About Air Source Heat Pumps
Cold climate air source heat pumps are one of the three technologies offered through HeatSmart CCL. Learn more about how they work and get your questions answered.
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- What is an air source heat pump and how does it work?
- What types of air source heat pumps are available?
- What are the benefits of using an air source heat pump?
- Don’t air-source heat pumps perform poorly in cold climates?
- Are there other drawbacks to air source heat pumps?
- Is an air source heat pump right for me?
- Why are air source heat pumps considered “clean heating and cooling” technologies?
- How efficient are air source heat pumps?
- How do the annual maintenance costs of an air source heat pump compare to other heating systems?
- How long do air source heat pumps last?
- How noisy are air source heat pumps?
- Can air source heat pumps provide domestic hot water?
- How complicated is installing a heat pump and how much time will it take?
- How can I maximize energy savings from my heat pump?
- I've heard that heat pumps can sometimes blow cold air?
- How much will an air source heat pump cost?
|What is an air source heat pump and how does it work?||
Air source heat pumps (ASHP) are electric appliances that provide heating and cooling by moving heat into a home or building (for heating) or out of a building (for cooling). Heat pumps do not create heat like electric resistance heating or fossil fuel-fired heating systems; instead, they move heat from one place to another. ASHPs use the outdoor air as a source of heat, while ground source (or geothermal) heat pumps use the ground as a source of heat.
They accomplish this by using a refrigerant that absorbs heat from colder air to move that heat into a space with warmer air—much the same way that a refrigerator or air conditioner works, except that it can move heat in both directions to provide both heating and cooling. Since it takes far less energy to move heat than it does to create heat, ASHPs are one of the most efficient home heating systems available.
Check out this video from Mass Save, the state's utility energy efficiency program, for a visual explanation of how ductless mini-split heat pumps work (and read on to learn more about the types of heat pumps available!).
|What types of air source heat pumps are available?||
There are two primary types of ASHPs, both of which are offered by HeatSmart CCL’s ASHP installer:
Ductless air source heat pumps are exactly as they sound: heat pumps that don't require that you have ductwork in your home to provide heating and air conditioning. Each ductless system includes one outdoor unit connected to one (single-zone) or more (multi-zone) indoor wall, floor or ceiling air distribution units. Ductless ASHPs are often referred to as ductless mini-splits.
Ductless air source heat pumps can be installed as a primary source of heating and cooling or installed to heat and cool specific rooms. This could include, for example, installing ductless units in the most frequently used rooms like family rooms or master bedrooms to displace heating or cooling from your existing system, or placing ductless units in rooms or new additions that never seem to be warm or cool enough.
These systems can be used for heating, cooling, dehumidification or as a fan. Because each indoor unit can be controlled individually, you can reduce your energy use even more by lowering the temperature in rooms that are not being used.
Ducted air source heat pumps have an outdoor unit that is connected to a building's ductwork, which is used to distribute heating or air conditioning throughout the home. Ducted (also known as central or unitary) use your home’s existing ductwork, though not all ductwork is sized adequately for heat pumps. Our installer, New England Ductless, can tell you if your ductwork is sized adequately and what modifications may be necessary during a free site visit.
Regardless of whether a system is ductless or ducted, all ASHPs will have an outdoor unit (pictured below), which will be mounted on a ground platform or on the side of your home.
Above: A ductless ASHP outdoor unit; Below: A ducted ASHP outdoor unit
This outdoor unit will be connected to one or more indoor air distribution units. If you’re installing a ducted ASHP, this will be a central air handler similar to one used by a furnace or central AC system. If you’re installing a ductless ASHP, this will typically be a wall-mounted unit (pictured below).
For homeowners that might not have suitable wall space or don’t like the aesthetic look of the wall-mounted indoor unit, floor-mounted and ceiling-mounted units are also available, though these units cost more to install. Photo courtesy of E. Armstrong
|What are the benefits of using an air source heat pump?||
There are many reasons why an air source heat pump could be a good fit for your home:
|Don’t air-source heat pumps perform poorly in cold climates?||
Traditional 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 installed through HeatSmart CCL 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 air is well below zero: today’s cold climate air source heat pumps can extract heat from the air all the way down to -13°F.
Concerned about heat pump performance in January? 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—over 30,000 since 2013, and both states are significantly colder than Massachusetts in the winter!
|Are there drawbacks to air source heat pumps?||
While ASHPs are a great fit for many Carlisle, Concord, and Lincoln homes and businesses, they like other heating and cooling systems are not without a few drawbacks:
|Is an air source heat pump right for me?||
ASHPs can be installed in most homes. However, if you answer “Yes” to any of the questions below, a ductless or ducted ASHP could be a great fit for you:
|Why are air source heat pumps considered “clean heating and cooling” technologies?||
Air source heat pumps are considered to be “clean” heating and cooling systems because they do not create heat, but rather they move renewable heat from the ambient air from one place to another. This process is powered by electricity, which can also be sourced from renewable sources like solar, wind, or hydro.
Even though our grid is only about 12% renewable today (and getting greener year by year), an ASHP system powered by grid electricity will still reduce your greenhouse gas emissions from heating by 20-60%!
|How efficient are air source heat pumps?||
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 fossil fuel boilers and furnaces can be 75-95% efficient.
ASHPs also provide high-efficiency cooling—better than window AC units and comparable to the highest-efficiency central air conditioners.
|How do the maintenance requirements and costs of an air source heat pump compare to other heating systems?||
Annual system maintenance, which consists of cleaning air filters and an annual maintenance checkup for the outside unit, costs about the same as annual servicing charges for a boiler or furnace. You can also clean the filters yourself, which can help to keep your system running well for many years (ask our installer for tips on how best to do this!).
Otherwise, the only other maintenance requirement would be to keep your outdoor unit clear of snow during the winter.
|How long do air source heat pumps last?||Heat pumps have an expected lifetime of about 15 years—similar to the average furnace or central AC system.|
|How noisy are air source heat pumps?||A ductless ASHP indoor unit is quieter when running than a refrigerator and much quieter than a typical window AC unit. A ducted ASHP is quieter than a typical furnace or central air conditioner.|
|Can air source heat pumps provide domestic hot water?||Most don't. There are water heaters that use heat pump technology (heat pump water heaters or HPWHs), though they are considered different technologies than ASHPs and are not included in the special HeatSmart CCL offer. Our installer does offer HPWHs, however, and can provide you with more information when they come for a site visit.|
|How complicated is installing a heat pump and how much time will it take?||
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.
|How can I maximize energy savings from my heat pump?||
While most ASHP systems work right out of the box, there are a few things you may want consider to get the most out of your system:
|I've heard that heat pumps can sometimes blow cold air?||
A properly-functioning heat pump may occasionally blow air that feels cooler than expected, particularly relative to a furnace. There are two reasons this may occur:
If your heat pump is providing inadequate heat, you may consider using your backup system during temperature extremes. If your heat pump continues to blow cold air, you may have a maintenance issue with your system and should contact an installer.
|How much will an air source heat pump cost?||Air source heat pump systems typically start at around $4,500 before incentives for a single-zone unit, increasing with additional zones and if you are interested in using a heat pump as your primary source of heat. Consult the New England Ductless HeatSmart CCL Pricing sheet here. If you have questions about pricing, consider discussing your various needs and options with New England Ductless during a free site visit. A more detailed version is available here.|