Calculate exactly what your oil-filled radiator costs to run per hour, day, and month. Includes thermal retention savings.
Oil heaters work differently than other electric heaters. Their sealed thermal oil retains heat for 30–60 minutes after the unit shuts off, meaning the heater cycles on and off rather than running continuously. To calculate cost: divide wattage by 1,000 to get kWh per hour, then multiply by your electricity rate. For a 1,500W oil heater at $0.15/kWh: 1.5 kWh × $0.15 = $0.23 per hour at full power.
But here's the key: oil heaters don't run at full power continuously. A good thermostat cycles the unit off once the room reaches temperature, and the retained heat keeps the room warm. In practice, most oil heaters effectively consume 60–70% of their rated wattage over time. So a 1,500W heater running 8 hrs/day actually costs ~$35–$45/month, not the $55/month you'd calculate at continuous full power.
For a detailed wattage-by-wattage breakdown, see our 1500-watt heater cost guide. To compare oil heaters against other types, check infrared vs oil heater cost or our oil vs ceramic heater comparison.
| Wattage | Cost/Hour | Cost/Day (8 hrs) | Cost/Month | Effective (Cycling) |
|---|---|---|---|---|
| 700W | $0.11 | $0.84 | $25.20 | $16.38 |
| 1,000W | $0.15 | $1.20 | $36.00 | $23.40 |
| 1,500W | $0.23 | $1.84 | $55.20 | $35.88 |
| 1,500W (ECO) | $0.15 | $1.20 | $36.00 | $28.80 |
US average $0.15/kWh. 30 days/month. "Effective" cost assumes 35% cycling reduction from thermal retention.