is 25mm pipe insulation worth it on 22/28mm pipes

[trevw]

Hi,

I have a longish primary run (10m flow + 10m return) in my loft in 28mm copper pipe.. I originally planned to lag with 25mm pipe insulation and have clipped it so that I can, however it's pretty expensive (1.75+Vat/m vs 1.10 + Vat/m) .. but so is gas
(at the end of the run the primary splits between two UFH manifolds and a vented hot water cylinder)

I was wondering if I will get any significant benefit from the extra 6mm of insulation? I know with loft insulation you get a diminishing return for additional thickness and that the larger the pipe the lower the rate of heat loss/vol (I think?)

I have the same question for the same length pipe run for a 22mm copper hot water loop, which for obvious reasons I want to loose as little heat as practicable

any thoughts?

cheers

Trevor

 

[Agile]

Heat loss in the loft is totally wasted so thick insulation is advisable.

Heat lost within the house has a useful heating effect for 8 months of the year so does not matter so much.

Tony

 

[trevw]

it's all in the loft so.. thick as in 25mm? or as in 19mm? (9mm is the thin stuff isn't it?)

I guess it's just one of those things, you get what you pay for.. I am just curious really.. all told the 25mm will cost me an extra £80 (180 instead of 100) I'm curious in a very handwavey kind of way whether I'm likely to make that back in gas savings in 1/10/100 years

 

[muggles]

19mm should be more than adequate

 

[trevw]

thanks! was hoping I could get away with 19mm given the price differential..

I'm guessing I'd be looking at closer to the 10 years than 1 to make the extra investment back..

 

[rssteve]

a cheaper option would be to lag it with the small studd then get some 100mm fibreglass insulation and wrap that over the pipe, will be way cheaper.

 

[trevw]

not a bad idea.. I have some 100mm insulation, might look into how easy that would be to do..

cheers

Trev