This is a sample scenario built from current Massachusetts program rules and typical 2026 installer quotes in the Boston metro area. No single homeowner matches this exact composite — the math below is a worked example of how Mass Save, pending HEEHRA, and manufacturer rebates stack for a moderate-income household in a Cambridge condo.
The point is to show what the rebate math actually looks like when you run the numbers layer by layer, not to profile a specific customer.
The homeowner and the home
The unit is a 1,600 square foot second-floor condo in a classic Cambridge triple-decker, built between 1910 and 1925 with balloon framing and plaster walls. Current heat is a 1998-vintage gas boiler feeding hydronic baseboard loops on each floor of the building, with the condo owner paying a share of the fuel bill through the condo association.
The homeowner wants to decouple from the shared gas system and control their own heating cost, which is why a self-contained ductless solution is on the table rather than routing new ductwork through a finished ceiling. The existing unit has window ACs in two bedrooms and the living room for summer cooling.
The climate zone is ASHRAE 5A. Boston's 99% design temperature is 9 degrees Fahrenheit, which puts this project squarely in the NEEP Cold Climate Air Source Heat Pump Product List territory for any equipment selection.
The equipment spec
The proposed system is a 3-zone ductless with a 2.5-ton outdoor condenser and three indoor wall-mounted heads. The zones are sized for the living room (12,000 BTU), the primary bedroom (9,000 BTU), and a shared zone covering the second bedroom plus small home office (9,000 BTU).
The condenser under consideration is a Mitsubishi MXZ-3C30NAHZ Hyper-Heat H2i, AHRI-certified for 100% rated capacity at 5 degrees Fahrenheit and 76% at minus 13 degrees. HSPF2 is 10.2 and SEER2 is 21.4, both well above the Mass Save minimum and both on the NEEP CCASHPPL. This is the baseline-quality equipment tier for Cambridge climate conditions — lower-HSPF multi-zone systems exist, but they lose rebate eligibility and run 20-30% more expensive to operate at design temperature.
The system includes three MSZ-FS wall units (the quiet-series indoor heads, approximately 19 dBA on low fan), refrigerant line sets sized per manufacturer spec, a single Mitsubishi kumo cloud controller, and a Honeywell T10 thermostat bridge for home-automation integration.
The pre-rebate quote
Three-installer bids from Cambridge-area Mass Save-certified contractors cluster in the $14,500 to $17,500 range for this exact equipment spec. The midpoint used in this sample is $16,000. The itemization below is the typical structure:
- Equipment (condenser + 3 indoor heads + controller): $8,400
- Labor (3-day install, 2-person crew): $4,200
- Electrical (new dedicated 240V circuit from panel, no panel upgrade needed): $1,400
- Refrigerant line sets + insulation + wall penetrations: $850
- Permits (Cambridge electrical + mechanical): $350
- Contingency (line rerouting, unexpected framing): $800
A 200A panel upgrade is not triggered in this scenario — the existing 100A service has headroom for the new 20-amp ductless circuit because the unit currently runs gas heat, gas range, and gas water heater. If the homeowner later adds a heat pump water heater or induction range, a panel upgrade would likely be required and would open the $4,000 HEEHRA panel rebate category.
The rebate stack
Four layers apply here, in the order they should be claimed.
Federal 25C — zero for 2026 installs. 25C was repealed for heat pumps by the One Big Beautiful Bill Act, effective December 31, 2025. For equipment placed in service in 2026, there is no federal tax credit on air-source heat pumps. See the federal tax credits status page for what remains. This line is on the stack only to make clear it is now worth zero.
Mass Save ConnectedSolutions rebate — $5,000. Massachusetts's utility-funded program pays $1,250 per ton for qualifying cold-climate multi-zone ductless systems, capped at $10,000 per household. The 2.5-ton system in this scenario claims $3,125, and the ConnectedSolutions whole-home electrification bonus adds $1,875 when the install includes removal of existing primary gas heating. The total Mass Save layer lands at $5,000 for this project. Mass Save is point-of-sale — the contractor files the paperwork and discounts the invoice.
HEEHRA (Massachusetts, pending launch) — $3,000. When Massachusetts DOER opens the HEEHRA portal in Q3 2026 (targeted, not confirmed), a household at 90% AMI in the 80-150% tier will qualify for 50% of project cost after prior rebates, capped at $4,000 for the heat pump. The net-of-Mass-Save cost is $11,000. Fifty percent of that is $5,500, but the $4,000 HEEHRA heat pump cap applies. The effective HEEHRA contribution in this scenario is capped at $3,000 after DOER's announced net-of-utility-rebate calculation methodology is applied — DOER has published that the 50% basis is computed against the full eligible project, not the post-utility-rebate remainder, and the cap binds at $4,000 on a $16,000 project with $5,000 already claimed. The exact amount will depend on final DOER regulations.
Mitsubishi Cool Cash manufacturer rebate — $500. Seasonal Mitsubishi promotions on Hyper-Heat H2i multi-zone systems typically run $400 to $600 in spring and fall. The contractor files the pre-approved claim at quote, and the rebate appears on the invoice. This stacks with everything above because it is funded by the manufacturer's marketing budget, not ratepayer or federal dollars.
Total rebate stack: $5,000 (Mass Save) + $3,000 (HEEHRA, pending) + $500 (Mitsubishi) = $8,500.
Application order
The practical filing sequence for a Cambridge homeowner pursuing this stack:
- At quote, ask the contractor to confirm Mitsubishi Cool Cash is active and lock in the manufacturer rebate in writing.
- Before signing, confirm the contractor is Mass Save-certified and will file ConnectedSolutions as point-of-sale at invoice.
- If HEEHRA is live at the time of install, confirm the contractor is also Massachusetts HEEHRA-certified (DOER is building a unified certification program that should cover both Mass Save and HEEHRA contractors after Q3 2026).
- At install, the contractor submits Mass Save and HEEHRA paperwork simultaneously. Mass Save processes in 10-14 days; HEEHRA processing times are not yet published for Massachusetts but cluster around 10-21 days in other live states.
- The manufacturer rebate lands as a credit on the invoice directly at install day, independent of utility or federal processing.
See our rebate stacking application order post for the general sequence across all program types, and the HEEHRA state-by-state status tracker for current Massachusetts launch timing.
The net number
Pre-rebate cost: $16,000. Total rebate stack: $8,500. Net out-of-pocket: $7,500.
If the homeowner installs before HEEHRA launches, the stack drops to $5,500 (Mass Save + Mitsubishi only) and the net lands at $10,500. The $3,000 delta is the value of waiting for HEEHRA go-live — but only if the homeowner's 80-150% AMI status holds through the launch and the DOER's final methodology matches the announced framework.
Operating cost comparison: the gas baseboard system currently costs roughly $1,600 per year for this 1,600 sqft unit at Boston gas prices (shared condo-association billing, approximately $1.85 per therm in 2026). A Mitsubishi Hyper-Heat multi-zone system at Eversource electric rates (approximately 32 cents per kWh in eastern Massachusetts) will run roughly $1,050 per year in heating plus $280 in summer cooling for the same unit. The old window ACs drew roughly $220 per summer, so the net annual operating delta is a savings of approximately $490 per year on combined heating and cooling.
Ten-year operating savings: $4,900 at current rates, higher if gas prices rise faster than electric rates over the decade. Combined with the $8,500 rebate stack, the effective 10-year cost of this electrification project is $2,600 — or about $260 per year, amortized, for a system with a 15+ year expected life.
Why this scenario is typical
The homeowner who fits this composite is a moderate-income professional in a Cambridge, Somerville, or nearby inner-suburb condo, earning between $90,000 and $130,000 for a two-person household. That income band puts them firmly in the 80-150% AMI tier — not rich enough to be excluded from HEEHRA, not low enough to qualify for the full $8,000 federal rebate.
This is also the most common rebate-aware homeowner in Massachusetts today. Under-80% AMI households frequently face financing friction that delays heat pump projects even when the rebate stack covers the majority of cost. Higher-income households often skip rebate paperwork entirely because the math is less transformative. The 80-150% AMI band in high-cost metros is the segment where rebate stacking makes the biggest behavioral difference — $8,500 off is enough to move the project from "maybe someday" to "this fall."
For Cambridge specifically, the triple-decker housing stock creates an additional wrinkle: condo associations often control gas-system decisions collectively, so self-contained ductless is frequently the only path for an individual unit owner to electrify without a full building-wide retrofit. The mini-split vs central heat pump decision tree walks through when ductless is the right call versus ducted retrofit in similar housing.
The numbers above assume Massachusetts HEEHRA launches as DOER has signaled. Current Q3 2026 target is not a commitment — use the rebate finder on the homepage to check live program status before signing any quote. The heat pump calculator lets you model the specific numbers for your ZIP, AMI band, and equipment choice.