Underfloor Heating Calculator
Cable/mat length and running cost for radiant floor heat.
Enter your values
ⓘ Live results
Results
- System power
- 960 W
- Daily energy use
- 3.84 kWh
- Estimated daily cost
- $0.61
- Estimated monthly cost
- $18.43
Quick answer
Underfloor heating cable length depends on room area and spacing, and running cost depends on wattage, hours of use and electricity rate.
power = area x W/sq ft; cost = power(kW) x hours x rate
How to use the Underfloor Heating Calculator
- 1Measure the floor area to be heated (not the whole room if under cabinets are excluded).
- 2Use 10-15 W/sq ft for supplemental heat in most climates.
- 3Estimate daily run hours and your electricity rate to see running cost.
Worked example
Using the values the calculator loads with:
Inputs
- Heated area80 sq ft
- Heating density12 W/sq ft
- Hours per day4 hr
- Electricity rate0.16 $/kWh
Results
- System power960 W
- Daily energy use3.84 kWh
- Estimated daily cost$0.61
- Estimated monthly cost$18.43
Frequently asked questions
Can underfloor heating be a primary heat source?
In well-insulated homes yes, but most systems are installed as supplemental comfort heat.
Electric or hydronic?
Electric is easier to retrofit into a single room; hydronic is more efficient for whole-house systems.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.