Air-Source Heat Pumps Q&A

Reader Contribution by Peter Callaway
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Photo by Oak Ridge National Labs

Homeowner Peter Callawaydocumented his experienceconverting his household to a heat pump system in a region that relies predominantly on fuel oil for home heating. Here, Peter follows that two-part series with a Q & A to help others determine whether air-sourced heat pumps are the right fit for their home heating.

MOTHER EARTH NEWS: Why did you do this installation?

Peter Callaway: Because home heating and cooling, including hot-water heating, is one of the biggest sources of a family’s carbon footprint — up to 60 percent. I was burning oil and gas from November to April heating my home in New York State and using oil all year long just for hot water. From June to September, I’m running air conditioners. Heat pumps use about half the electricity for cooling that air conditioners do and a quarter the electricity that electric heaters do. So, by using a 100-percent renewable electricity supply together with heat pump-based heating and cooling, I can eliminate fossil fuel use entirely while lowering energy use costs.

What was the straw that broke the camel’s back and triggered the leap to heat pumps?

My local energy system servicer told me that my furnace was old, inefficient, and rusting out and could crack open at any moment and dump foul liquids all over my finished basement floor. It made no sense to replace it with a new, 50-year oil or gas-fired furnace, knowing that science is telling us we have to stop burning fossil fuels immediately. Also, I learned that air-source heat pumps are now available with extra low-temperature technology that make the geothermal component unnecessary.

How did you become so sure you could rule out the geothermal piece?          

I saw graphs in a Fujitsu technology magazine that showed the difference between the old technology and the new, air-source, extra low-temperature technology that works down to minus 15 degrees Fahrenheit. I talked to a contractor who installs Mitsubishi heat pumps that work down to minus 13 degrees. A check of the manufacturer’s website confirmed the claims. Last winter, the outdoor temperature in Cold Spring, N.Y., where I live went down to -2 degrees and the heat pumps still kept the house nice and warm.

For those that are still a bit wary of the low temperature claims can you keep the old system as a backup?

Yes. Heat pump systems don’t occupy the same space as conventional baseboard or radiator/hot water oil/gas furnace systems. The compressor/evaporator units are placed on the outside of the house, while the air distribution components can be placed anywhere indoors, often high up on a wall or in the ceiling. Therefore you can keep your old system as backup and dispose of it when you have gained confidence.

How did you find a reliable local contractor?

Use online HomeAdvisor or Angie’s List or ask my neighborhood Facebook page. For homeowners in New York, you can also find an installer using NYSERDA’s list of participating heat pump contractors.

But what about the capital cost? Are heat pumps too expensive for most people?

Yes, prices are comparable to buying a new car. However, unlike a car that loses value until its virtually worthless after 10 years, heat pumps were designed to last a minimum of 15 years in the 70s and 80s and are expected to do much better today — 20 to 25 years — and they do the job of the system they replaced at 25 percent cheaper operating cost. So if you spent $4,000 per year heating and cooling using oil or gas and conventional air conditioners, you’ll save about $1,000 per year using heat pumps while producing no greenhouse gas emissions. This is a permanent, significant reduction in the cost of heating and cooling your home that can grow in size as you implement energy efficiency improvements as identified by your energy efficiency audit. As we get deeper into the inevitable process of eliminating fossil fuel use, homes already equipped with heat pump systems will likely experience increased value.

OK, but for oil and gas HVAC systems to be replaced by heat pump HVAC systems at scale, won’t the price need to come down?

Yes, and the only way that will happen is if the Federal and state governments make it part of a National and State energy policy and replace oil, gas, and coal subsidies with clean energy product subsidies and put a tax on fossil fuel production.

What about product and service quality?

I bought from a contractor who is a certified Fujitsu dealer. I feel that I have a high quality product and get quality but expensive service.  There are two kinds of service plan coverage. The first is required and that is the semi-annual tune-up and cleaning before the winter season of heating and before the summer season of cooling. Deep cleaning of coils and fins and inspection for mildew is very important and is an expensive extra. Frequency of deep cleaning depends on environmental conditions.

The second kind of coverage should be optional and that is more like an insurance policy against system failure. The manufacturer should provide a warranty that covers the cost of failed components within at least the first 7 to 10 years, but you may have to pay your contractor labor costs for coming out and doing the work. This kind of insurance can be expensive and can wipe out any savings in HVAC running costs. Make sure your contractor doesn’t roll both kinds of service into a single expensive package and make sure that you have the option of choosing the semi-annual preventative maintenance service only. Know what’s covered and what’s not and be sure it’s what you want before you sign.

How likely is it that temperatures will go below 0 degrees in the Northeast U.S. region and if they do, what will you do?

According to, the average minimum winter temperatures for nearby Stewart Airport is 4 degrees, with the highest minimum 10 degrees, and the lowest minimum -5 degrees. The XLTH technology used by Fujitsu (and others) is designed to provide 100-percent efficient heating down to 0 degrees, tailing off to 0 percent by -15 degrees. Based on these data, I figure I will never need backup heating because Cold Spring, located on the river, is always about 5 degrees warmer than Stewart. But just in case, I maintain a backup propane gas insert heater in the basement. I also have a couple of standalone electric heaters. I also have inserted a diverter unit into my electric drier exhaust so that all that hot, moist air in the winter isn’t wastefully blown outdoors. The diverter has its own lint filter, so that recirculated air is double filtered.

OK, but some people may still be nervous about a very low probability extended period of  minus 15 degrees weather and large electricity bills for use of the standalone heaters and maybe the heat from one propane fireplace may not be enough?

These homeowners will need to consider the additional expense of adding a geothermal loop as provided by companies, such as Dandelion, which makes the heat pump output virtually independent of outside air temperature.

These systems use a single air distributor for one large room. How do these mini-split units achieve even heating and cooling?

The heat pump air distributor is equipped with horizontal louvres that direct air up or down or anywhere in between. Behind them are vertical louvres that swing left or right or anywhere in between. Using the remote control you can independently set these two sets of louvres in a fixed position or set them to scan automatically. After running on AUTO for a while with your selected settings, your rooms will settle to the conditions you prefer.

What about your hot water heat pump heater? How is that going?

It does a great job and I like the fact that it has four modes of operation: heat pump only, electric only, hybrid and vacation (allows the temperature to drop to the safest level without compromising the unit). The biggest pleasant surprise is a bonus in the summer: It draws heat and humidity out of the basement air and transfers all those condensation BTUs into your hot water, so you’ve got significant additional air conditioning.

Did you have any problems with your contractor and learn anything worth passing on?

Yes. The initial contract was negotiated verbally with the salesman and then handwritten and signed with a down payment. The agreement was contingent upon the use of the Fujitsu XLTH (extra low-temperature, high-heat) heating units and the free removal of the existing old oil furnace. The exact models to be used were not specified because that depended on detailed measurement of the heating requirement of the house which would take the time and expertize of a Fujitsu trained technician. The technician came the next day and produced a multi-page, detailed report which he shared with me and explained. The exact model numbers to be used were based on this report and included a 36,000 BTU XLTH heat pump. So far, so good.

As installation commenced, it was decided that maybe the 36,000 unit was not enough, because I have a cathedral ceiling and lots of large old leaky windows that need to be replaced To be on the safe side, I should probably go for the next higher model  at 45,000 BTU. I agreed, but the extra expense meant that I would have to postpone installing the basement heat pump for a year and keep the oil furnace for the basement.

Later, when it got below about 20 degrees in winter, I noticed the heat pump was not producing enough heat and I had to supplement it with the oil furnace baseboard heat. This was puzzling and disappointing until I discovered that the 45,000 BTU unit was not an XLTH unit. I confirmed by calling Fujitsu that it would be a couple of years before their 45,000 BTU XLTH unit would be available. Coincidentally, I was contacted by a third party customer satisfaction surveyor and found myself saying that I was seriously dissatisfied. This information got back to the contractor rapidly and they called me the next day and promised to fix the problem by replacing the 45,000 unit with two 24,000 XLTH units that would match the existing indoor units and ductwork, etc. The person who had done the technical assessment said he didn’t know that I wanted only XLTH models and that I wanted to get rid of the furnace. This was a costly lack of communication, because the 45,000 unit had to be thrown away and they could only give me $1,000 credit for it but, yes, they would now take out my old furnace and drain and seal off the old pipes (which they said was worth at least another $1000).

The lesson learned is get the contract fully developed to include verbal agreements with sales and typed up with all model numbers before signing and making a significant down payment. Also go over the contract with the installers the day they start.

Peter Callaway is a Philipstown, N.Y., Climate Smart Community Task Force member and veteran environmentalist in the Hudson River Valley region of New York. He took on this extensive heat-pump conversion project to respond to recommendation 42 of the Project Drawdown framework.

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