Older ASHPs are known for their poor cold-climate performance: these systems have been primarily used in the South for decades and are optimized for a warmer climate where air conditioning needs are higher. The ASHPs being offered today are cutting-edge cold-climate models that are optimized for New England weather. These cold climate ASHPs are certified based on their performance at 5°F and can continue providing heat even when winter temperatures are well below that. Today’s cold climate air source heat pumps can extract heat from the air all the way down to at least -13°F.
Concerned about heat pump performance in winter? Don’t be! Mainers and Vermonters have installed the most cold-climate heat pumps out of any New England state in the past few years, and both states are significantly colder than Massachusetts in the winter!
Air source heat pumps are considered clean heating and cooling technologies because they run on electricity rather than burning fossil fuels in your home. Although the New England electric grid is not yet fully renewable, it already includes a significant share of low-emitting energy and continues to get cleaner—meaning heat pumps reduce emissions today and even more over time.
ASHPs are typically rated for heating efficiency based on their Heating Seasonal Performance Factor (HSPF) or seasonal Coefficient of Performance (COP), both of which describe the system’s efficiency over the course of the heating season. The seasonal efficiency of ASHPs can range from 220% to 300%+ (i.e. COP of 2.2 to 3.0) depending on the system type, application, and how cold it is outside. That means that for every one unit of electricity used, 2.2 to 3 units of heat are transferred into the home. By comparison, electric resistance heating has a COP of 1, and many fossil fuel boilers and furnaces are 80% efficient. Even the most efficient models will never be more than 98% efficient. ASHPs also provide high-efficiency cooling—way better than window AC units and comparable to the highest-efficiency central air conditioners.
Annual system maintenance, which consists of cleaning and an operational checkup, costs about the same as annual servicing charges for a boiler or furnace. You can clean the filters yourself, which can help to keep your system running well for many years (ask your installer for tips on how best to do this!), though it is recommended to have a professional inspect your equipment annually. The only other maintenance requirement is to keep your outdoor unit clear of snow during the winter.
A ductless ASHP indoor unit is “whisper-quiet”—quieter than a refrigerator and much quieter than a typical window AC unit. A ducted ASHP can be quieter than a typical furnace or central air conditioner. The outdoor unit will make the same or less noise than a conventional central AC unit during operation. Occasionally during the winter, the outdoor unit will briefly operate in “defrost mode” to keep the unit clear of any frost buildup and keep airflow constant. Switching into defrost mode can make a brief whooshing noise.
A heat pump installation is typically a straightforward process with minimal disruption to your home. A simple, single-zone ductless ASHP system can be completed in less than a day and only requires a single 2-3 inch hole to be cut (and later, sealed) in your wall. If you are installing a “multi-zone” ductless system or a ducted system that requires modifications to your ductwork, your installation may take a few days or more to complete.
Yes, you can always add additional single-zone ductless units, though if you are installing a multi-zone unit, additional units can be added up to the maximum number of units as long as the capacity is sufficient. If you are interested in this approach, installers typically recommend installing at least 2 indoor units, which allows for better future capacity planning and enables the systems to perform more efficiently.
The typical lifespan of a heat pump is typically the same as a conventional furnace or central air conditioner.
If you have 100-amp electrical service you may need an upgrade, depending on the size and type of heat pump you’re installing and what electric appliances (e.g. central air conditioning, water heating, electric baseboards, stove, dryer, etc.) you currently have. In particular, most homes with 100-amp service will likely require upgrading to 200-amp service for a larger multi-zone or whole-home system. If your electrical service is sufficient but your circuit breakers are full, you may need to add a subpanel to make room for the heat pump. If you already know what your home’s electrical service capacity is, ask your installer about it when they call you to schedule a free site visit. Once on-site, your installer will assess the current state of your electrical service and make recommendations regarding whether an upgrade might be needed for the heat pump solution that meets your needs.
Homeowners switching to heat pumps from inefficient systems that run on fuel oil, propane, or traditional electric resistance can save close to $1,000 per year.