ProDave

Different meters behave differently. At our last house the red light would flash when exporting power, but not count it on it's display. I believe even the basic dumb meters have an export register but you can't read it on the display but you can read it via the IR port. Our present meter goes solid red when exporting. And now the display alternates between the reading and RED (Reverse Energy Detected) which was intended as a function to detect if you have been tampering with the metering. I know my diverter is doing a good job, i have installed my own export meter, and it so far in 3 years has clocked up a total of 275kWh of export, which is mostly when the surplus is more than the immersion can absorb, or when away and not using hot water and the HW tank temperature has maxed out. I built a crude data logging function into my diverter. I know when the immersion is on, it draws 2.8kWh so simply counting each on period and a simple summation tells me last time I checked, that about 1/3 of what we generate ends up in the immersion heater.

Thanks @Bramco My PV diverter is partly my own design based on another design I saw published some time ago. My works on a half second time slice, on the basis that at full power a 3kW immersion will deliver 1Wh in just under a second, so at half second time slicing I should remain comfortably under 1Wh regardless of how much power is going to the immersion heater. In that half second interval the immersion can be at anything from 0% to 100% power in 2% increments. I have not looked at how the OpenEnergyMonitor one works but I guess it's a similar principle. With mine I only read the import and export power once every half second and update the immersion power percentage to be applied to the next half second. And my time slicing is synchronised to the grid, I have an ac input rectified but not smoothed and read by a digital input to give me 100 time events per second at close to zero crossing of the ac waveform. I know it works correctly with the present standard electricity meter. There are times when the PV surplus is more than the immersion heater can absorb (in practice I find mine consumes 2.8kW at full power) so I also turn on a radio controlled remote switched socket when it is getting close to 100% and in the shoulder months I have a 700W electric convection heater plugged into that. In the summer such surplus just gets exported. Good to know a smart meter does appear to work on a similar measurement principle to a standard meter.

Make two stud wall frames interleaved so the outer wall cladding is on one frame and the inner wall cladding on the other. It will make the wall thicker but there will be no direct contact between inner and outer.

Yes I am sure it was Jeremy that came up with the energy bucket description. I suspect there are not any issues with a smart meter as there are a lot of them installed now and conventional solar PV diverters were not working with them, we would have heard a lot of chatter about it by now.

The energy bucket idea I think is just a way someone explained it when explaining how a PV diverter works. It might measure the power at rapid intervals but the register does not clock up any usage until 1 watt hour has been measured. To this allows the PV diverter to burst fire a 3kW immersion heater for short bursts. So imagine your solar PV is generating 1kW of excess power. As long as the immersion heater on time is 1/3 of the off time between bursts, then the net result is the immersion heater is using the same power as the excess PV and nothing is metered either way. Now if a smart meter registers the power used in a different way or a smaller energy bucket than 1 watt hour, the solar PV diverter as we now it would not work. We would instead have to switch to a phase angle firing or something similar which is more complicated and likely to have EMC issues if not done properly.

It really is my dislike of the smart meters that is holding me back from going ahead with this. Another question to anyone with a smart meter and uses a solar PV diversion device to dump excess solar PV into an immersion heater. Are there any issues using these devices, that usually work on burst firing the immersion heater with a smart meter? The reason I ask is I was at a customers house the other day where one was fitted so I decided to have a play with the buttons and see what it was capable of showing on it's screen. Scrolling through all the options of different displays, I came across one that was displaying the total registered power to several decimal places and the decimal places were updating very quickly. Now I have always understood the standard with conventional meters was they worked on an "energy bucket" and the reading clocked up each tome 1 watt hour had passed. The solar pv diverters work on the principle of short bursts of higher power but never enough to exceed 1 watt hour in each burst, so think of the bucket partly filling when the immersion is on and then emptying when the immersion stops due to solar pv export. I got the impression due to the very fast display update that the smart meter might be working on a different measurment principle or a much smaller energy bucket. What I don't want is to swap to a smart meter to save a few ££ on my electricity usage, only to find a solar PV diverter does not work. Yes I am probably over thinking it.

If the image was not so big I could paste it here. 9.1MB it does not need to be that high resolution. There was probably a reason the two separate circuits have been put as one now, perhaps they were always linked? Or more likely a borrowed neutral situation.

Someone bought a wooden log cabin at the top of our road 15 years ago to knock down and build a new house. He never questioned why it sat on a prominent high point, and never thought that it's name ".... mill" referred to the former saw mill that used to be on the site. When he started digging he found the prominent mound it was on was a large pile of sawdust covered with a thin layer of soil. I would have thought he would have piled it, but no he dug down and down and down until he hit solid ground to the point he could have installed a basement. A test pit or 2 with a mini digger would soon have found that.

I would put the ASHP under the window where is says "no" as long as your chosen ASHP model was no higher than the window sill outside. That might mean careful choice of which ASHP to use. I am not aware of any building regs that prohibit an ASHP being under a window. Ours is on the back of a garage but we do have a small, non opening window in the end of the living room that looks down onto it. Obviously you might hear some noise from it yourself but in the summer when you want the windows open it will not be doing much. If you used 15000 kWh of gas, expect the ASHP to use at least 5000kWh of electricity. i.e. your electricity usage will double. How will a doubling of your electricity bill compare to your present electricity and gas bills? You do NOT want a "thermal store" you want an unvented hot water cylinder and because the hot water is usually not quite so hot from an ASHP you need it bigger than your present one so probably 300 litres. Now what size heat pump? you really need a proper heat loss analysis but very roughly my 5kW ASHP uses about 1600 kWh of electricity each year, yours is going to use about 5000kWh each year so a very rough guess is you will need something about 15kW. That might be the problem that a 15kW unit is too tall to fit under the window without being seen from inside? And the last question, how is the heat delivered? I will guess standard radiators. Those will all need to be changed for larger ones as again the water flowing through them will not be as hot as from the gas boiler.

+1 to replace with a current unit, adapting the ducting as necessary. The loft not currently being insulated is a bit of a bonus. You can insulate the loft ensuring ALL the ducting is enclosed within the insulation, e.g loft roll insulation simply going OVER all the ducting. Box in an enclosure for the new mvhr unit and take the insulation over that. Add external inlet and outlet vents with those also enclosed by the insulation.

SAP still "penalises" electric heating even using a heat pump. Is your objective to get a comfortable house heated at low cost? Or to achieve a particular EPC score? Are you expecting to have a proper full SAP analysis done or the much cheaper, much simpler, much less accurate RDSAP that is the normal for house selling and rental etc? If the issue with keeping the existing system is you can't extend it, then that surely means it is an issue with not being able to get compatible air ducting to extend it with? so if you can't extend the air ducting how would you expect to be able to use an A2A heat pump?

I disagree with that. A room sealed wood burning stove while I accept it will lose some heat up the flue by convection, in practice it is not massive. We have one room with a stove and one room without, and the room with the stove does not cool down noticably quicker than the one without. Wile living in a house that has dropped in temperature to 10 degrees due to a prolonged power cut might not be life threatening, it is certainly not what we have accepted as being comfortable so I am glad to have the option to light the stove and keep the whole house at a comfortable temperature. The difference between our present near passive house and our older "normal" house that we used to live in, is the new house with the stove going will heat the entire house to a nice temperature. The old house due to less insulation and a less well thought out layout the stove would do little more than heat the one room it was in. And in a prolonged power cut we can cook and boil water on the LPG gas hob.

I have a Titan mains powered SDS drill. Nearly 20 years old now, battered and well used but still going. On it's third set of motor brushes, and second (much longer) mains lead. I guess most people would have binned it and called it rubbish when the first brushes wore out?

I would say 5kW is marginal, by the time you have allowed time for DHW heating, a 5kW ASHP would be running practically 24/7 in the coldest period to keep up. If like us you want a silent house at night I would go for probably an 8kW ASHP

The stairs go the wrong way. Have them start at the front door and finish at the back of the landing upstairs. What's with going through the garage to get to the downstairs loo? Have that opening from the lobby into the utility room. Can't comment on the rest of the layout without seeing how it sits on the plot, which way is north, which way gets the views etc.

Perfect for a composting toilet with easy access to the "receptacle bin" for easy emptying.

Textured masonry paint like Sandtex?

Oh didn't notice that was missing. No wonder it was so wobbly. Whoever "designed" it did a cost analysis to see how much they could remove without the customer noticing. What's your hourly rate? How many hours will you have spent on this? What is the cost of a new builders barrow?

I am showing my age. I remember paying £5 per sheet.

I should have commented earlier. I bet you could have solved the problem simply by drilling 2 holes and 2 more nuts and bolts, so that the bits coming off the handle were each bolted to the tub in two places, not one.

Ours was "sandy clay" so no real problem for strip foundations. Our only issue was there was a LOT of organic top soil, which had to be removed over the whole house area, and then the strip foundations dug from there. We think the excess top soil was a previous owner 40 years ago levelling what was a sloping site before getting planning. Unless you have local knowledge, you are never going to know without digging test holes.

Okay just googled and found a typical non submirsible water pump similar to what you might be using. Starting current 4A Starting method DOL Power rating 0.55kW

So for a 15kW heat pump, assume about 7kW worst case continuous electrical power which at 230V is 32 Amps. So starting current 32A Soft Start inverter driven rating 7kW They are paranoid about starting current, as older direct on line heat pumps had a very high starting current which would cause a momentary dip in voltage.

Obvious solution is make the deck smaller than final size so it drops less than 600mm and not onto a boulder field. Then extend it and add your own railings after completion.

This is just the sort of thing Highland Council like to check on, I am sure the tape measure will come out.