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 inside the walls, because every major mechanical system is new. Together they form the dollars redirected against principal each month.
Energy.
Maintenance.
Every major mechanical system is new — heat pumps, a 200-amp service with all-new wiring, all-new drain/waste/vent and supply plumbing, a heat-pump water heater, and a re-insulated interior envelope. There is no near-term replacement queue inside the walls. 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 ~$42k of redirected energy-plus-maintenance dollars 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.
Vacant · available now.
The house is vacant and ready for new ownership — performing as designed, with measured systems and a renewed insulation envelope.