Pipe insulation & different types

[Mjward]

Hello

Just put in new Hep2o pipework for CH system and now looking at insulating/lagging the pipework.

There is quite a big jump from the basic polyethylene foam (70p/m) up to the Kingspan Kooltherm (468p/m) with quite a few options in between.

Is it like going from single to double glazing i.e. going from no insulation to any is 90% of the energy saving, and paying up for triple glazing or in this case Kingspan will only give marginal improvements? Keen to save money but if its an extra few hundred quid now but that's breakeven on savings in 5 years, worth doing.

 

[Ric2013]

Good to see someone thinking about insulation.

In very simple terms, the cheapest way to get improved insulation is to have thicker insulation, even if that means using old jumpers to wrap the pipe. You can get insulators that are better for a given thickness, but you see my point, I hope. Most wooly insulators (fibreglass, wool, cellulose fibre etc.) have a k value of 0.4 and I think polyethelene foam is around there too, whereas a phenolic foam will have a k value aound 0.2. This lower value basically means it's twice as effective for a given thickness, but you'll probably find it costs many times more. It might cost less to have a thicker layer of less effective insulation, if you have the space for it.

So your glazing analogy isn't far off.

If you are really into insulation, instead of using normal pipe clips, use large diameter Munsen type rings around the lagging itself to avoid leaving thermal bridges (holes in the insulation, basically).

Bear in mind that heat lost from a pipe will give heat to a room same as a radiator, so only really worth lagging pipes that run through areas that aren't being heated by the water in that pipe.

 

[Mjward]

Good advice re thickness playing big role as that will definitely come into play when looking at cost perspective.

However your last point has me thinking... This has been run between the joists for first floor bedrooms ie heat "loss" will be heating rooms that should be heated anyway ie better to leave as is?

 

[ShaunCorbs]

Kingspan is good for - temps eg external water mains / garages

If it’s just under floors the normal grey insulation is fine 13mm plus wall thickness

 

[Mjward]

Kingspan is good for - temps eg external water mains / garages

If it’s just under floors the normal grey insulation is fine 13mm plus wall thickness

Perfect, will go down that route, thx Shaun

 

[Tim Court]

Depending on the age of your house I would check for underfloor draughts before I do away with pipe insulation between floors.
The residual heat coming from your pipework may be getting wafted away through perimeter brick/blockwork. Joist penetrations in external walls are notorious for gaps into the cavity and worse.
Sometimes with a nice thick carpet and underlay you might not easily notice the gales blowing about under your upstairs floors. And your floor coverings can also insulate against most residual heat ever reaching your tootsies.

 

[Mjward]

Bizarrely enough got around to lagging today, came up 15m short on the 15mm but that just leaves boiler area. Rest house all done and hopefully start to see some energy savings

 

[Gasmk1]

Earth strap looks a bit dubious

 

[Mjward]

Earth strap looks a bit dubious

It is. New boiler only put in last week, central heating guys back tomorrow to finish off.


Good eyes!

 

[exedon2]

That's a really horrible way to do a drain off with press fittings!

 

[Mjward]

That's a really horrible way to do a drain off with press fittings!

Oh dear... What's wrong with them, do I need to complain?

 

[exedon2]

Wrong drain off should be long stem type then you would not have that scruffy bit of soldering.
Holds water but any decent engineer looking at it will always think what?8

 

[Mjward]

Understood. In the future if I need to drain system, how can I tell which of those two valves to use?

 

[Ric2013]

They look like flow and return pipes. You may need to use both as the water in the top pipe will probably have no way to get into the lower pipe in a draindown situation (this is normal and is probably why 2 valves have been fitted.).

 

[Mjward]

They look like flow and return pipes. You may need to use both as the water in the top pipe will probably have no way to get into the lower pipe in a draindown situation (this is normal and is probably why 2 valves have been fitted.).

Ah very good to know. Thanks for your help