Vaillant ASHP non RHI Install possible?

[daunker]

Hi! Long time lurker. Midway through build at the moment, and ASHP quotes are coming in super expensive - they are also coming in at different sizes! And generally don't seem to know much about what they are selling. So I am wondering is it possible to avoid the RHI altogether and go for a self/plumber/heating engineer install.  I've watched the Vaillant youtube videos and it rather looks like it is plug and play. So a plumber and electrician used to heating systems should be able to do it? I'd probably rather a cheaper up front cost than receiving the RHI over 7 years- provided it is a reasonable saving. 

 

So far, I've had a 14kW, 13kW and a 5kW recommended... The house is single storey, built to building regs (wall 0.24 floor 0.1 roof 0.15 u values) with not excessive windows. I suspect air tightness isn't great, and the ceiling is vaulted so a bit of extra volume there, but I just can't understand why two such massive ASHP are being spec-ed. Also the quotes are fairly wild.

 

I've downloaded @Jeremy Harris v helpful calculator and put in my figures, getting a heat loss of just around 5000W @ -10 degrees outside and 20deg C inside. To my mind that shows heating requirement, and bearing in mind outside temp of -10 for the calculation, surely a smaller say 7kW Vaillant would be more than sufficient? I'd also like a 300l cylinder, as it is a 4 bed, albeit one shower is electric.

 

I can pickup the Vaillant easily enough, and it seems very capable unit. Surely the install cost can't be £6-7k, or that complicated? The youtube videos make it seem that it is really just connections that need to made to get it going...

[ProDave]

RHI is NOT compulsory, indeed some of us are a but cynical that the install prices are hiked so the only person that benefits is the installer.

 

It is the worst case heat loss you need to know.  If yours is really about 5kW then bear in mind you will need an ASHP larger than that as otherwise it would need to run 24/7 just to keep up  with the heat demand leaving no time for hot water or no off time.

 

 

[daunker]

Thanks so much for coming back so swiftly, I have read a few topics of self installed, but they were using older models and also a few years ago.

 

I guess my question was if I don't use an MCS accredited rhi installer- what level of competency is required for install. Is it something a good say oil central heating installer can turn their hand to?

Edited April 4, 2021 by daunker

[ProDave]

I would say the plumbing is pretty much the same as plumbing a system boiler, so any plumber should be able to do that.

 

Electrical wise, the controls can be a little more complex than a boiler and it varies a great deal from one make to the next.  What you need is a competent electrician that is familliar with heating systems and is prepared to read and digest what it says in the installation manual.

 

You may have an issue if not installed by a heat pump specialist that you may only get 1 year warranty, and any extended warranty offered may be conditional on using a particular installer.

[J1mbo]

You won't get the full warranty without the approved installer and given RHI will pay almost the entire cost, it's seems counter-productive to pass on it to me.

[Bonner]

I am starting to think the same. I know many here have installed their own but not sure if it is for me. With so many other things to do, I would prefer to get an approved installer to do my ASHP, cylinder and controls. I know they load the price but at least the installation cost will be paid by RHI (not sure if it will pay the entire cost?). Then the warranty is a big bonus to me.

[patp]

Not sure what area you are in but we bought our ASHP cylinder etc from Huws Gray (Ridgeons around here). They sent our plans off to the maker, Joule, who drew us a detailed plan. The ASHP is, we believe, a Samsung rebranded by Joule to sell with their cylinder. We went with a complete system (no need for a buffer tank) that looks a lot neater and is much easier to install! We got the idea from the National Self Build Centre course for ASHP installation at Swindon.

[daunker]

10 hours ago, J1mbo said:

You won't get the full warranty without the approved installer and given RHI will pay almost the entire cost, it's seems counter-productive to pass on it to me.

It's paying the full cost now and then getting reimbursed over 7 years, it will take a few years to be in a better financial position. I would rather save the money now if it was £3-4k as I have a more pressing cash crunch than I would have in a few years time.

 

I take your point, but without going into it, in my situation I also might not be eligible for rhi. So just exploring alternate options.

[SteamyTea]

Worth remembering that the RHI payment id based on estimated usage.

So if your house is thermally efficient, then you will not get much in the way of payments.

[Bruno]

On 04/04/2021 at 21:47, ProDave said:

RHI is NOT compulsory, indeed some of us are a but cynical that the install prices are hiked so the only person that benefits is the installer.

A bit off topic, but different country yet same situation.

I got a quotation for replacing my windows 3 years ago. This year we have incentives for these improvements (up to 1500€ for each home) so I asked for an update of the quotation. Guess what: almost 2000€ more expensive.