markharro

Hi @KTB did you find any ASHP installer yet?

Can anyone recommend a company with MCS accreditation? thanks

We are just finalising our plans and our architect has allowed for a lift and slide door that will be the exit to the back garden from our kitchen diner and a separate door from the adjacent living room that will be a conventional hinged door also opening to the back garden. Its location is basically adjacent to the lift and slide. I am questioning whether we need the expense of a further 3g door when we could substitute a much cheaper window for example. The question then is how practical is a lift and slide as the only exit into our back garden which is the main outdoor area of the plot. We often come into the house from the back as well rather than use the front door. Would we find sliding the lift and slide open and shut constantly a complete pain in practise, especially in winter I guess when it couldnt be left open? thanks

Thanks thats reassuring - is it relevant though that we plan on a 11.04kw PV array and 22kw EC charger for the house as well?

Thanks thats interesting. Not sure that would work for us. We are having an insulated concrete slab poured.

We are arranging for a disconnection before we demolish our house (mid July). I have powered outbuildings and want to keep them powered and so I am talking to the DNO about a temporary supply. We want to bring 3 phase and its nearby so that should be ok. My issue is trying to plan for where to locate the temp supply. The spot nearest to where our new plant room will be looks impossible as it will be in the way of buildings works I think. The best spot further away from any groundworks etc will be right on our boundary with the pavement so a short cable run from there but what I don't understand is whether we could keep it the meter there and then run 3phase into the house privately? we would need about 7 or 8 metres of cable run approx from this point to where our consumer unit would be housed in the new house? Would this cause any problem - I think someone I spoke to from the DNO mentioned voltage drops ? thanks

Thanks @AliG and I think you are with the same supplier as me so that's reassuring. The Scottish Power guy appeared to be suggesting that the simple fact you had a 3phase supply in itself could render you liable to a higher standing charge which was something I had never heard of.

A little bit off-field but I have heard that 3phase supplies can result in higher standing charges from your suppliers? Is this correct?

We are about to demolish too. Got the elec in motion but unclear about water. Our house is built right on to the pavement and I suspect that means that there might not be any option to divert the supply ourselves to serve eg a site tap? Does this mean I have to pay Scottish Water ££ to disconnect in the pavement? Or is there a stopcock valve in the pavement that I can turn off to cut the supply from the pavement? Then presumably when the house is down if we haven't damaged the supply pipe majorly I can joint in an extension off to a site tap? Would this be feasible? We are obviously in Scotland and our supply pipe is lead.

Can I check I understand this logic? You are suggesting that over winter a 12kWp array would produce about 25% of peak generation during summer? So that makes 3kWp? What I don't understand is what you mean by 4 less 1000w? To recap, I really need to make a one time decision on the size of the array as it will be integrated with the roof. This is why I am tending towards 11-12kw as its the one chance I have to do this. I will have an EV to soak some of the power up and possibly an ASHP and I work from home so can achieve the max self-use but it seems from what @AliGis saying that this will still force a big export over summer and little payback for this. One of the unknowns it seems to me is what the export price might rise to down the line. Policy changes may force the big power companies to start paying proper £ for to exporters. If that transpires (and we would plan to see out then next 20 years + in the house) then this may make a material impact on the economics. That plus a home battery at some point down the line...

Thanks - this has raised another issue - do you really need to finish external landscaping to get a CC? If so why? For us we assumed that this would be our "gardening" projects for years after we move in!

Ah thats interesting thanks Dave. What sort of state does the house need to be in to get that cert?

A slightly different question on this thread - our project might start as early as July when we intend to demolish our existing house and obviously at that point I will need to transit over to site insurance. My question is when can I expect to transit back again to a standard buildings and contents policy? If it matters I am based in Scotland. Is the trigger when you get a completion certificate or is it possible to go back to "normal" insurance if you move into the unfinished house yourself as we intend to do and you can show that you are actually living in the unfinished house?

Even in Edinburgh which is where we are? But my thinking is to future proof. The excess may go to "waste" atm with export limitation but the hope would be for future policy changes which might make it easier/cheaper to get permissions to stick the whole excess output into the grid coupled with enhanced export prices. What do you mean by a "listing"? I am still struggling to understand this. Lets forget about 3phase for the moment. I understand that you use a G99 if you want to be able to export more than the 3.68 on single phase and that the DNO charge for this application. But the other thing it seems to me is that until you have made this application you dont know if it will allowed and I need to know now what I can instal. So that takes me to the export limitation option. I had understood that with the same example of a 12Kw array but using an export limiting inverter the DNO only got advised after the instal via G98 and then had to accept it assuming the inverter you use is compliant. So why is export limitation more expensive? Does the G98 application carry a higher fee?

Still struggling to get my head around PV plans not made any easier by absolute failure to engage with any installers at the moment - they all seem too busy. This and the clock ticking down to finalising our BW application. I remain keen to fit around 11/12 Kw to maximise our roof space real estate as I am only going to get one chance to do this if using inset GSE trays to fit. That is also a convenient number for a pallet purchase. The problem however is in knowing that I can safely plan to make use of these on single phase (I think I have been convinced out of 3 phase and in any event have no idea how much it would be to get a 3 phase connnection)? Is there an export limited inverter that would deal with this size of array that would satisfy the DNO? And if so, does that mean that I can be guaranteed that I can plan for this size of instal with a G98 going in afterwards to advise the DNO? And on the separate issue of MCS instal or not, perhaps @AliG can comment on this, if not getting an MCS instal does that mean that you can't qualify for the Octopus Tesla package? What are the other implications? Is it only that you wont get paid for any export - if so I cant see this being a problem for me unless there was a serious rise in the price paid for export in the future. Also @AliG could you recommend your installer and if so provide me with their details? thanks

Air source pump supply/install. Solar Panel supply/install Same for me for these two as well.

I can't afford a designer and am having to research it myself. Any top tips you are able to share from your scheme? thanks

Thanks - I dont disagree that there needs to be control. My point is that the DNOs should be forced by legislation to make the process much easier for residential punters like me and also scrap all fees.

I can't believe how much hassle this is. I don't have the budget for a specialist to make these applications for me and I doubt I would have a clue how to fill in the forms myself. To summarise, if I want to put a standard system on my roof of up to 3.68 then I still need this G98 permission? I thought there was no admin involved with that at all!? anything above that if I want to export back unpaid (because it wont be MCS installed) I need to make this G99 application? If I want to export limit, then I need a G99 and G100? This is ludicrous for a residential punter. I simply want to have a >3.68 system to use my whole roof capacity and not waste the generation potential and the DNOs should be forced to accommodate this it really makes me fume. Btw I have already contacted the Scottish Gov and our DNO to complain about the process/fees involved in a supposed age of climate change but to no avail.

One of our preferred suppliers of passive house triple glazed windows doesnt offer installation in Scotland. Can anyone recommend a local contractor for fitting only? thanks

Thanks Alastair, I must have been forgetting the MCS requirement to be paid for export. Ok so I need to factor in getting £0 for any export as I am not paying a premium for a MCS instal. I would rather wait to see if policy changes and becomes more enlightened over time. So back to the 1/3 phase thing. There are extra costs with 3 phase which I can't determine right now. If I ignore exporting then I think I am right that I can have a 20kw array for instance on single phase without any DNO permissions as long as I have an export limitation on the inverter? If this is correct then am I also right in thinking that if I was generating at full capacity on a sunny day AND I had sufficient load connected to self use the entire generation then I could theoretically use all the generation? It is only if I cant which I guess would happen frequently that the system would throttle to avoid export? If I am right so far then is the only real benefit of 3 phase for me the faster charging speed for an EV? And given that we don't drive every day maybe it would still top up enough over a few days to do a lot of its charging from the PV? I hear what you say about Octopus tariffs but I would rather not rely on these as they could easily change over time....I am much more focused on how I can minimise my draw from the grid whether this is during the day or overnight.

This topic is of interest to me. We have single phase atm but we plan to demolish and rebuild so presumably the cost to re-connect with 3 phase wouldn't be much more than single? We have roof space for a 11kw plus array. I dont want the hassle/cost of getting permission to instal over 3.68 and had planned therefore to get an export limiting inverter and stick with single phase. But I then wondered if I could easily unlock the whole 11.04 by upgrading to 3 phase. The incentive would be to allow fast daytime charging for our electric car and not "waste" our export potential although do we get paid for this without a MCS instal? Anyway, having read this thread I suspect that there are other issues/costs I am blind to eg it seems if you use a 3 phase inverter you need permission? As @AliG said (hello btw) you can use 3 x single phase inverters and avoid this issue but I guess the cost of 3 of these inverters will be a lot more than one single phase inverter? Are there any other cost issues or complications with a 3 phase domestic instal that I am ignorant about? I dont have a lot of technical knowledge in this area so it would be great to get a simple overview. thanks

?What about FC with slight gaps on purpose and a feature made of screws and leave the wall that way. Any visual examples of this sort of thing?

Hi we are in Edinburgh and after a 2.5 yr battle finally got planning last month to demolish our existing house and build a new passive house. Now its a frantic rush to get a BW and sort out all the other 101 things to allow us to get the slab down before the Autumn frosts. A number of factors have conspired to persuade me that I will project manage and dispense with a main contractor. I think I'd read somewhere that it was a good idea to incorporate a company if doing this and wondered if anyone could comment on this? Presumably to protect in case of a contractual fall-out with a contractor but any other reason for this? eg VAT reclaim? thanks

When is this (Westminster) gov going to do anything as progressive as that! You are right though and I am learning the hard way. We have just got planning for our passivhaus build and I had hoped to aim for PH+ which requires a solar PV array much bigger than the 3.68 max without permission. Our new roof will have space for in excess of 40 panels so my thinking had been for something like a 14-16kw array. But then I started to do some reading and now understand this DNO permissions stuff where we have to pay (Scottish Power) around £600 for them to tell us if we can connect this or not. There should be no fee for this and on top of that the DNO should be forced to accommodate. Now it looks like I will be forced to cut back to 3.68 or else something a bit higher with the export throttle thing - whatever it is simply a waste of potential. On a connected topic, can anyone recommend a good general electrician in the Edinburgh area who could wire a system if I fitted it to the roof first? thanks