Single or Double radiators? And can I put it behind a sofa?

[LadyOfWaffle]

I have to buy a radiator for my living/dining room tomorrow and have no idea what the real difference is between double and single. Is one more economical than the other? Or is it literally getting double the heat from the same wall space? I thought all radiators were the ones with grills on top (double I presume?) nowadays but everyone seems to sell both... thanks so much, I know it's about the dullest question on MN but have no one to ask

Oh, and I wanted to put it under the window but the sofa is going under the window also - is that ok? Will the radiator still give off enough heat? Will my sofa explode? (seriously, had very hot curtain issues in the past!)

double rads (we have just had our central heating done and we have the ones with grilles on the top)

IME, if a sofa is in front of the radiator it will block most of the heat (you will have to pull the sofa out by a few inches i would have thought)

No it's not the dullest question on Mumsnet. But I am possibly the dullest person on earth for posting this reply

Have a look at this website -
www.heatandplumb.com/acatalog/Radiators.html
and look at the BTU calculator near the bottom of the page. It will tell you what size radiator is suitable for your particular room, depending on its size, number of windows etc.
We used it when choosing a new radiator for DS's room, and found we could fit a single radiator with fins at the rear, instead of the existing horrible bulky double radiator that was there. The new radiator gives off loads of heat and the room is toasty.

Make sure you leave a space between the new radiator & sofa. We've left about a foot between our sofa & the radiator.