Estimate greenhouse heating energy, fuel input, and operating cost from heat load, runtime, system efficiency, and energy price. This planning tool makes efficiency losses explicit and can compare a typical day with a longer operating period.
Delivered heat = Load × Hours/day × Days
Purchased energy = Delivered heat ÷ Efficiency
Cost = Purchased energy × Unit price
The main result is variable energy expense for the modeled period. Purchased energy is higher than delivered heat whenever efficiency is below 100%.
Use an energy price expressed per input kWh. Convert fuel units with the supplier heating value before entering the price.
At 120 kW for 10 hours/day over 30 days and 85% efficiency, input energy is 42,352.94 kWh. At $0.07/kWh, cost is $2,964.71.
No. Enter the average heat delivered to the greenhouse; the calculator derives purchased input using efficiency.
Yes, after converting the fuel price to cost per input kWh using an appropriate heating value.
Only if their energy is included in the entered heat load and price; normally they should be budgeted separately.
Purchased energy equals delivered energy and conversion loss is zero.
Outdoor temperature, wind, solar gain, infiltration, and set point change the heat load over time.
| Item | Meaning |
|---|---|
| Delivered heat load | Average useful thermal power supplied to the greenhouse |
| Efficiency | Useful heat divided by purchased energy |
| Purchased energy | Energy billed before conversion losses |
| Unit price | Cost per purchased kWh |