MikeSharp01

I forgot to add that not only would you save the waste water charge but also the fresh water charge so that adds up to £6.50 m3. That means that if you had 2 IBCs buried in the garden you would have £13 of liquid assets

Correct. Sewage assumed to be the same m3 as mains water bought. I don't know if that applies everywhere. True for Southern at least so assume the same everywhere. I have put in the parallel plumbing to the three loos in case we choose to go that way.

What I was thinking of was deleting the sewage treatment cost that is worked out as a proportion of the metered water. If I use grey water for the cisterns then the mains take will reduce and that's worth £3.70 per cubic meter of mains water not used.

Given discussion elsewhere and cost it struck me that a bore hole might be a cheap option for grey water delivery to your toilets etc than using storage where you need a big hole. A bore hole would perhaps deliver water that needed no treatment for such a purpose. Anybody any experience of doing this?

OK- rather hijacked this thread hear so started a new topic.

Do you need an extraction licence or some such?

Congratulations and enjoy the onward journey.

+1 to that. We built our garden room as a model for the house as timber frame using the same techniques - I Joist etc, but with thinner insulation. However if you are going brick / block for the extension then perhaps raft is not such a good choice.

The chap we used was from Umbay. Energy & Design Services [email protected]. The final invoice was only a couple of hundred.

I will dig it out - I think I mentioned it here probably 6+ years ago.

I worked my way through this on our build and in the end I chose to get a professional to do the calcs for me and then give me a full report which is a sort of guarantee that the design is sound. The cost was less than the licence as I recall and de-risked our journey through that bit of the design.

Tell him after the scaffold is moved?

That does not look good - relying on a couple of screws and not the top string and / or a hanger feels very wrong, send these images to the joist manufacturers and see if they are cool with it - I doubt they will be although the runs are relatively short and the steel frame is doing the vast majority of the work assuming the roof load is appropriately transferred to it and I am not sure it is here. If things are as wrong as I suspect you will need to work up a strategy to tackle your contractors on Monday. Others with much more experience will be along to help with that I suspect.

Great word - assume it means busted?

+1 doing this here.

Ah yes but will you also be showering and cooking at the same time? Anyway as you say just dump the electric showers and all will be well. Back to sizing the ASHP - you have all the data you need so looks to me like you need a 5kW unit. The one we are looking at is 6kW the modulates down to 1.8kW - according to the blurb, we have a heating load of of 1.2kW at -1oC (We are in Kent so not the -10oC of @JohnMo and @ProDave )

You cannot operate that much unless you have very large plant - in which case you should be on 3ph, on your own, assuming 1kW extraction plant and perhaps 1.2kW motor on the machine you are running your need is actually only 2.2kW so that's an example of the diversity that @ProDave was talking about. Only the background load of the place will run 24/7 so needs slicing off the top everything else will only run occasionally and rarely together. There must be a standard way of working out the diversity, somebody on here must have discussed it, or at least estimating it, e.g assume 75% of the 'equipment' running worst case doe that get you under the 100A?

And there was me trying to simplify it down to 2 choices. One thing Buildhub is very good at is offering a range of tried and tested schemes none of which ae quite perfect even for the people who advocate them. The challenge is to make your choice from that lot or synthesise your own solution as a combination of several. Perhaps what we need to do on BH is develop a definitive guide to this fundamental decision that has longevity at the start of any build. Otherwise you start off in one direction and end up swithering all over the place. We are past first fix now and have just decided - yesterday to install a fan coil coil unit in each of the bedrooms - the location of which will be sub optimal because we didn't factor it in at the start. We did think of cooling and designed in a passive stack system which has proved very useful over the past few weeks but still has the other half worried the bedrooms will be too warm. Same has gone for our change from gas boiler to ASHP but that, at least, was a choice we made way back but not until after we had moved the gas meter and installed the gas pipe in the slab!

Yes - would agree cycling is a better term.

Looks like the JS Harris spreadsheet to me.

Calculation is a good plan but won't account for absolute capabilities of the ASHP itself so your outcome will inevitably be a compromise between the absolute theoretical demand worst case (which you already have for heating @ 2kW) the rate at which you want to reheat your domestic hot water (DHW) and any additional strategies you may want to put in place e.g. direct electric heating of the DHW to support fast re-heat and your overall control strategy - see below. You will need to decide what operational strategy you are going for as this also impacts the final system - will you just run the system as a single open loop with weather compensation or have a number of zones all controlled separately by their own thermostats or some other combination. In the end you will arrive at a simple set of high level options all of which will have details that define the physical system and its components: Small ASHP say 3kW able to modulate down to 1.5kW which will run your heating, with some short cycling (ON/OFF) because only on the coldest days does the ASHP match the load perfectly on all others it has more output than you need and a slow heating of DHW, if you want faster then the immersion heater is available. A larger ASHP say 6kW that might modulate down to about 2kW which will run your heating but with more short cycling because it is oversized but your DHW reheat will be much quicker and so direct heating is less likely to be needed. Do not forget that ASHPs have a standby power drain, keeping the crankcase warm etc, that may be factor for you and you may want to factor in cooling as a possibility which will ask more questions of ASHP particularly the smaller ones.

Sorry yes ours is aluclad timber. Yes have a buffer with a locking stop on wide open and are looking at a damper to stop it moving too quickly.

Most of the big 3G companies have them, ours is from Norrsken.

6.8kW peak, Inverter limits export to 6kW as per our UKPN GXX certificate

Just ran our system through the PVGIS system. Previously I just used the PHPP calculator to work out how much we should be getting, as this is the final arbiter of whether or not we get Passive house status. Interesting that the PVGIS finds our total generation should be 7,829.84 kWh while the PHPP package using the same data gives 5,723 kWh. The PVGIS has no settings for shading but even if I remove the shading from the PHPP sheet it only gets to 6,500 kWh. So with shading the PVGIS should be a little lower I think. Interestingly though the reality gives another angle - see below. PVGIS PHPP Actual production this year (Exceptional I know) yet to be established but for export alone we have for the first two full data months: May @ 993.262 kWh June @ 1,052.983 kWh The predictions are not in agreement and actuality seems to favour the PVGIS prediction (May @ 1026 kWh and June @ 1061kWh) if anything but only given we have had an exceptional May / June and these are EXPORT amounts not generation. Both May and June were a fraction out, by hey who is counting, - everyone of course.