By Richard Faesy, Energy Futures Group, Inc.
Heat pumps seem to be in the news recently. In April, Efficiency Vermont launched a new program promoting them and Green Mountain Power recently launched a heat pump rental program that appears to be wildly successful. They expected to hear from about 200 customers but instead received inquiries from more than 600. What’s up?
Members of Building for Social Responsibility are intrigued with the technology and are excited to see heat pumps designed for Vermont’s climate now available at reasonable costs. Besides biomass, we now have a fossil fuel alternative that can automatically heat (and cool) our homes at about half the operating cost of oil or propane. And since heat pumps run off electricity, we can now deliver zero net-energy heating and cooling systems by adding PV panels to offset the heat pump load. If all this is so good, what’s the catch? Is this another one of those too-good-to-be-true technologies that will be gone after an initial flash in the pan?
Actually, heat pumps have been around for decades and are the primary means of heating and cooling buildings in most of the world outside of North America. The technology is the same as that used in refrigerators to concentrate heat and move it from one place to another. With a refrigerator, it works to gather up the heat in the food storage area and then dump it into the kitchen. With today’s heat pumps, in winter they concentrate heat from outside (even in temperatures below 15 degrees below zero) and then deliver it inside. In the summer they do the opposite to cool the building by moving heat from inside to outside.
While we have been installing “ground-source” heat pumps in the Northeast for decades that are able to move heat between buildings and the ground (or water wells within the ground), they tend to be pricey, typically $20,000 to $40,000 installed. The new “air-source” heat pumps do not require drilling expensive wells or digging long trenches like those that are necessary for the ground-source units, and can be installed for about $4,000 per unit for those systems that work in Vermont’s cold climate. These “cold-climate air-source” heat pumps can provide up to about 20,000 Btu per hour, so you would typically need a few systems for a well-insulated tight Vermont house, provided the layout works to allow heat distribution. For two systems, that’s $8,000; not bad for a heating and cooling system that cuts oil bills in half!
If you want to know more about which units work best in Vermont’s winters and what incentives are available for installing cold climate heat pumps in existing homes to displace oil and propane, take a look at Efficiency Vermont’s Cold Climate Heat Pump Overview
Richard Faesy is Co-founder and Principal of Energy Futures Group, Inc. www.energyfuturesgroup.com