Ductless heat pumps: the lowdown

A conversation with Efficiency Maine

Ductless heat pumps are one of the most popular technologies for highly efficient heating in cold climates. More than 20,000 high-efficiency ductless heat pumps have been installed in Maine homes and businesses in the past three years.

We sat down with Efficiency Maine program managers Dana Fischer and Andy Meyer to find out more about why Mainers are choosing this technology.

SunriseGuide: Now, you two are not only working to get the word out about ductless heat pumps, you have heat pumps installed in your own homes as well.

Andy Meyer: Yes, Dana and I have very different homes but both of us heat almost entirely with ductless heat pumps. We talk about them all the time.

Dana Fischer: It’s true. The carpool to work often includes a chat about news regarding the installation or output of heat pumps.

SunriseGuide: Do all ductless heat pumps save the same amount of energy?

Dana Fischer: Efficiency Maine provides rebates for the best heat pumps in the marketplace, which are incredibly efficient.  But not everyone who owns them really takes full advantage of their heating capacity.

SunriseGuide: What do you mean by “taking advantage”?

Dana Fischer: You need to experiment with your heat pump settings to find the right balance over the season. Homeowners who save the most use heat pumps as their primary source of heat. Set the temperature as high as needed and supplement with your conventional heating system.

Andy Meyer: I always set the conventional heating system’s thermostat to at least 10 degrees cooler than the heat pump thermostat. By doing that, I ensure the conventional system comes on only as backup. You can also get the most out of the heat pump system when you maximize the heating zone.

SunriseGuide: That makes sense. You want the heat pump to be the primary heating system. Tell me more about maximizing the heating zone.

Dana Fischer: If you’re trying to heat multiple rooms, you should open doors between the heat pump and any rooms you’d like to heat. Conversely, close doors to adjacent rooms if you’re trying to heat only the room where the heat pump is installed.

SunriseGuide: Do you have any recommendations for setting the temperature on a heat pump?

Andy Meyer: I always recommend setting your heat pump to the temperature that makes your home feel the most comfortable. It may be a higher number than people are used to setting their conventional thermostat.

Dana Fischer: And as Andy always says, avoid using the “auto” mode to control whether the unit is providing heating or cooling. Set it on heat in the fall and on cool if you need it in the summer.

Andy Meyer: And you really want to set it and forget it. Find the right set-point to keep comfortable and only adjust up or down a degree or two.  Heat pumps are designed to maintain a steady temperature so leaving it at one set point day and night will provide the best results and savings.

Dana Fischer: Start off with your heat pump’s fan on “auto fan” and if that doesn’t spread the heat far enough, try the manual settings to find the lowest level that will meet your needs.  I keep mine set on “medium-high” all the time so there is good circulation anytime it turns on.

Andy Meyer: Unlike Dana, we find that the “auto fan” mode works for our house. We also adjust the air flow direction. Generally speaking, warm air is best directed towards the floor and away from occupants.

SunriseGuide: Do heat pumps require any maintenance?

Dana Fischer: You want to keep the dust filters and allergen cartridges clear. I check mine monthly during the winter and rinse it in the sink. If you notice a difference in how much heat you are getting, check the filter first.  The more pets you have the more frequently you may need to check the filter.

Andy Meyer: It is also important to keep the outdoor unit clear of leaves and snow. Be sure to consult the heat pump manual for other manufacturer recommendations.

SunriseGuide: Do they require professional maintenance?

Dana Fischer: Most manufacturers recommend having the outdoor unit professionally cleaned every one to two years. Costs are comparable to a boiler or furnace service visit.

SunriseGuide: Thanks for telling us more about how to get the most of your heat pump. I’ve heard that heat pump water heaters are also a good energy-saving technology.

Andy Meyer: Heat pump water heaters have become very popular. I installed a heat pump water heater at my house. I always have hot water, it provides some added dehumidification of my basement, and reduces my water heating bills. In fact, ENERGY STAR® reports that these highly efficient water heaters can save a four-person household more than $3,000 over ten years when compared to electric water heaters.  Efficiency Maine offers rebates for heat pump water heater installations.

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One Response to “Ductless heat pumps: the lowdown”

  1. stephen sheehy March 9, 2017 at 1:15 pm #

    For a new, tight, well insulated, open plan house like mine, no supplemental heat is needed. My Fujitsu heat pumps have no trouble heating the house no matter how cold it gets here in Maine.

    Heat pump water heaters are great, but noisy. If you can locate one in the basement, they work well, but my house is on a slab and we opted for a regular electric water heater to avoid the noise. In addition, the efficiency is reduced somewhat in heating season because they take heat from the air that has been heated.

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