Mass Save heat pump rebates: contractor documentation

Mass Save is the energy efficiency program run by its Sponsors: Massachusetts gas and electric utilities and Cape Light Compact. For contractors installing residential air-source heat pumps, three things decide whether your customer gets paid: you must be in the Mass Save Heat Pump Installer Network, the system must be sized to the heating load using ACCA Manual J design conditions, and the paperwork must match the rebate type.

Who runs Mass Save

Mass Save rebates are offered by the program's Sponsors. The residential air-source heat pump page lists Cape Light Compact, Eversource, National Grid and Unitil as electric Sponsors, and Berkshire Gas, Eversource, Liberty, National Grid and Unitil as natural gas Sponsors. Which Sponsor applies depends on the fuel being displaced:

• Customers replacing oil, propane or electric resistance heat apply through their electric Sponsor's residential electric account.
• Customers replacing natural gas heat apply through their gas Sponsor's residential gas account.

The Heat Pump Installer Network

Residential air-source heat pump rebates require installation by a contractor in the Mass Save Heat Pump Installer Network (HPIN). Members are listed in the Mass Save Find a Contractor tool and get access to residential rebates, 0% financing opportunities, technical training and marketing support.

To enroll, an authorized company representative submits:

• A signed Mass Save Heat Pump Installer Participation Agreement
• A business W-9
• A Massachusetts license: Sheet Metal, Refrigeration, Electrical Contractor or Plumbing
• A certificate of comprehensive general liability insurance
• Training certification. Air-source and VRF primary installers need EPA Section 608 certification and manufacturer air-source heat pump installation training.

Within the first year of participation, residential air-source installers must provide certification of manufacturer cold climate sizing and design training, and all installers must complete assigned cold climate heat pump trainings in the Mass Save Heating & Cooling Learning Center. Each installer must register for the Learning Center.

Rebate types

Mass Save offers three air-source heat pump rebate types, based on equipment tonnage. Tons are AHRI cooling capacity divided by 12,000 BTU.

Source: Mass Save Air Source Heat Pumps page, accessed 2026-10-16. Enhanced incentives require a pre-existing fuel of oil, propane or electric resistance.

Whole-home

The heat pump is the sole source of heating and cooling. Requirements from the rebate page and the 2026 Whole-home Heat Pump Verification Form:

• Equipment is new and sized to be capable of being the sole heat source.
• The pre-existing heating system is removed or disconnected. If it stays for domestic hot water only, space heating must be disabled.
• The home is sufficiently weatherized: built in 2000 or later, or a Home Energy Assessment recommended less than $1,000 of weatherization, or weatherization recommended in 2013 or later has been completed.
• The home is occupied full time in winter. One whole-home rebate per account.
• The verification form is signed by the customer and the HPIN installer.

Whole-home projects that do not meet the weatherization requirement may still qualify for partial-home amounts.

Partial-home

The existing boiler or furnace stays to supplement the heat pump. Where oil, propane or gas heat remains in a zone, you must install an integrated control from the Mass Save Integrated Control Qualified Product List, set at or below the maximum switchover temperature. Partial-home projects that fully displace a heating zone do not need an integrated control, but the old source must be removed or disconnected and documented on the invoice.

Two $500 bonuses are available on partial-home rebates:

• Sizing bonus: equipment sized to meet the home's total heating needs (see below), with the load calculation submitted.
• Weatherization bonus: Home Energy Assessment plus recommended weatherization within one year before or six months after installation.

Basic

For projects not displacing fossil or electric resistance heat: replacing an existing heat pump or central AC, a new addition, or a home not occupied in winter. No bonuses.

Sizing and load calculation requirements

This is where most documentation questions come up. The rule, from both the rebate page and the verification form:

Contractors must install equipment sized to meet 90-120% of the total heating load at the outdoor design temperature, per ACCA Manual J Design Conditions, throughout 100% of the conditioned space.

What that means in practice:

• Whole-home: the 90 to 120% sizing rule applies. The form states Manual J and/or Manual D documentation is "only required upon request," and the customer acknowledges that sizing documentation may be requested. Keep it on file for every job.
• Partial-home sizing bonus: the same 90 to 120% rule applies, and "a copy of the heating load calculation must be submitted with the application."
• The capacity you compare against the load is the heat pump's heating capacity at the outdoor design temperature, not nominal tons.

If you need a refresher on running the load, read our Manual J guide. For selecting equipment on capacity at design temperature, read cold climate heat pump sizing. For a quick starting estimate, use the heat pump sizing calculator.

Estimate only. Not a substitute for a room-by-room Manual J.

Equipment eligibility

• Equipment must meet ENERGY STAR Cold Climate and be on the Mass Save Heat Pump Qualified Products List.
• Partial-home projects keeping fossil heat need a listed integrated control.

Deadlines and paperwork

• 2026 equipment must be installed between January 1 and December 31, 2026.
• The rebate form and documentation must be received by February 28, 2027.
• From October 1, 2026, serial numbers are required on all heat pump rebate applications, with a clear photo of each outdoor unit's nameplate.
• Projects may be selected for a random verification inspection before payment.
• Rebates cannot exceed total installation cost and cannot be combined with other Mass Save incentives for the same equipment.

How Tradewright helps

Tradewright runs a room-by-room Manual J, selects equipment from real performance data at the outdoor design temperature under Manual S, and generates the Mass Save documentation from the same design. It also reads existing equipment from a nameplate photo. See rebate documentation.

See Mass Save documentation generated from a real design