By the way, do you have heating in your basement? If not, it might be a good idea to look into infrared radiation heating. If you direct the lamps onto the walls and the floor, they stay comfortably warm and the temperature does not need to be as high because you won't be heating the air (less dust in the air is also a bonus). Also, because the walls and the floor will stay dry all the time, they will insulate better leading to lower power requirements. Not to mention the fact that the risk of moisture damage to the walls is lower. Also, infrared lamps are cheap to buy and install.
But if you want radiators, you might want to check out this product and calculate if it makes economic sense:
https://techcrunch.com/2018/03/08/qarnot-unveils-a-cryptocurrency-heater-for-your-home/
We are planning on floor heating and have a heating system that can handle it - but will have to likely take the floor out to do so - not what I wanted.... Will look into infrared and see what the deal is :)
Do you have a link for IR home heating in Finland that isn't for Saunas?
Here's one:
https://fi.trotec.com/tuotteet-ja-palvelut/koneet-homecomfort/laemmitys/infrapunalaemmitin/
Another:
https://www.heat4all.com/en/infraredheating-advantages
Thank you, I will see how it will go. The problem is that we supposedly shouldn't lay a surface of concrete sown on the existing one because of the potential for moisture from the ground coming up and getting trapped. but I don't get this since there is already concrete there, so why cant we add a couple extra cm. Even with the walls heated, the surface isn't nice and there are large undulations in the old boiler room