How do I measure replacement radiators?

you need to work out the "heatloss" for the rooms before you decide on radiator size.. I got a program download from www.myson.co.uk called heatloss manager 98 which seems daunting at first but isn't at all. Unfortunately this had been withdrawn forupgrading last time I looked. Try a search for "heatloss calculator" I've seen others around, try www.stelrad.com I think they do one also.
If you are just going to guess rad size buy and fit it with valves to wall first and join pipes to suit.

 

I'm no expert but hope I can help...
Do you mean that the pipes have been left in situ sticking out of the floor boards but no valves or radiators attached? What size pipes are they?
If you have pipes sticking out of floor yes you need to attach valves first and measure between them. You will have to allow for the radiator valve tails which attach to rads before fitting. You will probably find that you need a standard radiator size (see sizes at myson or stelrad websites) If not you should either move one pipe or if the adjustment needed is small you may find extendable rad valve tails give enough play.

 

take the room sizes i.e lenght by lenght and height sixes take these to your rads surplier and he will tell you the size rads you want.
bear in mind that if you already have the pipes showing then messure what the centres are and take these with you and write down what rooms they are to.
then put the valves on the end of the rads and fit the pipe sto suit. easy,
bthomemain@aol.com
cheers bry

 

Heatloss calculator - try http://www.barlo.co.uk