Energy formula for each device
Multiply watts by quantity, daily runtime, and days, then divide by 1,000 to get kWh. Multiply kWh by your planning rate for estimated cost.
Enter always-on filters and timed lights as separate devices.
- Energy (kWh) = W × quantity × hours × days ÷ 1,000
- Estimated cost = energy × entered rate
Heater and filter example
A 100 W heater averaging 8 hours daily uses 24 kWh in 30 days. A 10 W filter running continuously uses 7.2 kWh, for 31.2 kWh combined.
At a flat rate of 0.15 per kWh, the simple estimate is 4.68, while a real bill may use tiered household pricing.
Estimating heater runtime
Thermostat heaters cycle off at the target temperature, so entering 24 hours may overestimate use. Consider season, room temperature, lid, and insulation.
A smart plug that records several days of kWh provides a better input when available.
Limits of the estimate
A flat-rate result excludes base charges, taxes, environmental charges, and household tiers. Compare bills or meter readings to isolate the aquarium's real effect.
Do not disable filtration or necessary temperature control solely to reduce the estimate.