markharro

Hi I am getting 3phase put in shortly. I have had our electrician fit a box to accept it on a shed wall. The plan is to wire up our outbuildings' supply to it during the build and then take the new 3phase into the house from the same box. I thought I had read somewhere that the box had to be locking ie come with a key or have some option to use a padlock but the box fitted has neither. Is that an issue (in Scotland)? thanks

I have read this whole thread now - has no-one spoken to Mitsubishi direct to get a firm answer on this standby power from them? I may try now as I am interested in one of their ASHPs. On a separate point, we are getting 3phase into the new house - does this give any issues to be aware of with an ASHP? thanks

Thanks - will try them.

Would you be able to say which companies - maybe by private message?

What are the pros and cons of the different refrigerants you see mentioned?

Anyone got any comments on Daikin or NIBE heatpumps? Finding it hard to find any local options for Ecodan.

I am sure that's correct but I took it from the PHPP summary I received from my architect - will need to ask him about that.

Yes it is to be a certified PH! I didn't understand that I needed a PH certified ASHP for a certified standard PH but I think you have confirmed that I don't in your answer! That's just as well as I am not familiar with the majority of the products on the certified list

I had wondered about a 300 litre and then for the "annexe" part of the house which is where (potentially) another 2 adults could be housed, an electric shower and potentially an electric instant hot water solution for the washhandbasin and hot water for the kitchenette there. The thinking being that it may only be used sporadically and even if it is then we are hoping to put in a 9kW solar PV system that may power it directly during daytime use? But anyway back to what I was asking - any leading manufacturers of the main ASHP unit?

Hi Treated floor area m² is 189.1 m2 Heating demand kWh/(m²a) 17 Heating load W/m² 10 Not sure of the hot water usage - 2 adults and a child but the house is flexible enough to provide accom for 4 adults and a child down the line

I am looking to get quotes and see that a number of local installers appear to specialise in Daikin. Are they any good? Or is there a leading brand? Is looking for the highest COP the main consideration? thanks

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?