solar powered heat pump system - maine

Katherine Simmonds and son Pi keep cool while enjoying summer reads thanks to their heat pump!

Since the early 2000s, our clients have asked us how to use solar to heat their homes. For years, that solution involved literally trapping the sun’s heat using solar thermal collectors and transferring it to water, which could then circulate using a radiant loop. No more!

Today, efficient air source heat pumps are the system of choice for both new construction and existing homes to heat and cool, with or without solar.

An air source heat pump uses the same technology as a geothermal heat pump, but since it uses ambient air as its source (hence ‘air source’) it is a much simpler project, and hence, a smaller upfront investment. Heat pumps used to mainly be seen in the Mid-Atlantic or Southern States, but thanks to dramatic improvements in their low temperature performance, they are being rapidly adopted in the Northeast. The latest generation of heat pumps can provide heating to temps as low as -17 Fahrenheit.

The vast majority of the systems we install are ductless, consisting of an outside compressor/evaporator and an inside air handler. The units are connected using copper refrigerant line and we triple evacuate the lines with a deep vaccum and dry nitrogen purge, before charging them with an advanced refrigerant for the most efficient and reliable installation.

Based on current grid electric prices, it costs the equivalent of around $1.5/gallon of oil to heat with a heat pump, and using solar, as little as $1/gallon! See our website for a more detailed chart comparing heating fuel choices and relative prices and efficiency for each: https://www.revisionenergy.com/at-home/air-source-heat-pumps/

In cooling mode, a modern heat pump is roughly 1/2 the operating cost of a window unit air conditioner.

Customers Keep it Cool

Solar PV and heat pump - Camden, Maine

A homeowner in Camden, Maine with solar PV on the roof and a heat pump to keep warm and cool! (lower left, tucked behind tree)

We asked some recent heat pump customers what they thought of their system – why they bought it and how it’s working out. Here’s what they had to say:

“We had 2 window units that could never make the house comfortable. My wife has a medical condition and is affected negatively from the heat. We were impressed that the heat pumps use LESS energy than the window units – and are much quieter. They are also much more attractive than the old window units.

We’ve also been impressed with the winter performance, we have used the units in temperatures as low as -5 degrees and they work great! We installed a large grid tied PV array and it appears we are making more power than expected and using fewer kilowatt-hours than we had in the past. If this is the case, we plan to run the heat pumps instead of the oil boiler in the winter.”

– Customer from Swanville

“We love, love, love our combination of solar and heat pumps! We live near the ocean so don’t really need the cooling, but the heating has been great. Three years ago, the island fuel company was filling our tank about once a month for a cost of $800.  The following year, after installing two heat pumps, we had the oil tank filled only once.  Our electric bill went up by about $100-$150 in the coldest months.”

– Customer on Peaks Island

“We had two very old window units in the living room and bedroom.  They worked, but had no thermostats, and were large heavy things, awkward to install and remove, and loud.  With our casement windows, we had to exchange the entire windows each spring/fall.  We’d use them only a few hours at a time when we were actually in the room with them and awake.

The heat pump (we have just one) results in a much more comfortable environment – consistently cool and not just a blast of cold air. It’s certainly quieter than its predecessors and much more attractive.  We let it run a lot more and the air is better throughout the house.”

– Customers in New London, New Hampshire

Got a heat pump? We’d love to hear from you too! On the next hot (or frigidly cold) day, please leave us a Facebook comment or Send us a tweet to let us know how your systems is performing.