Use our BTU calculator for new build homes to estimate radiator size. Input room size, insulation, and more. Supports metric & imperial units. Multi-currency cost.
Enter your measurements above to see the results.
Calculate room volume (length × width × height). Determine the temperature difference (desired - outside). Multiply volume by insulation factor (based on insulation level), number of external walls, and temperature difference to get BTU/hr. Convert BTU/hr to Watts (divide by 3.412). Calculate estimated radiator cost by dividing BTU by 1000 (kBTU) and multiplying by price per kBTU.
Inputs: Metric, Room length: 5m, Room width: 4m, Ceiling height: 2.4m, Insulation level: Excellent (40), External walls: 2, Desired temp: 21°C, Outside temp: 0°C, GBP, Price per kBTU: 30. Volume = 5 × 4 × 2.4 = 48m³; Temp diff = 21 - 0 = 21; Base BTU = 48 × 40 × 21 = 40,320; Wall multiplier = 1 + (0.1 × 1) = 1.1; Required BTU = ceil(40,320 × 1.1) = 44,352 BTU/hr; Required Watts = 44,352 / 3.412 ≈ 13,000 W; Total cost = (44,352 / 1000) × 30 = 1,330.56 GBP.
Accurate BTU calculation is crucial in new build homes to avoid over- or under-sizing radiators. Modern builds often feature excellent insulation, meaning traditional rules of thumb can lead to oversized systems and wasted energy. Using a tailored calculator ensures you match your heating system to your home's true requirements.
Simply select your unit system, enter your room’s dimensions, insulation level, number of external walls, and desired and outside temperatures. The calculator instantly provides the required BTU and wattage output, along with an estimated radiator cost in your selected currency.
New build homes typically have excellent or good insulation, significantly reducing the BTU required compared to older properties. This calculator adjusts the insulation factor accordingly, helping you choose the right radiator size for energy-efficient heating.
Many radiators are rated in both BTU and Watts. This calculator automatically converts your required BTU to Watts, making it easy to compare and select suitable radiators from any supplier.
Enter your expected cost per kBTU based on typical radiator prices in your region. The calculator multiplies your required BTU by this rate, giving you a quick estimate of total radiator costs in your chosen currency.
To calculate BTU for a new build, measure each room's length, width, and ceiling height, select the insulation level, count external walls, and enter your desired and outside temperatures. The calculator multiplies these factors to estimate your required BTU for optimal heating.
New builds with excellent insulation typically require 30–40 BTU per m³ (or about 8–12 BTU per ft³), but the exact figure depends on insulation, external walls, and temperature difference. This calculator uses your precise room details for an accurate result.
For a 1000 sq ft (approx. 93 m²) new build, enter your room or house dimensions, insulation level, and temperature settings in the calculator. It will output the required BTU/hr so you can choose the right size furnace or radiator.
Yes, the insulation level greatly affects the required BTU. Better insulation reduces heat loss, so new builds usually need less heating output than older properties. Select the correct insulation level for best results.
Absolutely. Enter your local radiator cost per kBTU and select your currency. The calculator estimates the total radiator cost based on your room's heating requirement.
