What Makes Heat Pumps So Efficient Anyway?

Thanks to Jake Marin (HVAC Program Manager) and Efficiency Vermont for contributing this especially relevant piece on burgeoning heat pump products. Heat pump technologies transfer heat much more efficiently than traditional methods and are quickly becoming a financially viable alternative. 

As the name suggests, a heat pump transfers or “pumps” heat from one place to another. How does it work? I often explain heat pumps as an air conditioner working in reverse. Air conditioners do not make cold air. Instead, they extract heat from inside a building and “pump” it outside, leaving the air cooler.  

The illustration below shows how heat is taken from the air outside, compressed, and brought into the house at a high temperature. Even very cold air contains heat energy, and there is a significant amount of heat to be extracted from outdoor air, even during a cold Vermont winter. Because they move heat rather than generate heat, cold climate heat pump systems consume much less energy than traditional electric, propane, or oil heating systems. As I wrote about in a previous blog post, Who Says There is No Such Thing as Efficient Electric Heat?,” by efficiently capturing the heat energy of cold outside air, heat pump technology has become a realistic heating option for cold regions, like Vermont.  

Heat Pumps: Not Just For Home Heating

In Vermont, air source heat pumps (also known as mini-splits or ductless heat pumps) have garnered a lot of interest as Vermonters continue to struggle with controlling the cost of heating their homes. However, heat pump technology is found in a variety of new innovative products. For instance, until recently, electric water heaters and clothes dryers have been big energy users in a home, but heat pump technology makes these appliances much more efficient.

At Efficiency Vermont we’ve excitedly watched this technology develop. The potential energy cost savings that heat pump products can provide to Vermonters is huge, and we've jumped at the opportunity to make these savings attainable. We’re currently offering rebates or discounts on ENERGY STAR 2014 Emerging Technology Award winning heat pump clothes dryers,  heat pump water heaters, cold climate heat pumps, and anticipating additional offerings as more products become available in Vermont.   

Choosing Heat Pumps for Your Home: What to Expect

If you heat with electricity, the U.S. Department of Energy estimates that a heat pump can trim the amount of electricity used for heating by as much as 50%. If the heat pump is displacing the use of a system using a combustion fuel, such as fuel oil or propane, actual energy savings will depend on the costs of the combustion fuel relative to the cost of electricity. Like any heating system, heat pumps work most effectively in buildings with high levels of thermal efficiency. Basic improvements in your home, such as proper air sealing and insulation are recommended before installing any heat pump technology.

If you are choosing a new clothes dryer with heat pump technology, these units are about 20-60% more efficient than their standard issue counterparts. Heat pump water heaters cost about 50% less to operate than traditional electric resistance water heaters. These units are estimated to save as much as $3,250 over the lifetime water heater.