Formula
The room starts at 25 BTU per square foot, then occupants and windows add fixed amounts:
BTU/h = area × 25 + people × 600 + windows × 1,000
The BTU page uses 20, 25, or 30 by sun and stops there. This page always uses 25, then adds the people and windows.
Assumptions
- The area is floor area in square feet.
- Each person adds 600 BTU per hour.
- Each window adds 1,000 BTU per hour, with no separate sun choice.
Worked example
A 200 square foot room with 2 people and 1 window has a guide of 7,200 BTU.
Input definitions
- People
- Occupants in the room while it is being cooled. The first person is required.
- Windows
- Ordinary windows counted one by one. Zero is allowed.
Limitations
This is a planning estimate. The rate, sun hours, and losses are numbers you type. It is not a utility bill, a solar design, or a room-by-room load calculation.
Questions
Why is the sun factor missing?
Sun is the other page's only adjustment. Here the extras are people and windows, on a fixed 25 BTU per square foot.
Can the guide be zero windows?
Yes. The window term drops out and the result is area and people only.