JohnMo

To go off grid is no easy or that cheap a task. PV, plus batteries, plus generator, that can run a few days without complaint, i.e. continuous duty rated. What did the quote include for power supply. Ways to reduce is get someone yourself to do trench digging and backfill.

Screwfix do an aluminium foil tape.

You can control each one individually, but your boiler will only have limited turndown, so if the minimum turndown is 4kW and a single circuit or zone calls for heat that can only absorb 1kW, the boiler cannot get the heat away quick enough. It will trip when the return temperature is too high. This will lead to a 10min or so outage while the boiler goes through a reset cycle. This will keep repeating until more circuits come back online. This is the least efficient way to run your boiler. And will result in much bigger fuel usage.

here you go, they do 15mm euro cones for your pipes. I had good service from them. https://www.outsourcedenergy.co.uk/product-category/manifolds/underfloor-manifolds/ Suspect you will have lots of boiler or heat pump short cycling if the have a thermostat on each loop. Been there and then removed and simplified, after I saw my first months gas usage. If I was you I would have a single zone and use the bedroom stats as limit stops (balance flow to get the temperature correct). Join all other loops to operate off a single thermostat.

Your boiler flow has to be higher than the set temperature of the cylinder. So if you want 60 degs in the cylinder, the flow temp coming from the boiler will have to higher. That the first thing to check. If the flow temp is 50 the cylinder will only get to 50 if direct or lower if indirect (heats via a cylinder coil).

Could you not use an immersion diverter, after all, a storage heater is just a series of immersion elements in stone/metal/concrete blocks

I would be speaking to the structural engineer first, all respect to the ground workers but they are not qualified to make engineering design changes.

From what was attached it makes to up the efficiency to 90%. Looks like the individual room rates will need to changed to reflect the total ACH of 0.3.

But I wasn't talking about your sofa or your dashboard I was specifically talking about spray foam insulation. Which isn't seat foam.

Here you go, most in the low 80s, some in the 70s some in 90s. Those all passivhaus certified, other may not be as good, even if they are. https://database.passivehouse.com/en/components/list/ventilation_small

Your MVHR is just a ventilation tool, which also recovers heat from the outgoing air and gives it the incoming air. All houses need to be ventilated, an airtight house has to be ventilated by mechanical means. Building regulations require a balance supply and extract. Building standards normally require around 0.5 ACH (varies with UK country) Your ventilation rate is 0.3 ACH, it nothing to do with with your air tightness test. In addition to your MVHR flow rate, you will have a natural infiltration through the building fabric, which is not controlled, this will be small and is linked to your air test results and the prevailing wind speed and direction. The rate of flow of the MVHR is based on a number of ACH, in your case 0.3 ACH. Your SAP report will have a number it which represents natural infiltration, this should really be added to MVHR rate to get the worst case heat loss. So your ventilation rate would be 0.3+ something, of which heat recovery would be 80-90% efficient. So your effective ACH would be 0.3x0.2 = 0.06 ACH, with respect to heat loss. Qv = 0.33 × n × V × ΔT watts. =0.33x0.3x your volume X 24 =0.33x0.06x your volume X 24 The difference between the two figures is the benefit of MVHR. Less the running cost for electricity and filters. Which is generally lower the energy saved for heating.

So where does this appear in any building loss heat calculations? You are normally after the worst case heat loss, so if it's as significant as you seem to suggest, it should there?

In a close to airtight house an exposed windy location, shouldn't have any undue effect on the heat loss calculation as the wind cannot get into the house. Unlike a humans, objects such as house do not suffer wind chill. The air temperature is what it is.

Not sure why you are not just using the heat loss calculations in the boffins corner, it lets you set the ACH and MVHR efficiency. It free easy to use and pretty good representation of what to expect from your house.

Well my smart meter installed failed to communicate correctly, so has now been abandoned. Now have a manual read smart meter. Neighbour applied today to get meter installed, after a bit of a ring round, EDF are installing in two weeks.

just measure back from rad edge X metres, then along the road x metres depending on the speed limit, see attached trbo-advice-on-planning-for-small-development-march-2016.pdf

Basically doing a bodge job, while demanding money to do so. Interesting the article refenced specifically states polyurethane foam. The foam mentioned at the start of the thread is a polyurethane, while something like Icynene isn't. Its cater oil and water based that open cell and quite soft and flexible compared to polyurethane foam, which is quite rigid.

Strange my structural drawings show PIR with 75mm concrete screed. Many on here have also used the same, other not but more to do with cost, choosing thicker EPS/XPS at a lower cost for same U Value.

New owners, so back from the abyss. BBA certs are available if you do a search, would assume the build manual is still on their website, which has all sorts of info. We have stone slips, adhered to the Durisol wall directly and wooden cladding.

Makes sense primary and secondary air come from duct. Outside air connection is just a hole in the wall connected to stove by a duct. Air is controlled the same way with or without duct via normal stove control

20mm PIR would be 30 to 40% better performing than your suggestion. The other option is aerogel (not cheap), 30% better performing than PIR. I have a single piece of UFH pipe in the kitchen, between the wall kitchen units and the island. Not sure it actually contributes that much. Kitchen is always warm. The single pipe at the bottom of the image by the red thing, that is the kitchen, the bit to the right is the dining area.

dMEV, decentralised Mechanical Extract, Ventilation. Only extracts, no heat recovery. Aereco, Vent Axia, Greenwood Some bedtime reading below https://www.aereco.co.uk/knowledge-centre/how-to-choose-between-a-humidity-controlled-mev-and-mvhr/ Atamate_SDAR+Paper+2019+(1).pdf

normal cement, and hydrated lime. I mixed mine as 1x 25kg bag of cement, 3x 25kg bags of building sand, and think it was about 2 to 3 shovels of lime. The lime gives a creamy consistency. Add enough water to make a double cream. Makes a mess, wear safety glasses

Unless your airtightness is better than 3m3/m2 you would be wasting loads of money and time installing MVHR. You would be better with dMEV, constant background ventilation low running cost, easy to install. You can get them so they operate the ventilation rate based humidity, increase and decrease ventilation rates.

Whatever the insulation you use you will be installing a Vapour control air tightness layer below it. This is draped on to the wall internally and glued or taped to the wall.. That is is your airtightness sorted. Then use whatever insulation to the required U value.