What size mini-split for a 400 sq ft tiny home?
Many 400 sq ft tiny homes need 9,000–12,000 BTU with good insulation. Open lofts with high ceilings may need 12,000–18,000 BTU — use the high-ceiling toggle.
Mini-Split Sizing for Tiny Homes
Well-built tiny homes often insulate better per square foot than average stick-built houses. We start with a moderate BTU factor but add kitchen load for galley layouts in 200–400 sq ft footprints.
Space dimensions
ft
in
ft
in
ft
in
Sizing settings
One head for the whole tiny home
Most tiny homes use a single 9k–18k BTU head in the main living area. Sleeping lofts need airflow — a ceiling fan or ductless multi-head setup if the loft is isolated.
Our tiny home mini-split sizing guide and insulation guide pair with this calculator.
THOW vs foundation-built
Tiny homes on wheels may leak air at the hitch flex and wheel wells. If the shell feels drafty, set insulation to “poor” or upsize one BTU step even if walls are well insulated.
Frequently asked questions
One mini-split for whole tiny home?
Most tiny homes use one single-zone head in the main living area. Sleeping lofts benefit if airflow reaches them — otherwise consider a second head or fan circulation.
THOW vs stationary tiny home — same sizing?
Similar BTU math, but THOWs may have more air leakage at hitch flex points. If walls feel drafty, choose “poor” insulation or upsize one BTU step.
Related calculators
HVAC Calculators · https://hvaccalculators.net/mini-split-for-tiny-home/