JohnMo

The PIR I got came direct from the factory, manufactured two days before. All the Rockwool came from a builders merchant just down the road, for a third the price of me going to builders merchant direct.

I got all my insulation from insulation hub, mostly with free delivery to Elgin. 145 sheets of 100mm PIR, for £3500 two years ago, just looked the same stuff is £5500. That's a lot more expensive.

I got both my units off eBay. A HRV10M and a 1.75, for £570 for both units. Both new and unused.

All the info is on their site, in fact a lot more than most manufacturers. Have included a link just go to the document tab. https://www.titon.com/uk/products/ventilation-systems/heat_recovery_mvhr/hrv-10m-q-plus/

Titon, made in UK, I have two, you get them basic or with lots of bells whistles.

I just picked lots of bargains when available, Alpha boilers brain back system, end of line solar panel, end of line insulated flex pipes, spent about £450 in total and have everything I need except a couple compression joints and 4m of copper pipe.

Cylinder heated purely by solar, when the heating is off. It got up about 65 degrees yesterday. I also intend to add solar thermal, have everything in place just need to find time to hook it all up.

As long as you have the access shouldn't be an issue.

Pretty much the same set up as me, I'm using a Watts solar valve. https://wattswater.eu/catalog/safety-control-accessories-for-heating/valves-for-solar-applications/thermostatic-kit-solarkit/ My heating buffer operates at 25 to 30 degree range during the heating season, so a phase change store is no use to me. Plus my cylinder only cost £150.

Think you may have lost the plot, making a simple reliable ventilation system in to something it's not. Sounds like a recipe for failed ventilation system, that also does little or no cooling as the flow rates are way to low to be effective.

I have tried various layouts. It either preheats, but if above 43 it does not go to the boiler at all. Last week I set it up so the cylinder was heated by the boiler (same as system boiler), but abandoned the trial as I used way more gas compared to the system as described previously. My average gas consumption was around 4kWh per day even with the sun out, when heating as per a system boiler. The last 3 days I have used 0.6kWh in total as preheat, as per mode 2 above.

Have a similar system installed. I'm using an open vented 180l thermal store. Basically I have the following. Combi boiler, with a large buffer, with domestic hot water coil. Basically a Thermal store. Run in two modes or can also run modes 1 and 2 together. Mode 1 heating season, a 2 port buffer for the central heating. But any water heading towards the combi is preheated by the buffer, leaving combi less to do for DHW. Mode 2 off heating seasons, solar PV heat heats cylinder via a diverter. To get the best out of the system you need a solar diverter valve and thermostatic valve. Mode 2 works like this. If water from cylinder is above 43 deg, it is sent directly to the thermostatic valve and on to the taps, if below 43 deg, it is forwarded to the combi before going to the thermostatic valve. Prior to installing the solar valve, the boiler would still fire any time you opened the tap, as it saw a cold slug of water, so gas consumption was still a couple of kWh with a hot cylinder. Since valve installed gas consumption is 0 to about 0.5kWh most days a poor solar day a couple of kWh. Simple sketch, it's the same cylinder in both drawing just split the system to make it simpler to understand.

Toolstation Elgin has bylaw 49 in stock 11 lengths, Inverness has 1. When I bought it last it was climaflex.

B&q do climaflex, I know Elgin had stock at the weekend, maybe Inverness have stock also?

Just chamfer the timber to get an off the shelf duct piece through - job done. 10mm or so chamfer for 200-300mm done.

Would think without a check valve, as mains pressure decreases, there will be a backward flow through the softener, as pressure increases againe flow would go forward. The motive force for reverse flow is the diaphragm in the accumulator. With a check valve water will pass through the softener once and then cannot return.

It's not normal to extracts in hallways, this would normally be a pass through area. So you supply a dry room the air flows through that room through corridor and across a wet room to the extract. Master bedroom flow looks low, I would bump up to 40-45m3h, also bump up the lounge. Wet room flows look a little low also. You need to get the flow and return rates the same, so the system is balanced. I set mine as follows Passivhaus house asks for 0.3ACH, Scottish building regs 0.5ACH. worked out the room flows at passivhaus flow rates, prorated the flows up to Scottish building regs flow rates, to give an overall 0.5ACH. After sign off, I can easily slow the fan speed down to get 0.3ACH. I would delete the extracts from the hallways, only extract from the workshop and plantroom. An airing cupboard if you do anything should be extract not supply, as its for drying damp things out. Once you have sign off, you will find that with a big house in cold weather your relative humidity may be low, unless you have a house full of people. As you are really over ventilating the house. Passivhaus say on a large low occupancy house 0.25 ACH may be the correct figure.

You need to add boost also, if you haven't done so already. You need to look at min and max flow rates and size bigger than you think you need, so next size up ideally. Otherwise the system will have too much fan noise. You want the fan running as slow as possible while meeting your flow requirements. Flow is the same for supply and extract, the manufacturer figure is either the extract or supply rate, as they are both the same.

I need the same sort of thing so watching with interest.

I bought some stuff pre Brexit others at the start of the first lockdown. I had, MVHR a full system, UFH pipes and all system components, gas boiler, cylinder, solar panel, inverter and mounts for panels, a car and two motorbikes in my garage - couldn't move it was so stuffed. Got the roofer to preorder and store Spanish roof slates, until I was ready, which he did. Asked the kitchen people to pre order everything, they said they had, but in reality they didn't, so we had a 6 week delay fitting the kitchen. Only things left on site, were in a loft space with hatch key taken off site each day. Except for floor insulation 400m2 of 100mm sheets, a couple of shovels and wheel barrow - the wheel barrow was the only thing stolen.

Think you can look at the parts as half the job, the rest could be labour. But in the mix you have bathrooms, is that parts and labour or just labour in the quote, how many bathrooms and what's in each. Lots of variables. So you have a kit of parts, assume someone has to supply all the interconnected pipework, zone valves and other stuff to make system and the radiators etc. So you really need to go over each line item in the quote, assess if the plumper supplied parts or if they were free issued, what was missing from the free issue parts and were a cost adders, labour associated to that line item. Identify the changes and why

If your well insulated you can really do what ever spacing suits you. We did 300mm in a 100mm of concrete and 200mm PIR below. Flow temp on the coldest day is below 30 degrees, so ready for a heat pump if I wanted. Most the time closer to 25 degrees. Closer pipe spacing helps reduce your buffer size or even the need for a buffer if you can a heat pump small enough.

Not sure if you have done the percolation test yet, but it make a huge difference to the size of the soakaway. So that is the first thing to get hold of. Also remember that SEPA has to approve the treatment plant and soakaway design to issue you with a permit to operate it. They wanted the full results of the test and the qualified the person completing the test from us.

Also be careful with overheating, we are further north than you, and the roof extended over our living room windows, but in the evening we get the westerly sun coming in and can overheat the room very quickly if we are not careful with the blinds.

Our differences was around £15k. We originally planned uPVC double, then we started looking and didn't like what we saw. So went wooden framed triple glazed made a couple of miles from the house.