Start with the space
Square footage alone is not enough. The calculator also asks for climate band, insulation, sun exposure, and ceiling height before it returns a BTU range.
Mini-split sizing for US homeowners
Find a practical BTU range
for your
actual
space.
Answer five questions and get an approximate mini-split or heat-pump size in BTU/hour. The calculator shows the result immediately, keeps the estimate brand-neutral, and explains when a larger project needs a formal load calculation.
5
inputs that affect load
8
standard sizes checked
0
contact fields required
Sample calculator output
20,200-23,800 BTU · shop the 24k class
1,100 sq ft · mixed climate · average insulation · medium sun
The approach
A range first. A product later.
Most quick sizing tools start and end with square footage. Splitsizer treats that as the first input, then adjusts for the factors that routinely move a room up or down one standard equipment size.
Snap to real sizes
The result is a usable range, not a false-precision number. It then points to the nearest standard mini-split or heat-pump size class.
Know when to call
A single room and a whole-home replacement are different projects. Larger jobs get a clear note to use the result as a screen before a formal load calculation.
Start here
Three checks before you buy.
The calculator is useful because it narrows the search. It is not the last word on code, rebates, installer design, or final equipment choice.
Before you buy
DIY or installer?
Small single-zone kits are the easiest to compare online. Whole-home and multi-zone projects need load calculations, electrical checks, permits, and local code review.
Sizing 101
Range first, model second
Use the calculator to avoid shopping blind, then compare equipment inside the recommended size band. Bigger is not automatically better.
Money check
Verify incentives late
Federal, state, utility, and local programs change. Check official rebate and tax-credit rules close to purchase, not at the start of research.
Start with the estimate
Five inputs. One useful range. Yours.
Square feet, climate, insulation, sun, ceiling. The calculator returns a BTU range, the nearest standard size class, and a plain note when the project should move from quick estimate to installer calculation.
Run the calculator