These pipes should be insulated?

[saveasteading]

The plumber is reluctant to insulate these hot and cold (and hot loop) pipes, although they have done in the cold attic.

He says it isn't necessary in the warm side of the wall.

They will be contained in the service gap.

We think there will be condensation on the cold pipes, so they must be insulated as a minimum.

Also heat exchange from hot to cold which is wasting energy, and not desirable anyway.

And it will heat the service gap unnecessarily.

 

1. Are we wrong?

2. Is there a published standard to quote  to hasten agreement?

 

 

[markc]

I would say insulating makes perfect sense, hes right they won’t freeze but if they aren’t done it will grate on you for a very long time

[JohnMo]

Building regs states you should insulate hot water recirculation. (Or pretty sure it does).

 

Hope you do a good leak check on all these joints prior to plasterboarding.

[Conor]

I'd be wanting a few more pipe clips up there.

 

If it's a hot water recirculation system you absolutely would want to insulate. And insulate well. They are wasteful enough systems to start off with. 

[Andehh]

100% insulate the hot circulation pipe at the very least, otherwise it's basically a radiator dumping valuable heat in a non valuable space!!

 

Im also 90% sure it's in the building regs to do it as well....

 

 

[saveasteading]

There appear to be recent stricter rules on the subject, which perhaps our plumber hasn't noticed.

It's not easy reading so I will have to print and get the magic marker working. This commercial one is easier than the nhbc 

https://insulation-more.co.uk/blogs/the-pipe-duct-lagging-expert/new-guidance-on-pipe-insulation-for-domestic-heating-systems-2023?utm_source=shopsheriff&utm_medium=amp&utm_content=cookie-consent&_gl=1*1bkzay0*_ga*bHUwZUNCQnc0UnJOT21meGxKd2haYklyM3RkclhxcUhSRktweUtHWlJhU0tFYVpKdWVMWHFwLUV6NUF0Zl9tQw..#

 

It seems that the rules were crazily relaxed and now are sensible, but still  not strict enough to my mind.

[crispy_wafer]

This thread was piquing my interest as I've some pipes to insulate too, then I remembered there were some snippets of info in this thread that I'd saved.

 

and

pipeinsulation.pdf (nhbc.co.uk)

Edited November 29, 2023 by crispy_wafer
nhbc guidance

[Iceverge]

I would insulated the hot recirculation only. 

 

If you have a handle on the internal humidity the cold won't condensate. Insulating any other hot's is a bit of a waste of time. Tried to insulate my way out of an issue with 50mm pipe insulation but it still lost all it's heat in 15-20 mins. 

[Andehh]

6 minutes ago, Iceverge said:

If you have a handle on the internal humidity the cold won't condensate. Insulating any other hot's is a bit of a waste of time. Tried to insulate my way out of an issue with 50mm pipe insulation but it still lost all it's heat in 15-20 mins. 

 

I did exactly the same, and have exactly the same loss. It still bugs me, massive insulation around the pipe, fastidiously applied... Nigh on bugger all difference! Grrr

[Iceverge]

A new house might have a 1:1.25 ratio on internal volume:surface area with 200mm insulation. Running at a delta T of 15 deg maybe. 

A 15mm pipe will have an internal volume:surface ratio or over 1:400 and runs at a delta T of 30 with 10mm insulation. 

 

 

 

The pipe has proportionately 380 times more surface area to loose heat, twice the heat difference and 20 times less insulation. 

 

The numbers explain it all. 

 

 

 

 

[jfb]

I’m in the side of it not being worth insulating everything! 

[Hastings]

Pretty sure it is a regulation in Scotland, similar to the rest of UK. My first (Gas Safe) plumber put insulation on all his hot and cold water pipes (there is no wet central heating piping) and labelled them. It means leaving a good amount of spacing between. My second plumber didn't know the regulation and made it impossible for me to follow with pipe insulation where crossing pipes almost touched.

 

As @Iceverge shows, there is little point to it in terms of saving energy. That grey foam insulation isn't a close enough airtight fit to work anyway, even on straight sections of pipe, never mind the clips and tight elbows.

 

The only place it DOES make some sense to me is all pipes 1m connected to the hot water cylinder. But only if carefully taped and airtight to the pipe.

 

Maybe the reason for requiring it is for frost protection in the event of the house heating system failing completely, long power cuts in freezing weather like I remember in the 70s.

Edited December 1, 2023 by Hastings

[Kelvin]

Seeing all those joints that will be hidden in walls underlines why I used Rehau pipe with no hidden joints! 
 

I can’t see how insulating them will do much given the clips, elbows and difficulty in access around them. I had the same challenge with my cold water pipes in the garage. The garage is insulated but unheated. However I insulated all the exposed pipes with the thin grey stuff anyway. 
 

 

[Roger440]

On 29/11/2023 at 13:11, saveasteading said:

The plumber is reluctant to insulate these hot and cold (and hot loop) pipes, although they have done in the cold attic.

He says it isn't necessary in the warm side of the wall.

They will be contained in the service gap.

We think there will be condensation on the cold pipes, so they must be insulated as a minimum.

Also heat exchange from hot to cold which is wasting energy, and not desirable anyway.

And it will heat the service gap unnecessarily.

 

1. Are we wrong?

2. Is there a published standard to quote  to hasten agreement?

 

 

 

Sadly, thats not been installed with any thought to insulating. Many are too clodse together.

 

If you are expecting the plumber to do it, i fear you will be disappointed. Id be very surprised if there werent gaps all over the place. Rather defeating the point. Bit like builders do with insulation...............................

 

 

 

[Andehh]

Could at lest expanding foam over the pipe? Do insulate the recirculation pipe at least!!

[Thorfun]

I've read 'insulate the recirculation pipes' a lot but no one has every said why? if the HRC is turned on by some automated means, e.g. when someone walks in to a bathroom, then surely the insulation is not needed as the pump will turn on and get hot water to the tap for when the person who entered the bathroom needs it. unless that person is spending 15 minutes doing their business surely the water will still be hot by the time they need it?

 

[SimonD]

2 hours ago, Thorfun said:

I've read 'insulate the recirculation pipes' a lot but no one has every said why? if the HRC is turned on by some automated means, e.g. when someone walks in to a bathroom, then surely the insulation is not needed as the pump will turn on and get hot water to the tap for when the person who entered the bathroom needs it. unless that person is spending 15 minutes doing their business surely the water will still be hot by the time they need it?

 

 

It's because the hot water is circulated around the pipework, usually at programmed times of high usage. It doesn't get pumped when someone opens the tap. Therefore, if it weren't insulated you lose a load of heat from the hot water circulating around the house and then going back into your hot water cylinder and cooling that down too. So you could in theory end uplosing all your hot water. Think of the recirculation pipework being an extension of your hot water cylinder.

[Thorfun]

1 hour ago, SimonD said:

 

It's because the hot water is circulated around the pipework, usually at programmed times of high usage. It doesn't get pumped when someone opens the tap. Therefore, if it weren't insulated you lose a load of heat from the hot water circulating around the house and then going back into your hot water cylinder and cooling that down too. So you could in theory end uplosing all your hot water. Think of the recirculation pipework being an extension of your hot water cylinder.

but as @Iceverge said he'd tried insulating hot pipes and it didn't really help. so I still fail to see the point as the water in the HRC pipes still won't stay 'hot' for long, although obviously longer than without. I get that the cool water is recirculated back to the tank which could cool the water in the tank but in a 300l tank how much effect would the little in the pipes have on the large amount of water in the tank?  

 

I didn't bother insulating my HRC so I might've made a mistake but, tbh, I only ran the HRC as a 'just in case' scenario as most of my hot runs are relatively short so my dead cold leg might not be too bad. I will only find out once we're in and have lived with it for a while. and then if it is bad we can get the HRC working. if that means I have to run the ASHP a bit extra to top up the DHW cylinder then so be it.

[JohnMo]

Think the insulation of hot water return piping is a bit of a historic issue or if you install without proper controls. If you run on a timer and thermostat at a time period you are likely to use the hot water, not much of an issue without insulation.  If you want it running hot all the time, the heat loss us going to be ridiculous without insulation.  Horses for courses really, use common sense.

 

 

[Thorfun]

1 hour ago, JohnMo said:

Think the insulation of hot water return piping is a bit of a historic issue or if you install without proper controls. If you run on a timer and thermostat at a time period you are likely to use the hot water, not much of an issue without insulation.  If you want it running hot all the time, the heat loss us going to be ridiculous without insulation.  Horses for courses really, use common sense.

 

 

that was what I thought. and as we're having presence sensors in every bathroom I'm confident I can get our HA system to circulate the HRC when someone enters the bathroom so that hot water is ready once they've finished their business. it might work, it might not! at the end of the day it's not a massive issue if it doesn't and not something I will lose sleep over.

[saveasteading]

All interesting.

I think all hot pipes must be insulated.

It used to be only outside the insulated envelope, but now it is everywhere, unless exposed pipes are intended to heat the room.

 

I take people's points about the energy loss being small but that it depends on control.

However, there is also comfort to be considered. When hot and cold are sitting together, they will average out and so the user of a shower may get surges of average temperatures that are uncomfortable, and perhaps even upsetting.

Plus, people run a tap until it is the temperature they want, wasting water and energy, so if it is already warmer, then there is less waste.

 

• The NHBC document "technical guidance 8.1/35 is rather vague  or ambiguous (to me) upon first and second readings.

• A paper on the subject by "Insulation and More" interprets it as saying we must "insulate almost everything....and buy it from us."

3. Hot Water Pipes Must be Insulated

Whereas previous guidance focused mainly on space heating pipes, the new guidelines specifically mandate insulation on domestic hot water pipes. This includes hot water flow and return pipes, as well as primary circulation pipes connecting to hot water storage tanks.

 

• So i have now read 'the domestic building services compliance guide for Scotland (2022)' Section 9.3 is applicable.

I think it is also saying to insulate all hot pipes wherever they are, except when it is exceptionally impracticable...(.and we designers should not allow it to be so)

my italics

 

Here is a bit of it:

Direct hot water and heating pipework Pipework serving space heating and hot water systems should be insulated in all areas outside of the heated building envelope. In addition, pipes should be insulated in all voids within the building envelope and within spaces which will normally be heated, if there is a possibility that those spaces might be maintained at temperatures different to those maintained in other zones. The guiding principles are that control should be maximised and that heat loss from uninsulated pipes should only be permitted where the heat can be demonstrated as ‘always useful’. In a new system, all of the following new pipework should be insulated. a. Primary circulation pipes for heating circuits where they pass outside the heated living space, including where pipework passes into voids. b. All primary circulation pipes for domestic hot water. c. All pipes that are connected to hot water storage vessels, for at least 1 metre from the point at which they connect to the cylinder. d. All secondary circulation pipework that is kept hot by that circulation. Where a new boiler or hot water storage vessel is installed, or where existing systems are extended, new or existing pipes, ducts and vessels that are accessible or exposed as part of the work should be insulated as for new systems. Replacement hot water storage vessels should be insulated as for new systems. It is recognised that complete insulation will sometimes not be possible, where such services pass through or around structural building components, floor joists, for example, or where Domestic Building Services Compliance Guide for Scotland 2022 Edition 61 existing systems are wholly or partially retained as part of conversion works. In such cases, insulation should be fitted as for new systems as far as is reasonably practicable.

 

 

• Somewhere I read that similar rules will apply in England later this year, or next.

[cherryfountain]

 I agree with Kelvin .Every joint is a possible leak in the future . Why do plumbers still use copper and fittings for these situations? If the plumber had used Pegler MLCP or Rehau all that could have been done with minimal joints and in half the time.

[saveasteading]

It's only my observation of a few plumbers, but some insist on copper with joints, and I've never had a leak. And they have done the best job with regards to other issues.

There must be a reason that they are not saying. 

I'm guessing that they have had a problem with the long pipe systems, and also that complex runs are tidier with rigid pipes.

Conversely, the ones who used flexible pipes didn't have leaks but did have the odd other problem, perhaps related, perhaps not.

I'm talking of dozens of projects.

[Thorfun]

1 hour ago, saveasteading said:

unless exposed pipes are intended to heat the room

most pipes will be behind plasterboard. I'd be interested to know how much heat from an uninsulated hot pipe would actually get through plasterboard and a skim! surely minimal, right?

 

1 hour ago, saveasteading said:

When hot and cold are sitting together, they will average out and so the user of a shower may get surges of average temperatures that are uncomfortable, and perhaps even upsetting.

is this really the case? we've used plastic throughout anti was my understanding that these lose less heat than copper and so even with a cold pipe sitting next to a hot pipe I'd be amazed if either had a noticeable effect on the other. and for showers in a new build surely the showers would have thermostatic valves in them so as to regulate the  temperature and stop the fluctuations?

1 hour ago, saveasteading said:

Plus, people run a tap until it is the temperature they want, wasting water and energy, so if it is already warmer, then there is less waste.

agreed. this is why I was suggesting using a PIR to run the HRC when someone enters a room. I guess as is argued above if the HRC is uninsulated then the tank temp could be affected by putting cool water back in the tank but if the tank is being heated twice a day then I still think we're talking minimal impact on energy use to maintain the tank temperature.

 

btw, I have absolutely no data to back up any of my points! I'm just hypothesising. I'm also not that fussed. if I have to run my ASHP a little extra each day then so be it. during the summer it'll be powered by solar and in the winter it'll be on most the day keeping the ufh at temp anyway. 🤷‍♂️

[Hastings]

1 hour ago, cherryfountain said:

Why do plumbers still use copper and fittings for these situations? If the plumber had used Pegler MLCP or Rehau all that could have been done with minimal joints and in half the time.

Rodents can and do eat through anything but copper pipe. That's the reason plumbers I know don't like to use it where pipework is hidden.