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Self install, wise or otherwise ?


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Hi Guys

Monday question.

Getting closer to , hopefully, Planning permission. Quote for ASHP is in( first one) and i notice that it is apparently 'notifiable works' . This appears to imply professional installation.

I  have read a number of posts on here where people have installed their own, forgone the grant money and just got on and made a good job of it.

The same appears to be true of the UFH quote i have also received today. basically ' dont install it yourself'.

What is the truth of this ?

I dont want to name the company on here today. They might be brilliant and its not fair yet to criticise but i need to understand the value of the thing.

The house is a 200 metre new build, not passivehaus but well insulated with a target 1.5-3 airtightness value. They have quoted for UFH upstairs as well, see spreadsheet. I dont know if this is required.

My numbers are UFH= £6700 Suply only.

ASHP = £13000 supply only

 

What do you think?

UFH parts list per quote.xls ASHP Quote supply only.xls

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In what context are they saying it is "notifiable work"?

 

In England and Wales the wiring comes under Part P, so at least some of the electrical work will have to be done and notified by a suitably qualified electrician.

And at least part of connecting an unvented hot water cylinder will need to be signed off by G3 plumber.

 

Other than that you can do the lot your self.  As I am an electrician I did it all apart from the very final water connection, testing and sign off of the UVC by a suitably qualified plumber.

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ASHP is a heating appliance so I’ve seen it covered as “notifiable works” before but if you have it on your building regs application then you’re covered already - just make sure the BCO knows it’s part of the sign off !! The point up to the isolator outside should be done by the sparks but other than that you can crack on.

 

So the quote is about £3k more than I would expect but it’s from “that” supplier so I’m not surprised … you don’t need 14 zones, so 14 Neostats is overkill. I don’t like their clippaplate system as you end up heating a lot of air under the floor space and if you install it as per their spec then you end up with a lot of easily damaged pipes as it loops under the joists. 
 

They have also not bothered to include any mixers, there is one pump for 2 manifolds and 1400m of pipe, and it will be a complete nightmare to commission as @Nickfromwales has had bitter experience of and so have I..!!

 

12kW ASHP is overkill - they haven’t done the heat loss calcs as 10kW is barely building regs losses and you’re going better. No-one gets sacked for spec of Nibe ASHP but they are expensive. For supply only that is about £4K over the odds. 

 

 

 

 

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Guys, thank you so much.

I dont even think i need heating up stairs but am happy to take advice from anyone that knows for sure in a well insulated house. Their rational was that if the upper floor is not quite hot enough the UFH has to work harder. This has a ring of ' that sounds plausible' to it. I am anewby at this and doing my research.

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1 hour ago, ProDave said:

In what context are they saying it is "notifiable work"?

 

In England and Wales the wiring comes under Part P, so at least some of the electrical work will have to be done and notified by a suitably qualified electrician.

And at least part of connecting an unvented hot water cylinder will need to be signed off by G3 plumber.

 

Other than that you can do the lot your self.  As I am an electrician I did it all apart from the very final water connection, testing and sign off of the UVC by a suitably qualified plumber.

As PeterW says. Part P and the plumbing version which i forget for the moment.

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Install electric UFH in the bathrooms and heated towel rails and you’ll have loads of heat in the shoulder months when you need it and can also dry towels in the summer too. Other option is to add a wet battery heater to the ASHP - much better if drawn off the buffer pre-blender as water at 40°C will soon heat the air up and take any chill off the bedroom air flow.

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Your house is pretty much the same size as mine, although mine a single storey, so most likely a bigger heat loss; way more floor and roof to loose heat too.

 

Whole house is done with 7 loops and one zone, pipes are on 300mm centres.  Even before Christmas at -9 our flow temp was only 34 degs, housecat our chosen 19 degs. We have just over 500m of 16mm pert-al-pert pipes in the floor.  Mine started with loads of zones and it just didn't work.  Doing it again I would do 200 to 250mm centres to make the floor more responsive.

 

Things to do

A heat loss calc.  Your max heat loss could be closer to 3 to 4kW.

 

Download a copy of loopcad, and build your house and do a proper design your self.

 

If you single zone or two zone with the correctly sized heat pump you should not need a buffer.

 

Electric towel rads.

 

Do bathroom at 150mm centres, you can get them warmer than the rest of the house on same flow temp.  Or electric UFH.

 

Once you know size of heat pump shop around, call people once you have internet prices, they will all try to beat others prices.  I ended up buying a 6kW heat pump for £1300 the other day, from eBay, so there are bargains out there.  Viesmann sell the same heat pump for over £4k.

 

 

 

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1 hour ago, Post and beam said:

The house builder, Potton, have always said that a couple of heated towel rails would be enough.

I would appreciate it if you would elaborate on the wet battery thing Peter


standard wet heater battery or duct heater - stick it on the buffer with a £80 pump and you can just push heat (or cold….) into the duct. Just make sure it’s insulated and has a drain if used for cooling too.

 

https://www.ventilationland.co.uk/product/43887/heating-coil-for-circular-ducting-o125-4-67-kw.html

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13 hours ago, Post and beam said:

My numbers are UFH= £6700 Supply only.

ASHP = £13000 supply only

Ouch.

 

As @PeterW says "this" supplier loves to install one pump to x number of manifolds. The client they left without the final ( 2nd ) fix ( that I then went to in the 11th hour to make everything work ) had the same type of spec; 13 stats in a single-storey ZEB standard Certified Passivhaus ( :S ) and a load of satellite manifolds off one pump. I told the client they wouldn't get the flow, the designer insisted they would, so I hooked it up temporarily to show them which person would be correct.........

 

Cue your's truly then completing the install, trying to adapt pipework / manifolds etc after the house had been boarded and skimmed, and what a mess. Client was very upset as "they" wouldn't get involved again.

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59 minutes ago, JohnMo said:

I am, they are exactly the same, even the manual for the heat pump is the same, except manufacturer name.  Name plate engineering at its best.

Yeah can’t find a UK supplier though, might still be worth getting one from Italy 

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On 17/01/2023 at 00:05, ReedRichards said:

There are many people on this forum who are "handy" and advocate installing a heat pump yourself.  My opinion is that your decision should be taken in context with what other contributions you will make to the house build; will you do your own plumbing for example?  

No i am not capable of doing a competent job of this. My knowledge extends only as far as knowing that i dont know enough to even attempt it.

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A question for the experienced people here.

 

Is it reasonable to expect that an ASHP installation for a new build would include some kind of hot water tank/cylinder.

 

The reason for me asking is that if i have been quoted for a system i expect it to be for the 'system'. And all that that would typically include.

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1 hour ago, Post and beam said:

Is it reasonable to expect that an ASHP installation for a new build would include some kind of hot water tank/cylinder.

 

 

Yes, of course the system should include a hot water cylinder.  It should be of a type designed to be compatible with a heat pump so with a particularly large surface area coil so it can be heated quickly with not-very-hot water.  And you are going to want the water in the cylinder to be heated to 50 C (or less) so when you run a bath (or similar) you will need more hot water and less cold, so the cylinder needs to be generously sized to take this into account.

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15 hours ago, Post and beam said:

On top of my quoted prices for the supply of an  ASHP, see above. The install figure was estimated at 50% of that. So, £6500 to install the heat pump and cylinder. I estimate that to be just over 3 weeks work.

 

The costs regularly being quoted for these jobs is just eye-watering. I get that it's more than just a day rate for the installer, because the company needs to turn a profit etc, but we regularly see installation quotes that suggest there's weeks of work involved.

 

I had our ASHP installed by the plumber and electrician who did the rest of the house. Neither could possibly have spent a full day on their part of the work.

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I had the majority of my heating pipes (which had been just under the floor, unprotected, in screed) moved to the loft at the same time as my heat pump, 14 replacement radiators and a new hot water cylinder were installed.  That required 3 fitters for the first 2 days and 2 for the next four days plus an electrician for about a day.  So that's 15 man-days of labour - and they worked hard.

Edited by ReedRichards
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There would be a massive difference between installing in a new build with a designed plant room compared to a retrofit.

In a new build build with plant room just the other side of the heat pump, I can’t see how it should take more than a couple of days for plumbing and electrical.

 

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