Copper or plastic & new radiatorsor re-use - opinions pl

Hi,

we've been getting quotes for a new combi & central heating system (2 bed semi, 65 sq m floorspace, 7 radiators, 1 shower room) and we're getting some differing opinions... Cost is a consideration but we'd rather spent a bit extra now than in 20 years time.

some people say to use 22mm pipe with 15mm branches to the radiators others say to use 15mm throughout.

some people say use copper others say use plastic pipe (double wall HEP?) with copper / chrome to the rads. Been told no difference except plastic was better insulator, less likely to burst, wasn't rodent proof (we've had mice in the past) and that there's been some (very rare) problems with plastic pipe furring up but the cause(s) weren't known.

Radiators are between 2 months and 14 years old, some of the older ones had a small quantity of a black (oily?) residue when we drained them. No obvious corrosion (either internal or external). Should we re-use them or should we buy new ones?

Any comments or additional pros/cons not covered would be welcome

Thanks

P

If problems with rodents in the past then copper would prob be the best way to go, 22mm runs with 15mm branches off to the rads. would reccommend older rads replaced dependant upon their individual condition. But of course the whole system should be prperly cleaned out before any new boiler is installed and a magnaclean/spirotech added on to the return to the new boiler. if your planning on staying in house til old and grey then don`t skimp on your final choice of boiler quality. there are some installers from your area on this site. hope it all goes well for you

Personally prefer copper (22mm main flow/return with 15mm spurs to rads) - which can be wrapped with insulation in dead spaces. Takes longer to install runs than plastic coils.

You don't need to replace all the rads if they are flushed out properly, it's a matter of choice. You will need to replace the radiator valves with TRVs as a matter of course.