What is the Mass Save HEAT Loan interest rate?

0% APR. The rate is fixed at zero for the full term of the loan — there is no introductory period, no reset, and no rate hike if you miss a payment. Participating Massachusetts banks underwrite the loan and Mass Save buys down the interest.

How much can I borrow with the HEAT Loan?

Up to $25,000 per project. The cap covers equipment plus install for qualifying upgrades — heat pumps, ductless mini-splits, insulation, water heaters, and similar high-efficiency improvements. Multiple loans across separate projects are possible but each is capped at $25,000.

How long is the HEAT Loan term?

The term is tiered by State Median Income (SMI) as of January 1, 2025: 84 months (7 years) for households below 135% SMI, 60 months (5 years) for 135–300% SMI, and 36 months (3 years) above 300% SMI. The shorter terms for higher-income households reflect a budget allocation that prioritizes longer no-interest financing for lower-income borrowers.

What credit score do I need for the HEAT Loan?

Each participating bank sets its own underwriting criteria, but most look for a FICO score of 660 or higher and a debt-to-income ratio under approximately 45%. Mass Save does not impose a credit-score floor; the bank does. If your credit is borderline, ask the bank for the specific decline reason before re-applying elsewhere.

Can I use the HEAT Loan with the Mass Save heat pump rebate?

Yes — and you should. The standard workflow is: get the rebate paperwork from your Mass Save HPIN installer, deduct the rebate from the project cost, and finance the remainder via the HEAT Loan. A $24,000 install with an $8,500 rebate becomes a $15,500 HEAT Loan, which at 0% APR over 84 months is roughly $185/month.

I live in an MLP town. Can I still get the HEAT Loan?

No. The HEAT Loan is for customers of Mass Save sponsor utilities only. Massachusetts MLP residents (Belmont, Braintree, Reading, Wakefield, Concord, Hingham, Holyoke, and roughly 35 others) instead have access to the Massachusetts MLP Zero-Interest Energy Efficiency Loan — same 0% APR, same $25,000 cap, but administered through your MLP rather than Mass Save.

Are there income limits for the HEAT Loan?

No upper income limit applies — anyone in a Mass Save sponsor utility territory can apply, subject to bank underwriting. Households below approximately 81% SMI typically route into Mass Save's no-cost / enhanced-rebate programs rather than the HEAT Loan, because those programs are usually a better deal at that income level than financing the remainder.

The Mass Save HEAT Loan: 0% APR Financing for Massachusetts Heat Pumps

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

The headline numbers

Three numbers are worth memorizing if you're financing a Massachusetts heat pump install in 2026:

0% APR — fixed for the entire term. Not introductory. Not promotional.
Up to $25,000 per qualifying project.
84, 60, or 36 months depending on your State Median Income tier.

SMI tier table (effective January 2025)

SMI band	Term	Monthly payment on $20,000 loan
Below 135% of State Median Income	7 years (84 months)	~$238/mo
135%–300% of State Median Income	5 years (60 months)	~$333/mo
Over 300% of State Median Income	3 years (36 months)	~$556/mo

State Median Income for Massachusetts in 2026 is approximately $121,000 for a four-person household. 135% SMI is approximately $163,000 for the same household size — the threshold where the 84-month term ends and the 60-month term begins. Mass Save publishes the current SMI thresholds by household size.

What the HEAT Loan can pay for

Air-source heat pumps (cold-climate, on the HPQPL).
Ductless mini-split heat pumps (also HPQPL).
Ground-source (geothermal) heat pumps.
Heat pump water heaters.
Air sealing and insulation (often paired with heat pump installs).
Solar hot water systems (still eligible despite the federal §25D credit expiration).
Some triple-pane window replacements.

It cannot pay for: maintenance and repair work, non-qualifying equipment, projects that won't pass a Mass Save Home Energy Assessment, or anything installed by a non-HPIN contractor (in the case of heat pumps).

How to apply

Get a Mass Save Home Energy Assessment. Free, on-site, 60–90 minutes. The energy auditor will determine which upgrades qualify and prepare the rebate documentation.
Get a written quote from a Mass Save HPIN installer. For heat pumps, the quote must come from an HPIN-enrolled contractor.
Mass Save sends you the HEAT Loan paperwork. They identify which participating banks can underwrite your loan based on your address.
Apply at the participating bank. Standard credit and income underwriting; the bank pulls credit, evaluates DTI, and approves or denies.
The bank funds the install. Funds go directly to the installer; you make monthly payments at 0% APR for the term length matching your SMI tier.

For MLP residents: the parallel zero-interest loan

Customers of Massachusetts Municipal Light Plants — Belmont, Braintree, Reading, Wakefield, Concord, Hingham, Holyoke, Mansfield, Marblehead, Norwood, Peabody, Shrewsbury, Taunton, Wellesley, Westfield, and roughly 25 others — cannot use the Mass Save HEAT Loan because their utility is not a Mass Save sponsor. The Commonwealth instead operates the Massachusetts MLP Zero-Interest Energy Efficiency Loan: also 0% APR, also up to $25,000, for the same kinds of qualifying upgrades. Apply through your local MLP rather than Mass Save. Mass.gov reference.

Why 0% APR matters more than usual

Heat pump installs in Massachusetts in 2026 commonly net $10,000–$18,000 after rebates. Financing that at 0% APR for 84 months versus a 7.99% home-improvement loan at the same term is a difference of roughly $3,200–$5,800 in interest over the life of the loan. The HEAT Loan is one of the rare cases where the financing instrument is itself a substantial subsidy.

HEAT Loan FAQ

What is the Mass Save HEAT Loan interest rate?: 0% APR. The rate is fixed at zero for the full term of the loan — there is no introductory period, no reset, and no rate hike if you miss a payment. Participating Massachusetts banks underwrite the loan and Mass Save buys down the interest.
How much can I borrow with the HEAT Loan?: Up to $25,000 per project. The cap covers equipment plus install for qualifying upgrades — heat pumps, ductless mini-splits, insulation, water heaters, and similar high-efficiency improvements. Multiple loans across separate projects are possible but each is capped at $25,000.
How long is the HEAT Loan term?: The term is tiered by State Median Income (SMI) as of January 1, 2025: 84 months (7 years) for households below 135% SMI, 60 months (5 years) for 135–300% SMI, and 36 months (3 years) above 300% SMI. The shorter terms for higher-income households reflect a budget allocation that prioritizes longer no-interest financing for lower-income borrowers.
What credit score do I need for the HEAT Loan?: Each participating bank sets its own underwriting criteria, but most look for a FICO score of 660 or higher and a debt-to-income ratio under approximately 45%. Mass Save does not impose a credit-score floor; the bank does. If your credit is borderline, ask the bank for the specific decline reason before re-applying elsewhere.
Can I use the HEAT Loan with the Mass Save heat pump rebate?: Yes — and you should. The standard workflow is: get the rebate paperwork from your Mass Save HPIN installer, deduct the rebate from the project cost, and finance the remainder via the HEAT Loan. A $24,000 install with an $8,500 rebate becomes a $15,500 HEAT Loan, which at 0% APR over 84 months is roughly $185/month.
I live in an MLP town. Can I still get the HEAT Loan?: No. The HEAT Loan is for customers of Mass Save sponsor utilities only. Massachusetts MLP residents (Belmont, Braintree, Reading, Wakefield, Concord, Hingham, Holyoke, and roughly 35 others) instead have access to the Massachusetts MLP Zero-Interest Energy Efficiency Loan — same 0% APR, same $25,000 cap, but administered through your MLP rather than Mass Save.
Are there income limits for the HEAT Loan?: No upper income limit applies — anyone in a Mass Save sponsor utility territory can apply, subject to bank underwriting. Households below approximately 81% SMI typically route into Mass Save's no-cost / enhanced-rebate programs rather than the HEAT Loan, because those programs are usually a better deal at that income level than financing the remainder.

Related guides

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