Accurately calculate radiator BTU needs for any room, factoring in insulation, size, and climate. Supports metric & imperial units and cost estimation.
Enter your measurements above to see the results.
Calculate the room volume (length × width × height). Adjust for the number of external walls (each extra wall increases demand by 10%). Multiply by the insulation factor and desired temperature difference. If using metric, convert the result to BTU/hr. Multiply total BTU by price per BTU for estimated cost.
Inputs: Metric, Room length 4.5 m, width 3.2 m, height 2.4 m, average insulation (1.0), 2 external walls, 20°C temp difference, GBP, £0.08 per BTU. Volume = 4.5×3.2×2.4=34.56 m³; wallFactor=1.1; heatLoss=34.56×1.1×1.0×20=760.32; requiredBTU=760.32×3.412=2595 BTU/hr; totalCost=2595×0.08=£207.60.
Insulation quality has a significant impact on how much heat your room retains, directly affecting the BTU rating needed for your radiator. Better insulation means you can achieve the same comfort with a lower BTU output, saving both energy and money.
For reliable results, measure the length, width, and height of your room in either metres or feet, depending on your preference. Accurate measurements ensure your BTU calculation is tailored to your exact space.
Select the insulation level that best matches your room: 'Poor' for older properties with single glazing, 'Average' for homes with double glazing and some insulation, and 'Good' for modern, well-insulated spaces. This ensures your BTU calculation reflects real-world heat loss.
Rooms with more external walls lose heat faster. This calculator increases the BTU requirement by 10% for each additional external wall, helping you size your radiator more accurately.
By entering your local currency and the price per BTU, you can instantly see an estimated cost for the radiators needed. This helps with budgeting and comparing heating solutions.
Measure your room's length, width, and height to get the volume. Factor in insulation quality and the number of external walls. Multiply by your desired temperature difference. This calculator does the maths for you and gives a precise BTU/hr requirement.
A BTU calculator estimates the heating power (in BTUs) needed to keep a space comfortable. Using one ensures you choose the right radiator size, considering your room's size, insulation, and other heat loss factors.
Better insulation reduces heat loss, so you need fewer BTUs to heat the same space. Poorly insulated rooms require more heating power, which this calculator accounts for when you select the insulation level.
Rooms with poor insulation need more BTUs. Select 'Poor' in the insulation level dropdown, enter your room details, and the calculator will show the increased BTU requirement.
Input the price per BTU and select your currency. The calculator multiplies your total BTU requirement by the price per BTU to give an estimated radiator cost.
