FAQs

Heat pumps use a highly temperature-sensitive refrigerant and a series of fans and compression and expansion valves to absorb heat and move from one place to another. Refrigerators and air conditioners use the same principles, but a heat pump can reverse the cooling process to provide heat in winter.

Yes, many heat pump models are built to provide 100% of New England’s heating needs. When you contact installers, request a quote for a “cold climate heat pump.” These models are designed to work efficiently in sub-freezing, even sub-zero, temperatures.

The size of your heat pump should be based on an accurate measurement of your home’s “heat load.” That’s the number of BTUs (British Thermal Units) of heat needed to keep the building cozy on the coldest winter nights. This measurement is called a “Manual J calculation.” When you meet with potential installers, ask them if they would perform a Manual J calculation or to explain how they would estimate your heat load. 

It’s important the installers do not oversize the equipment. Oversizing not only leads to higher installation and operating costs, but also to inadequate dehumidification in summer. You may be able to estimate your home’s heat load. This short video provides an overview of CoolCalc, a free software program that makes it easy for you to estimate your own home’s heat load: https://youtu.be/fnVZ884Tvdg.

You can find trusted installers through our partners at Heat Pumps: Get Advice and Shop Installers.

The cost of installing a whole home heat pump system in our region is averaging between $15,000 - $25,000, but the cost depends on what percentage of your heating the heat pump will provide, how large your home is, and how well-insulated it is. A heat pump for a relatively small, well insulated house might cost only $6,000, but a large, under-insulated home might cost $45,000.

Whether you will save money on heating costs depends on what you pay for electricity and for the fuel you’re currently using for heat. If you now use electric resistance baseboard, a heat pump will definitely save you money on operating costs. If you currently heat with oil or propane, heating your home with a heat pump will likely cost less. If you currently heat with gas, whether you save money will depend on the electricity and gas rates in your area. 

We recommend you consult with a building science expert from one of our partners  to help you estimate relative costs based on the individual characteristics of your home, your current fuel and electricity costs, and other factors. 

You could also input your particular costs of electricity and the cost of your current method of heating into this interactive calculator from Efficiency Maine: Residential Heating System Cost Calculator | Efficiency Maine.

Yes, if you already have ductwork for heating, you can likely plan to replace that equipment with a cold climate heat pump, pending an assessment of your existing ductwork. The heat pump can provide cooling as well as heating, giving you year-round comfort.  To read about a family that replaced its fuel oil forced air furnace HVAC system with air source heat pumps, go to Friedman Case Study_2.pdf (neep.org).

Yes, replacing your electric baseboard resistance heating system with heat pumps will save you money in winter because heat pumps are 2 to 3 times more efficient than electric baseboards. Heat pumps also provide efficient air conditioning with the same equipment.  To read about a homeowner who replaced her baseboard heating and window units with an air source heat pump, go to Nia's New Floor Mounted Air-Source Heat Pump - Massachusetts Clean Energy Center (masscec.com).

It is often possible to use existing ductwork with a heat pump, but you will need to have a professional inspect your home to confirm if your existing ductwork would be adequate for a heat pump.

Existing central A/C ductwork can often be used with a central heat pump, but you will need a professional assessment to confirm if that ductwork would be adequate.  In some cases, you might need to augment the central heat pump with one or more ductless heads.

For now, there are no simple heat pump replacements for boilers. Unless you increase your insulation or add wall radiators, currently available air-to-water heat pumps are not be able to provide as much heat as your current boiler can provide.

Your boiler system was designed to use steam or very hot water – 180 to 200 degrees – to provide the heat needed to keep your home warm in winter. “Air-to-water" or “hydronic” heat pump technology is able to deliver water heated only as hot as 120 degrees. (One air-to-water heat pump – Artic’s high temp cascading design – is able to achieve temps of 180 degrees but it uses refrigerants that will not be permitted in the U.S. after Jan. 1, 2025.)  

Converting your current hydronic distribution system to a low-temperature – 80 to 120 degrees – air-to-water heat pump may be a good option if you already have radiant flooring, are able to add radiant flooring or wall radiators, or if you can increase your insulation and air-sealing. To find potential installers of air-to-water heat pumps, consult the Mass Save or Clean Heat Rhode Island website.

You can also replace your boiler or reduce the amount of time your need to rely on it by installing one or more ductless air source heat pumps. To read about homeowners who replaced their oil-fired boiler with air source heat pumps, go to Slack Case Study_4.pdf (neep.org).

If you have radiant floor heating already or are considering installing it, you could consider an “air-to-water” heat pump. Expect the process to take longer and the cost to be higher than the common air-to-air heat pumps, because, for now, there are not many installers in our region with experience installing these systems. To learn how air-to-water heat pumps work, go to 4BED0381F5C1422085B90A7C8A864B4B.ashx (masssave.com).

You can! Mass Save and other energy efficiency programs incentivize the use of a “smart control” thermostat to seamlessly toggle between the current system and the heat pump. Your heat pump installer will program the new thermostat with a specific set point – often around 30 degrees – above which the heat pump works and below which your current system turns on and the heat pump turns off.

The smallest capacity heat pumps produce 6,000 BTUs, roughly enough to heat a room about 15 ft x 20 ft., or about 300 square feet. If you have multiple small rooms next to each other, you might be able to use one head with short duct runs to serve those adjacent rooms. Depending on how a small room is used and how much heat it needs, you might be able to warm it sufficiently with a small strip of electric resistence heat or with a dual-hose portable heat pump or a window a/c with heating capacity. For more information on heat pumps for small spaces, see this 2023 webinar: Micro Heat Pumps - Window, Portable and Saddleback - YouTube.

The average lifespan of an air-source heat pump is about 15 years.

Ground-source heat pumps are generally more efficient than air-source heat pumps, and thus have lower energy demand and lower operating costs. They are more expensive to install, however, and not all properties are appropriate for ground source heat pumps.  A professional would need to inspect your property to determine if the installation of a ground-source heat pump is possible.  For more information on ground source heat pumps, go to Ground-Source Heat Pumps - Massachusetts Clean Energy Center (masscec.com).

A heat pump condenser (the outdoor unit) needs air flow in all directions. It is generally placed a foot away from the house and needs a foot clearance from the ground and any landscaping. It can be placed on or under a porch. It should not be put under a roof overhang where falling snow or icicles might damage it. The condenser can be up to 150 feet away from all indoor units.

You would need to work with your condo association to identify an appropriate place. Condensers can be located on or under a deck or on the roof.

You may need to upgrade to a 200-amp service to support heat pumps. Many older homes have only 100 or 60 amp service. If you're not sure what you have, check the main electrical shut off switch to see if there is a number embossed in the switch. Ask your electrician about an upgrade and if there are other ways to manage the various electrical devices in your home to avoid an upgrade. If you do need to upgrade your service and your main shut off switch and panels are currently in your basement, you will likely have to move those to a location on an outside wall (to meet modern fire codes). Rhode Island residents who meet income qualifications may be eligible for rebates related to electrical upgrades: Home Energy Rebate Programs | Rhode Island Office of Energy Resources.

All modern furnaces and boilers rely on electricity in some way, so fossil fuel heating is no more reliable in a power outage than an electric heat pump would be. Heat pumps can be powered by a generator or by battery backup systems. Some consumers have chosen to have a wood stove as a back-up for power outages.

Most LG and Samsung equipment have wifi built in. For equipment from other companies, such as Mitsubishi and Fujitsu, a wireless module can be added to the unit, for approximately $250/unit.

Residents can easily clean the filters on the indoor units. Do this at least every season according to the owner’s manual. For the outdoor unit, remove leaves and snow from all sides. No other regular maintenance is required.

Heat pumps are vulnerable to mold in a way similar to all air conditioning systems. Warm air is pulled into the machine, then as heat is extracted, some of the moisture in the air, along with whatever microscopic impurities floating in the air, clings to the inside of the machine. Water is constantly being drained to the outside during cooling mode.

To prevent any mold growth during the cooling season, if the outdoor temperature is such that you do not need your heat pump to actively cool your home, switch the setting from cooling mode to fan only. That air flow will completely dry out the internal components and prevent mold proliferation.

If you see dust or mold in your indoor head, schedule a professional deep cleaning (which should be comparable in cost to an annual furnace tune-up).

This video by a heat pump expert offers a longer examination of this issue, Should I be worried about moldy mini splits (youtube.com).

Residents can easily clean the filters on the indoor units. Do this at least every season according to the owner’s manual. For the outdoor unit, clean leaves and snow away from all sides. No other regular maintenance is required.

Heat pumps are vulnerable to mold in a way similar to all air conditioning systems. Warm air is pulled into the machine, then as heat is extracted, some of the moisture in the air, along with whatever microscopic impurities floating in the air, clings to the inside of the machine. Water is constantly being drained to the outside during cooling mode.

To prevent any mold growth during the cooling season, if the outdoor temperature is such that you do not need your heat pump to actively cool your home, switch the setting from cooling mode to fan only. That air flow will completely dry out the internal components and prevent mold proliferation.

If you see dust or mold inside your indoor head, schedule a professional deep cleaning (which should be comparable in cost to an annual furnace tune-up).

This video by a heat pump expert offers a longer examination of this issue, Should I be worried about moldy mini splits (youtube.com).

Generally, heat pumps work most efficiently at a steady temperature.  Turning a heat pump down when you're away or asleep may actually use more energy than leaving it on, because it has to work harder to come back to the desired temperature than it does to maintain it.  This is why most heat pump experts suggest that consumers “set it and forget it.”

If you have a heat pump with the capacity to gradually return to ideal temperature after a set-back, BetterBuilt NW suggests no more than a 2 degree set-back for nights or if no one is home for more than 6 hours during the day. If you are going to be away from home for at least 48 hours and you are able program your thermostat to increase the temperature just 2 degrees every hour, then you could potentially save energy with a 5- to 8-degree set-back. 

For more information and tips on maximizing the benefits of your air source heat pump, go to Getting the Most From Your New System - Massachusetts Clean Energy Center (masscec.com). This article provides a case study with some data confirming the “set it and forget it” advice for heat pumps: Set It & Forget It: How Heat Pumps Resolved a Long Term Marital Dispute - CleanTechnica.

If you get your electric bill from Eversource in eastern Mass, you may request a change to a slightly discounted electric heating rate. Eversource currently has four residential rate classes:

• R1 - Residential 
• R2 - Residential Assistance 
• R3 - Residential Space Heating  
• R4 - Residential Space Heating Assistance

The MA Department of Public Utilities (DPU) sets the rates that Eversource can charge their customers, and this changes twice a year for winter rates (January - June) and summer rates (July - December). The current Eversource Delivery charges – the lower half of your bill – are nominally lower for customers using electricity as their primary heating source. You can contact Eversource by phone or through your online account to change your rate class to reflect electric space heating; although you will only save fractions of a cent per kWh, in the future the DPU may authorize further discounts for those with electric space heating. Plus, changing to the electric heating rate class may be helpful for local or statewide data collection/analysis — to identify customers who have converted to heat pumps and those who still need to electrify.

At present, no other utility in the state offers this reduced rate. This discounted rate is not available to households that still have fossil fuel heating for part of their home.

There are a few measures you can take to optimize the efficiency of your heat pumps. Our thanks to Heat Pump User Tips - Efficiency Maine for many of these tips.

If your system is having performance issues, do not use “economy” mode (not all systems have this option). “Economy” mode caps the power of the heat pump at 70% of its capacity.

Check the batteries in your remote, if the batteries are drained, the remote may not be properly communicating with the air handler, also known as the head.

Leave your heat pumps running at a constant temperature (“set it and forget it”).  Big temperature adjustments when you’re away for short periods or asleep could use more energy than leaving the thermostat at a steady setting. This is because the heat pump has to work harder to come back to the desired temperature than it does to maintain it.

If you won’t need cooling or heating for 48 hours or more, turn off the system. Use “fan” mode when transitioning from “cool” to “off’ to prevent mold growing in the head. Running in fan mode before turning off allows the interior cooling elements to come to room temperature and dry out. The head uses very little power on a low fan setting, so it’s fine to leave the fan on for multiple hours. 

When you turn on a heat pump, adjust the temperature gradually; for example, in summer start 6 degrees hotter than your target temperature goal and decrease the temp a degree or two every hour.

Match the summer mode to your needs. “Fan” uses the least energy and may suffice when you need only a little temperature control. When it’s warm and muggy, “dry” mode reduces humidity and makes higher temperatures feel more comfortable. Use “cool” mode when “fan” and “dry” are not adequate for comfort.

Avoid “auto” mode, which allows the heat pump to alternate between the “cool” and “heat” modes to maintain a constant temperature. 

Optimize air flow direction. To maximize reach, air should be directed toward the open space that is the farthest away from the head, and away from any obstructions.

Clean your dust filters. As directed by your user manual, vacuum or rinse the dust filters in the head when they become visibly dirty or when the indicator light comes on. The frequency of cleaning can range from weeks to months depending on use and dust volume.

Follow your heat pump manufacturer’s recommendations for professional cleaning in addition to regular dust filter cleaning.

Keep your outdoor units clear of shrubs, leaves, snow drifts, and any other obstructions.