timhowes

As per subject. Looking for recommendations in North Somerset/Bristol region please. Considering changing plans from renovation to replacement dwelling, using modular build but same drawings. Initial approval took more than 2 years so we are wondering how likely the planners are to present problems, given that the ecology, objections etc are all dealt with and situation is unchanged. TIA

Any ideas why I can't edit my original post? Regretting putting a location link (perhaps I should relax...)

@Nickfromwales I tried to identify a suitable Panny, say 9kW down to 3kW, but got lost with their various ranges (T-CAP etc). I would welcome any suggestions if you have a moment...

@JohnMo so it is... min/nom/max in top row. Thanks. It is presented differently in every brochure which I find challenging!

Struggling to find a Hisense datasheet which shows modulation capabilities... Trying quite hard!

@SimonD this is all very helpful, thanks. DMing you a list now

Good to know - thanks for this. This was what led me to the aroTherm - the best data representation of any manufacturer I've seen so far. Why can't they all do this?!

130m2 heated area - mixture of their between-joist system and the "rapid response" overlay for the concrete area, with 150mm pipe centres Designed and supplied as follows: Isolation Vales with temperature gauges - pair 12 Port Manifold 16mm Pipe Actuator Valve Smart Hub V4 & Boiler Switch - 48 Zones Smart Connection Box V4 - 12 Zones V1 - Wunda Thermostat Sensor (Slim) Perimeter Strip Insulation - Overfloor (25m Roll) 20mm Overfloor EPS 400 Transitional Panel 20mm Overfloor EPS 400 Plain Panel 20mm Premium Rapid Response Main Panel 20mm Premium Rapid Response End Panel (x2) Wunda Panel Spray Adhesive Joist Insulation Main Panel (200 Micron Aluminium Coating) 16mm Wundapipe (80 metre Coil) 16mm Wundapipe (100 metre Coil) 16mm Wundapipe (120 metre Coil)

Thanks to all those who have already assisted me on these topics. We are embarking on a major renovation of an 1949 bungalow, extended through the late 1900s to dormer bedrooms. Building a new first floor with timber construction, extending ground floor a little, adding external insulation to any existing walls, new DG windows and doors throughout. South-westerly aspect without shade. Will have PV and battery storage (not got to work on planning this yet). GF heated area 148m2 FF heated area 85m2 Total vol approx 600m3 Location N Somerset, just west of Bristol I have run Jeremy's heat loss calcs as best as I can, yielding the following (with soil temp 6C, ACH 0.5, no heat recovery) Looking at UFH throughout ground floor - mainly suspended timber and will be able to add plenty of insulation, but small area (kitchen/dining) of existing concrete floor to be extended slightly. Probably FCUs upstairs, although not decided yet, with the intention of some heating if necessary (maybe not needed?) but definitely active cooling, Family of 5 with 3 kids who will be teenagers soon - I am firmly against long showers but their mother is harder to persuade. Envisaging 300L UVC emptying rather fast so considering a larger one. Have been offered plenty of high output heat pumps through MCS-certified installers, with the accompanying eyewatering costs. Trying to get my house in order to challenge them, but also want to know I'm not going to regret going smaller! Questions: I am looking at ASHPs with max ouput 8-9kW based on previous advice from this forum. However my interpretation of the above calcs is that I need to be able to modulate down towards 3kW for efficient running in the less cold months. Is this correct? I've earmarked the Vaillant aroTherm + 10kW model as one option but finding it hard to identify other models with enough modulation (mainly due to poor documentation by the manufacturers - is there an "uber sheet" with these data anywhere?!) Wunda have offered me a 2-zone UFH system for the GF for £4.4k inc VAT - 2 zones needed as, whilst most is suitable for a between-joist system, the concrete floor area needs their "rapid response" to give similar performance. I had asked them for a screed system throughout the GF and need to ascertain why they think their proposal is better. Also sounds like a lot of £ compared to what others have posted. Thoughts? System volume is 148m3 As will be evident, I've never done anything like this before and am doing as much reading as I can to defend myself against blowing a big chunk of the budget on an inappropriate heating system! Floor plans attached. TIA GAP000 - Level 0 General Arrangement Plan.pdf GAP001 - Level 1 General Arrangement Plan.pdf

I had my first non-ridiculous quote yesterday (Cool Energy) and am pursuing this. Will keep you posted

Yes there are a couple of other options - I have today submitted the plans via the Heat Geek portal (seemed to need to be channelled into their "black label" system which sounds even more expensive!) - waiting to see what happens.

Thanks @JohnMo By this, do you mean I should look at the heat loss in the deltaT columns 15 and 20 (assuming I want 20C in room)? So multiple 5689 by 1.4, allow for DHW and go from there? (Values slightly greater as I had underestimated roof area)

Thanks @Sparrowhawk - I contacted a HeatGeek recommended installer back in July who sent me a quote for a mere £25k!!! This included 7kW ASHP (a premium Stiebel Eltron model), all of the UFH I will need, and before the BUS grant. But still... So this sort of put me off. I have gone back to them to ask to discuss, as they are the only company who have entertained the idea of an appropriately-sized ASHP. I have said no buffer, single zone... Let's see what comes back!

We are using a design and build company for the renovation. They are good and I have seen evidence of decent plumbing as our neighbours used them last year. I am happy to waive the grant as it looks as though I am going to have to pay for an oversized system if using MCS-accredited company. It looks as though I need a 7kW ASHP rather than the 14kW I am being offered. I have accounted for DHW production. However, as someone with no prior experience, I will have to be quite brave to source my own ASHP, design the system and ask them to fit it. How much faith should I place in the calculator? I am confident I have used the correct figures, according to my architect's tender package (so hopefully not a case of sh!t in, sh!t out). I am greatly reassured by the expertise of those in this forum, but it is still a little uncomfortable challenging the "experts" who have delivered the quotes thus far.

Thanks @JohnMo very helpful as ever - my lack of understanding on the ACH was fundamental!