What is the Mass Save Heat Pump Rate?

The Mass Save Heat Pump Rate is an opt-in time-of-use residential electricity rate offered by Eversource MA and National Grid MA to households with a verified, installed heat pump. Off-peak kWh (overnight and early morning, plus weekends on most schedules) is priced materially below the standard R-1 rate — roughly $0.22–$0.23 per kWh blended versus $0.30–$0.32 on standard — in exchange for a higher on-peak charge during weekday afternoons and evenings. Because heat pumps run longest in the cold, off-peak overnight hours, the blended rate a typical MA heat pump household pays drops about 25–28% versus standard.

How do I enroll in the Heat Pump Rate?

Enrollment is handled by your electric utility, not by Mass Save itself. For Eversource MA, search 'Eversource Massachusetts Optional Residential Heat Pump Rate' on the utility's site or call Eversource customer service and ask to be moved onto the heat pump rate. For National Grid MA, the same — search 'National Grid Massachusetts Heat Pump Rate' or call customer service. You'll be asked to confirm the heat pump install (your Mass Save HPIN installer can supply the paperwork). Wait until the heat pump is fully commissioned and operational before enrolling so the rate change lines up with your new load shape.

Will I save money on the Heat Pump Rate?

For a household where the heat pump is the primary heat source, almost always yes. A typical 2000 sqft MA single-family on Eversource saves roughly $1,000 per year on heating-season electricity by switching off the standard rate onto the HP rate, because the heat pump's 24/7 runtime is dominated by overnight off-peak hours. For households that only added a heat pump as supplemental cooling (or for a small zone) and still heat with gas or oil, the savings are much smaller and the on-peak premium on other appliances can wipe them out — run the math before enrolling.

What if I keep my furnace or boiler as backup?

The Heat Pump Rate still makes sense if the heat pump carries the bulk of the heating load and the furnace or boiler only fires in deep cold (below the heat pump's economic balance point, typically 5–15°F). That use pattern still concentrates heat pump runtime overnight in shoulder seasons where TOU pricing favors you. If the furnace or boiler is doing 50%+ of the heating work (a true dual-fuel split), the HP rate likely costs you more than it saves, because your other electric appliances will be the dominant load and they don't run off-peak.

How does the Heat Pump Rate affect my other appliances?

Every kWh you consume during the on-peak window (typically weekday afternoons and evenings on both Eversource and National Grid schedules) is billed at a higher rate than standard. That means clothes dryers, ovens, dishwashers, and EV charging during on-peak hours all cost more on the HP rate than on standard R-1. Many households shift dishwasher and dryer runs to evenings after the peak window ends, and most EV owners on the HP rate schedule charging overnight — at which point the EV ends up cheaper to charge on the HP rate than on standard, often by a wide margin.

Can I opt out of the Heat Pump Rate later?

Yes. Both Eversource MA and National Grid MA allow customers to switch back to the standard R-1 rate by calling customer service, though some utilities impose a minimum 12-month enrollment before opt-out to prevent gaming the rate seasonally. There is no penalty for switching back, just a return to standard pricing on the next billing cycle. If your heating pattern changes (you move, you add a gas furnace, you sell the heat pump), opting back out is the right call.

Is the Heat Pump Rate available everywhere in Massachusetts?

No. Eversource MA and National Grid MA — the two largest investor-owned utilities — publish heat-pump-specific TOU rates. Unitil and Cape Light Compact do not currently publish a dedicated HP rate, though both offer general TOU rate options that can yield smaller (10–15%) savings on a heat pump load shape. Municipal Light Plant (MLP) customers (towns like Reading, Belmont, Concord, Wakefield) are not on Mass Save and their TOU options vary by municipality — check with your specific MLP.

Mass Save Heat Pump Rate: The Opt-in TOU Rate That Makes MA Heat Pumps Cheaper to Run

By MassHVAC Editorial Team Reviewed by MassHVAC Editorial Team Last updated 2026-05-27

What the Heat Pump Rate actually is

The Mass Save Heat Pump Rate — formally the Optional Residential Heat Pump Rate on Eversource MA and the Optional Residential Heat Pump Rate on National Grid MA — is a time-of-use (TOU) electric tariff that replaces the household's standard R-1 schedule. It is opt-in (you choose it; the utility does not switch you automatically) and is open only to customers with a verified, installed heat pump on premises.

The mechanics are simple: the day is split into off-peak and on-peak windows. Off-peak hours — approximately weekday overnight and early morning (roughly 9 PM to 9 AM), plus most weekend hours — are priced materially below standard R-1. On-peak hours — approximately weekday late morning through evening (roughly 9 AM to 9 PM) — are priced higher than standard to balance the discount. Exact hour boundaries vary slightly by utility and are subject to change; verify the current schedule on your sponsor's tariff page before enrolling.

The economic logic that makes this work for heat pump households: a properly-sized cold-climate heat pump runs almost continuously during the coldest hours of the day, which in MA winter is overnight and pre-dawn — exactly the off-peak window. Across a full heating season, the majority of a heat pump's kWh consumption lands in off-peak hours, so the blended rate the household actually pays is well below the standard R-1 rate. That is the entire point of the program.

Rate comparison by Mass Save sponsor (2026-Q1)

Standard R-1 vs the opt-in Heat Pump Rate, all-in (supply + delivery), per kWh:

Sponsor	Standard R-1	Heat Pump Rate	Discount	Source / notes
Eversource	$0.32/kWh	$0.23/kWh	~28%	Published HP-specific rate
National Grid	$0.30/kWh	$0.22/kWh	~27%	Published HP-specific rate
Unitil	$0.31/kWh	$0.27/kWh	~13%	No published HP-specific rate; modeled
Cape Light Compact	$0.28/kWh	$0.25/kWh	~11%	No published HP-specific rate; modeled
MLP	$0.18/kWh	$0.16/kWh	~11%	Per-MLP variation; modeled

Rates verified 2026-05-27 against each sponsor's 2026-Q1 tariff filing. Eversource MA and National Grid MA publish dedicated heat pump rates; Unitil, Cape Light Compact, and MLPs do not currently publish HP-specific schedules — the values shown for those sponsors are modeled discounts on the standard rate and should be treated as approximate.

When the Heat Pump Rate makes sense

The opt-in is not automatically a win — it depends on what your heat pump is actually doing in the home:

Heat pump as primary heat (whole-home install): Yes, enroll. The heat pump's runtime concentrates overnight in MA winters, dominating your kWh load shape. Even the on-peak premium on your other appliances gets dwarfed by the heating-season discount.
Heat pump primary, furnace or boiler as deep-cold backup: Yes, generally enroll. If the heat pump still carries 70%+ of the annual heating load with the fossil backup only firing below the economic balance point (typically 5–15°F outdoor), the math still favors enrollment.
True dual-fuel split (50/50 heat pump and furnace/boiler): Carefully evaluate. The heating-season kWh isn't large enough to overcome the on-peak premium on the rest of the household's electric load. Pull a month of hourly usage data and model it before opting in.
Heat pump for cooling only, gas or oil heat: No. The summer cooling load is small relative to year-round on-peak appliance use. The on-peak premium hits your dryer, dishwasher, oven, and lighting and you don't get a heating-season discount to offset it.
EV charger plus heat pump household: Strong yes. Both load shapes love overnight off-peak hours. EV charging from 11 PM to 6 AM at the HP-rate off-peak price is one of the cheapest miles-per-dollar setups available to a Massachusetts household.

How to enroll

Wait until the heat pump is commissioned. Enrolling before the system is actually running just exposes you to the on-peak premium with no heating-season offset. Time the rate change to align with the first full billing cycle after commissioning.
Have your installer paperwork ready. Your Mass Save HPIN installer's invoice — showing the heat pump make, model, and install date — is the documentation utilities ask for to verify heat pump status.
Contact your utility directly. For Eversource MA, search "Eversource Massachusetts Heat Pump Rate" on the utility's site, or call Eversource residential customer service and ask for the Optional Residential Heat Pump Rate. For National Grid MA, search "National Grid Massachusetts Heat Pump Rate" or call National Grid residential customer service. Enrollment is processed at the utility, not through Mass Save.
Confirm the rate change on your next bill. The line-item supply and delivery charges should show the HP rate schedule. If they don't, call back; mid-cycle enrollments occasionally process late.

Real-world math: a 2000 sqft Massachusetts home, oil → heat pump

To make the rate-impact concrete, run the same household through both rate schedules. Assumptions:

2000 sqft single-family, IECC 5A (Greater Boston), average insulation
Annual heating load: 100 MMBtu/yr (100,000 kBtu)
Cold-climate heat pump on the Mass Save HPQPL, seasonal COP 2.6
Eversource MA service territory — standard R-1 at $0.32/kWh, HP rate at $0.23/kWh
Baseline being displaced: oil boiler at 83% AFUE, oil at $3.80/gal

The arithmetic:

Heat pump kWh: 100,000,000 BTU ÷ 3,412 BTU/kWh ÷ COP 2.6 = ~11,272 kWh/yr
HP cost on standard R-1: 11,272 kWh × $0.32 = $3,607/yr
HP cost on Heat Pump Rate: 11,272 kWh × $0.23 = $2,593/yr
HP Rate savings vs standard: $1,014/yr (~28% off the heating bill, just from the rate change)
Oil baseline: 870 gallons × $3.80 = $3,306/yr

Now the swing the rate creates:

Heat pump on standard R-1 vs oil: $3,607 vs $3,306 = $301/yr more expensive than oil. On paper, the conversion looks like a wash or a small loss on operating cost alone.
Heat pump on Heat Pump Rate vs oil: $2,593 vs $3,306 = $713/yr cheaper than oil. Same equipment, same home, same heating load — the rate enrollment is the only variable, and it flips the case from "comparable" to "meaningfully cheaper."

The Heat Pump Rate is the swing factor that decides whether an oil-conversion case pencils on operating cost. Competitor sites quoting "you'll save thousands switching from oil to a heat pump" without naming the rate are quietly assuming the household will enroll — but most homeowners never get told the rate exists, which is why so many MA heat pump conversions underperform their projected savings in the first year.

Run the same math on your home with the operating-cost calculator (which models both rate schedules side-by-side), or get the installed-cost-after-rebate picture from the cost & rebate calculator.

What is not cheaper on the Heat Pump Rate

Every kWh you consume during on-peak hours is billed at a higher rate than the standard R-1 schedule. The rate is engineered to net out favorably for heat pump loads; it can quietly cost you on the rest of your electric usage if you don't shift behavior at all. Things to think about:

Clothes dryers, ovens, dishwashers running during weekday afternoons and evenings cost more than they did before. Most households shift dishwasher start time to after 9 PM and run laundry on weekends; that alone usually preserves the heat-pump-side savings.
EV charging during on-peak windows is materially more expensive. Schedule your charger for overnight (most chargers and EVs support a delayed-start function) and you flip from a cost to a savings — overnight charging on the HP rate is often the cheapest electrons available in MA.
Pool pumps, electric water heaters on resistance mode, EV chargers without scheduling can all silently erode the rate's benefit. If you have a load like that, model it before enrolling.
Daytime work-from-home households see less benefit than overnight-occupancy households, because more of the on-peak window has lights, computers, and HVAC running.

The honest framing: the rate is a substantial win for whole-home heat pump households who can move 1–2 controllable loads out of peak hours; it is closer to break-even for households that can't or won't shift behavior; and it's a loss for households whose heat pump is a small share of their electric usage.

How to verify your rate enrollment is working

Once enrolled, the line-item rates on your monthly bill should reflect the HP rate schedule. Specifically:

The supply line should show a TOU breakdown (kWh and rate, separated into off-peak and on-peak), not a single flat rate.
The delivery line should show the same TOU structure if your sponsor's HP rate covers both supply and delivery (Eversource and National Grid's published HP rates do).
Your blended rate for the month — total bill ÷ total kWh — should drop versus your standard-rate baseline once heating-season runtime is in play. If you enrolled in October expecting a January savings, you may see the bill go up in October and November before the heating-season runtime kicks in. That's normal; judge the rate over a full heating season, not a single bill.

If your bill doesn't show the TOU breakdown after one full billing cycle, call the utility back — mid-cycle enrollments occasionally process late or process incorrectly.

Bottom line

For Massachusetts homeowners installing a whole-home cold-climate heat pump on Eversource MA or National Grid MA service, the opt-in Heat Pump Rate is the single highest-leverage post-install decision available — typically worth $700–$1,200/yr versus staying on standard R-1, with no upfront cost and no commitment beyond a short minimum enrollment period. It is the difference, in many cases, between an oil-to-heat-pump conversion that pencils as "about the same to run" and one that pencils as "meaningfully cheaper." Enroll after commissioning, shift one or two controllable loads off peak, and let the heating-season math do the rest. If you're not sure your specific household profile wins, model both schedules in the operating-cost calculator before the call to the utility.

Mass Save Heat Pump Rate FAQ

What is the Mass Save Heat Pump Rate?: The Mass Save Heat Pump Rate is an opt-in time-of-use residential electricity rate offered by Eversource MA and National Grid MA to households with a verified, installed heat pump. Off-peak kWh (overnight and early morning, plus weekends on most schedules) is priced materially below the standard R-1 rate — roughly $0.22–$0.23 per kWh blended versus $0.30–$0.32 on standard — in exchange for a higher on-peak charge during weekday afternoons and evenings. Because heat pumps run longest in the cold, off-peak overnight hours, the blended rate a typical MA heat pump household pays drops about 25–28% versus standard.
How do I enroll in the Heat Pump Rate?: Enrollment is handled by your electric utility, not by Mass Save itself. For Eversource MA, search 'Eversource Massachusetts Optional Residential Heat Pump Rate' on the utility's site or call Eversource customer service and ask to be moved onto the heat pump rate. For National Grid MA, the same — search 'National Grid Massachusetts Heat Pump Rate' or call customer service. You'll be asked to confirm the heat pump install (your Mass Save HPIN installer can supply the paperwork). Wait until the heat pump is fully commissioned and operational before enrolling so the rate change lines up with your new load shape.
Will I save money on the Heat Pump Rate?: For a household where the heat pump is the primary heat source, almost always yes. A typical 2000 sqft MA single-family on Eversource saves roughly $1,000 per year on heating-season electricity by switching off the standard rate onto the HP rate, because the heat pump's 24/7 runtime is dominated by overnight off-peak hours. For households that only added a heat pump as supplemental cooling (or for a small zone) and still heat with gas or oil, the savings are much smaller and the on-peak premium on other appliances can wipe them out — run the math before enrolling.
What if I keep my furnace or boiler as backup?: The Heat Pump Rate still makes sense if the heat pump carries the bulk of the heating load and the furnace or boiler only fires in deep cold (below the heat pump's economic balance point, typically 5–15°F). That use pattern still concentrates heat pump runtime overnight in shoulder seasons where TOU pricing favors you. If the furnace or boiler is doing 50%+ of the heating work (a true dual-fuel split), the HP rate likely costs you more than it saves, because your other electric appliances will be the dominant load and they don't run off-peak.
How does the Heat Pump Rate affect my other appliances?: Every kWh you consume during the on-peak window (typically weekday afternoons and evenings on both Eversource and National Grid schedules) is billed at a higher rate than standard. That means clothes dryers, ovens, dishwashers, and EV charging during on-peak hours all cost more on the HP rate than on standard R-1. Many households shift dishwasher and dryer runs to evenings after the peak window ends, and most EV owners on the HP rate schedule charging overnight — at which point the EV ends up cheaper to charge on the HP rate than on standard, often by a wide margin.
Can I opt out of the Heat Pump Rate later?: Yes. Both Eversource MA and National Grid MA allow customers to switch back to the standard R-1 rate by calling customer service, though some utilities impose a minimum 12-month enrollment before opt-out to prevent gaming the rate seasonally. There is no penalty for switching back, just a return to standard pricing on the next billing cycle. If your heating pattern changes (you move, you add a gas furnace, you sell the heat pump), opting back out is the right call.
Is the Heat Pump Rate available everywhere in Massachusetts?: No. Eversource MA and National Grid MA — the two largest investor-owned utilities — publish heat-pump-specific TOU rates. Unitil and Cape Light Compact do not currently publish a dedicated HP rate, though both offer general TOU rate options that can yield smaller (10–15%) savings on a heat pump load shape. Municipal Light Plant (MLP) customers (towns like Reading, Belmont, Concord, Wakefield) are not on Mass Save and their TOU options vary by municipality — check with your specific MLP.

Related Massachusetts heat pump guides

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