Convert BTU per Hour-Square Foot to Kilowatts per Square Meter
Instantly convert BTU per Hour-Square Foot (BTU/(hr·ft²)) to Kilowatts per Square Meter (kW/m²) with our free online calculator.
Formula: BTU/(hr·ft²) to kW/m² — multiply by 0.00315459
Reference Table
| BTU per Hour-Square Foot (BTU/(hr·ft²)) | Kilowatts per Square Meter (kW/m²) |
|---|---|
| 1 | 0.00315459 |
| 5 | 0.0157729 |
| 10 | 0.0315459 |
| 25 | 0.0788647 |
| 50 | 0.157729 |
| 100 | 0.315459 |
How to Convert BTU per Hour-Square Foot to Kilowatts per Square Meter
Formula
To convert BTU per Hour-Square Foot (BTU/(hr·ft²)) to Kilowatts per Square Meter (kW/m²): multiply by 0.00315459
Step-by-Step
- Start with your value in BTU per Hour-Square Foot (BTU/(hr·ft²)).
- Multiply by 0.00315459 to perform the conversion.
- The result is your value expressed in Kilowatts per Square Meter (kW/m²).
Conversion Factor
1 BTU/(hr·ft²) = 0.00315459 kW/m²
Reverse Factor
1 kW/m² = 316.998 BTU/(hr·ft²)
Worked Example
Convert 25 BTU per Hour-Square Foot to Kilowatts per Square Meter: 25 BTU/(hr·ft²) = 0.0788647 kW/m²
About BTU per Hour-Square Foot (BTU/(hr·ft²))
An imperial heat-flux unit (≈ 3.1546 W/m² per NIST SP 811) used universally in US HVAC engineering, building-envelope thermal analysis, and shell-and-tube heat-exchanger design per TEMA standards. ASHRAE design cooling loads (per ASHRAE 90.1 / 62.1), solar heat-gain coefficient (SHGC) tables for fenestration per NFRC 100/200, and US HVAC equipment-output ratings all use BTU/(hr·ft²). Reference values from ASHRAE Handbook: peak summer solar heat gain through a south-facing window in Phoenix ~200-300 BTU/(hr·ft²) at solar noon; design cooling load for a US suburban home 30-50 BTU/(hr·ft²) of conditioned floor area; commercial-building design heating load 20-30 BTU/(hr·ft²) (mixed-humid climate per ASHRAE 90.1). US shell-and-tube heat-exchanger thermal-design specifications per TEMA Standards routinely quote heat-flux design points in BTU/(hr·ft²) — typical ranges 50-500 BTU/(hr·ft²) for liquid-to-liquid service; 1,000-10,000 BTU/(hr·ft²) for boilers and condensers; up to 100,000 BTU/(hr·ft²) for once-through-steam-generator superheater sections.
About Kilowatt per Square Meter (kW/m²)
A heat-flux unit equal to exactly 1,000 W/m². Used for high-intensity heat-transfer contexts where W/m² values would be inconveniently large: combustion-chamber walls of jet engines and industrial furnaces (100-500 kW/m² typical), rocket-nozzle regenerative cooling (Space Shuttle SSME ~50,000 kW/m² = 50 MW/m² in the throat region, requiring active cooling), concentrated-solar power tower receivers (1,000-1,500 kW/m² target flux on the cavity-receiver absorber per NREL CSP design studies), industrial furnace and reformer interiors. Also the standard unit in fire-protection engineering per NFPA 921 and SFPE Handbook: radiant heat exposure from flames is quoted in kW/m² because human pain threshold and material ignition thresholds fall conveniently in 1-50 kW/m² range. Reference thresholds: human pain at 4-8 seconds exposure ~2 kW/m²; second-degree burns at 30 seconds ~4 kW/m²; piloted wood ignition ~12 kW/m²; spontaneous wood ignition ~25-30 kW/m²; structural-steel softening (60% strength loss) at sustained 50-60 kW/m².
Quick Facts
- 1 BTU per Hour-Square Foot equals 0.00315459 Kilowatts per Square Meter
- 1 Kilowatt per Square Meter equals 316.998 BTU per Hour-Square Foot
- BTU per Hour-Square Foot is a unit of heat flux
- Kilowatt 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 Kilowatt per Square Meter belongs to the metric system
Common BTU per Hour-Square Foot to Kilowatt per Square Meter Conversions
| BTU per Hour-Square Foot (BTU/(hr·ft²)) | Kilowatts per Square Meter (kW/m²) |
|---|---|
| 0.01 | 0.0000315459 |
| 0.1 | 0.000315459 |
| 0.25 | 0.000788647 |
| 0.5 | 0.00157729 |
| 1 | 0.00315459 |
| 2 | 0.00630918 |
| 3 | 0.00946377 |
| 5 | 0.0157729 |
| 10 | 0.0315459 |
| 15 | 0.0473188 |
| 20 | 0.0630918 |
| 25 | 0.0788647 |
| 50 | 0.157729 |
| 75 | 0.236594 |
| 100 | 0.315459 |
| 250 | 0.788647 |
| 500 | 1.57729 |
| 1000 | 3.15459 |
| 5000 | 15.7729 |
| 10000 | 31.5459 |
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 (≈ 3.1546 W/m² per NIST SP 811) used universally in US HVAC engineering, building-envelope thermal analysis, and shell-and-tube heat-exchanger design per TEMA standards. ASHRAE design cooling loads (per ASHRAE 90.1 / 62.1), solar heat-gain coefficient (SHGC) tables for fenestration per NFRC 100/200, and US HVAC equipment-output ratings all use BTU/(hr·ft²). Reference values from ASHRAE Handbook: peak summer solar heat gain through a south-facing window in Phoenix ~200-300 BTU/(hr·ft²) at solar noon; design cooling load for a US suburban home 30-50 BTU/(hr·ft²) of conditioned floor area; commercial-building design heating load 20-30 BTU/(hr·ft²) (mixed-humid climate per ASHRAE 90.1). US shell-and-tube heat-exchanger thermal-design specifications per TEMA Standards routinely quote heat-flux design points in BTU/(hr·ft²) — typical ranges 50-500 BTU/(hr·ft²) for liquid-to-liquid service; 1,000-10,000 BTU/(hr·ft²) for boilers and condensers; up to 100,000 BTU/(hr·ft²) for once-through-steam-generator superheater sections.
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 Kilowatts per Square Meter
The Kilowatt per Square Meter (symbol: kW/m²) is a unit of heat flux. A heat-flux unit equal to exactly 1,000 W/m². Used for high-intensity heat-transfer contexts where W/m² values would be inconveniently large: combustion-chamber walls of jet engines and industrial furnaces (100-500 kW/m² typical), rocket-nozzle regenerative cooling (Space Shuttle SSME ~50,000 kW/m² = 50 MW/m² in the throat region, requiring active cooling), concentrated-solar power tower receivers (1,000-1,500 kW/m² target flux on the cavity-receiver absorber per NREL CSP design studies), industrial furnace and reformer interiors. Also the standard unit in fire-protection engineering per NFPA 921 and SFPE Handbook: radiant heat exposure from flames is quoted in kW/m² because human pain threshold and material ignition thresholds fall conveniently in 1-50 kW/m² range. Reference thresholds: human pain at 4-8 seconds exposure ~2 kW/m²; second-degree burns at 30 seconds ~4 kW/m²; piloted wood ignition ~12 kW/m²; spontaneous wood ignition ~25-30 kW/m²; structural-steel softening (60% strength loss) at sustained 50-60 kW/m².
It belongs to the metric measurement system.
Kilowatts per Square Meter are commonly used in fire protection engineering, electronics cooling, and solar energy.
Why Convert BTU per Hour-Square Foot to Kilowatts per Square Meter?
Converting between BTU per Hour-Square Foot and Kilowatts 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 Kilowatts per Square Meter?
An imperial heat-flux unit (≈ 3. To convert BTU per Hour-Square Foot to Kilowatts per Square Meter, multiply by 0.00315459. For example, 25 BTU/(hr·ft²) equals 0.0788647 kW/m².
How many Kilowatts per Square Meter are in 1 BTU per Hour-Square Foot?
There are 0.00315459 Kilowatts per Square Meter in 1 BTU per Hour-Square Foot.
How many BTU per Hour-Square Foot are in 1 Kilowatt per Square Meter?
There are 316.998 BTU per Hour-Square Foot in 1 Kilowatt per Square Meter.
What is the formula for BTU per Hour-Square Foot to Kilowatt per Square Meter conversion?
The formula is: multiply by 0.00315459. This means 1 BTU/(hr·ft²) = 0.00315459 kW/m².
Is a BTU per Hour-Square Foot bigger than a Kilowatt per Square Meter?
Yes. One BTU per Hour-Square Foot is larger than one Kilowatt per Square Meter because 1 BTU/(hr·ft²) equals 0.00315459 kW/m², which is less than 1.
When do you need to convert between BTU per Hour-Square Foot and Kilowatts per Square Meter?
A heat-flux unit equal to exactly 1,000 W/m². BTU per Hour-Square Foot and Kilowatt 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.