Hi, I had a new boiler (Baxi Duotec) installed with radiators a while ago. One room stays fairly warm and that has one of the original rads in it. All the others were replaced and the other rooms seem to not stay so warm. I said at that the time, this seems to keep the heat for longer and he said something about it being "a good one". The old one seems to be an iron one without the fins. 80s style I suppose. The ones he installed seem to be generic ones that look just like these: https://www.screwfix.com/c/heating-plumbing/central-heating-radiators/cat830988 However, these new ones barely seem to retain the heat. I'm wondering, is it because they're rubbish or because these are convector ones and are supposed to move the heat around the room better. Is it worth replacing the radiators? I need to insulate the house better but seeing how the old radiator kept warm for ages after the new radiators had already got cold made me wonder about it. Thanks.