What each cover costs you, same house and season
| Cover | Heater size | Fuel / season | Cost / season | vs single poly |
What a shorter season saves
| Season | Fuel | Cost | vs year-round |
Method: steady-state envelope loss (U × A × ΔT) plus air-change
infiltration, with seasonal energy from heating degree days rather than a single design day.
Envelope areas are computed from the same 3D geometry the configurator builds and cuts cover to.
Real fuel use also depends on wind exposure, humidity, thermal screens, soil heat and how tightly
the house is built.