Oikodomisis
Thermal Loss Calculator

Estimate your home's heat loss.

Find out how much energy your space loses through walls, roof, floor, windows, and ventilation - and how insulation can reduce your heating costs.

thermostat Heat loss in kW bolt Daily energy use kWh savings Heating cost estimate

Results are estimations - this is not an official energy study.

Important

info How the calculator works

The calculation is based on a steady-state thermal equilibrium model. It does not account for solar gains, internal heat loads, thermal bridges, or thermal mass. The goal is a reliable first estimate.

Scenarios

Start from a scenario

Pick a scenario to auto-fill the form - you can change anything afterwards.

Room Geometry

Room dimensions
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Enter the interior dimensions of the space. The calculation models a rectangular room (or an apartment as a single zone).

Walls

North wall

Openings
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Place openings (windows, doors) on the wall. Position is measured from the left edge of the wall.

Walls

East wall

Openings
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Place openings (windows, doors) on the wall. Position is measured from the left edge of the wall.

Walls

South wall

Openings
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Place openings (windows, doors) on the wall. Position is measured from the left edge of the wall.

Walls

West wall

Openings
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Place openings (windows, doors) on the wall. Position is measured from the left edge of the wall.

Roof

Roof insulation
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If there is a heated apartment above, there are no losses. If it is a flat roof or pitched roof, losses are calculated.

Floor

Floor insulation
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If there is a heated apartment below, there are no losses. If it is a pilotis or ground floor, losses are calculated.

Airtightness

Ventilation / infiltration
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Critical factor! ACH (air changes/hour) depends on the number and quality of openings, sealing, and ventilation habits. Use "Custom" if you know the value for your building. The presets are indicative.

Temperatures

Indoor & outdoor temperature
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Outdoor temperature should correspond to the lowest typical value for your area (e.g. 0°C for Athens, -5°C for Thessaloniki, -10°C for mountainous areas).

Energy Cost

Heating cost parameters

Results

Floor plan

Seems too complex?

Contact us and we'll guide you through insulation evaluation and the best solutions for your home.

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This calculator provides indicative estimates based on a simplified steady-state model. It is not an official energy study or a binding offer. Actual performance depends on many factors (construction quality, thermal bridges, climate conditions). See Terms of Service