Thermal Resistance Converter
Convert thermal resistance measurements between different units quickly and accurately
Thermal Resistance Conversion Calculator
Popular Thermal Resistance Conversions
Quickly convert between the most commonly used thermal resistance units.
Understanding Thermal Resistance Measurements
Thermal resistance is a crucial concept in heat transfer, electronics cooling, and building insulation. It quantifies how much a material or system resists the flow of heat. The kelvin per watt (K/W) is the base unit in the International System of Units (SI), representing the temperature difference required to transfer one watt of heat power.
Common Thermal Resistance Units
SI Units
- Kelvin per Watt (K/W) - Base unit
- Celsius per Watt (°C/W) - Equivalent to K/W
- Square meter-Kelvin per Watt (m²⋅K/W) - For materials
Imperial Units
- °F⋅hr/BTU (IT) - International Table BTU
- °F⋅hr/BTU (th) - Thermochemical BTU
- °F⋅s/BTU (IT) - Per second basis
- hr⋅ft²⋅°F/BTU - Per unit area
Common Applications
| Field | Common Units | Typical Uses |
|---|---|---|
| Electronics Cooling | K/W, °C/W | Heat sinks, thermal interface materials |
| Building Insulation | m²⋅K/W, hr⋅ft²⋅°F/BTU | Wall, roof, window R-values |
| HVAC Systems | °F⋅hr/BTU | Heat exchanger design |
| Thermal Management | K/W | Component thermal design |
Conversion Tips
- K/W and °C/W are exactly equivalent (same temperature scale)
- Higher thermal resistance means better insulation
- R-value in building insulation is thermal resistance per unit area
- Thermal resistance is inversely proportional to thermal conductivity
Thermal Resistance Conversions
| Conversion | Formula | Quick Answer |
|---|---|---|
| K/W to °F⋅hr/BTU (IT) | 1 K/W = 0.5275 °F⋅hr/BTU (IT) | Multiply by 0.5275 |
| °F⋅hr/BTU (IT) to K/W | 1 °F⋅hr/BTU (IT) = 1.8956 K/W | Multiply by 1.8956 |
| K/W to °F⋅hr/BTU (th) | 1 K/W = 0.5274 °F⋅hr/BTU (th) | Multiply by 0.5274 |
| °F⋅hr/BTU (th) to K/W | 1 °F⋅hr/BTU (th) = 1.8961 K/W | Multiply by 1.8961 |
| K/W to °F⋅s/BTU (IT) | 1 K/W = 1899 °F⋅s/BTU (IT) | Multiply by 1899 |
| °F⋅s/BTU (IT) to K/W | 1 °F⋅s/BTU (IT) = 0.000527 K/W | Multiply by 0.000527 |
| K/W to °F⋅s/BTU (th) | 1 K/W = 1898 °F⋅s/BTU (th) | Multiply by 1898 |
| °F⋅s/BTU (th) to K/W | 1 °F⋅s/BTU (th) = 0.000527 K/W | Multiply by 0.000527 |
| K/W to °C/W | 1 K/W = 1 °C/W | Exactly equal |
| °C/W to K/W | 1 °C/W = 1 K/W | Exactly equal |
Our thermal resistance conversion tool provides accurate conversions between all major thermal resistance units, essential for thermal management, building insulation, and heat transfer calculations. Whether you're designing electronics cooling systems, evaluating building materials, or conducting thermal analysis, our converter ensures precise thermal resistance conversions.
Thermal Resistance Conversion Questions
Everything you need to know about thermal resistance measurements and conversions
What is thermal resistance?
Thermal resistance is a measure of how much a material or system opposes the flow of heat. It's defined as the temperature difference across a material divided by the heat flow rate. Higher thermal resistance means better insulation properties. It's the thermal equivalent of electrical resistance.
What does K/W mean in thermal resistance?
K/W (kelvin per watt) represents the temperature rise in kelvins for each watt of heat power applied. For example, if a heat sink has a thermal resistance of 2 K/W, it will be 20°C hotter than ambient when dissipating 10 watts of heat.
How is thermal resistance related to R-value in building insulation?
R-value is thermal resistance per unit area, typically expressed in hr⋅ft²⋅°F/BTU (imperial) or m²⋅K/W (metric). It indicates how well a material insulates per unit thickness. Higher R-values mean better insulation. For example, R-19 fiberglass insulation has better insulating properties than R-13.
What's the difference between thermal resistance and thermal conductivity?
Thermal resistance and thermal conductivity are inversely related. High thermal conductivity means low thermal resistance (good heat conduction), while low thermal conductivity means high thermal resistance (good insulation). Thermal resistance = thickness / (thermal conductivity × area).
Why are there IT and th versions of BTU in thermal resistance units?
IT (International Table) and th (thermochemical) refer to slightly different definitions of the BTU based on different reference temperatures for the calorie. The IT BTU (1055.06 J) is more commonly used in engineering, while the th BTU (1054.35 J) is used in some thermodynamic calculations. The difference is small but matters for precision work.
How do I calculate thermal resistance for multiple layers?
For materials in series (like layers of insulation), thermal resistances add directly: R_total = R1 + R2 + R3. For parallel paths (like heat flowing through different materials side by side), use the reciprocal formula: 1/R_total = 1/R1 + 1/R2 + 1/R3.
Have more questions? Contact us!