Posted by: @batpred

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I am however getting very high estimates from EDF and local installers, up to like £12k on top on BUS.  

It is making me wonder if this is just not the time to get into it...

Could the quotes come down from the clouds into reasonable territory after a survey? 

Unless there is something particularly difficult about your installation £12K plus BUS seems high IMHO although that's based on 2 years ago.  It may be price gouging, or it may be just that they are cr*p installers who want to replace all sorts of things unnecessarily and add lots of unnecessary kit.  Either way you probably don't want them.  They may come down after survey, but I wouldn't bet on it.   I got numbers up to 20K plus BUS and some totally silly suggestions for unnecessary replacement pipework, but ended up paying £5K (corrected figure in later edit) plus BUS.  That was possibly particularly good; I did some of the building myself in fairness to expose the route for the primaries.  However yours sounds potentially simpler than mine  I cant see any reason that the timing is especially bad, but people in the industry may be able to comment.

Shop around, check Octopus, check HG zero disrupt, work out for yourself routing for pipework/wiring, particularly the pipework from outside to where the indoor pipes converge (presumably where the boiler is).  If possible think through the job so they cant try to pull the wool over your eyes with loads of BS.  Its worth doing this anyway to minimise disruption - you know your house better than even the best installer ever can. 

Best of all work out exactly what you want and set it out for prospective installers giving them the option to suggest reasoned improvements of course.  Many wont quote because they don't like to be told, those that do are the ones to work with because it means that they actually listen to the customer and, because they actually know their stuff, aren't frightened of customers that actually understand things.

Just my view of course, probably controversial.

@batpred - PS in case it helps here is the briefing I gave to suppliers when I was seeking quotes (there were some slight variants but this is the essential brief).  Needless to say I got some questions back; I engaged with those where the questions were sensible and politely thanked the others for their time.

I am looking for a quote to supply and fit a 8-10kW heat pump and UVC (replacing a 140l vented cylinder), plus a small number of rad upgrades (4-6). I want a simple system operated on weather compensation with no buffer (2 port volumiser acceptable) and no external heat exchanger between ODU and emitters, for max efficiency.

I can provide: full dimensioned drawing, schedule of existing radiators, schedule of possible upgrades, measured consumption, likely pipe routes, and much more.

If you plug the 'MCS' default assumptions into the plan you will calculate a heat loss of approx 10.5-11kW however I have detailed consumption data for the past 2 seasons (which included an especially cold period in December 2022) showing that the actual loss (including an allowance for DHW heating) is ~7.5kW,   The difference is believed to be accounted for by air change rate. My boiler output has been capped at 8.5kW for the past 18 months to prove the point.

Exiting primaries are 2*22mm (one each to first and ground floor) and 22mm to the DHW tank. These converge the existing boiler location in the garage. Existing rads have 15mm feeds so I dont believe any pipework upgrades are required.

Upstairs radiators, other than the bathroom, are already upgraded for 45C flow temp (or probably a bit less).  Some downstairs rads will need upgrading

A location and probable pipework routes for the feeds from ODU to the point where the current primaries converge, and for the D2 drain for the UVC, have been identified.  Full planning permission has been obtained including a screen which is (just) necessary to meet the MCS noise criteria.  Any installation will need to conform to the conditions of this permission, the material ones of which are

• The ODU is QuietMark and MCS certified
• its dimensions is no greater than 1018 (H) x1270 (W) x533 (H) mm
• its specified sound power does not exceed 60dB(A)

Preference will be given to machines with lower noise than 60dB(A).which look smart.

My default machine is the '7kW' Vaillant', which meets or betters all the technical and planning criteria, assuming one accepts the consumption data.  However this is not set in stone, I just want a sensible, reasonably cost effective installation which I am hoping is not beyond the capability of the industry to deliver.

@jamespa 
Thank you, these days I found that reputable local heating system installers all seem to use a common website calculator. It produces simple schedules and probably overprices… 
In some cases, email is the way and there i can leverage something similar to what you used! 

@batpred 

Ouch!

Our install officially finished a couple of weeks ago as we decided to re-pipe the old part of our house radiator circuit after the install, which added another £1000.

The total bill after the grant was £4200 (including the extra re-pipe).

We had a lot of work done, replacing 12 radiators, new cylinder, heat pump, volumiser and a chunk of electrics.

We too had ours fitted in the existing cupboard where the old gas boiler and megaflo were.

@bash Cor thats tightly packed in, obviously quite an agile plumber!  Good price too.

@batpred if you have a short list of heat pump(s) you are selecting from, then most manufacturers have a list of accredited installers.  Thats actually how I found mine.  As it turns out he is very local but I didn't know about him until he popped up on a list of 3 provided by Vaillant.  Some of these (including the one I ended up with) wont advertise much because they don't need to!  Its another route to getting a spread of quotes which is never a bad thing.

@jamespa 
For sure, hopefully nothing needs to be done to it for some while!
Thankfully we had some very experienced heating engineers, 3 of them for the week and an excellent electrician for 4 days.

Posted by: @bash

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We too had ours fitted in the existing cupboard where the old gas boiler and megaflo were.