Embodied-Energy Break-Even Chart (2D)

Product Preset

Amortization Levers

Embodied energy E₀ 50 kWh

Annual savings vs. baseline ΔE 15.0 kWh/yr

Product lifetime L 6.0 yr

Live Readouts

Break-even year

3.3 yr

Within lifetime?

Yes

Net energy balance at end of life

+40.0 kWh

How it works

Every product carries an embodied energy E₀ — the sum of extraction, manufacturing and end-of-life processing energy paid once when it's made (First Law: energy only changes form, ΔU = Q + W, and that energy debt exists the moment the item leaves the factory). If the product then saves ΔE kWh of operating energy every year compared to whatever it replaced, the running balance is:

Balance(t) = ΔE · t − E0
t* = E0 / ΔE                    (break-even year: Balance = 0)

Before t*, the manufacturing debt hasn't been repaid yet and the running total is negative (red). After t*, every extra year of use is pure energy profit (green). If the product's lifetime L ends before t*, it was never worth the embodied cost — the classic failure mode of chasing "greener" replacements too often instead of keeping what you have.

Embodied energy slider — a bigger manufacturing debt pushes the break-even point further right.
Annual savings slider — a steeper savings rate (steeper line) pays the debt back faster.
Lifetime slider — sets how far the chart extends and whether the break-even marker falls inside or outside the usable life.
The shaded region under the curve is red while the balance is negative and turns green once it crosses zero.

This is the same physics as the amortization principle behind "buy less, keep it longer" — a product that never earns back its embodied energy within its own lifetime is a net energy loss no matter how efficient it is while running.

Debt (pre break-even) Surplus (post break-even)