How Many kW of Heating Does My Villa Need? (Free Load Calculator)

Why "watts per square metre" gets villas wrong

The quickest way to size a heating system is to multiply floor area by a fixed figure. It is also the quickest way to end up with a boiler that is too big, rooms that never warm up, or both in the same house.

Heat loss is not proportional to floor area alone. Two rooms of identical size can lose very different amounts of heat depending on how much glass they have, how many walls face outside, which direction they face, and how well the building is insulated. A corner bedroom with two external walls and a large window is a different problem from an internal room of the same square metres.

What a real load calculation accounts for

Room by room, not whole-house. The total tells you the boiler size; the per-room figures tell you the radiator or underfloor loop for each space. You need both.
Glazing area and type. Usually the single largest loss in Egyptian villas.
External wall count and orientation. Corner and north-facing rooms lose more.
Ceiling height. Volume matters, not just floor plan.
Insulation level. Changes the answer more than any equipment choice.
Target indoor temperature. Comfort is usually 20–22 °C; asking for more raises consumption with little comfort gain.

Emitter type changes the answer

Underfloor heating spreads output over a whole floor, so it works at low water temperature — typically 35–45 °C — which is what makes it so efficient and why it pairs naturally with heat pumps. Radiators need hotter water, around 55–70 °C, but respond far faster. Sizing has to be done for the emitter you actually intend to install; the same room needs different numbers for each.

Calculate it for your own home

Our engineers use a room-by-room load calculator, and you can use the same tool. Add each room with its area, floor, glazing and exposure, and it returns the heat load per room and for the whole property — then builds the system around it.

Open the space heating calculator — free, and it gives you a figure you can hold any quote to.

What the calculator sizes against

The tool matches your load to the equipment we actually supply, so the output is a real specification rather than a number:

Boilers — Unical WMB 24 kW and 32 kW.
Underfloor heating — PEX pipe and insulation by the square metre, with manifolds and actuators per loop; Giacomini, De Dietrich and Unical.
Radiators — panel radiators from 40 cm to 100 cm and Sira elements, with piping, manifolds and install kits per point; Giacomini, Sira, De Dietrich, Unical and Ariston.
Towel radiators for bathrooms, and zone thermostats for room-by-room control.
Alternative emitters — ThermaSkirt skirting-board heating and CosyStone stone-finish radiators where wall space or aesthetics matter.

Prefer we do it? Book a free site assessment and we will calculate the loads on site.