Heat pump decisions

Many people are seeking to shrink their personal carbon footprint.  Many also seek to participate constructively in the energy systems transitions necessary to achieve net zero carbon emissions.

There is a broad consensus among climate planners in Massachusetts that we need to electrify heating in buildings.  However, each building raises unique challenges.  This post attempts to summarize the environmental and consumer considerations for people seeking to electrify heating in a home.  Many of these considerations are explored in more depth in this heat pump outline.

Scope of this discussion

This post is about replacement of existing heating systems with air-source heat pumps.

There are several good heat pump applications that are beyond the scope of this post:

  • In a new home, it is easier to build-in heat distribution systems (ducts or piping) that are fully compatible with efficient heat pumps. I generally favor electrified heating in all new construction. 
  • When adding heating to an unheated or inadequately heated part of a home, a heat pump is likely to be a good solution, especially since it will also provide air conditioning. A single-head mini-split installed to serve a single room is often relatively inexpensive and often relatively efficient.
  • When adding, expanding, or replacing air conditioning, heat pumps are likely to be a good solution. Anecdotal reports and crude survey evidence indicate that air conditioning upgrades may be the most common occasion for a heat pump installation. Heat pumps are more efficient and quieter than conventional air conditioners and also provide heating. Air conditioning is becoming more necessary for health as temperatures rise. It’s reasonable to add or expand air conditioning — even though additional cooling will mean increased greenhouse gas emissions.
  • Ground source heat pumps are not usually an option for people in my district because they usually require large lots.  They are considerably more expensive to install, but they are less expensive and more environmentally beneficial to run.

Environmental benefits of heat pumps

A heat pump conversion from an existing heating system is likely to reduce greenhouse gas emissions:

  • When running in place of electric resistance heating, heat pumps substantially reduce electricity use and related emissions.
  • When running in place of fossil fuel heating, heat pumps are typically efficient enough that they will reduce greenhouse gas emissions.  In other words, they are typically efficient enough that the fossil emissions they will eliminate from heating in the home will exceed the emissions that result from increased demand on our electric power grid.
  • The environmental operating benefits are greater for conversions from oil and propane than for conversions from natural gas.
  • Typical heat pump installations replacing natural gas are beneficial, but the net benefits are smaller and more sensitive to inefficiencies in the particular installation.  (See this discussion of efficiency challenges and for an example of a net-benefit analysis, see slide 18 in this presentation.)

Every heat pump installation should be designed carefully to assure efficient operation that maximizes environmental benefits and minimizes operating costs.  Good design is also important for comfort.  Most people will want to work with a heat pump coach or consultant to assure that they are getting objective advice as to how to achieve the best results in their own home.

Putting aside the minority of installations where heat pumps are so inefficient that they do not generate GHG savings, the more a heat pump actually runs and replaces heat from the existing heating system, the more savings it generates.

People seeking to benefit the environment should use heat pumps in a consistent and disciplined way to displace heating – either by doing a full replacement of existing heating or using integrated controls as recommended by Mass Save.   With integrated controls, your legacy system will only run when it is quite cold out. Mass Save has a major study underway which will shed light on the extent to which consumers achieve both comfort and operating savings with integrated controls.

Heat pumps can leak refrigerants.  These refrigerants are potent greenhouse gases.  If heat pumps are used heavily, the savings they generate will likely exceed substantially the expected harms from leaks.  If the heat pumps are lightly used, there is real risk that harms from leaks will exceed operating environmental benefits.

If replacing an air conditioning system, then the risks of environmental harms from refrigerant leaks from heat pumps are not necessarily greater than the already-existing risks of leaks from the air conditioning system and may not need to be weighed in the decision. However, it is important to confirm the lawful disposal of harmful refrigerants from the system being displaced. 

Coming technology improvements

Over the next two or three years, the heat pump and air conditioner markets are likely to shift to refrigerants that are more efficient and less-potent as greenhouse gases. Current industry statements suggest this will result in an improvement of approximately 10% in efficiency. Additionally, the risks of significant environmental harms from leaks will go down by a factor of 3 or more.

These changes will increase the net environmental benefits of heat pump installations. They are most likely to be worth waiting for where the conversion is from natural gas, especially when the planned conversion is only partial – in partial natural gas conversions, the risk that leaks will offset operating benefits is greatest.  The case for waiting is also stronger if the heating system is relatively young and would be fully replaced.

Think creatively about your home

If one has limited resources, it is important to think carefully about one’s options for spending money to benefit the environment — insulation measures or partial heat-pump conversions may take stretch your limited resources further than a full heat pump conversion.   In some heat pump conversions, especially those from natural gas, the cost per ton of greenhouse gas savings may exceed $1000 per ton, well above the Biden Administration’s estimated social harms from carbon emissions. (See slide 18 in this presentation.)

Every home is different and different households have different needs. For example, an empty-nester couple staying in a single-family home might be able to save money and carbon emissions by turning their fossil heat system way down and adding small minisplit heat pumps in only a couple of heavily used rooms. Constituents have shared many hybrid permutations that keep them comfortable while saving costs and emissions.

The cost and benefits of insulation and other energy efficiency measures are beyond the scope of this post.  The possible savings from these measures depend on specifics of the home.  However, in some cases, the payback can be quick. Mass Save requires basic weatherization as a condition of larger rebates and covers 75-100% of the cost.

Cost considerations with heat pumps

In Massachusetts, given our relatively high electric rates, heat-pump conversions from fossil fuels are not usually motivated by cost considerations. The benefit-cost analysis of heat pump conversions depends on several factors.

  • What heating fuel are you converting from?
    • Converting from electric resistance heat, heat pumps will likely cut your operating costs by 50% or more. Depending on your electric rates and on your home’s energy efficiency, this may be enough to recover your capital costs.
    • Converting from oil or propane heat to heat pumps, cost-savings will depend on market conditions and your own local electric rates. Electric rates vary substantially across communities in Massachusetts. Do not trust an online savings calculator that does not ask for your fuel cost and electric rate assumptions. Generally, in an oil or propane conversion, savings are uncertain and likely to be very modest.
    • Converting from natural gas to heat pumps will rarely result in operating cost savings (and may result in increased costs) unless the historical price relationship between the cost of gas and the cost of electricity changes substantially in the future.
    • See more discussion of fuel prices and operating economics here.
  • How much will you actually use your heat pump? Substantial fuel displacement is only guaranteed in whole home installations; in partial conversions, where the existing heating system continues to serve part of the load, results will depend heavily on customer behavior.
  • How much does your heat pump cost to install? Installation costs have risen substantially above projected levels due in part to high incentives. Installation costs vary widely across homes. Each consumer will need to solicit several bids and get a feel for how installers view their particular situation.  Each installer will bring a different perspective to the possibilities for your home.
  • What is the condition of the systems that the heat pump is replacing? If your heating system is aging, then it’s reasonable to factor in a percentage of replacement costs as a partial offset to your initial investment.

In addition to these fundamental heating system factors, one may consider possible costs or savings associated with replacements or expansions of air conditioning.

Policy Implications

This post is not intended as a comment on public policy. This post is intended to help individuals think about their next steps with heat pumps. While some of the analytic points made in this post are relevant to heat pump policy, there are many other considerations which have to be part of any discussion of heat pump policy. In particular, even if heat pump prices have risen and some heat pump measures have a very high cost-per-ton of carbon saved, continued heavy incentives may be fully justified by the need to provide clear and steady support for small businesses and individuals who are seeking to become heat pump suppliers or installers.

Please comment!

I hope people will make this post more useful by sharing their own experiences and perspectives below.

Return to heat pump document list

Published by Will Brownsberger

Will Brownsberger is State Senator from the Second Suffolk and Middlesex District.

19 replies on “Heat pump decisions”

  1. I wish our politicians, who are at the helm of helping us achieve no roaming blackouts, would concentrate on the big picture,”our horrendous electrical infrastructure”.
    We need a large effort put into this issue.
    I am aware you have installed (personally) in your own home, heat pumps.While that is good,the power for that unit, is the big issue.
    Please,please put your efforts into our power plant issues and insure ,we will not have roaming blackouts in our future.
    That is the bigger picture and one only our elected officials can help control.
    Thank you

    1. It’s all about government compulsion, Randy.
      You must not question the good that the Green Groupies are doing you.
      When are you buying your EV car and how much will it cost you?

      1. Compulsion it is not just the Green Kool-Aid drinkers. Watertown banning natural gas for new construction? Senate just voted to include couples filing jointly to be subjected to the additional 4% “Millionaire” Tax? (And, yes, Brownsberger voted for it).. Extremely draconian changes for gun laws in the works? Once enough is enough, my tax dollars are going elsewhere, so I will not contribute to this non-sense anymore. In the meantime, I am enjoying my 5.5 Liter,V8 MB enormously.. 0 to 60 in 3.9 secs is fun.

      2. Hi Dee,
        The current fully burdened rate for electricity in Watertown is around .28cents a KWH.Rather high and will come down a bit for next 6 Months and probably go higher than .28 cents when cold weather returns.
        That hopefully answers your question as to when I will buy an electric car!!
        With the looming (soon to come) roaming blackouts we should all expect,that also helps answer your question.
        I want our elected officials to work on these issues.This is a regulated industry, and we should empower ourselves to remember, we ordinary citizens can only try to influence our politicians to “do their jobs”.
        I am all for reducing our footprint,but my foot is not anywhere the size of this issue.
        While I appreciate Will trying to help himself (in his own home), I do not want to provide shelter for him,when he has no power to hear his home.
        I got my $50.00 rebate for putting in a high efficiency appliance and now they want me to plug in my electric car!!
        Am I missing something?
        Let’s get our electric industry solidified first.Then we can think about the new methodologies to power our homes, cars, businesses,etc.
        You with me? Thanks in advance.

      3. Out of curiosity I got a quote for replacing an ailing AC with a heat pump. Mind you the area is fully ducted and roughly 700sf more or less. $23k and it would have to be completely discarded when the new coolant becomes mandated.

        There is no escape. Cult tyranny is coming right inside your home. The plan is to strip you of all power, bankrupt you, transfer all your wealth upward and then sign you up for a MAID program like Canada’s

  2. I am told that some electrical bills remain largely the same even as more efficient devices such as LED lights are being used.

    The reason, I am told, is that in order to earn the same level of profits electricity providers must raise their rates.

    I would also like to know from the Green groupies where all this new electricity generating power is coming from. Fossil fuels? Will we have the capacity?

    There is also something wrong with the following picture:
    .You must soon buy an electric car … by LAW in certain states. Cost no object. Poor? Tough luck.
    .You must convert your house’s utilities systems.
    .You must get rid of your gas stove.
    .If you build a new home, it must have certain utility features by law.
    .If you retrofit your house in certain ways, these must be “green” ways.
    .Cost does not matter in the final analysis. You must do it, or else.
    .No wood allowed in new houses as the forests become depleted?
    .You and your child must get Covid vaccinations … or else, despite the questions surrounding their safety. We’re pro-choice but not in that way.
    -Your child during the Pandemic (in Massachusetts) must have gotten a flu (yes, FLU) vaccine to attend school. This was an order, not a law. Do it or suffer the consequences. We’re pro-choice and all for freedom but not in that way.
    .To continue to attend certain colleges you must have gotten a Covid vaccination. Or get out.
    Do you alleged freedom lovers see a common thread in the above, namely government compulsion?

    1. Well said Dee. This is a fanatical religion. They are brainwashed. Unfortunately, we’ll all pay the price for this delusional thinking. The people who create the coming disaster, with these policies, will never face what they’ve done. They will just move up the establishment ladder and graduate to the next WEF agenda item.

      1. “The people who create the coming disaster, with these policies, will never face what they’ve done.”
        The same can be said about policies propping up the fossil fuel industry.

  3. Thank you! As always, thank you for being a rational, down-to-earth, and trustworthy voice on this topic.

    As you’ve pointed out here, folks may realize the most energy cost savings during the conversion from oil or gas to ASHPs during the air sealing and insulation part of the overall project.
    Conservation of energy is key!

  4. Will,

    I don’t see the disadvantages listed here. I have been told there are several.

  5. Will,
    Thanks for this great summary. I would love to find a companion summary in one place of the federal, state and town rebates/tax credits. I find the patchwork confusing especially if you have an oil system and live in Belmont – so no MassSave program applies. It is very challenging to confirm that the heat pump you choose will be eligible since the lists seem to be a work in progress.

  6. As Will has repeatedly mentioned, heat pump conversions are a complicated issue, with no single solution. Therefore, the most important thing you can do is use a qualified, experienced, educated installer who will recommend a specific system for your home. As Will also mentioned, various installers may recommend different approaches, so get several quotes and ask a lot of questions.

    In all new construction, heat pumps are a no-brainer. There are also hydronic (air-to-water) systems which allow radiators (ultra thin walled, light-weight) or radiant (in the floors or ceilings) heating to be implemented. However, air-to-air heat pumps also give you air conditioning.

    If you have existing ductwork, from either a forced hot air system or central A/C, then a ducted system is usually the way to go. It will result in better air distribution at the expense of efficiency (ductwork is somewhat lossy) and possibly noise (depending on the location of the air handler).

    Otherwise a ductless system (mini-splits) is better. There are options for units installed on walls, floors, or ceilings. Be aware that there will not be a unit in every room, so in older homes there may be remote locations which will be tricky to heat or cool. Older homes typically have many smaller rooms, making air distribution more difficult, though that can be overcome by turning up the fan speed.

    Our whole-house cold-climate air source heat pump (mini-split) system has served us well over the past 4 years, though there was a learning process which I am willing to share with others. This past winter when it went well below zero we did fire up our natural gas boiler (for a few hours), but that was a rare situation. There is no ‘integrated control’ to do a switchover at a particular temperature, and I believe that is unnecessary. Some people deliberately go for heat pumps unrated for cold weather, using them primarily for cooling and some shoulder season heating. But the goal should be to go all the way to a whole-house cold-climate system, perhaps keeping an old system in place for backup in extreme weather.

    By the way, we still have a 100A electric panel and it is sufficient for the heat pump. No upgrade was required.

    Thank you, Will, for sharing your thoughts and presenting a comprehensive, well researched review.

    Darrell King

  7. Will, thank you for this careful analysis, as well as you previous emails and surveys on this topic. Heat pumps are a wonderful technology, but as you point out, they are not without their downsides. I’ve been sharing your mailings about them with families and friends in other jurisdictions.
    Excellent work–very much appreciated.

  8. I have concern about the electric power generation industrial complex hijacking the climate movement in an unholy alliance. The utilities are usually have 2 services, Gas and Electricity. They started loosing business to behind the meter rooftop solar from the retail customer. The gas business will be going away, so by pushing heat pumps they can at least gain back the electric customer. I was considering heat pumps but did the math. The payback time is more than my remaining statistical biological lifetime. I am on an unstable income that cannot be predicted so if I have a good year putting me even one dollar over the limit, I would loose big time with the current methods of financing/rebates/credits. for something that will save me nothing out of cash flow. If not, the long terms returns are minimal/non existent. Unlike solar that took me 11 years to payback it was predictable. In order to get the non-refundable tax credits, I did a Roth conversion of my IRA to create taxable income to claim the remaining tax credit against in my lower earning years, so at least I have the Roth returns that are not taxable, lower medicare insurance rates in addition to 11 years of “no payment due” electric bills. Even though oil may be slightly more expensive fuel source, I am able to ” weather the weather” during storm /power outage conditions with a simple generator system to backup the furnace. I am hard pressed to not think about how expensive electricity will become paying for all this e-infrastructure through customer charges. If I could afford an electric car, I would get a plug hybrid, but that is a pipe dream.
    However if there is some incentives I would install a wood stove. That does depend on the utility system to work.

  9. Thank you for your thoughtful and balanced overview here as well as your more in depth coverage! I wish I found your blog sooner before we signed on the dotted line for a whole home heat pump, but this helped educate me around what to expect when our install date arrives, and after the install.

    We are excited to get a full house cold weather Daikin heat pump installed in our 2nd floor condo (we live in half of a 1900s era two family). We’re actually going with a combined ducted/ductless system with a ductless mini split in the room where we see the most extreme temperatures due to it’s placement in the condo, and ducted units throughout the rest of the condo; all running off of the same outdoor unit. We are lucky to have an unfinished attic that makes install the ductwork between the ceiling joists easy. The main reason we are going with the ducted system is for the enhanced air filtration as I suffer from fairly bad seasonal allergies, which I wouldn’t have thought about unless we talked with the final of the three contractors we got quotes from. Plus we find the vents in the ceiling be a bit more aesthetically pleasing than the mini-split units. Either way, we are excited to get off of our old gas-fired steam boiler, which aside from being environmentally dubious, is on its last legs.

    The MassSave program makes the install of the heat pump as a replacement for our boiler a no brainer. Between the free insulation (we qualified for 100% off as a multi-unit building, but if we didn’t, it still would be really affordable), $10,000 rebate, and financing for 7 years at 0% APR, the cost ends up being quite reasonable. Plus we get central AC, which is a luxury we’ve wanted since we bought the condo and one that will increase the value of the unit. We also avoid dumping additional cash into a 20th century system that becomes more expensive to maintain each year (plus the tradespeople who know how to maintain are becoming rarer), while reducing our carbon footprint. The only issue we have right now is that there is such a demand for the things, we have to wait until September for the install even though we signed in April!

  10. With roughly 1.3% of U.S. emissions, Massachusetts does not affect world temperatures by a measurable amount. Nevertheless, Massachusetts energy officials “believe the state is in a position to show the way to a clean energy economy.” In other words, the Massachusetts plan is a quixotic, expensive, political show tailor made for and by politicians, bureaucrats, corporate interests, and Statehouse insiders. Significant alterations of buildings and equipment will be required to use heat pumps. Our 20 unit 10 floor condominium installed rooftop heat pumps for air conditioning. Design and approval of the project took several years and obtaining the necessary electrical capacity took another 1.5 years. The installation of the equipment was expensive and required extensive construction in common areas and individual living units.Will, you should be spending time on constructive activities, such as eliminating cost barriers and regulations, and beating back the radical leftist goal of zero fossil fuels. The current Mass policy will create unreliable electricity with increasing electrical outages.

  11. I think you hit the nail on the head on why heat pump conversion uptake is going to be a very long slow grind. If you can’t show the consumer that converting from conventional heating to a heat pump is going to be less expensive to purchase, cheaper to operate, and will provide at least a similar level of comfort, then consumers will continue to be wary of adoption. As it stands none of these things ring true in regard to heat pumps.

    One note on your comment regarding a hybrid application – where some rooms are heated with a pump and the remaining areas are turned down low – is fraught with peril. In a home with forced hot water baseboard, if circulation is curtailed by the use of a heat pump then you are just asking for split pipes in the non-heated areas. Spending thousands on pipe repairs and water damage remediation is not an incentive to make a switch.

    While most everyone cares about the environment, they also care about their personal finances. Given those constraints, the State’s obsession with electrifying everything is doing a disservice towards lowering GHG emissions. Avoiding solar (only a paltry $1000 credit), ignoring biofuels, and not providing better subsidies for weatherization simply means we stay at status quo. The aforementioned offer immediate benefits, while employing a sole solution via heat pumps means we are getting nowhere fast. In the quest for perfection (and heat pumps are far from perfect as you know) the state is shooting itself in the foot.

    One final note. Heat pumps, while reliable, do not have the longevity or serviceability of conventional systems. Last summer my company waited 9 weeks for a circuit board for a Haier heat pump. The business went without cooling for this period – can you imagine if it was the middle of winter? Even if we could have obtained the part, who’s going to work out in the cold, dark, or wet trying to replace a component part that is crammed into an impossibly small enclosure? Good luck with that as the first generation of pumps start to need repairs.

  12. See excerpts from an article from energy analyst John Kemp below. So long as this continues to happen in China, as well as with India, who have a combined population 2.82 billion (more than a third of the world total) then whatever we might do in Massachusetts (population 6.9million) won’t amount to much. What it will cause is undue economic stress for those families who are not affluent and can ill afford expensive to install and operate heat pumps.
    Your analysis has shown that heat pumps aren’t really the answer – so why is the State continuing to go full blast into electrification?

    Some of the deficit caused by hydro generation was covered by increased generation from wind farms (+82 billion kWh) and solar power (+25 billion kWh).

    But the rest of the deficit and all the consumption growth was covered by a massive increase in thermal generation (+218 billion kWh) mostly from coal-fired units.

    Thermal generation increased by +8% compared with the same period in 2022 and accounted for 71% of all electrical output, up from 69% in the previous year.

    China’s coal fleet kept the lights on, air conditioning working and industry operating in the drought-stricken south and more recently in the north in an unprecedented heat wave.

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