Alan Ambrose

>>> why is it even calling for heat? The dashed line is your programmed heating schedule - it says 'heat up from 16 to 20 degrees please from 3-7am, then don't heat after 7am unless it drops below 16'. If you check the profile for those rooms you should find that that's what is set. This is the basic operation of any typical timed programming device and is described in the manual. >>> Are those room temperatures? Depending on which thermostats and sensor set-ups you have - most likely room temperatures. You can add floor sensors and/or remote wired or wireless room sensors to the standard room temperature display - so it depends on your set-up. Ask you installer maybe? >>> I can't believe the room temperature goes up and down so rapidly, so I would be looking at some other local heat source confusing the thermostat It does look a bit rapid, but I've found it is surprisingly sensitive. Yes, you're seeing desired temperature (dashed line) and actual temperature (reddish graph) together with an indication of whether Heatmiser thinks it has called for heat (hence the red colour). If the call for heat somehow doesn't switch the heat source on, say, due to a fault or you light the log fire (which Heatmiser doesn't know about) then the actual temperature won't necessarily reflect the expected behaviour of the programmed temperature - i.e. slowly catching up with the programmed temperature.

OK will look for it, thanks. >>> But it was so long ago I can’t remember the formula! If I could remember even half of what I used to know, I would really be quite smart

Is there not a ditch nearby that you can drain the outfall from packaged treatment plant? By the time it's left the plant it's meant to be guaranteed to be clean enough for this.

Obviously there some insulation thingys which go over the tap. Screwfix etc. I put mine on a couple of weeks ago. My water company suggested one of the insulated green boxes that @Kelvin mentioned for a site tap.

OK suggest this is either your HP cycling or the UFH blending valve closing off as the water is too hot. You can see from the graph that Heatmiser is 'calling for heat' but something else is shutting off the heat supply for a bit - presumably until whatever it is has cooled down enough and then it starts up again. Suggest close observation of the manifold, actuators, mixing valves etc and the HP itself. Also checking what temperature the blending is set to. Looks like the cycle is about an hour? A temperature probe / thermal camera and a voltmeter might help.

>>> There's a procedure to formally request it It'll probably take a week or two for me to get to this. In the meantime, if you search 'wayleaves' and 'dno' or similar here on here, you'll get most of the info.

OK thanks all, much appreciated and thanks for the pointers, links and considerations. Like a lot of subjects, the answer appears to be 'it's complicated' BTW Jeremy's spreadsheet just has floor area x U-value and assumes steady state ground and inside temperature. There's no allowance for perimeter losses and it comes up with a constant heat loss rate over time. So, in an ideal world, I should model the ground conditions, ground water presence & flow, temperature fluctuations at various depths and seasons and the full thermal properties of the basement construction I'm just delving into PHPP modelling and I see they have some resources and calculation methods here: https://passipedia.org/basics/building_physics_-_basics/thermal_bridges/tbcalculation/examples/heatedb https://passipedia.org/basics/building_physics_-_basics/thermal_bridges/tbcalculation/examples/unheatedb But I was hoping for an easy answer.... I'll post back here with any progress I make.

Sadly even some dno staff don’t get 3 phase - at least the ones that deal with consumers. I once had a company send 4 bods on 4 visits over as many months trying to swap out my 3P meter. Eventually they sent the boss and he arrived with a mostly suitable meter.

For a quick read on type of soil, drainage etc you can ask any or all of building control, local builders, the seller, neighbours, septic tank emptying companies, british geological society bore hole records etc etc. All quick and free. Won’t give you a 100% read, but if two or three agree, you’re probably home and dry. A good solicitor will also check utilities and drainage records / easements etc for you.

>>> Some PV guru's could probably enlighten me. Hardly a guru, but each PV panel string usually sits on one central inverter input (or MPPT) and will be limited to the output current of the lowest panel - the panels are literally strung together in series. A string is usually limited up to, say, a dozen panels and is limited to the max inverter input voltage. Total voltage is approx. # panels x 40V. So shading one panel will reduce the output of all the panels to the same extent. With local inverters, there's usually one inverter for each panel (they sit on the roof too) and there's no such limitation. Of course, this option is usually more expensive.

Also, what's the best treatment for unheated spaces like lobbies?

>>> I now specify 3+E and cat6 Run in different conduits?

PHPP form factor apparently is total outside surface area (floor, roof, walls etc) / treated floor area (i.e. sum of internal area of rooms, not including internal walls etc)

As per title - I'm initially looking at Mr Harris' spreadsheet, but also curious about SAP / PHPP treatment? I can see that PHPP talks about unheated vs. heated basements. In practice, I'll probably lay UFH pipes but only use them if we feel the need. For unheated, am I right in thinking that there's an assumption of a constant heat loss through the ground floor just like the non-basement case? Maybe, total basement wall and floor area x constant heat flow per m^2 assuming inside & ground temperatures are fixed? What does that all do to 'form factor' - does it all fall apart in the case of house + basement? I think 'form factor' sort of implicitly assumes that floor, walls & roof have the same temperature gradient?

Mineral wool in the service void as it's more practical to install there than cellulose? Any utility in using posi joists rather than standard rafters so you could run MVHR ducting there? Can I ask how you chose 1.4 as a target u-value? Is that a typical optimum value in practice?

@joth I think the difference of opinion between various sparkys demonstrates that there is no accepted standard / little experience in the field / and not covered in detail by the regs.

Is there no possibility of adding more than 7mm of insulation?

@Iceverge Thanks for the very clear 'heat loss in a nutshell explanation'. Very useful for everyone, I think. Love the colourful fold-up cardboard cutout version of the house design - was that used somewhere, or just to illustrate the surface area? I just bought PHPP yesterday, so @Nic thanks for bringing this subject up at this time

>>> I can't recall the brand It would be fantastic if you could remember which one.

>>> contact the seller/supplier and ask for a VAT invoice. Yeah VAT registered businesses must issue invoices with the VAT clearly shown. You might have an order confirm or whatever instead of an actual invoice. You may have to hassle their accounts department to get it, of course.

>>> BUT there will be a canny waiting time I think they often use this strategy (a) to push cash flow and P&L impact down the track and (b) because a lot of people will need it done quicker and therefore have to ante up for it. There's a procedure to formally request it, I'll remind myself and post it up here is as I have to do this myself. Which DNO? >>> it seems a bit dicey putting them up A technique is to confirm the conversation re minimum distance (not the guy's off-the-cuff remarks of course) in an very polite and professional email and inform them that you are planning to proceed on that basis. Then give it a week or two and press ahead.

>>> I now am thinking I should just go fully for the Passivhaus certification. You don't say why? You can do the calcs yourself if you are happy with uncertified. Or if it's just insulation modelling, Mr Harris' spreadsheet.

Not minerals or car parks?

In these obvious cases, it's seems odd that the LPA don't allow themselves a bit more discretion - they seem to in lots of other areas Does anyone know - is this 'enforcement' action in the planning laws somewhere or is it just accustomed LPA practice.

Yeah agree (a) the simple cheap things like CurrentCost are not very accurate, but they may do, (b) putting in your own accurate in-board meter is a neat alternative, (c) there are also third party per-circuit set-ups with phone apps etc that quite useful (search the forums), (d) accurate 1/2 hour reporting is a benefit of smart meters - I know there are drawbacks but I think it's the future. For instance, you can't access the 'smart' time-of-day tariffs, like Octopus Agile, without one.