Heat Pump Support

Solar Powered Heat Pump System   MaineAir Source Heat Pump Guides & FAQs

ReVision Energy has installed hundreds of heat pumps for New Englanders. Air Source Heat Pumps are the most efficient way to heat and cool your home, and a powerful investment, especially when paired with solar.

Use our resources below to familiarize yourself with your heat pump and learn the best practices for keeping your system running smoothly. If you encounter an issue with your heat pump, view our troubleshooting guides and FAQs below to find solutions to common problems.   

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Operating Your Heat Pump

The success of a heat pump depends mostly on how the home's residents operate it. Here are some best practices to maximize your energy savings and comfort:

  • The temperature you choose is a suggestion and you may need to pick a higher or lower temperature to reach and maintain the comfort that you want. 
  • heat pump remote.pngThe remote does not sense temperature and does not receive feedback from the unit. It only gives commands. The indoor unit light will blink and the unit will give an audible beep to signify that it recognizes a command has been received. In normal operation, the light will be solid green.
  • Set It & Forget It: avoid turning heat pumps “on” and “off” to control the temperature; allow the thermostat to control the temperature instead.
  • The fan speed has a separate setting from the heating, cooling, or fan mode. The fan speed, which includes the left and right vane position, should be set to AUTO (flower icon) most of the time. If you need more heat or cooling from the unit, you may need to adjust the fan speed to the highest setting, which is just a bit more powerful than the "auto" setting, to achieve comfort.
  • ECONO COOL and SMART SET may not allow the unit to reach comfort but will save energy.

Cleaning & Maintenance

  • Clean your filters as recommended by manufacturer and replace as necessary.
  • Keep debris and snow away from outdoor units and ensure that there is sufficient airflow around them.
  • heat pump servicing.pngTo ensure peak performance of your heat pump system, we recommend getting them professionally serviced in addition to regular filter cleaning. Heat pumps collect more dirt in the summer, so it’s best to have them serviced in the fall. ReVision Energy offers heat pump servicing, and you can reach out to our Service Team for more information.  

Seasonal Impact

As the weather changes and you switch your heat pump modes from heating to cooling, make sure all indoor units attached to the outdoor unit are in the same mode. If they’re not, they won’t work right! This may be required even if one of the other units is off.


Dry mode should only be used for a few hours at a time. Prolonged use in Dry Mode can cause damage to the unit.

  • This mode is also the least efficient. Its primary objective is to remove moisture from the air by making the indoor unit coil colder than the room's temperature. A biproduct of this is that the unit will cool the space. Running it in this mode for too long can overwhelm the drain pan, causing the unit to leak. It may also damage the indoor unit shrouding. These units are heat pumps, not dehumidifiers.
  • After you are finished running the indoor units in COOL or DRY mode, run the unit in FAN mode at a lower speed for a few hours to dry it out.

Remember, the temperature you choose is a suggestion and you may need to pick a higher or lower temperature to reach and maintain the comfort that you want.

heat pump outside.pngFALL:

Try to keep the outdoor unit free of debris.


Defrost: periodically in cold weather the unit will stop heating for 15-minute intervals while it defrosts the outdoor unit. This is an automatic feature designed to keep the unit free of ice that can interfere with performance.

Our Service Team has shared their tips to maximize savings, efficiency, and comfort with heat pumps. Click here to download a PDF to see all their user tips. 

1. Use your heat pump all winter. 

winter heat pump.pngHigh-performance heat pumps are an incredibly efficient heating system, even on the coldest winter day in New England, and are more energy-efficient than a boiler or furnace. We suggest choosing a heat pump for consistent, cost-effective heating all winter long.  

2. Choose your heat pump before your boiler or furnace. 

For homes heated by both a heat pump and a boiler or furnace, we highly recommend relying on the heat pump whenever possible to maximize your savings and efficiency. Depending on your set-up, this could mean setting your boiler or furnace thermostat lower or closing a radiator or damper in the rooms served by the heat pump. Our Service Team is happy to provide suggestions given your home’s unique set up.  

3. Avoid “Auto” mode in summer and winter. 

heat pump auto.pngIn “Auto” mode, heat pumps maintain a constant temperature by alternating between the “Cool” and “Heat” modes. We recommend using “Heat” mode, rather than “Auto” in the winter to avoid accidentally triggering the air-conditioning from the rare winter sun beam or a wood stove running hot. Likewise, to avoid accidentally heating on a cool summer night, use “Cool,” “Dry,” or “Fan” mode, not “Auto’ in the summer. 

4. Optimize air flow direction

heat pump room layout.pngIt’s easy to redirect airflow on a heat pump to optimize the flow of heated or cooled air throughout your home. To maximize your heat pump's reach, air should be directed toward the open space that is the farthest away from the indoor unit, and away from any obstructions. You may need to experiment to see what’s most comfortable for you in your home. 

How often should I clean my heat pump?

Cleaning your filters monthly and having a professional deep cleaning and inspection annually will ensure optimum operation and will reduce unnecessary power consumption. Clean units increase energy efficiency and limit exposure to condensation.

Indoor Unit

We recommend cleaning your heat pump filters with every seasonal change. You can do this yourself by using a domestic vacuum cleaner with a small brush attachment. If you prefer you can organize a service company to regularly clean and service your heat pump for you.

Outdoor Unit

We recommend having your outdoor unit professionally cleaned every year. During the year, we suggest keeping it clear of any rubbish, plant matter or debris.

It is also important to not place any outdoor furniture, plants, or ornaments on or around your outdoor unit. Anything that compromises the airflow around the outdoor unit will compromise its performance.

How does my heat pump work in extreme cold temperatures?

Heat pumps will continue to operate until the temperatures get below -13°F (including wind chill). At that point they may shut down or have a difficult time keeping the desired temperature. 

If you have an alternative source of heat, make sure it's functional and be prepared to use it. This could mean ensuring there is propane, oil, or wood chopped and ready.

Remember that the temperature setting on the remote should be treated like a comfort meter, rather than an exact expectation of degrees. In a cold snap, setting the temperature on the remote higher will not necessarily provide more heat if the heat pump is not able to keep up.

We recommend the "auto" fan speed settings in general for maximum efficiency. In extremely low temperatures, set the Fan Speed to 4, or the highest it will go. This will provide the maximum BTU output available. Remember to set the fan speed back to “auto” when outdoor temperatures return to normal winter temperatures.

What is “defrost mode”?

All heat pumps will perform a defrost cycle eventually when operating in cold winter conditions. The defrost mode removes ice build up from the outdoor unit. In defrost mode the heat pump stops heating for short periods. Intervals for the defrost cycle can last up to 15 minutes. Some heat pump brands spend longer in defrost than others.

This is part of what makes Mitsubishi Electric Heat Pumps + HyperCore® so efficient, more heating and less defrost cycles. With a Mitsubishi Electric heat pump you get more heat and less defrost cycles, which means less overall power usage and higher, real energy efficiency.

Why doesn't the temperature on my remote match my thermometer?

The number on your remote doesn’t match the thermostat because it's more of a relative guide. Think of your heat pump as a comfort system, and set it for the number that keeps you comfortable.

My unit isn't keeping the room comfortable, what can I do?

The automatic fan setting is 100rpm less than fan speed 4. If the unit isn’t keeping up on auto mode, bump it up to fan setting 4.


When should I use Dry Mode?

Page 2 of the install manual says do not use dry mode for more than 2 hours with relative humidity under 80%, and never run it for more than 5 hours. If you need to use it longer, use AC instead of dry mode – it will not dehumidify as much, but it will pull some moisture from the air.


Why is the room too cold first thing in the morning?

The iSee sensor changes the temperature based on occupancy (the temperature is lower when room is empty). If you find it’s cold in the morning just don’t use that sensor.


Should I use "automatic" mode?

We recommend avoiding automatic mode especially with multiple heads on one outdoor unit because the unit will switch between heating and cooling to maintain the set temperature. Not all units will change modes at the same time which will prevent them from working. It is also less efficient because the unit may switch to heat mode on a cool summer night.

Why does Powerful mode keep stopping?

Powerful mode only runs for 15 minutes at a time.