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Heat Pump Efficiency Rating & Sizing

April 29, 2015

When shopping for a new heat pump, pay attention to efficiency ratings and appropriately sizing the unit. This will affect the cost of operating the heat pump, as well as its effectiveness at heating and cooling your home.

All heating and cooling appliances carry a federal “Energy Guide” label that rates the unit’s energy efficiency for both cooling and heating modes. These ratings are based on a relative scale; they let you know how a particular model compares to other low- and high-efficiency models.

energy_guide_label1b Manufacturers commonly use two indexes for measuring—the Seasonal Energy Efficiency Rating (SEER) for cooling and the Heating Seasonal Performance Factor (HSPF) for heating. Both are arrived at through sophisticated testing and reflect performance over an entire season.

The SEER evaluates the efficiency of the heat pump when it is in air-conditioning (cooling) mode. The ratio is calculated based on the amount of cooling generated (measured in BTUs) divided by the amount of electricity used during the cooling season. A high SEER rating indicates a more energy-efficient unit.

In the United States, air-conditioning systems must be manufactured with a minimum SEER of 13. The HSPF is a more important number when it comes to warming a house. This is basically the same as the SEER but evaluates additional energy usage such as defrosting the unit during winter and back-up heat requirements. Energy Star–qualified heat pumps have a higher SEER and HSPF than standard models; as a result, they are about 8 percent more efficient than standard new models and 20 percent more efficient than older models.

Sizing a Heat Pump

Most heat pump manufacturers make products in several sizes according to the amount of air they move. Units are designated by “tons”—a measurement that originally referred to the amount of ice needed to cool an equivalent amount of air. Typical home sizes range from 1 1/2- to 5-ton capacity.

Though sizing a system should be handled by a professional, you can get a rough idea of size by figuring about 400 square feet of living space per ton in older houses, so, a 1,600-square-foot house would normally require about a 4-ton system. Newer houses with double-paned windows and more insulation can get by with smaller systems.

Prices for materials run from just under $2,000 for small, low-efficiency models to $7,500 for top-of-the-line, high-efficiency units.

by Don Vandervort, HomeTips © 1997-2015

Jim Lavallee Plumbing
Serving Eastern Massachusetts and the Boston area
Phone: Toll-free (888) 884-4122


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