Thermal Resistance Converter

Thermal resistance (R-value) measures a material's opposition to heat flow. SI unit: m²·K/W. The higher the R-value, the better the insulation.

Related Thermal Converters

• Temperature Interval Converter
• Thermal Expansion Converter
• Thermal Resistance Converter
• Thermal Conductivity Converter
• Specific Heat Capacity Converter
• Heat Density Converter
• Heat Flux Density Converter
• Heat Transfer Coefficient Converter
• Temperature Converter Hub
• Triple Point of Water to Kelvin

Thermal Conductivity and Heat Transfer

Thermal conductivity (W/m·K) measures how quickly heat flows through a material. Copper (385 W/m·K) conducts heat far better than glass (1 W/m·K) or air (0.025 W/m·K) — which is why copper is used in heat sinks and cookware. Specific heat capacity (J/kg·K) measures how much energy raises 1 kg by 1 °C. Water's high specific heat (4,186 J/kg·K) makes it ideal for cooling systems and explains why coastal climates are milder than inland ones.

Thermal Conductivity Reference

Thermal Measurement Units Explained

Thermal measurements cover temperature, heat energy, and heat flow rate. Heat energy units include the joule (J, SI), calorie (cal, 1 cal = 4.184 J), kilocalorie (kcal, food calorie), British thermal unit (BTU, 1 BTU = 1055.06 J), and therm (100,000 BTU). Heat flow rate (thermal power) uses watts (W = J/s), BTU/hour, and ton of refrigeration (12,000 BTU/hr). Thermal conductivity uses W/(m·K).

HVAC systems in the US specify cooling capacity in BTU/hr or tons (1 ton = 12,000 BTU/hr). European systems use watts or kilowatts. Boiler output in the UK is rated in kW; in the US, BTU/hr. A typical home in the UK uses a 24–30 kW boiler; in the US, a 100,000–150,000 BTU/hr furnace. Insulation is rated in R-value (US, ft²·°F·hr/BTU) or RSI (metric, m²·K/W); 1 RSI = 5.678 R.

Thermal Unit Conversions

Thermal Energy and Heat Transfer Units

Thermal converters measure heat energy, thermal conductivity, and heat transfer rates across a variety of units used in engineering, physics, and HVAC design. The joule (J) is the SI unit of energy, including thermal energy. The calorie (cal) is defined as the heat needed to raise 1 gram of water by 1°C; the kilocalorie (kcal or food calorie) raises 1 kilogram. The British Thermal Unit (BTU) raises 1 pound of water by 1°F and is standard in US heating and cooling specifications. Watts measure power (energy per second) and appear in both electrical and thermal contexts. Thermal conductivity (W/m·K) describes how readily a material conducts heat; insulation R-values in US construction use ft²·°F·h/BTU. Choosing the correct thermal unit prevents costly errors when sizing boilers, specifying insulation, or comparing international HVAC equipment. Engineers working with both US and international suppliers routinely convert BTU/h to watts when selecting heat pumps or air-conditioning units rated under different systems.

Thermal Unit Reference Table