Grilles and Diffusers Calculator
Size supply and return air grilles.
The Grilles and Diffusers Calculator is a free tool designed for construction professionals and enthusiasts. Size supply and return air grilles. Instantly get the required materials broken down by purchase units, with an option to add a wastage allowance so you never run short on site.
Inputs
Result
Result
How to Use This Calculator
- Measure the room area in m² and clear ceiling height in meters.
- Indicate the predominant orientation of the space.
- Enter the thermal transmittance values for walls and roof (U in W/m²K).
- Enter interior and exterior design temperatures.
- Click 'Calculate' to get thermal load and recommended equipment power.
Frequently Asked Questions
As a rule, estimate 100–150 W/m² (350–500 BTU/m²) for hot climates and 75–100 W/m² for temperate climates. This calculator accounts for orientation and insulation.
For heating, heat loss in winter is calculated (ΔT between indoor and outdoor). For cooling, summer heat gain is calculated, which includes solar radiation.
Filters should be cleaned every 3 months and replaced annually. A full service (refrigerant, heat exchanger) should be done every 2–3 years by a certified technician.