A family of four just bought a $750,000 home in Andover. Decisions need to be made: the roof, the heating system, the cars. We ran two complete 30-year projections. Here's what the numbers say.
A couple with two young kids just closed on a 34-year-old colonial in Andover. It's a solid house — but it needs work. The roof is aging, the oil furnace is original to the house, and they're replacing one of their two cars as part of the move. Six years from now, they'll replace the second car too.
The question isn't whether to spend money. They're spending it either way. The question is: which set of spending decisions leaves them better off 10, 20, or 30 years from now?
We modeled two complete paths from day one, accounting for energy costs, incentives, and every major purchase — at real Massachusetts prices, with realistic annual escalation built in.
Both paths include the exact same car purchase amounts ($45,000 at year 0, $50,000 at year 6). The difference is what fuels those cars — and what fuels the home.
Massachusetts has strong programs for solar, heat pumps, and storage. These are already reflected in the $179,750 Path A starting number above.
Incentive amounts reflect current MA program rates for Eversource territory. Programs are subject to change. Additional utility and other programs may apply.
Every home is different. Book a remote consultation and we'll walk through a projection built specifically for your house — your roof, your heating load, your utility bills — on a shared screen together.
Book a Remote ConsultationA screenshare video call where we walk through the numbers together. No in-home visit. No obligation.
Model assumptions and methodology: Path A assumes a 25 kW DC solar array at a 1.1 kWh/watt/year production factor (27,500 kWh at installation), degrading 0.5%/year; net metering credit at $0.20/kWh for surplus export; MA SMART incentive at $0.05/kWh × annual production for years 1–10; grid interconnection fee of $150/year; MassSave heat pump rebate of $10,000 applied upfront; MassSave battery rebate of $1,250 applied upfront; MA solar income tax credit of $1,000. Heat pump electrical load modeled at 9,000 kWh/year, replacing 900 gallons of heating oil annually. Each EV modeled at 15,000 miles/year at 3.5 mi/kWh (charging cost covered by solar). Path B oil furnace replacement cost $6,000 installed; gas car modeled at 28 MPG. Electricity escalates at 3%/year; heating oil at 4%/year; gasoline at 2%/year. Both paths include identical car purchase amounts ($45,000 at year 0, $50,000 at year 6). All figures are estimates for illustrative purposes only and do not constitute financial advice. Actual results depend on your specific home, energy use, utility rates, and available incentives. Incentive programs are subject to change.