Does each unit in a multifamily building get its own Mass Save rebate?

Generally yes. Mass Save treats each of the (up to four) dwelling units in a small multifamily as its own whole-home project, so each unit converted to a heat pump as its sole heating source can qualify for its own rebate of up to $8,500. A two-family can reach up to $17,000, a three-decker up to $25,500, and a four-unit up to $34,000 in combined rebates across the building.

Should I heat the whole building with one system or one per unit?

One system per unit, in almost every case. Separate per-unit systems respect the individual electric metering (each tenant pays to run their own), let each unit file its own rebate, and mean a problem in one unit never takes down heat for the others. A single shared system muddies who pays to run it and caps you at one rebate. The standard MA multifamily design is one outdoor condenser per unit feeding 2–4 indoor heads sized to that unit's Manual J.

How does metering affect the rebate on a multifamily?

The Mass Save rebate for each unit follows that unit's electric account of record. In individually-metered buildings (the norm for MA triple-deckers and most 2–4 families), each unit files through its own account, which is clean. In master-metered buildings, the whole building is one account — talk to your installer and sponsor early, because it changes how the units are treated for rebate purposes.

How do heat pump rebates work for a condominium?

For an individually-owned, separately-metered condo unit, the owner typically pursues the rebate for their own unit as a whole-home project (up to $8,500), the same as a single-family. The wrinkle is condo governance: exterior condenser placement, wall penetrations, and lineset routing usually touch common areas or the building exterior, which means condo-association or trustee approval. Sort out association sign-off before scheduling the install.

What about condenser placement on a tight urban multifamily lot?

This is the tightest constraint on triple-deckers and dense 2–4 families statewide (Worcester, Boston, Lynn, Somerville, Fall River, etc.). Common placements are rear-yard ground mounts, vertically-stacked wall brackets up the side of the building (one per floor), or a low-slope rear roof. Refrigerant linesets run vertically through an interior chase or a neat exterior raceway, and must stay within the manufacturer's maximum length and lift — a design item to confirm on the quote.

Can I phase the project one unit at a time?

Yes, and owner-occupants commonly do. Convert your own unit first — you capture both the rebate and the operating savings — then phase the rental units as leases turn over or old systems fail. Each unit files its own rebate when it's done, so phasing does not cost you any rebate value. It also spreads the capital cost and reuses the same installer and condenser plan each time.

Multifamily & Condo Heat Pump Rebates in Massachusetts

By MassHVAC Editorial Team Reviewed by MassHVAC Editorial Team Last updated 2026-09-19

The rule that changes everything: rebates are per unit

Massachusetts is a multifamily-heavy state — triple-deckers in Worcester, Boston, Lynn, and Fall River; two- and three-families across every gateway city. The single most important rebate fact for all of them: Mass Save treats each dwelling unit as its own whole-home project. Convert a unit to a heat pump as its sole heating source and it earns up to $8,500 — building-wide that stacks:

Two-family: up to $17,000 across both units.
Three-decker: up to $25,500 across all three.
Four-unit: up to $34,000 across all four.

A single shared "one big system for the building" install caps at one rebate. That's why the standard MA multifamily answer is a separate system per unit.

Massachusetts incentives

Mass Save rebates that apply per dwelling unit

See the full Mass Save rebates hub

Verified 2026-09-19

Most homes

Whole-Home Heat Pump Rebate

$2,650 /ton

Capped at $8,500 per home

The installed heat pump must be the sole source of heating and cooling for the spaces served. Equipment must be ENERGY STAR Cold Climate certified and listed on the Mass Save Heat Pump Qualified Products List (HPQPL). A Manual J load calculation is needed to qualify for the sizing bonus and is industry-standard practice on Mass Save projects.

Partial-Home / Supplemental Heat Pump Rebate

$1,125 /ton

Capped at $8,500 per home

Heat pump installed alongside an existing primary heating system. Equipment must be on the HPQPL. Lower per-ton rebate reflects supplemental rather than sole-source use.

Basic Heat Pump Rebate

$250 /ton

Capped at $2,500 per home

New for 2026. Applies to replacing an existing heat pump with a new qualified HPQPL-listed heat pump, or conditioning a previously unconditioned space.

$500 Right-Sized Equipment Bonus Partial-home

Partial-home installs only. Equipment must be sized to meet 90–120% of the total heating load at the outdoor design temperature, documented via an ACCA Manual J load calculation submitted with the rebate application.

$500 Weatherization Bonus Partial-home

Partial-home installs only. Requires a Mass Save Home Energy Assessment plus installation of the recommended weatherization (typically air sealing and insulation) within one year prior to or up to six months after the heat pump installation.

Financing

Mass Save HEAT Loan

0% APR up to $25,000

Below 135% of State Median Income: 7 years (84 months)
135%–300% of State Median Income: 5 years (60 months)
Over 300% of State Median Income: 3 years (36 months)

Subject to bank underwriting through participating Massachusetts lenders. Covers equipment + installation costs for qualifying high-efficiency upgrades (heat pumps, ductless mini-splits, insulation, water heaters, and batteries enrolled in ConnectedSolutions). A Home Energy Assessment is mandatory before financing a whole-home heat pump. Households below approximately 81% SMI typically route to Mass Save's no-cost / enhanced-rebate programs rather than the HEAT Loan.

No federal heat pump tax credit applies in 2026.

Section 25C Energy Efficient Home Improvement Credit (heat pump portion) (30% of cost up to $2,000 annually for qualifying heat pump installations (inflation reduction act expansion)) ended for property placed in service after 2025-12-31 under the One Big Beautiful Bill Act (P.L. 119-21).
Section 25D Residential Clean Energy Credit (geothermal portion) (30% of installed cost for ground-source (geothermal) heat pumps, with no dollar cap) ended for property placed in service after 2025-12-31 under the One Big Beautiful Bill Act (P.L. 119-21).

Status as of 2026-09-19: neither 25C nor 25D has been reinstated or replaced by Congress. Pending bills (e.g. H.R. 616) have not advanced. Pre-2026 §25D installs may carry forward unused credits.

Rebate amounts and eligibility verified 2026-09-19 against primary program documentation. We re-check before any publish.

Get a quote using these rates

Per-unit vs whole-building design

Do separate systems, not one shared plant, for three reasons:

Metering. Each unit pays its own electric bill. A shared system muddies who pays to run it — a dealbreaker on rentals and condos.
Rebates. Each unit files its own whole-home rebate; a shared system forfeits the stack.
Resilience & control. A fault in one unit never takes down heat for the others, and each household controls its own comfort.

The typical per-unit design is one outdoor condenser feeding 2–4 indoor heads, sized to the unit's Manual J load — not its square footage or bedroom count. These are ductless mini-split systems, which fit old buildings without central ductwork.

Condos: the same rebate, plus association sign-off

A separately-metered condo unit is, for rebate purposes, much like a single-family — the owner pursues up to $8,500 for their own unit. What's different is governance. Condenser placement, wall penetrations, and lineset routing almost always touch the building exterior or common areas, so you'll need condo-association or trustee approval. Get that sign-off in writing before scheduling, and coordinate with neighbors if multiple units convert together (shared condenser locations and staging can lower everyone's cost).

Individually-metered vs master-metered buildings

Most MA triple-deckers and 2–4 families are individually metered, one electric account per unit — the clean case, where each unit files its own rebate through its own account. Master-metered buildings (one account for the whole building) are more complicated for per-unit rebate treatment; raise it with your installer and Mass Save sponsor early so the filing approach is set before work starts.

Condenser placement on tight lots (statewide)

Whether it's a Worcester three-decker, a Dorchester triple, or a Lynn two-family, the tightest constraint is where the outdoor condensers go on a narrow lot. Common placements: rear-yard ground mounts (above snow line), vertically-stacked wall brackets up the driveway-side wall (one per floor), or a low-slope rear roof. Vertical linesets run through an interior chase or exterior raceway within the manufacturer's max length and lift. The Worcester triple-decker deep dive walks through this in detail; the same logic applies statewide.

If the units are rentals

Rental multifamily has its own economics — the split-incentive problem and tenant-income-based enhanced rebates — covered on the landlord rebate guide. Owner-occupants of a 2–4 family should read both: this page for the per-unit design mechanics, that page for who claims what and how to unlock enhanced offers based on tenant income. Building a new multifamily rather than retrofitting one? The incentive path differs — see new-construction heat pumps.

Multifamily & condo heat pump rebate FAQ

Does each unit in a multifamily building get its own Mass Save rebate?: Generally yes. Mass Save treats each of the (up to four) dwelling units in a small multifamily as its own whole-home project, so each unit converted to a heat pump as its sole heating source can qualify for its own rebate of up to $8,500. A two-family can reach up to $17,000, a three-decker up to $25,500, and a four-unit up to $34,000 in combined rebates across the building.
Should I heat the whole building with one system or one per unit?: One system per unit, in almost every case. Separate per-unit systems respect the individual electric metering (each tenant pays to run their own), let each unit file its own rebate, and mean a problem in one unit never takes down heat for the others. A single shared system muddies who pays to run it and caps you at one rebate. The standard MA multifamily design is one outdoor condenser per unit feeding 2–4 indoor heads sized to that unit's Manual J.
How does metering affect the rebate on a multifamily?: The Mass Save rebate for each unit follows that unit's electric account of record. In individually-metered buildings (the norm for MA triple-deckers and most 2–4 families), each unit files through its own account, which is clean. In master-metered buildings, the whole building is one account — talk to your installer and sponsor early, because it changes how the units are treated for rebate purposes.
How do heat pump rebates work for a condominium?: For an individually-owned, separately-metered condo unit, the owner typically pursues the rebate for their own unit as a whole-home project (up to $8,500), the same as a single-family. The wrinkle is condo governance: exterior condenser placement, wall penetrations, and lineset routing usually touch common areas or the building exterior, which means condo-association or trustee approval. Sort out association sign-off before scheduling the install.
What about condenser placement on a tight urban multifamily lot?: This is the tightest constraint on triple-deckers and dense 2–4 families statewide (Worcester, Boston, Lynn, Somerville, Fall River, etc.). Common placements are rear-yard ground mounts, vertically-stacked wall brackets up the side of the building (one per floor), or a low-slope rear roof. Refrigerant linesets run vertically through an interior chase or a neat exterior raceway, and must stay within the manufacturer's maximum length and lift — a design item to confirm on the quote.
Can I phase the project one unit at a time?: Yes, and owner-occupants commonly do. Convert your own unit first — you capture both the rebate and the operating savings — then phase the rental units as leases turn over or old systems fail. Each unit files its own rebate when it's done, so phasing does not cost you any rebate value. It also spreads the capital cost and reuses the same installer and condenser plan each time.

Related guides

Heat-pumping a Massachusetts multifamily or condo?

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