Mini-Split & Air Source Heat Pump Education

What is a Heat Pump, and How Does it Work?

Air source heat pumps, sometimes referred to as mini-splits, are an energy-efficient electric heating and cooling system that can be used to heat and cool either part, or all, of your home.  

Air source heat pumps consist of two main components: an indoor unit and an outdoor unit. Refrigerant cycles between the indoor and outdoor units, carrying heat from one location to another, similar to how a refrigerator operates. In the summer, heat is moved from inside the home to outside, blowing the remaining colder air back into the house. In the winter, they reverse operation, extracting heat from the outdoor air and transferring it into the home.

How to Shop for a Heat Pump and Find an Installer

When choosing a heat pump installer, its a good idea to get quotes from multiple contractors, as installation costs can vary widely depending on who you work with. But, be sure your installer has experience installing heat pump systems as they are a more complex technology than conventional heating and cooling systems. One way to help ensure this is to check to see if the installer has a manufacturer's certificate of training. The Northeast Energy Efficiency Partnership (NEEP) has provided an Air Source Heat Pump Buying Guide to help you choose the right system for your needs. See pages 13 and 14 of the guide for best practices for choosing a heat pump system and questions to ask a contractor to ensure they are experienced with installing this system type. Different installation companies tend to stick to one brand - (only install Mitsubishi, or only Carrier, for example). 

Advantages of Heat Pump Technology:    

    • Air filteration
    • Energy Efficient (Many available systems are capable of an average efficiency of 300% throughout the course of the heating season)
    • Provide both heating and cooling
    • Powered by electricity
    • Low carbon emissions (especially for HG&E customers due to HG&E's high renewable and carbon-free electricity supply)
    • Ability to heat and cool individual rooms rather than an entire house (when installing mini-splits)

Ducted Heat Pumps vs Ductless Mini-Splits

Heat pumps can either be connected to ducts (where the heat travels through your ductwork), or, they can be installed without the need for ducts, known as ductless systems. Ductless systems are often referred to as "mini-splits" and typically consist of one or more wall-mounted indoor units connected to an outdoor unit. 

The main advantages of ductless mini-splits are their small size and flexibility for zoning (heating and cooling individual rooms). Many models can have as many as 4+ indoor units (for four zones or rooms) connected to one outdoor unit.

The image below is of a ductless mini-split heat pump with one outdoor unit connected to multiple indoor heads. This allows different areas of the house to be set to different temperatures. 



Cost to Heat with a Heat Pump vs. Other Heating Systems/Fuels (Based on HG&E's Residential Rates)

There are many factors that contribute to your annual heating costs, such as the efficiency rating of your heating system, the efficiency of your heating distribution system, fuel rates, etc. The chart below provides information on the annual cost to heat with heat pumps compared to other heating systems to help give some insight into average costs for various fuels/heating systems.

Please Note: The chart below assumes the ducted heat pump and the ductless mini-split heat pump have no electric resistance elements built into the system. While it is possible to install electric resistance elements as part of a heat pump heating system, this can increase the annual heating costs. However, it is also possible that installing electric resistance elements, such as electric strip heat, can reduce the system' installation cost. 

However, if you would like to make a more detailed comparison, we have developed a Heating Cost Comparison Tool where you can adjust various factors such as the efficiency of the system, fuel rates, etc. We have both an online calculator available in Google sheets, and a downloadable calculator created in Microsoft Excel.

  • Downloadable Heating Cost Comparison Tool: Click here to download the Excel version of the heating cost calculator.
  • Online Heating Cost Comparison Tool: If you would like to use the online calculator in Google Sheets, click here to get started. After you click the link, - press 'make a copy' to open to tool in your web browser. (You will need to be logged into your Google account to use to tool.) 


Annual Heating Cost Comparison of Different Heating Fuels/System Types:*
(This chart is for heating costs only; any installation or system upgrade costs are not included.):

Lifetime Heating Comparison by Fuel Type:*
(Installation Cost and heating costs over 15 years):

*Notes and Assumptions Regarding the Above Charts:
• It is assumed that the Ductless Mini-Split Heat Pump and the Ducted Heat Pump have no electric strip heat or electric resistance elements as part of the system. Installing electric resistance elements can increase annual heating costs. 
• Electric rate based on HG&E's average residential electric rate of $0.14/kWh
• Natural Gas rate based on HG&E's average residential natural gas rate during 2021/22 heating season ($1.41/therm)
• Heating oil rate based on Massachusetts EIA weighted 2021/22 heating season average consumer price ($5.22/gallon)
• Propane rate based on Massachusetts EIA weighted 2021/22 heating season average consumer price ($3.90/gallon)
• Ductwork is generally assumed to have an average distribution efficiency of 70% with the exception of the new 95% efficient gas furnace, which is assumed to have a distribution efficiency of 90%. Hydronic systems (boilers) are assumed to have an average distribution efficiency of 90%.
• Assumed annual home heating requirement: 80 MMBTU/yr


How Much Does a Heat Pump System Cost to Install?

Costs to install heat pumps range widely depending on a variety of factors, including the size of the system, how many indoor heads are needed, the installation company used, other design factors, etc. The average cost is $4,190/ton (based on data from customers who've received incentives through HG&E for heat pumps). Costs for "whole-home" heat pump systems (those that can supply all of a home's heating, rather than just some of the heating) tend to be much higher than conventional heating systems, with an average cost of $20,000. Because it generally costs much less to heat with heat pumps than oil or electric resistance, some homeowners will choose to install whole-home systems while others will install a smaller system, often in the rooms they use the most (kitchen, living room, etc) and use it as much as possible for heating and keep their current heating system as back-up. If a home already has ductwork in place, most installers will likely recommend a ducted heat pump system rather than a ductless system. With 'whole-home' ducted systems, its fairly common for installers to propose a system that includes an electric strip element which provides supplemental heat in addition to the heat provided by the heat pump. The electric strip can reduce the installation costs, but, since this electric strip creates heat using electric resistance, heat being produced through an electric strip can cost roughly 3 times more that heat being provided solely by the heat pump. 

Financial Incentives Available:

    • Residential Incentives: Please review our heat pump and mini-split incentives webpage for more information
    • Commercial Incentives: HG&E provides financial assistance at 0% interest for the installation of qualifying heat pumps through the Commercial Energy Conservation Program


Will a Heat Pump Work During Holyoke's Cold Winter Temperatures?

Because heat pumps work by using refrigerant to transfer heat energy from one location to another, and because refrigerant can start boiling at very, very cold temperatures, many heat pump models available on the market today can continue to provide adequate heat throughout the entire winter in Holyoke. If sized correctly, they can even be used as a home's primary, or only, heating system. The Northeast Energy Efficiency Partnership (NEEP) has published a list of verified Cold-Climate heat pump models that are capable of operating at a high efficiency of at least 175% when the outdoor air temperature is only 5°F.  Average winter temperatures in Holyoke fall below 5 degrees for only about 44 hours each year, with a low of negative 8.2 degrees. Therefore, if you are looking for a heat pump that can operate year-round in Holyoke's climate, it is recommended to choose a heat pump that is rated to provide heat down to -9°F.

The Importance of Weatherizing Your Home Before Installation

 Consider preparing your home for the heat pump before it is installed by first air-sealing and insulating to a proper extent. Having a tighter, more insulated home not only reduces annual heating costs, but might also allow you to buy a smaller heat pump system than you would have needed otherwise. HG&E provides free home energy audits to customers which determine cost-effective weatherization improvements you can make to reduce your annual heating and cooling costs. You can also take advantage of Holyoke's weatherization incentives to help cover the costs. 

Understanding Common Heat Pump Ratings such as SEER, HSPF and BTUs

System Size and Output Capacity: 

The amount of heating and cooling that a heat pump system can provide depends on its size, or "output capacity". Smaller heat pumps can be used to heat individual rooms or spaces. Larger, whole home systems may have multiple indoor units connected to one or more outdoor units.  The output capacity of a heat pump system can vary depending on the outdoor temperature. The NEEP Cold-Climate Air Source Heat Pump List provides the output capacity at various outdoor temperatures down to 5 degrees F. 


This is the average annual heating efficiency of the air source heat pump system. The HSPF indicates how much heat is produced for each watt of electricity that the system consumes. For example, if a heat pump has an HSPF of 10, this means that the system will output an average of 10 BTUs of heat for every watt consumed throughout the heating season. Ensuring the system has a high HSPF will help lower your annual heating bills. 


This is the average annual cooling efficiency of the heat pump. The SEER rating indicates how much cold air is produced for each watt of electricity that the system consumes. A higher SEER rating will reduce your cooling costs over the cooling season. 


The EER rating is the cooling efficiency of the system when its specifically 95 degrees outside. 


Resources on Proper Heat Pump Operation


Further Resources:

Northeast Energy Efficiency Partnership’s Air Source Heat Pump Buying Guide and MassCEC’s Heat Pump Guide are great resources to review to learn more about how air source heat pumps work, which design is right for your home, size and ducting options, and more!



Contact Sophie Theroux
Energy Efficiency Coordinator

Tel: (413) 536-9382