ProDave

I am trying to relate this to your rear extension thread So is this replacing the existing kitchen? What is to become of that? There appear to be 3 doors / windows in the back of the existing house but I only see 2 connections from the extension to the existing house, so is the existing kitchen rear window being bricked up?

You still need a plot to put it on with PP. No plot and a tiny house is not going to help you. In reality is is just a different take on a residential caravan or park home, so if you had a plot on a residential site you could put one there. There are a few UK companies that make modular built portable homes but they are not cheap. The static caravan we lived in for a while, and still have on our plot, cost us £4500 ready to live in once sited. There is a guy near here who bought a building plot a few years ago with outline PP and has been living there since in a yurt showing no sign of actually building a house on the plot.

It would be interesting first to see if this issue was ever resolved:

Yes that's right. the heat pump heats the tank via the input coil and uses a temperature probe in a pocket on the tank. I have the mechanical tank thermostat set to it's maximum of 65 degrees and that shuts the motorised valve to shut off the ASHP heat input in the event of a malfunctions (very unlikely) The PV heating is completely separate via the immersion heater which has it's own thermostat and will heat the tank way hotter that the heat pump ever will.

Make your own blower door with the largest fan you can find (I used a butchered old desk fan) then you can spend as long as you like going around looking for leaks with a smoke pen

Mine were short pivoting shower screens for a wet room where it does not matter that some "escapes" over or under the screen.

Re the weight. An UVC probably weighs the same, but at least you don't have to carry that up the stairs full of water.

Yes FIT stopped then for new installs. It has bee replaced by an export payment scheme that pays typically 5p perkWh exported. You need to have a smart meter to measure the export and have the install certified by an MCS installer.

I tested mine (DIY) as soon as I had finished the air tight membrane and taping. By that point all first fix penetrations were complete and sealed up. From that point on i have done all the internal work and that has not involved any more penetrations through the building so I can be pretty sure it would still give the same result. I think this is the first time I have heard of anyone getting a second test done. I am pretty sure everyone else just used the MBC test for their as built SAP.

I just put a few drops is a light oil around the gaps in the hinges then wiped off the excess.

If it is all tiled, choose the right stove and it only needs to be on a 12mm non constructional hearth and no need for a level change.

Export payments dictate you have the PV installed by an MCS installer with their premium. So far, if I had been eligible for the export payments, I would have been paid £9.90 for what I have exported. Now work out how much extra it would have cost for an MCS install Vs DIY install and tell me how long the tiny export payments would take to repay the MCS premium.

I am not yet convinced batteries make sense for a small PV system. I am easily using 90% or more of what we generate just with using the big appliances in the day, and water heating. The only argument at the moment for batteries is would storing the electricity to use for household stuff in the evening be better use of it than water heating? Once you get above a 4kW PV system then batteries would make more sense as that amount of power is harder to self use even with water heating.

You could remove all fences between your garden and the paddock and mow the paddock like a cultivated lawn, put garden type features like sheds and greenhouses in the paddock and plant flower beds. Then in (I think) 4 years seek a certificate of lawful development for change of use to garden. That would make it easier to get PP for a plot is the land is then "garden"

I don't know about anyone else, but am I the only one eyeing the paddock as a potential plot? So the existing driveway passes through the edge of the paddock. that would be good enough for me to route the new drive through the paddock. But in view of the above sentence, round the top edge of it, not through the middle.

Remember with solar PV there is no feed in tariff any more, so the cost has to be justified on self usage. I find heating the UVC with the ASHP to 48 degrees still leaves a lot of headroom for the solar PV to add more getting up to 75 degrees in the UVC on a good day with PV. That usually translates into the HP doing less or even nothing the next day to keep the UVC charged. I am not entirely convinced the controller of a sun amp will always allow surplus solar PV in if it senses it is "too full" A lot depends on your hot water usage. If like us you are mostly in the "shower in the evening" camp, you might well find the off peak has charged the sun amp and the solar pv goes to waste. If you are in the "shower in the morning" camp you are more likely to find the sun amp controller will allow surplus PV in after you have all showered.

The ground floor extension works because both kitchen and living are double aspect, so potentially blocking their back windows is not an issue. A loft conversion will probably mean a roof off conversion as I bet the trusses used for the loft are inadequate for a loft room. As the landing comes up at the back, how about a smaller rear extension upstairs that basically goes between the windows of the master, and the other rear bedroom, and gives you the 4th bedroom above the extension while still keeping the other rear bedrooms windows as they are? That would still leave the loft conversion to take it to 5 bedrooms later. What constrains the rear extension to only 3 metres?

Hi and welcome Who built the house? you or a developer? Can we speculate from your user name your job involves flying?

Or use grass blocks, those perforated concrete blocks that allow grass to grow through while still giving you a firm surface to drive on.

Not forgetting to specify the heat pump version of the UVC which has a larger surface area input coil to work with the lower temperature from an ASHP.

I would say that is simple. A sun Amp's main advantages seem to be the lower standing heat loss and the smaller size for a given volume of heat storage. If either of those are important to you for example to avoid over heating a very well insulated house, or to fit in a space too small for a conventional hot water tank, and you can work with all the other limitations such as not being able to heat the HW from an ASHP, then consider the sun amp. If those main selling points are not relevant to your build, then I see little point in using a sun amp.

I assume if SEPA have specified that floor level it is because of a flood risk?

If you are going to take this any further, then clarify just where the thermostat for that high power heater goes.

I think the issue is if you are building up 1.7M above ground, then the wall up to that point would have to be designed as a retaining wall to hold back the compacted infill that you fill it up with. It sounds FAR easier to use some form of suspended floor. What is your resistance to using a suspended floor?

We used a suspended timber ground floor because of the site levels and amount we had to excavate to strip the top soil etc, we would have needed to build up the ground level about 900mm at the lowest point. As it was we had to import quite a lot of inert infill just to get high enough to pour the no structural oversite under the timber floor. So for us it was cost, not any "act", Our builder did try his best to persuade us to build up and pour a solid slab which suggests there would have been no reason not to do so.