​It is generally assumed that the 10 m2 apartment takes 1 kW of installed heaters to warm up to 22-23 degrees. For example . 40 m2 apartment to 4 kW . Depending on the desired temperature set on the thermostat of the heating device and insulation of the apartment, heaters will work a number of hours . The better insulation and lower the required temperature heating devices will work fewer hours during the day. For cost consumers for heating, such as marble radiators usually the time that they work 30 % ( time ) when outside temperatures are too low (about 5 above zero ) . This time the work goes to 40 % for temperature minus 10 or more . Of course this means some , shall we say , mediocre insulation , good windows . Can be approximately calculated to 4 kW installed , if you do 40 % of the time spent 4×0.4x24h = 38.4 kWh per day . For the three- or two-person household , that usually lives in the apartments 40m2 and smaller sizes , the consumption of electricity for household usually does not exceed 450 kW . Total spending would be up to 1600kW . On the power consumption greatly affects the temperature we want to have in the apartment. Each level demands additional , not a small difference in consumption. Besides insulation area is also very important . No heater and its heat emission will have no effect or may be a cheap option for heating , if we heat ” escapes ” the little glass or poorly dihtujuće compounds on the windows , patio doors , or through uninsulated walls , ceilings or floors .. If our walls are or ceiling are not insulated and has heat constantly ” leaking ” it is normal that in these cases, our heaters have more and more likely to burn in order to maintain the set temperature .