Air conditioning installation in Sant Joan d'Alacant

Sant Joan d'Alacant is a separate municipality from Alicante, mostly detached and semi-detached housing rather than blocks.

A house exposes far more surface to the sun than a flat does, and that changes the calculation room by room.

Why a house needs room-by-room sizing, not one figure

In an apartment, most rooms are surrounded on several sides by other heated or cooled spaces, and only one or two walls face outside. In a detached house, every room has external walls on two or three sides, and the top-floor rooms have a roof above them. That difference means the variation between rooms in the same house is far wider than in a flat, and a single figure for the whole property is close to meaningless.

A first-floor bedroom under an uninsulated flat roof facing west is the worst case in this kind of housing. It takes sun on the wall all afternoon and heat radiating down from a roof that has been absorbing it since morning. The same-sized room on the ground floor facing north, shaded by the building itself, can need less than half as much.

This is why we measure each room rather than working from total floor area. What matters is orientation, the glazed area and its shading, what is above the ceiling, and whether external walls are insulated. Four rooms of identical size in one house here routinely come out at three or four different capacities.

The practical consequence for choosing a system: a multi-split lets each indoor unit be sized for its own room, which suits this housing well. Ducted systems distribute a single capacity across the whole floor and need the zoning designed properly, or the hot west bedroom stays hot while the shaded north room is freezing.