Radiator BTU & Heat Loss Calculator
Hydronic and electric heating radiator sizing calculator. Computes room volume, external wall heat transfer loss, glazing heat loss, and required heat output in BTU/hr and Watts at standard Delta T50.
Radiator BTU & Heat Loss Calculator
Calculate the exact British Thermal Units (BTU/hr) and wattage required to heat any room based on dimensions, insulation, and windows.
6,930 BTU/hr
At Delta T50 (standard)2,031 W
2.03 kW equivalent1,440 ft³
180 sq ft floor21°C / 70°F
Living Room / Dining RoomUnderstanding Radiator Sizing & Delta T50
In heating engineering, radiator outputs are measured at ΔT50 (Delta T50), which assumes an average water temperature of 70°C and a room temperature of 20°C. If your room requires more than 6,000 BTU, it is often best to install two smaller radiators at opposite ends of the room rather than one giant radiator for more balanced heat distribution.
How to Use Radiator BTU & Heat Loss Calculator
Enter Room Dimensions
Input length, width, and ceiling height in feet.
Select Room & Insulation Details
Choose room type, wall count, and window glazing quality.
Review Required Output
Inspect the required BTU/hr and equivalent electric wattage for single or double convector radiators.
Frequently Asked Questions
Related Tools
2D Shape Area & Perimeter Calculator
Calculate area, perimeter, and circumferences for rectangles, circles, triangles, trapezoids, ellipses, and regular polygons.
3D Volume & Liquid Capacity Calculator
Calculate volume, surface area, and fluid capacity (liters, gallons) for boxes, cylinders, spheres, cones, pyramids, and capsules.
Percentage Calculator
Calculate percentages, percentage increases, decreases, and percentage differences.
Discount & Sale Price Calculator
Calculate final sale prices, discount amounts, and savings with sales tax.