How to Calculate Heating Oil Cost
What is Heating Oil Cost?
A heating oil cost calculator estimates annual fuel consumption and running costs for oil-fired central heating systems. Commonly used in rural UK, Ireland, and parts of North America not connected to mains gas.
Formula
gallons_needed = degree_days × constant / gallons_per_hour; cost = gallons × price_per_gallon
- DD
- Heating degree days (HDD) — Cumulative daily (65°F - avg_temp)
- gph
- Heating rate (gal/hr) — Oil furnace consumption rate
- needed
- Oil needed (gallons) — Seasonal consumption estimate
Step-by-Step Guide
- 1Annual consumption = floor area (m²) × litres per m² (insulation factor)
- 2Poor insulation: ~25L/m²/year, Average: ~18L/m²/year, Good: ~12L/m²/year
- 3Cost = annual litres × price per litre
- 4Average UK home uses 2,000–3,500 litres per year
Worked Examples
Input
100m² average insulation at £0.70/litre
Result
1,800 litres/year = £1,260/year
Input
150m² poorly insulated at £0.75/litre
Result
3,750 litres/year = £2,813/year
Input
After insulation upgrade (poor → good)
Result
~50% reduction in fuel and cost
Frequently Asked Questions
What are heating degree days?
HDD = (65°F - daily_avg_temp), summed for season. Harsh winters = high HDD = more oil needed.
How do I know my furnace consumption?
Check furnace specs or past fuel bills. Typical: 0.8–1.0 gal/hour during heating season.
How can I reduce heating oil usage?
Insulation, weatherstripping, thermostat setback, regular furnace maintenance. 1°F reduction ≈ 3% savings.
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