A practical guide to the measures that actually reduce energy use and heating costs in Slovenian homes.
The average Slovenian detached house uses around 150 kWh per square metre per year for space heating alone - several times more than current construction standards allow. Because roughly 70 % of Slovenia's building stock was built before 1990, the great majority of houses still have an uninsulated or poorly insulated envelope. That is precisely why energy renovation is among the most predictable investments available to households here - but only if the measures are carried out in the right order and with realistic expectations.
Below are the measures we discuss most often in advisory conversations, together with indicative costs, expected savings and current co-funding terms. All figures are indicative and apply to a typical detached house; for an estimate specific to your building, use our energy calculator or consult a free adviser from the ENSVET network.
The most common - and most expensive - mistake in energy renovation is getting the sequence wrong. Owners often replace the boiler or install a heat pump first, and only then think about insulation. The result is an oversized, overpriced appliance that never reaches its rated efficiency in a poorly insulated building.
A heat pump is today the most efficient way to heat a detached house, but its economics depend entirely on the building you install it into. A unit with a seasonal coefficient of performance (SCOP) of 3.2 produces roughly 3.2 kWh of heat from one kWh of electricity - but only if it can operate at low flow temperatures.
A typical older house loses roughly 25-35 % of all its heat through uninsulated external walls. A brick wall without insulation has a thermal transmittance of around 1.6 W/m²K; with 16 centimetres of good insulation that value falls to approximately 0.22 W/m²K - less than a seventh of the original.
Windows are usually the weakest element of the thermal envelope. Old single or double glazing has a thermal transmittance of 3-5 W/m²K, while modern triple glazing reaches values below 0.9 W/m²K. Since windows typically make up around 17 % of a house's heated floor area, their contribution to total losses is disproportionately large.
Photovoltaics have become considerably cheaper over the past decade and are technically reliable - panels typically carry a 25-year power warranty and an expected service life of over 30 years. In Slovenian conditions you can expect around 1,038 kWh of annual output per kilowatt of installed capacity, meaning a 5 kWp array produces roughly 5,200 kWh a year.
On 16 April 2026 Eko sklad published public call 126SUB-OB26, which raises incentives substantially compared with the preceding call 114SUB-OB24. The increase was introduced following guidance from the Ministry of the Environment, Climate and Energy as a measure to cushion the effects of the energy crisis.
Not every saving requires an investment. The following measures are free or very cheap, and you can act on them today:
Enter your house details and see in a few minutes how individual measures affect your energy use, energy class and annual heating costs.