Posted by: @ivanopinion

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Posted by: @derek-m

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@editor

Does anyone think that the cost of an installation would ever be proposed less than £7500, while the grant remains at £7500?

If it just saves money for the government, I'm sure no installer would ever bid lower than zero (net of the BUS).

 

It is not actually the Governments money, it is our money (the taxpayer), though I doubt whether some of the installers will be too bothered whose money it is, so long as it goes into their pocket.

Going back to the OP.

Since you’ve come out as needing a 8kW Daikin, you won’t get the extra performance penalty associated with the 9-16kW model.

Do you know what your heat loss is from your bills?

The price is consistent with what our plumber was saying, namely they’ve increased their prices having made some losses on the ones they quoted with little to add to the bus grant, after the cost to them of putting things right afterwards.

Well done for getting further discounts, more radiator changes and do persist with them piping the buffer as (aka 2 port buffer) volumiser

@judith 

Hi Judith, 

There's no heat loss figure I can see on the report I received. 

The surveyor did say when he was finishing he up, it was around 5500 to 6000.

I'm still waiting for them to get back to me about whether they'll set it up as a volumiser.

He did say he'd get back to me today, but he didn't.

I'll report back once he does.

I've had a response from Octopus. 

"At Octopus Energy, we install a Volumiser, which has one inlet and one outlet for connection to the heat pump and heating system, however, we do also refer to it as a buffer too."

Valid or not I'm unsure 🤔 

@njt that’s fine then. One input and one output is a 2 port buffer=volumiser

Posted by: @judith

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output is a 2 port buffer=volumiser

Not always true. A buffer can be plumbed in 4, 3 or 2 port configuration, a buffer straddles the flow and return, it can be either hydraulically separated, so a pump either side of it or not. It can assure a minimum volume flow at all times and increase system volume.

A volumiser is never hydraulically separated and is installed either in the flow or return, never both, it purely adds system volume. It cannot assure minimum volume flow on systems with multiple zones.

@johnmo My friend who was quoted £20K for an installation contacted OE for a quote at my suggestion … £8K less. He now awaits a survey! Regards, Toodles.

When comparing quotes, it's very important to try to ensure technical parity. Very crudely, the higher the system design temperature, the lower to capital cost, as fewer radiators and pipework will need replacing. But there's an expensive trade-off in operating costs for a higher temperature system. It's possible of course to upgrade rads at some future point, thereby enabling a lower maximum temperature. But always check you are comparing apples with apples. 

@allyfish I have explained that to my friend and also explained that due to MCS influences, they will survey based on a FT of 50 degrees C. I have suggested he request the survey be based on 45 or even 40 if he can twist their tentacles. Regards, Toodles.

@allyfish 

I quite agree.

But the final price was £3600 less than Heat Geek quote and that's way more than any potential radiator upgrades that may be needed.

Oh, and they wouldn't entertain doing a system design less then 50 Deg, even though I'd read somewhere someone got a 45 Deg design off them.

@njt My Daikin 8 kW based system was assessed around 50 degrees C. calculations, but in fact runs very happily at ~ 35 degrees C a lot of the time; when we experienced ~-7 or -8 in late November - early December 2023 I noted that the Homely smart controller cranked the system up to a FT of 45 degrees C. and coped very well in keeping us at 22.5 degrees C 24/7 throughout the house. We had 8 out of the 10 radiators replaced and I did influence the surveyor into being generous on the sizes - looks like that paid off! We are well insulated and technically, a ‘B’ now for the EPC. Regards, Toodles.

@toodles 

Hi Toodles, 

That's good to know.

I'm rated a "B" also on EPC.

5500 heat loss, 6700 rad output, 8 KW Daikin.

I have been reading a lot on these forums over the past few weeks and because of the Madoka controller/thermostat being wired and needing to go diagonally to opposite side of the house, I've read about your Homely controller and looked into it. 

Unfortunately Octopus won't fit it on the heat pump install, and Homely say the only sell to installers, so there's the problem.