JohnMo

Do mean mean 4 zones (independent thermostats) or 4 loops? 90m loop could be well less than 1kW, our combi had a min turndown of 6kW.

Assuming 100mm thickness https://www.insulationhub.co.uk/product/100mm-celotex-ga4100-2-4m-x-1-2m/

Sorry an answer to your question, but be careful with your zone sizing, as combi boilers tend to be huge kW wise. If you have too many small zones, your boiler could just short cycle, not really effective at producing heat, but very effective in using lots of gas. This is especially true in the shoulder heating months when demand for heating is low.

I like the first one, as there appears to be less bends to do.

As @joth says we need a bit more info. Anything can be retrofitted, just matter how much hassle it is. what pump? anything specific that's not up to scratch? any photographs of what he was talking about?

There is a possibility of a cold bridge at the location of the blockwork under dpc and the insulation of the SIP. The interface being the timber plate the SIP sits on. This could rot over time, or so the theory goes. I was going to use Marmox blocks for timber frame build, instead decided to go ICF build, in the end used Thermolite blocks instead. Ask the SIP company for advise, don't ask with a leading question, just ask for general advice on foundation blockwork and ask a general question about any cold bridges in that area, see what they come back with.

Had fibre at the last house, 4G this, don't really notice much difference. We surf internet and watch on demand TV mostly, no heavy gaming. Biggest difference I have ever seen is getting a new TV, opening Netflix, for example is way faster on the new TV, compared to older digibox. On the same 4G, both are hardwired not WiFi. Some slowness is down to hardware design, not internet speed from the looks of it.

But that's nearly £1000 in the first year for internet access!

Basically they work as follows They manage the flow rate through a loop by keeping a fixed delta T. As zone valves close on a manifold this can upset the flow rate of the open zones. Auto balance valve just modulate to maintain the delta T of its loop. At temps below 30 I believe the delta T is managed at 4 degrees, above that at 7 degrees. I removed all mine and now operate the whole floor as a single zone. The actuators got in the way of balancing the flow rates to get room temps where I wanted them. i.e. I couldn't balance the system.

Why is there, my gas boiler required a buffer, my ASHP doesn't. A single thermostat, a 3 way valve and some pipe and insulation. Cylinder pretty much the same in both cases, if a system boiler. My ASHP cost about £2000 installed, the gas boiler cost a similar amount

That is huge, my house is basically 200m2, so half yours, but average ceiling hieght is well over 3m. I just installed a 6kW ASHP and it's really nearly double the size I could get away with on the coldest day (-9). But it cost £1300 so happy to comprise. But sized nicely for cooling. You really need to understand the heating required, otherwise suppliers will give you something fit for purpose.

Other options are dMEV and trickle vents trickle vents. Can be set to run with humidity control trickle vents. Super cheap to run compared to MVHR or dMVHR. I just installed a Greenwood CV2GIP (dMEV), in my wife's summer house (massage room - so needs to be silent), it's 16m2. Have set to just above min speed, so about 5-6 l/sec, and pulls about 1.1 W. Stated noise is 10.1db(A). Cost £55 delivered from eBay. Has smart humidistat and smart over run timer. You could set it the speed higher for building control sign off, then set to low speed.

Out of interest what size heat pump are they quoting? Although that price is taking the Micky.

True

Some more numbers If you build it right your heat demand should be circa 6kW or better on the coldest day. An A2W or A2A installed and designed correctly should give a SCoP of 4ish. But CoP would reduce as temperature drops. So reducing the electric input down to let's say 2-3kW (by using a heat pump), so you need 48 to 72kWh per day approx on coldest day. Otherwise you will need circa x4 the kWh with storage heaters or direct electric. So assume you get an optimistic 6 hours PV generation, you would need 8kW or more output averaged over the 6 hours in December. So make use of that you need a storage medium, big battery or concrete floor via UFH. You need circa 90kW array for that, I believe, based on a heat pump.

Use these https://www.toolstation.com/dewalt-aerated-concrete-anchors/p75727?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dm&pcrid=&pkw=&pmt=&gclid=Cj0KCQjw4s-kBhDqARIsAN-ipH01knBc3i0p0Sxw59Rj8yuWZV-wkfevVC2ONNnszRkJrbYCbECL-aMaApQyEALw_wcB&gclsrc=aw.ds Don't try to screw in in one go, in a turn, back 1/2 a turn. Work great.

Saving interest is still pants

I think if a fire does start in these batteries it is very hard to suppress. Not sure if it's the same tech as car batteries, but cars gets put in a skip of water for 12+ hours. So if it did happen you possibly have more to worry about. Most likely it would trip the RCD anyway and that would kill the MVHR. Also in most domestic situations you faff about not believing it's a fire, so some smoke and all the alarms going off would prompt you to get and family out of the house.

Hi and welcome. Plenty of experience on here. Big house, just be careful it doesn't end up looking like a commercial building. The big glazing may end up melting you on a sunny day. So you may need some shading. So something to discuss with your architect.

It does make you wonder. All the talk about heating poverty, global warming... So on a slightly different tack, could your high consumption of gas be due to short cycling? You mentioned you had 3 zones in the conservatory, did you actually mean 3 loops operating from a single thermostat? When you are heating the conservatory are you heating the rest of the house at the same time? What boiler do you have? Do you know how your boiler runs, does it run for a long period while doing heating or is it a fairly short on time and off for about 10 mins, then on - repeat?

With 200mm PIR you can can do just about any centres you like and still have low flow temps. Mine on 300mm and flow temp at zero degs outside is just under 30. On 150mm centers you gain a degree or so. I would just put it in - divide room into 2 one loop each side, so the loops are similar lengths. Put the supply pipe near the outside walls and return coming back out the middle. Done

What flow temp are you currently using? that will get you close determination of expected running cost. But you are chucking huge amounts of heat at the conservatory. Sounds like a small area to heat, why on earth would a gas boiler heating that area cost so much? £25 a day at 11p per kWh is 230kWh or about 10kW average heat input. 36m2 area so about 230W/m2 Which if correct is insanely high. It a wonder you can walk on the floor. So something in the original post is not right. So we need more information. What are the pipe centres in the floor. What is the flow temp Do you know the floor buildup What glazing do you have, single, double..?

Only have a plant room upstairs, so all bedrooms are on ground floor. But wife wanted thick wool carpets in bedrooms, so UFH in bedrooms is pretty limited. Have been debating a fan coil in the hall and lounge, but that will have to wait until next year.

ASHP flow will come in to house, the split to cylinder and UFH will not be a tee it will be a three way diverter valve. So it's no good in the floor. If you have a service void in the wall I would be running the pipes in that not your floor. Same with the power and Comms cables.

I use UFH. Not as good as Aircon, but takes the edge of the temp and stops us melting completely, unlike last year every time the sun came out.