Mass Save Whole-Home vs Partial-Home vs Basic Heat Pump Rebates

The current Mass Save air-source heat-pump page lists three standard paths. The amounts below are current as of September 25, 2026 and are based on eligible tonnage, which Mass Save calculates from AHRI cooling capacity divided by 12,000 BTU/h.

Rebate path	Heating plan it describes	2026 standard amount	Key proposal question
Whole-home	Heat pumps are capable of serving the entire conditioned home and are the sole source of space heating.	$2,650 per ton, up to $8,500	Will the installed system cover 100% of the conditioned space at the outdoor design condition, and will existing space heating be removed or disabled?
Partial-home	Qualifying heat pumps displace fossil-fuel or electric-resistance heat, but an existing boiler, furnace, or other heating source may remain in service.	$1,125 per ton, up to $8,500	Where does existing heat remain, and which zones require a qualified integrated control?
Basic	The project does not displace fossil-fuel or electric-resistance heating.	$250 per ton, up to $2,500	Is this a heat-pump or central-AC replacement, a newly conditioned space, or another non-displacement project?

These are not three quality levels. A well-designed partial-home system is not an incomplete whole-home system, and a basic rebate is not a judgment on the equipment. Each label describes a different project condition.

All three paths still require the applicable customer and utility-sponsor eligibility, qualifying new equipment on the Mass Save Heat Pump Qualified Product List, and installation by a contractor in the Mass Save Heat Pump Installer Network. The live page currently applies its 2026 offer to equipment installed from January 1 through December 31, 2026, with supporting documents due by February 28, 2027. Do not copy those dates into a future-year proposal without checking again.

Mass Save separately lists income-based enhanced incentives. Treat that as a separate eligibility conversation and link to the current income-qualified guidance; do not infer household qualification from the standard path.

1. Is the project displacing fossil-fuel or electric-resistance heat?

• No: start with the basic path. Mass Save gives examples including replacing an existing heat pump or central-air system, conditioning a previously unconditioned addition, and work in a home not occupied during winter. Confirm the customer and equipment still meet the basic-form requirements.
• Yes: continue to the whole-home-versus-partial-home question.

An addition is a useful trap to catch. New heat pumps in previously unconditioned space are listed as a basic scenario, not partial-home work. A replacement heat pump may also fall under basic; Mass Save says replacing existing heat pumps is not eligible for its whole-home or partial-home rebates.

2. Will the heat pumps be the sole source of space heating for the entire conditioned home?

• Yes: test the job against the whole-home requirements.
• No: the project is generally a partial-home candidate if it displaces qualifying existing heat.

The 2026 Whole-Home Heat Pump Verification Form makes “whole-home” concrete. The new equipment must be sized to meet 90–120% of the total heating load at the outdoor design temperature throughout 100% of the conditioned space. Existing space-heating equipment must be removed or disconnected. A boiler may remain for domestic hot water, but its space-heating function must be disabled. The home must also satisfy the program’s weatherization and full-time winter-occupancy requirements, and the homeowner and HPIN installer sign the verification form.

Do not reduce that to “every room has a head.” Coverage, load, equipment performance at the design condition, distribution, and the displaced system all matter.

3. If existing fossil heat remains, what happens in each served zone?

For partial-home work, the live Mass Save requirements call for an integrated control from the program’s qualified list in zones where oil, propane, or natural-gas heat remains in use. Record the selected control and the intended switchover setting rather than writing only “smart thermostat.”

There is a narrower exception: when the heat pump fully displaces a heating zone, an integrated control is not required for that zone if the existing fossil heating source is removed or disconnected there and the invoice documents it. That exception does not turn a partly served house into a whole-home project.

4. Have the cross-cutting checks been completed?

Before showing a number, verify the sponsor and account, pre-existing fuel, full-time winter occupancy where required, HPIN installer, qualified equipment combination, AHRI capacity, weatherization status, controls, installation timing, and the correct current form. If one of those facts is open, label the path proposed and name the outstanding check.

A homeowner may read “$8,500 rebate” as money already approved. Keep the full contract price visible, show the incentive separately, and place the qualifying assumptions beside it. These templates give a sales advisor enough structure without pretending to make Mass Save’s decision.

Whole-home wording

Proposed 2026 Mass Save path: whole-home. The potential incentive shown assumes the listed heat pumps qualify, are sized to serve 100% of the home’s conditioned space at the project’s outdoor design temperature, and will be the sole source of space heating. It also assumes the home satisfies current weatherization and occupancy requirements, the existing space-heating system is removed or disabled as documented, and the customer and installer complete the Whole-Home Verification Form. Final eligibility and payment are determined by Mass Save.

Partial-home wording

Proposed 2026 Mass Save path: partial-home. The potential incentive shown assumes the listed heat pumps qualify and displace existing [fuel] heat in the areas identified. The existing [boiler/furnace] will remain in service for [zones]. Qualified integrated controls are included for the zones where fossil heat remains, subject to the current program rules. Final eligibility, bonus eligibility, and payment are determined by Mass Save.

If a served zone uses the removal-or-disconnection exception, say exactly which heat source will be disabled and where that work appears in the scope and invoice.

Basic wording

Proposed 2026 Mass Save path: basic. This project does not displace fossil-fuel or electric-resistance space heating because [existing heat-pump replacement / central-AC replacement / newly conditioned space / project-specific reason]. The potential incentive assumes the customer, installer, equipment, and installation meet the current basic-rebate requirements. Final eligibility and payment are determined by Mass Save.

Language to remove before the proposal goes out

Avoid “your rebate,” “approved rebate,” “guaranteed,” and a net price that silently subtracts an unapproved incentive. Replace them with “potential incentive,” the proposed path, the calculation basis, and the checks still open. The 2026 rebate form also says the same equipment installation cannot receive multiple rebate offers, so do not present whole-home, partial-home, and basic amounts as stackable choices.

A path label is only useful when another person can follow the reasoning. Put these items in the proposal or its controlled project record:

• Existing heating: fuel, equipment, and the areas or zones it serves today.
• Proposed heating: the areas served by each heat-pump system and whether any existing source remains available for space heating.
• Design basis: total and area heat loss, outdoor design temperature, and the proposed equipment’s heating output at that condition.
• Equipment identity: outdoor and indoor model numbers, AHRI reference, qualifying-product check, and eligible tonnage used for the incentive estimate.
• Whole-home checks: weatherization basis, 90–120% sizing across 100% of conditioned space, displaced-system plan, and verification-form owner.
• Partial-home checks: retained heating zones, qualified integrated-control model and setting, or the documented removal/disconnection for a fully displaced zone.
• Basic-path reason: the specific fact that makes this a non-displacement project.
• Investment: full contract price first, then the dated potential incentive and homeowner responsibility if the rebate changes or is not approved.
• Open items: the person responsible and the next step for every unresolved program assumption.

Keep the proposal, equipment schedule, load calculation, and rebate form on the same revision. A model substitution can change the AHRI combination, eligible tonnage, output at the design condition, and path explanation at once.

Escalate unusual cases instead of forcing them through the tree. Existing supplemental heat pumps, mixed-fuel or mixed-use buildings, municipal utility arrangements, five-plus-unit properties, and projects split across additions and existing conditioned space deserve a current program answer before the homeowner signs around an assumed incentive.

The 2026 page lists two $500 bonuses for qualifying partial-home projects: a sizing bonus and a weatherization bonus. They do not create a fourth rebate path.

The sizing bonus requires equipment sized to meet 90–120% of the total heating load at the outdoor design temperature throughout 100% of conditioned space, with the required Manual J documentation. The weatherization bonus has its own Home Energy Assessment, work, timing, and joint-application conditions. Verify both on the live page and current form.

Show a bonus as a separate potential line only after its condition is documented. Do not let an available bonus turn a partial-home heating plan into “whole-home” language, and do not blend standard and income-based incentives into one number.

HomeWise is an operating system for home energy contractors. Quote Studio is its proposal capability: it brings the home’s heating needs, selected equipment, contractor pricing, and relevant program information into one homeowner presentation.

That creates a practical release gate. Before a proposal goes out, the estimator and office team can ask whether the stated rebate path agrees with the equipment, zones, retained heating, controls, and price. HomeWise does not determine program eligibility, replace the load calculation, or approve the rebate; your team owns the technical design, current program check, and final quote.

If your team is still rebuilding this explanation across spreadsheets, PDFs, and office notes, see how HomeWise helps turn the job record into a proposal your team approves.

What is the difference between a whole-home and partial-home Mass Save heat pump rebate?

Whole-home requires heat pumps capable of serving the entire conditioned home as the sole source of space heating, along with the current sizing, weatherization, displaced-system, occupancy, and verification requirements. Partial-home is generally the path when qualifying heat pumps displace existing fossil-fuel or electric-resistance heat but another heating source remains in service.

Can a boiler remain in a whole-home project?

The 2026 verification form allows the pre-existing system to remain for domestic hot water, but its space-heating function must be disabled. If it remains available to heat the home, describe the job as a potential partial-home project and verify the controls and other requirements.

Does every partial-home project need an integrated control?

A qualified integrated control is required in heating zones where propane, oil, or natural-gas heat remains in use. Mass Save describes an exception for a fully displaced zone when the existing source is removed or disconnected there and documented on the invoice. Check the current rules for the actual layout.

When does the basic heat pump rebate apply?

Basic applies to eligible heat-pump work that does not displace fossil-fuel or electric-resistance heating. Mass Save examples include replacing an existing heat pump or central-air system, installing in previously unconditioned space, and work in a home not occupied during winter.

Can a whole-home project finish weatherization after heat-pump installation?

Official Mass Save materials use slightly different timing language. The live eligibility section and verification form describe sufficient weatherization as a requirement before installation, while the current FAQ says an assessment or weatherization completed within six months after installation may still allow payment once the work is complete. Resolve the schedule with Mass Save for the specific project instead of promising the rebate on the more permissive reading.

Can the proposal show the 2026 rebate amount before approval?

Yes, as a dated planning estimate with its path, calculation basis, cap, and unresolved assumptions visible. Keep the full contract price on the page and state that Mass Save determines final eligibility and payment.