ProDave

Aren't these trench blocks technically a 2 man lift per block due to their weight?

I don't see any profiles set out so how do they know they are building the walls in the right place? The exact centre of the strip foundation is not always the right place. Our brickies set out all the corners first up to DPC level then filled in from there, using rotary laser and measuring staff to get them level, then string lines between to get each course straight and level.

Related to this is the real benefit of an air tight house with mvhr and no trickle ventilators. You can open one door or window, even on a windy day, and virtually no wind enters or leaves through that open door, and none of the internal doors blow shut. Our previous house, open the front door on a windy day and the kitchen door blew shut as the wind passing through exited the cooker hood vent and the cat flap.

We are going to start fitting thousands of ASHP's to replace fossil fuel boilers, yet there are not enough ASHP's available to meet the present demand. Good well thought out plan.

Technically any such system would be off grid so really complicated and in the realms of experimenting I suspect. I wish the DNO's would be more flexible.

Yes, and 20mm thick boards.

No, that is what he was installing. Because he was so far through, he ended up with 2 separate mvhr systems for upstairs and downstairs to limit how much he had to strip back and re do.

Nope. A near neighbour had started installing basic whole house mechanical ventilation, had his air test done, better than 3, Building control told him he had to have full mvhr.

I did on my sun room.

A lot on here (including me) have gone with an architectural technician. For what most self builders need, they seem to offer a better service. In my case I had a plot with OPP and a pretty good idea of what I wanted. The AT took that design to something actually buildable that would pass building regs, produced all the drawings and in conjunction with a structural engineer all the details and calculations required for building control. That gave me a building warrant and a COMPLETE set of drawings to build the house all for a reasonable fee that seemed to be based on the amount of actual work done not some notional value of what the house was worth. That set of drawings was given to the builder to build it. As I said in my first reply, it was the simple inability to get that package of work at a sensible cost from an architect that put me right off them. Perhaps they don't want "simple" tasks like that? Perhaps all they are interested in is managing a complete project, putting the build out to tender and delivering a turn key solution to the client. But I suspect that is not what a lot of self builders want?

Our brickie charged by the block laid, so I could not give two hoots how long he took.

Yes ours is silent at normal speed. It can be a little noisy on full boost. Just don't let anyone take a shower in the middle of the night.

Some of us have low opinions of Architects. Nothing personal but here is my reason. When stating on our first self build I had a pretty good idea of what we wanted sketched out so I approached some architects. What I got back was quotes based on astromomical figures. they both wanted to charge a fixed percentage of the estimated build costs and both managed to estimate the build cost at roughly double what it actually turned out to be and neither would negotiate. All I wanted was someone to do some design work and produce drawings and I was looking for a fair fee based on an acceptable hourly rate and hours actually worked. That sorry experience means I have never spoken to an architect since. It would be good to hear that things have moved on since then (nearly 20 years ago)

In terms of living with it. Almost nothing to do. Just enjoy the fresh air and lack of condensation. Ours has a manual boost to speed it up for showering or cooking so we just press a button. Some systems boost automatically based on humidity. Routine servicing is simply inspect the filters and clean or replace as necessary.

That's why we painted ours. Ask me in 5 years how it is doing.....

Ignore panel efficiency. Nobody has yet invented a PV panel much above 20% efficient. It only affects the space they take up. Concentrate on minimum price per kW of panel unless you are really restricted for space.

My panels came from Bimble Solar. Some they had on offer at the time, a pallet load split with another forum member. Inverter and other bits like isolators and generation meter from ebay. Mounting frame made of Unistrut. Cheaper than aluminium rail.

Stick with 4kWp and a 3.68kW inverter grid tied so no DNO problems and self use as much as you can. anything else gets expensive with obstacles in your way. You can buy all the parts and DIY install that pretty cheap or pay an electrician. To claim the insulting 5p export payment requires an MCS install which we all know adds ££££ to the bill and you will never reclaim the MCS surcharge with the export payments. I export about 100kWh per year that I am unable to self use for which I would get paid about £5 were I able to claim the payment. Simply NOT worth paying the extra than an MCS contractor would charge. If you want even more than 4kWp them make that off grid for battery charging to be used in the evenings for example?

Since the thread has woken up again, my finished sun room

If your wife will tolerate putting the washing in the machine and then waiting some unknown time before the electricity is cheap enough to process it, she is more tolerant than mine.

I don't agree. The alternative is no ventilation and trust to natural leaks in the building which is usually poor and unreliable. Or mechanical extraction that draws COLD air in to replace the heat you are expelling from the building and in 99% of cases allows cold air to blow IN when the fan is not on. Of course mvhr works better in an air tight building but I bet it would still be of benefit in a less than perfect building.

I can see some merit in smart light control, self closing curtains etc. BUT I can see no merit whatsoever in a smart dishwasher or fridge etc. That is a "solution looking for a problem"

The doors don't look good. Bifolds have a reputation for being leaky and hard to make reliably air tight. But the whole frame looks cold. What make are they?

Just to add to this debate, we have an enthalpy mvhr unit. It was not deliberately chosen, but like a few other bits in this house one came up cheap on ebay. Kingspan had been re badging mitsubishi units and I believe Kingspan abandoned that enterprise and several ended up cheap on ebay. I did not know until we had it that it was indeed an enthalpy unit. I have had no problems with it, and the only window that gets any condensation is the 2G velux window in the en-suite. At the time of buying that window I debated 2g or 3g and as it was a small window I concluded the heat loss of a 2g window was low enough not to worry about. I do wish now I had paid a bit more for the 3g version to reduce or eliminate the small amount of condensation we get around the edges of the window.

Can we see thermal image pictures of the flow and return pipes into the ASHP. Assuming they are covered in pipe insulation, remove a section of that for the photos so we can see the actual pipe temperatures.