Package Quote vs Constituent Parts

[Tony K]

Hi

My selfbuild is 100m2 single storey. I've got a quote for £25k all in from what seems a good guy at a good firm to supply and install...

 

MVHR throughout.

NIBE 2040-12kw air source heat pump.

NIBE VPB 300 litre unvented hot water cylinder.

NIBE UKV 200 litre buffer vessel.

Underfloor heating.

Heat recovery unit.

And all the various bits and bobs that go with it to form a working overall system.

 

Apart from this one quote, I cannot get any other prices to design a system, supply and install.

 

I can search for seperate MHVR, ASHP, UFH etc and probably save some money, even with labour to fit, but if I do that am I missing some very important element of overall system design? Or is it the case that these elements can be installed without any great overview of how they operate together?

 

Thanks

 

[Oz07]

2.5k you mean surely?

[Oz07]

Sorry just seen mvhr not the other bits. Still seems strong though but not my area expertise

[Savage87]

It depends how much you want to get involved in it. I have installed and commisioned my underfloor heating, redone the plumbing in the whole house, moved the gas boiler myself (this was checked by a gas engineer) and have also designed and fitted my MVHR. If you have the money and you don't want the headache, pay it and let someone else deal with it. If you don't have the money and you have some spare time then do it yourself. There is a lot of info on the internet about everything that you can think about..

Edited May 14, 2020 by Savage87
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[SuperJohnG]

12kW sounds way overkill for a new self build of that size assuming itll be relatively air tight and good levels of insulation.

 

Assuming a 5kW would do..I'd estimate £10k for all the materials. That's 15k fitting...not chance I would pay that. 

 

As above..if you have the money and want someone else to have the responsibility then go for it...but at least get a few quotes. 

[Tony K]

11 hours ago, SuperJohnG said:

12kW sounds way overkill for a new self build of that size assuming itll be relatively air tight and good levels of insulation.

 

Assuming a 5kW would do..I'd estimate £10k for all the materials. That's 15k fitting...not chance I would pay that. 

 

As above..if you have the money and want someone else to have the responsibility then go for it...but at least get a few quotes. 

 

I've struggled to get quotes, but that's perhaps because I've been looking for someone to design an overall system.

 

Do you think I can just buy the separate components, or is this something that needs to be designed as one overall system?  

[SuperJohnG]

4 hours ago, Tony K said:

 

I've struggled to get quotes, but that's perhaps because I've been looking for someone to design an overall system.

 

Do you think I can just buy the separate components, or is this something that needs to be designed as one overall system?  

@Tony K absolutely. 

 

In my experience, I've never came across a plumber or heating engineer as a sole trader type person who would ever design a system. My best friend has a plumbing / heating business and he wouldn't dream of doing any of that design side. Thats not to say it's all plumbers but I would say the vast majority. 

 

If you want something like that done, you'd be high end high cost with someone to get it properly designed, which would likely be even more then the £25k quoted.

 

do you know the heat input requirements? there is a simplified spreadsheet on here somewhere, done by @Jeremy Harris that can give you the required nominal figures for your construction type to get a max required heat input which would help you size the ASHP. (Attached below)

 

For the the hot water cylinder, 300l seems to be the go to number for a DHW storage with an ASHP as you store water at a lower temp hence you need more volume. It would suit a normal sized family. You could go smaller if there is less than 4 people but IMO better to have 300L, unless you are tight on storage. 

 

MVHR - Contact BPC ventilation, give them your plans and they will give you a price and design and its very easy to self install .

 

Underfloor heating - Wunda for all the components (lots of threads to read on here about that) but general consensus is wunda system with a wilo pump option (very quiet apparently).

 

The heat recovery unit is the MVHR. 

 

The above is what I have selected based on countless hours of reading on here and going with general consensus, but obviously your build method, U value, airthightness will all be specific to you. 

 

Do you have high levels of insulation and air tightness? what stage are you currently at? 

 

hope this helps

 

 

Heat loss calculator - Master (1).xls

[Conor]

5 hours ago, Tony K said:

 

 

Do you think I can just buy the separate components, or is this something that needs to be designed as one overall system?  

 

No need to think of it as one system at all. Especially the MVHR... It has nothing to do with heating and its sole job is to maintain good indoor air quality (whilst recovering some of the heat energy). So you can go to one of the many online companies that will do a design and supply you with all the components, BPC for example. You can then chose whether to fit it yourself. A lot of systems now just use semi rigid ducts that go back to a central manifold. Would just be a matter of pulling ducts through the house, hardly highly skilled. The units themselves are almost out of the box, screw to the wall, connect up and go. You'll just need somebody to wire it up, and you'll also have to commission it properly. Plenty here have done it and will give you loads of advice. Expect to pay anywhere from £2k for a supplied system for that size of house. Double that to £4k for supply and fit.

 

Same goes for UFH... It's just pipes under the floor. Wunda will design your layout and sell you a kit. You can then install all the pipework yourself and have it terminate at the plant area. Let's say £1k for supply only.

 

Then your left with the ASHP and cylinders etc... At this point it might be worth getting a plumber in to supply and fit. Fyi monoblock units are much simpler and cheaper than split, if a little less efficient. So, lets say £5k for 5kw ASHP and pipework connection to buffer tank and controls.

 

Buffer tank, cylinder, controls, room stats etc, all traditional plumbing and you could get that all done for £3k or so. Maybe £5k if there are lots of pumps, manifolds etc required. But shouldn't be on a 100m2 house. I'd question the need for a buffer tank, but I'll defer to the likes of @Nickfromwales

 

The supply and fit prices for all these new things are sky high as it falls under that new/different/eco category which means companies can charge a fortune. I've heard of people paying £15k for an ASHP... That's about £7k materials and £8k labour for a couple days of work.

 

At a guess, if you did things seperately, and even paying for partial installations, no reason why you couldn't get that all done for about £10k-£15k.

 

Edit: I've just spotted the post above and I swear I wasn't copying John!

Edited May 15, 2020 by Conor

[Tony K]

1 hour ago, SuperJohnG said:

 

The above is what I have selected based on countless hours of reading on here and going with general consensus, but obviously your build method, U value, airthightness will all be specific to you. 

 

Do you have high levels of insulation and air tightness? what stage are you currently at? 

 

hope this helps

 

 

Heat loss calculator - Master (1).xls 92.5 kB · 0 downloads

 

@SuperJohnG That is incredibly helpful, thank you.

 

We are about to start the footings. The heating etc is therefore theoretical at this stage but about to become very real later this year, hence my looking at it in more detail now. 

The building will be as airtight as I can get it, and has been certified (on paper at this stage) as meeting building regs, but an overall Uvalue is not stated (it's split into the component parts of the build with a score for each). I will of course be going as far as I can to ensure very good airtightness and insulation throughout the build, but not to passive standards.

 

28 minutes ago, Conor said:

Edit: I've just spotted the post above and I swear I wasn't copying John!

 

@Conor thanks very much. I will look at some of the products you and @SuperJohnG have recommended.

Edited May 15, 2020 by Tony K