House
Air conditioning for a house: sizing a whole floor and choosing the right system
In an apartment the question is "which unit"; in a house it is "which system". More rooms, two floors and often a need for primary heating. The four solutions we offer, with honest pros, cons and prices.
5 min readUpdated
First: what you want from the system
Summer cooling in 2–3 rooms is easy. Primary heating of the whole house in winter depends on insulation, whether there are radiators or underfloor heating, and budget. Answer this before looking at models.
Separate units in the main rooms
Living room 12000–18000 BTU plus 2–3 bedrooms at 9000 BTU, each with its own outdoor unit. Cheapest, most reliable and most flexible; the downside is 3–4 outdoor units on the facade.
Multi-split
One or two outdoor units for 3–5 indoor ones. Clean facade, rooms within 15–20 m; a failure stops the whole floor.
Ducted
One indoor unit in a suspended ceiling and ducts to every room. Invisible, even temperatures; needs a ceiling void or planning at build time. The best choice for a new house or a full renovation.
Air-to-water heat pump
For a house with radiators, underfloor heating or fan coils that wants one system for heating, cooling and hot water. Higher investment, lowest whole-house running cost.
Sizing a 100 m² floor
100–120 W/m² per room, not per floor: living room 35 m² → 12000 BTU; two bedrooms at 15 m² → 9000 BTU each; study 12 m² → 7000–9000 BTU. For primary heating add 15–20% for an uninsulated roof and size by output at −7°C. A survey for a house is free in our service area.
Frequently asked questions
Can one air conditioner heat a whole house?
No. Warm air does not pass through closed doors; bedrooms need their own units or another system.
Multi-split or heat pump for a house?
2–4 rooms without a water heating system: multi-split or separate units. A whole house with radiators or underfloor heating and hot water: an air-to-water heat pump.
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