete stand needs to be 1 to 2 feet above ground level to minimize loss of efficiency caused by snow accumulation. Also try to place the outdoor unit away from the drip line of the roof to prevent water, ice, and snow falling on it. The distance between the outdoor and the indoor unit should not exceed about 60 feet.

Virtually all air-source heat pumps will need a 200 amp electrical service. Most new homes have 200 amp or larger electrical service, many old homes do not. If you need to upgrade your service, include the cost of this work in the total estimate for your heat pump installation.