Btu/hr·ft² to W/m² Converter
Instantly convert heat flux measurements for HVAC sizing, insulation ratings, and thermal engineering. Precise, free, and easy-to-use.
Convert Heat Flux Measurements
Enter your measurement below to get instant, accurate conversions. Perfect for engineering calculations, building physics, and HVAC load estimations.
Measurement Converter
Type in either field to convert instantly in both directions
Enter Btu/hr·ft² to convert to W/m²
Enter W/m² to convert to Btu/hr·ft²
Metric power density
Alternative thermal unit
Conversion Result
Exact measurement breakdown and formula
Common Conversion Chart
Handy reference table for standard heat flux and HVAC load measurements. Bookmark this page for quick access during engineering or design work.
| Btu/hr·ft² | Watts/m² (W/m²) | Kilowatts/m² (kW/m²) | Common Application |
|---|---|---|---|
| 10 | 31.55 | 0.0316 | Low heat loss (super insulation) |
| 50 | 157.73 | 0.1577 | Standard wall U-value heat flux |
| 100 | 315.46 | 0.3155 | Typical residential HVAC design |
| 200 | 630.92 | 0.6309 | High-load commercial roofing |
| 500 | 1,577.30 | 1.5773 | Industrial equipment surfaces |
| 1,000 | 3,154.59 | 3.1546 | Heavy machinery / boilers |
| 3,412 | 10,763.91 | 10.7639 | 1 Watt per sq. ft. equivalent |
Conversion FAQ
Everything you need to know about converting thermal and heat flux measurements accurately.
1 Btu/hr·ft² is exactly equal to 3.15459 W/m². To convert, multiply the Btu/hr·ft² value by 3.15459. To convert W/m² to Btu/hr·ft², divide by 3.15459 (or multiply by 0.31699).
Btu/hr·ft² (British Thermal Units per hour per square foot) is a unit of heat flux density. It is commonly used in HVAC system sizing, building insulation ratings (like U-values and R-values), and thermal engineering to measure the rate of heat transfer through a specific surface area.
In practical HVAC and construction contexts, “Btu/ft²” is often used as shorthand for “Btu/hr·ft²”. However, strictly speaking, Btu/ft² is a measure of total heat energy per area, while Btu/hr·ft² is a rate of heat transfer (power per area). Always verify if the “per hour” is implied in your specific documentation.
First, convert the Btu/hr·ft² to W/m² by multiplying by 3.15459. Then, multiply that result by the total area in square metres (m²). Alternatively, multiply the Btu/hr·ft² by the area in square feet (ft²) to get total Btu/hr, then multiply by 0.293071 to get total Watts.