Convert BTU per Hour-Square Foot to Watts per Square Meter
Instantly convert BTU per Hour-Square Foot (BTU/(hr·ft²)) to Watts per Square Meter (W/m²) with our free online calculator.
Formula: BTU/(hr·ft²) to W/m² — multiply by 3.15459
Reference Table
| BTU per Hour-Square Foot (BTU/(hr·ft²)) | Watts per Square Meter (W/m²) |
|---|---|
| 1 | 3.15459 |
| 5 | 15.7729 |
| 10 | 31.5459 |
| 25 | 78.8648 |
| 50 | 157.73 |
| 100 | 315.459 |
How to Convert BTU per Hour-Square Foot to Watts per Square Meter
Formula
To convert BTU per Hour-Square Foot (BTU/(hr·ft²)) to Watts per Square Meter (W/m²): multiply by 3.15459
Step-by-Step
- Start with your value in BTU per Hour-Square Foot (BTU/(hr·ft²)).
- Multiply by 3.15459 to perform the conversion.
- The result is your value expressed in Watts per Square Meter (W/m²).
Conversion Factor
1 BTU/(hr·ft²) = 3.15459 W/m²
Reverse Factor
1 W/m² = 0.316998 BTU/(hr·ft²)
Worked Example
Convert 25 BTU per Hour-Square Foot to Watts per Square Meter: 25 BTU/(hr·ft²) = 78.8648 W/m²
About BTU per Hour-Square Foot (BTU/(hr·ft²))
An imperial heat-flux unit used in US HVAC, building-envelope analysis, and heat-exchanger design. ASHRAE design loads, solar heat-gain tables for windows, and HVAC equipment ratings commonly use BTU/(hr·ft²). Common peak solar heat gain through a south-facing window might be 200–300 BTU/(hr·ft²). 1 BTU/(hr·ft²) ≈ 3.155 W/m².
About Watt per Square Meter (W/m²)
The SI unit of heat flux density — rate of heat flow per unit area. W/m² is the universal unit in heat-transfer analysis, solar-irradiance measurements (solar constant ≈ 1,361 W/m² at Earth's top of atmosphere; ~1,000 W/m² at sea level on a clear day), building-envelope thermal modeling, and electronics cooling. Also the SI unit for radiation intensity.
Quick Facts
- 1 BTU per Hour-Square Foot equals 3.15459 Watts per Square Meter
- 1 Watt per Square Meter equals 0.316998 BTU per Hour-Square Foot
- BTU per Hour-Square Foot is a unit of heat flux
- Watt per Square Meter is a unit of heat flux
- This conversion is commonly used in fire protection engineering, electronics cooling, and solar energy
- The BTU per Hour-Square Foot belongs to the imperial system
- The Watt per Square Meter belongs to the metric system
Common BTU per Hour-Square Foot to Watt per Square Meter Conversions
| BTU per Hour-Square Foot (BTU/(hr·ft²)) | Watts per Square Meter (W/m²) |
|---|---|
| 0.01 | 0.0315459 |
| 0.1 | 0.315459 |
| 0.25 | 0.788647 |
| 0.5 | 1.57729 |
| 1 | 3.15459 |
| 2 | 6.30918 |
| 3 | 9.46377 |
| 5 | 15.7729 |
| 10 | 31.5459 |
| 15 | 47.3188 |
| 20 | 63.0918 |
| 25 | 78.8648 |
| 50 | 157.73 |
| 75 | 236.594 |
| 100 | 315.459 |
| 250 | 788.647 |
| 500 | 1577.29 |
| 1000 | 3154.59 |
| 5000 | 15772.9 |
| 10000 | 31545.9 |
Understanding BTU per Hour-Square Foot
The BTU per Hour-Square Foot (symbol: BTU/(hr·ft²)) is a unit of heat flux. An imperial heat-flux unit used in US HVAC, building-envelope analysis, and heat-exchanger design. ASHRAE design loads, solar heat-gain tables for windows, and HVAC equipment ratings commonly use BTU/(hr·ft²). Common peak solar heat gain through a south-facing window might be 200–300 BTU/(hr·ft²). 1 BTU/(hr·ft²) ≈ 3.155 W/m².
It belongs to the imperial measurement system.
BTU per Hour-Square Foot are commonly used in fire protection engineering, electronics cooling, and solar energy.
Understanding Watts per Square Meter
The Watt per Square Meter (symbol: W/m²) is a unit of heat flux. The SI unit of heat flux density — rate of heat flow per unit area. W/m² is the universal unit in heat-transfer analysis, solar-irradiance measurements (solar constant ≈ 1,361 W/m² at Earth's top of atmosphere; ~1,000 W/m² at sea level on a clear day), building-envelope thermal modeling, and electronics cooling. Also the SI unit for radiation intensity.
It belongs to the metric measurement system.
Watts per Square Meter are commonly used in fire protection engineering, electronics cooling, and solar energy.
Why Convert BTU per Hour-Square Foot to Watts per Square Meter?
Converting between BTU per Hour-Square Foot and Watts per Square Meter is a frequent requirement for engineers, scientists, and students working with heat flux values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate heat flux conversion is essential.
Frequently Asked Questions
How do I convert BTU per Hour-Square Foot to Watts per Square Meter?
An imperial heat-flux unit used in US HVAC, building-envelope analysis, and heat-exchanger design. To convert BTU per Hour-Square Foot to Watts per Square Meter, multiply by 3.15459. For example, 25 BTU/(hr·ft²) equals 78.8648 W/m².
How many Watts per Square Meter are in 1 BTU per Hour-Square Foot?
There are 3.15459 Watts per Square Meter in 1 BTU per Hour-Square Foot.
How many BTU per Hour-Square Foot are in 1 Watt per Square Meter?
There are 0.316998 BTU per Hour-Square Foot in 1 Watt per Square Meter.
What is the formula for BTU per Hour-Square Foot to Watt per Square Meter conversion?
The formula is: multiply by 3.15459. This means 1 BTU/(hr·ft²) = 3.15459 W/m².
Is a BTU per Hour-Square Foot bigger than a Watt per Square Meter?
No. One BTU per Hour-Square Foot is smaller than one Watt per Square Meter because 1 BTU/(hr·ft²) equals 3.15459 W/m², which is greater than 1.
When do you need to convert between BTU per Hour-Square Foot and Watts per Square Meter?
The SI unit of heat flux density — rate of heat flow per unit area. BTU per Hour-Square Foot and Watt per Square Meter are both heat flux units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.