Electrical requirements
Heat pump thermostat wiring diagram: what each wire does
A heat pump thermostat wiring diagram, terminal by terminal: Y, O/B, AUX/W2, E and the rest on 24VAC, and how two mini-split makers route control instead.
Blog
Field notes between guide updates: warranty changes, price moves, and things we got wrong. Same verification rules, lighter reads.
Sizing & scenarios
Heating BTU calculator: what your heat load means
Heating BTU calculator: a 400 sq ft zone 5 room with 8 ft ceilings and average insulation screens at 11,500 BTU/h on a typical zone 5 winter design day.
Sizing & scenarios
Mini split heat pump 12000 BTU: what it heats and cools
Mini split heat pump 12000 BTU: ENERGY STAR's AC table says 450 up to 550 sq ft, but at 5°F two 12k units heat 8,400 or 16,200 BTU/h. Size for the cold.
Brand reviews
Mitsubishi mini split not heating? What to check first
Mitsubishi mini split not heating? Defrost can pause heat for up to 10 minutes. Check settings, filters and snow; stop at a blinking lamp unless on standby.
Sizing & scenarios
1.5 ton mini split: 18,000 BTU/h, the room it actually fits
A 1.5 ton mini split is an 18,000 BTU/h unit. ENERGY STAR puts that at 700 to 1,000 sq ft, makers say 500 to 900, and one unit heats 12,800 BTU/h at 5°F.