Underground heating pipes

[Megaflo-Experts]

Can anyone recommend some pre-insulated pipe (or similar) to supply heating to an outbuilding about 20m away from the main house. The pipe will be buried in a underground trench, and therefore needs to be well insulated to avoid heating the ground!
I know Polypipe have a product with twin pipes within a larger pipe, which looks good, but is expensive at around £50/m.

Alternatively, is there a way to insulate and run standard Speedfit (or equivalent) to the outbuilding.

 

[Alanc]

Uponor have a system for this, won't be cheap though.

 

[Gray0689]

Ecoflex
Flex Allen
Rehau
They all make what you want but all expensive £40-£50 per metre

 

[bright spark]

Have you had a look at Calpex pipe. If you literally want to put a dual pipe down all in one, it's the one to go for. It's expensive but very well made, insulated etc. it doesn't need a duct and can be put straight in a trench.
have used it many times in commercial settings. You just order d length you want and it's delivered on a coiled up.

 

[missplumb]

as has been said, we use Rehau for all our underground pipework. There are two types, Ravitherm which is the same as Calpex (the inner carrier pipe is made by Rehau) will do the job but for better efficiency and far superior heatloss loss we use Rauthermex. It is more expensive and tbh for 20m i wouldnt waste the money on the extra cost. Also you will have to include the cost of tool hire as you have to use specific crimping tools.

 

[Megaflo-Experts]

Thanks for all your helpful replies, an the photos missplumb.
I've read up on most of the products mentioned, and Uponor and Calpex sound good. I like Uponor as it doesnt require special tools or couplers.
I guess £50/m is the typical price, so the customer may be in for a shock!