Preferred Contractor Lists
Customer Resources
- opens in a new windowYour Guide to Air Source Heat Pumps. Clean Energy Lives Here.opens PDF file MassCEC
- opens in a new windowAir Source Heat Pump Buying Guideopens PDF file NEEP
Contractor Resources
- Guide To Sizing & Selecting Air-Source Heat Pumps in Cold Climatesopens PDF file NEEP
- Guide To Installing Air-Source Heat Pumps in Cold Climatesopens PDF file NEEP
Contact CET
- Phone: 888-333-7525opens phone dialer
- Email: cet@cetonline.org
Air Source Heat Pump Consultation Services
Select municipal light plants in the Massachusetts including several in the Municipal Wholesale Electric Company (MMWEC) joint action network as well as Westfield Gas + Electric (WG+E) can participate in a program that supports their customers with making the switch to Air Source Heat Pumps (ASHP). Services include consultations with CET’s heat pump specialists, energy load calculations and evaluation of weatherization needs, contractor design reviews, and quality insurance inspections.
Air Source Heat Pump Technology

Schematic courtesy of MassCEC
Air source heat pumps (ASHPs) operate by moving heat between your indoor and outdoor environment. In the winter, they absorb heat from the outside air (even at below freezing temperatures!) and move it into your living space. In the summer, the cycle is reversed and they absorb heat in your home and move it outside. ASHPs comprise an indoor and outdoor unit, which are connected by a refrigerant—a substance that readily absorbs or releases heat based on its temperature compared to the surrounding air (see figure right).
ASHPs are incredibly efficient compared to other heating systems like boilers, furnaces, and electric baseboards. For every 1 kWh spent running an ASHP, they yield over 3 kWh of heat and remove as much in summer. This often results in lower utility costs (especially for homes using oil, propane, or electric resistance) and a lower carbon footprint.