Insulating external hot pipes

[Timothy Murphy]

There is a short (2 metre) outside pipe on the central heating system on my cottage. Is there any special way of insulating such pipes? Or do people use the same circular insulating tubes as indoors?

[newshound]

Do you mean a "hot" pipe where you want to reduce energy loss, or something like a vent or overflow that you don't want to freeze?

Assuming it's 15 mm and close to the wall, you could put on a 15 mm sleeve, then split a 22 mm sleeve and fit that over the top to get a bit more average insulation thickness, but still a reasonably neat appearance.

[The Natural Philosopher]

Depends a lot on what your house is made of.

You could encase it on polystyrene board as well, inside a timber frame, or build a little brick housing or a bit of drainpipe and use expanding foam..

The main thing is to realise that whats needed is a much bigger weatherproof attractive enclosure than the pipe itself, and lots of insulation between the pipe and that enclosure.

[Timothy Murphy]

Thanks for your useful reply. It is a hot pipe. The central-heating boiler is in a kind of outhouse, and this is the pipe connecting it to the cottage proper. It could actually have gone through an internal wall; I'm not sure why it didn't - maybe the stone wall was too thick.

I'll try that.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Timothy Murphy saying something like:

Build an enclosing box and fill it with foam. Insulate the pipes first with a layer of conventional foam sleeve and one of Armour-flex (iirc).