For cooling, heat pumps and AC units are sized by BTU removal load — our BTU calculator applies to both. Heat pumps add reverse operation for winter; efficiency drops as outdoor temperature falls.
Mini-splits are almost always heat pumps today — one outdoor unit heats and cools a zone.
Climate and backup heat
See SEER ratings explained for efficiency shopping — higher SEER saves kWh over years, not first-season comfort.
Mild climates: heat pump often replaces furnace for moderate loads
Cold climates: auxiliary heat strips or furnace backup may run below ~20°F
Cooling-only window units: no heat — cheapest upfront, no winter value
HSPF and SEER: read both on heat pump labels
Frequently asked questions
Is a mini-split a heat pump?
Most ductless mini-splits are heat pumps — they heat and cool. Confirm on the spec sheet before buying cooling-only listings.
Do heat pumps work in cold winters?
Modern cold-climate models operate below 0°F with reduced output. Sizing must account for design heating load — not cooling BTU alone.
HVAC Calculators provides estimates for planning only — not professional HVAC engineering or installation advice. Verify sizing with a licensed contractor before purchasing equipment. Read disclaimer
