Size an air conditioner or heater to a room instead of over or underbuying capacity. Enter the room length and width in feet to get the floor area, then adjust for ceiling height, sun exposure and how many people typically use the space. The calculator starts from a baseline of about twenty BTU per square foot for cooling, scales it for tall ceilings, adds capacity for very sunny rooms and subtracts a little for shaded ones, and includes an allowance for occupants and a kitchen if you mark one. The result is an estimated BTU rating you can match to a window unit, mini split or portable AC. These are planning estimates, and a professional load calculation is best for a whole home system, but this gets a single room close. All math runs instantly in your browser with no signup.
It starts from the room square footage using a base of about 20 BTU per square foot, then adjusts for ceiling height and sun exposure.
A sunny room needs more cooling capacity, so the estimate is raised, while a heavily shaded room is lowered.
The BTU estimate sizes air conditioning or heating capacity for the room based on its size and conditions.
Size an air conditioner or heater to a room instead of over or underbuying capacity. Enter the room length and width in feet to get the floor area, then adjust for ceiling height, sun exposure and how many people typically use the space.
Yes. Room BTU Calculator is completely free, with no sign-up and no usage limits.
Yes. Room BTU Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Room BTU Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.