The economics of
a quiet house.
A tight, all-electric house carries a smaller monthly energy bill than a comparable home with gas and forced air. The arithmetic of that gap is straightforward; the compounded result, over a twenty-five-year mortgage, is not. The model below is indicative — real numbers vary with occupancy and behavior — but the direction of the gap is robust.
Two questions, asked in sequence. First: what does it cost to heat, cool, and power this house, versus the alternative? Second: what happens if the difference is redirected — every month, automatically — against the principal of a twenty-five-year mortgage?
Two streams of savings.
Two parallel streams. Energy — the gap between this house and a comparable inefficient one, modeled conservatively. Maintenance — the absence of a near-term replacement queue, because every major system is new. Together they form the dollars redirected against principal each month.
Energy.
Maintenance.
Every major system is new — heat pumps, a 200 A service with all-new wiring, all-new drain/waste/vent and supply plumbing, a heat-pump water heater, new roof and envelope. There is no near-term replacement queue. The result is a deliberate underspend on system maintenance over the next decade and beyond — modeled here at $60/mo against a household budget that would otherwise carry it.
Together, the dollars redirected.
The same dollars, redirected.
A $400,000 mortgage at 6.5 % APR over twenty-five years has a base monthly principal-and-interest payment of $2,701, and ultimately costs $410,200 in interest. Each column below shows what happens when the combined energy-plus-maintenance delta is paid against principal every month — the savings, simply not spent.
| Base | +$120 (low) | +$140 (baseline) | +$200 (high) | |
|---|---|---|---|---|
| Total interest paid | $410,200 | $363,100 | $356,300 | $337,800 |
| Interest saved | — | −$47,100 | −$53,900 | −$72,400 |
| Years to payoff | 25.0 | 22.5 | 22.2 | 21.2 |
| Years saved | — | 2.5 | 2.8 | 3.8 |
The +$140 column reflects the baseline combined delta of this house ($60 maintenance + $80 energy). Low and high columns vary the energy component only; maintenance is constant. Calculations are exact within rounding; interest figures rounded to the nearest hundred dollars.
Total interest paid, by scenario.
The leverage.
in mortgage interest avoided · over 25 years
Baseline ~$54k · range depending on energy use
More than the $42,000 of energy-plus-maintenance money it took to get there at the baseline. The interest you don't pay is bigger than the dollars you don't spend.
Modeled on a $400,000 mortgage at 6.5 % APR over 25 years. The $48k energy figure is independent of loan size; interest avoided scales with the loan — a smaller mortgage saves less in interest, a larger one saves more. Real-world results are likely better than shown: energy prices are assumed flat for 25 years, which is conservative, and Ohio's deregulated electricity market lets the all-electric figure drop further, often below $100/mo.
A tight envelope is a quiet form of compound interest.
Same square footage. Same address. Same school district. The variable is what you don't pay each month — and what that, redirected, becomes by year twenty-five.
Currently tenant-occupied · available end of June 2026.
The house is in active use today — performing as designed, with measured systems and a verified envelope. Turning over to new ownership at the close of June.