In my appartment I mainly use one oven for heating. This has a max capacity of 2 kW. I have calculated (roughly) that my appartment has a need for about 1.8 kW at the minumum temp of -19 C outside. Now, my question is do you immediately think that it's more economical for me to turn the oven off during the day (when I'm at work) and then turn it on when I come home, or should I have in on 24/7? This without sacrificing too much comfort due to lower temp of course... Naturally I'm looking to have about 20 C at all times when I'm in the house, except maybe during night time. The building is mainly of concrete, and so I'm not sure how long it takes for the heat to escape, and how long it would take to bring the temp up again... Thoughts?