ASHP - choices, choices. Feel like I’m back at square one

[-rick-]

10 minutes ago, Nickfromwales said:

Planning a solution for 50 years or even 30 years from now is bonkers imho, as at that point lifting the floor and re-piping the UFH wouldn’t be considered a real drag. Would also be the end of the serviceable lifetime of the system anyways.

 

I took 50 years as that's what the pipe manufacturers are claiming is the lifetime of their pipes. If you are putting pipes into an insulated raft that is also the foundation you are unlikely to rip that up for the lifetime of the building.

 

3 minutes ago, Nickfromwales said:

Always best to remain completely sane when deciding how to do these things, as way too many people stare into a crystal ball and try to navigate ‘right now’ into ‘the future’.
 

10 to 20 year plans are reasonable, but after that it’s just money and time down the drain. 

Definitely not proposing to spend significant time or effort on it. From my POV, not worrying about precisely where kitchen units go, etc, at UFH design stage just means less dependencies on progress. You can get on with UFH install while still deciding between a couple of kitchen options, etc.

[Dillsue]

53 minutes ago, Nickfromwales said:

Shouldn’t. Not couldn’t. Anything can be done etc etc, just why would you is my point.
 

You don’t need a solution if you don’t create a problem, basically, so you would put the pipe in the open area and go for tighter cc to get more w/m2 in the room vs emit the heat in an closed space such as the kick space and then have to push it into the room mechanically.

 

And when you remodel the room so the areas you left unheated are now exposed and the areas with heating are now covered??

[Nickfromwales]

3 minutes ago, Dillsue said:

And when you remodel the room so the areas you left unheated are now exposed and the areas with heating are now covered??

If you have a kitchen space that can be remodelled with a full 180° flip, then you have the first one I’ve ever seen.

 

Kitchens are quite specific and usually the space will be used and optimised from day 1, so a refurb would be bound by those terms.

 

Hypothesising about a room that would likely never exist isn’t a great way to use the limited days off we get.

 

I pipe under most islands, and peninsulas, if going low temp / raft down etc, unless it’s completely obvious that the space will only ever be dressed the same way, even if it’s fully remodelled; a peninsula may become detached and become an island and vice versa, so the only other consideration for future proofing is to cable and pipe for an island, maybe adding hot and cold + waste connections there (to use from day 1 or to install in abeyance) to allow that to become an island. 
 

After that…..we’d all need Mystic Meg to sign up and show us the future…. 🧙‍♀️ 

[JohnMo]

44 minutes ago, Nickfromwales said:

10 to 20 year plans are reasonable, but after that it’s just money and time down the drain. 

 

16 minutes ago, Dillsue said:

And when you remodel the room so the areas you left unheated are now exposed and the areas with heating are now covered??

Who in right mind remodels a kitchen in under 10 years, 20 years isn't that likely. Most kitchen units have a decent long warranty. We have been in our house for 5 years now, redecorating isn't even on the horizon, remodeling a perfectly good kitchen is unlikely ever in my life time. I would possibly build another house first, that's unlikely also.  May upgrade a laminate work top but nothing else likely.

 

Your just planning for thing unlikely to occur, adding complexity likely to go wrong.

 

[Nickfromwales]

Most would just refresh doors / worktops etc anyways.

 

Another BH Sunday afternoon lol. 😝 

 

I expect @Great_scot_selfbuild will only want to fit his kitchen once lol. 

[saveasteading]

52 minutes ago, -rick- said:

adding more pipe than needed. 

On reflection I'm not thinking to add redundancy thtough extra piping, but to avoid petty savings. Eg does the utility room need any ufh?

Miss it out, or half of it and save £30?

Space the pipes further apart in some rooms? Likewise.

There are places to save hundreds or thousands or tens of thousands and this isn't one of them.

[JohnMo]

15 minutes ago, saveasteading said:

does the utility room need any ufh?

We have our UFH manifold in there, so whole house UFH pipes pass through it. No additional loops needed there, so why put them in?

[-rick-]

30 minutes ago, saveasteading said:

On reflection I'm not thinking to add redundancy thtough extra piping, but to avoid petty savings. Eg does the utility room need any ufh?

Miss it out, or half of it and save £30?

Space the pipes further apart in some rooms? Likewise.

There are places to save hundreds or thousands or tens of thousands and this isn't one of them.

 

I agree, I suspect that it might not come across in some of my posts but my thoughts are to try and keep things simple and avoid complexity.

 

- Do do the calculations about how much piping you need to emit enough heat

- Build a layout that allows you to output that heat at very low temperature

- Within reason try to avoid different length loops and transit areas where pipes group densely (hallways can be heated by the heat from loops traversing the hall way to other areas, doesn't need it's own loops), etc

- Minimise crossing movement joints (make sure you follow best practice where crossing happens to allow the pipes to move in the slab)

 

You don't need to design everything to the nth degree, the low temperature nature builds flexibilty so everything doesn't have to be perfect.

 

@Gus Potter I think would suggest to have more shorter loops with some overprovision on the assumption that loops will fail. This is my main disagreement. I think it adds complexity that is detrimental to the chances of a successful install. If you are paying someone to install pipes, rather than paying them to install more than you need and the complexity that comes with that, pay for an independent witness to test the system after it is layed, before slab pouring and after the slab has solidified but not fully hardened. That way you can detect faults and get them fixed at the right time rather than living with a damaged system long term.

 

Edit: Overall, if you are paying people to install the heating system, they should be involved in the UFH design and also be able to be the witness during installation (if they aren't installing the pipes)

Edited 11 hours ago by -rick-

[Nickfromwales]

I’ve only heard of 1 failed UFH loop in a new build, in over a decade. That didn’t fail, it was damaged during install / pour (insulated raft) and it just got isolated as there were plenty of loops and it was a “passive” house.

 

One project, where there were 3 pipes damaged by using an excavator to finish a concrete pour as the pump had failed, we just quickly made a box shutter and isolated those from the pour. These were fixed after the concrete could be walked on, and not had an issue since.

 

These pipes just don’t seem to fail in reality. Manufactures have to say 50 years lifespan as they can’t say these “might last 75 years or more”. 

[Dillsue]

4 hours ago, Nickfromwales said:

If you have a kitchen space that can be remodelled with a full 180° flip, then you have the first one I’ve ever seen.

 

Kitchens are quite specific and usually the space will be used and optimised from day 1, so a refurb would be bound by those terms.

 

Hypothesising about a room that would likely never exist isn’t a great way to use the limited days off we get.

Maybe Im unique in the world as we removed a wall together with 2.5metres of kitchen units. If we'd followed the mantra of only piping open spaces, we'd have a big cold patch where the old units were.

[Nickfromwales]

We’d have a very comprehensive and long thread….if it was tilted “future planning of heating now for, but must also encompass foresight for future moving or removing of walls, and its downstream impact…..”. 

 

  yes, I’m a pedantic tosser. I’ve already been and grabbed my coat.