Upgrading a radiator?

[777GE90]

Hi, I'm looking to buy and install a couple new radiators for my property as they are very outdated and lack the heating power to warm up the rooms.

The problem I have is that they are so old that I can't find radiators that match their exact size.

First radiator is a single sided 600mm x 960mm
Second radiator is a single sided 600mm x 1300mm

I'm hoping to replace them with modern doubles, with the first radiator I was thinking of getting a 600mm x 1000mm double radiator replacement but I'm not sure whether it is better to increase size or decrease it and I'm also not sure if I'll be able to get away with it without needing to get a plumber around to adjust the pipes.

For the second radiator it seems very hard to find a decent 1300mm radiator but you can get 1200mm and 1400mm radiators quite easily (sods law!). Same question here really, do you think I can buy the bigger / smaller size and install without needing to change the pipes?

EDIT: I guess the real question is, do I buy the new sized radiators and it'll be fine as the difference isn't much (the answer I hope for), or do I try harder to find an exact size and failing that I call a plumber to do a much bigger job and have my new carpets out, etc?

 

[ShaunCorbs]

You won’t sorry to say as your existing ones are imperial also the distance off the wall will be different eg pipe centre

Best to get a plumber in if you really want them doing

 

[nicam49]

You can buy longer tails to compensate for the size difference metric vs imperial. Toolstation do sell longer ones in different sizes. Telescopic ones also are available but according to the feedback, they tend to leak.
New rads come with wall brackets that you can fit so that the rad sits closer or further away from the wall to suit the existing pipework.

 

[777GE90]

Thanks for the replies, I was looking at this video and was hoping to do something similar with just bending the pipe, kinda like what this guy is doing here:
I wasn't sure how flexible these are but guess they have some play to go forwards / backwards like his?

So from what I understand if I do try this myself, I am better off getting slightly shorter radiators and then finding some sort of extension connector to them? Is that what you mean by longer tails?

 

[Ric2013]

Pay no attention to D Ireton. In my opinion he gives dangerous or simply bad advice, isn't aware of plumbing law, and however many years (or not) he's worked as a plumber, I wouldn't want him working in my house. A few howlers in that last video, to be fair.

It's true you can fiddle with adapters and even extension pieces of pipe if your radiators are a bit narrower than your existing valves. But you may struggle to get a double tight enough to the wall to fit where there was previously a single, however you set the brackets. If your pipes have plenty of play, you may get away with it, but likely you'll either have to work out how to modify the pipes at least a little, or you'll end up having to get a professional in. It oughtn't be a big job however as you can modify from the existing pipe without lifting carpets if that's not wanted.

Warning. The above will only work if the pipework is capable of carrying the extra flow for the extra heat output. British systems often have spare capacity in pipework, but it's not certain that this will be the case.