The old copper vs plastic pipe question

iwoot

Hi all,

I do a bit of plumbing using plastic and copper pipes and fittings and each have there place.

What i would like to know is whats is the pros and cons or plastic vs copper when heat is a factor. In other words what would be the most efficient system to retain heat.

I have a ground floor flat with vented wooden floors with no insulation between the joists.

I was think about piping 15mm copper pipes to all rads and then using the thicker bylaw insulation to lag the pipes.

Or was just going to use 15mm pex. But then it doesn't seem easy to insulate.

What would be the best way to keep the pipes as hot as possible regardless of the boiler output/money/usage etc.

Cheers all

27col

Why should 15mm pex be any more difficult to insulate than 15mm copper. They are both the same size.

iwoot

15mm plastic pipe can be insulated but the fittings are much bigger and cannot be insulated very easily which creates cold bridges in the insulation

Copper end feed are pretty much the same size as the pipe so is easier to insulate.

If you could insulate plastic with thick bylaw insulation it goes back to my question of what would be better at retaining the heat the copper or plastic ?

Mankysteve

Well a metal pipe clip will conduct heater better than a plastic one so you'd get equal bridging effect i suspect. Dont most copper install use the same plastic clip as copper anyway.

Though personally for me copper all the way I would trust it to hand around a lot longer.

iwoot

Nothing to do with clips. I mean the elbows / tees / joins. Speedfit are a lot bigger.

Like i say it doesnt matter which i use copper or plastic makes no difference to me to install.

Im just after some info about what would retain the heat better ?
Or which is the best system to use to retain the heat ?
Is there any specs anywhere about insulating pipes ?

Mankysteve

Plastic will retain heater better. Copper is a very good conductor of heat plastic is not

iwoot

so id be better off installing plastic with insulation then i guess.

I have a setup on my solid fuel rayburn which only has 1 rad which is about 12 meters away (25 meter pipe run) and i would like to keep the heat in the pipe as long as possible. The old rayburn was intended for DHW only but i chnaged it to do a single rad instead. Works a treat.

I have gas central heating throughout but we have this rayburn setup so when its on the rayburn heats 80% flat and the single rad heats the colder parts on the flat. Then we do not need to use the gas boiler only for heating the hot water tank.

Thanks for all your help

molerat

The heat leaks out pretty quickly when rodents chew through the plastic pipe.

iwoot

everyone needs a hot bath once in a while

TimBuckTeeth

The rayburn can get the water very hot so I would rather use copper, it is more robust and neater, like you say the joints and elbows can be insulated easily. Bare copper pipe will lose more heat than plastic, but when insulated with a thick foam insulation the difference will be insignificant.

iwoot

As its stands the rayburn is connected to 22mm copper from the back boiler both up to the header tank and down under the floor. Bascially the pipes you see are copper and painted and the pipes under the floor to the rad are plastic and again back into copper for the rad tails.