divorcingjack

LOL! The back of the house is tight up against a row of knackered old 50's prefab asbestos roofed garages, so it'll fit right in! But.. point taken. Although, we visited the house during a really hot spell on saturday and it was surprisingly cool inside, so this might not be as much of a problem as we feared. But, we're going to build in a hidden housing for an AC unit just in case. Many thanks for all the replies and advice.

That is actually a genius idea. I actually have an old freezer that I picked up for free when buying our fridge that's going in the house.

This discussion has been really helpful, thank you all. Looks like an split AC unit is going to be the simplest solution for us. Any advice on good brands/things to look out for? I know Panasonic are considered reliable and I'm assuming an inverter based unit is best? Thanks, dj

OK, thanks for all the replies chaps. Looks like an £370 air to air AC unit like the one jeremy recommended ( was that a recommendation, or just an example?) could be a good choice. If we think about it now, we could probably conceal it pretty well, as it's pretty ugly to have on show. The ground coil would have been an excellent idea, had we done it during our extensive excavations. Bugger it - it's all filled in with compacted hardcore now and would be an absolute arse to dig out again Sooooo... what would have to go through the wall with this unit? Typically, the zinc portion of the house has been clad now and I'm none too keen on trying to put a hole through it. The brickwork section is not complete yet though, so there are options.

Morning all, Due to the unseasonably warm weather, and the imminent on-site arrival of our plumber, my thoughts have turned to the cooling of the house. We have a lot of glazing, and have already designed in external shading. I read with interest the JSHarris blog post about using the ASHP in cooling mode with the UFH to cool the floor slab - genius idea. Unfortunately, we don't have an ASHP. We have a system boiler and thermal store. My plumber scratched his head a bit and talked about additional valves and whatnot, but was a bit puzzled by the whole idea of using the UFH for the opposite to it's intended purpose. Questions - will switching the UFH to use the cold water supply actually make any difference to the temperature of the floor, or is this a stupid idea? I'm thinking that the area in front of our large windows will get super-hot, so circulating the heat away from this area to the cooler areas of the house would surely help? What on earth does my plumber need to do to make this work? Please feel free to tell me I am being an idiot. I have just had a baby, so I'm not firing on all cylinders at the minute. Thanks all

@Nickfromwales LOL, surely you are entirely fed up of my questions by now ...

Just to update on this with a frankly ambitious quote from one brickie - we managed to source reclaims and have had half delivered already. The other half are another story - the guy is a bit dodgy to say the least, so we may have to get a threatening gang together to get the rest They weigh an absolute ton, but will look great once laid. So we had a brickie round yesterday who offered to have 2 gangs on site, and said they could lay 2000 bricks/day. All looked good while he was on site, but then he has sent us a labour only quote of £60/sqm for single skin. No lintels (zinc panels above windows), no decorative anything or fiddly details. The bricks are to be painted, so we don't require an absolutely perfect finish. We have a total area of 120 sqm with potential for additional work for a large garden wall as well. Am I right in thinking this is a little toppy, to say the least? Could anyone with SPONS give me an idea of recommended prices either /1000 bricks laid or psqm for single skin, facing reclaimed bricks? We are supplying the bricks, ties and all materials. Cheers, dj

Hi all, Time to bump up this thread again as we have to make these purchases before new baby arrives (due yesterday!). After moving house into another rental with inadequate HW setup, we're more keen than ever to make sure we get this right. So - more questions: - Am I right in my assumption that you cannot have a HW return circuit with a combi? So, you could potentially be waiting for HW at far away taps? - If we oversize the thermal store now (perhaps to 400l), we could run it at a lower temp and add in PV via an immersion at a later date if we decide to install it? - If we are ordering a thermal store, we need one with a 28mm 46kw DHW instant coil and 2 immersions to future proof for later PV? I'm going to read through the thread again and probably come back with more questions Cheers, dj

OK lads and ladies - being trapped in the house under feet of snow has meant that we finally got a chance to discuss the heating and PV again and we have come up with more stupid questions for you. As regards the PV - we're still tending towards not having it. We live by the sea and have a lot of seagulls. We are putting in special measures to avoid them landing/nesting on the flat roof - we think they will perch on the panels and shit all over them, so we'd have to factor in fairly regular cleaning, presumably at a cost. This would pretty much wipe out the earnings from FIT. However, it's not a complete no - depends on where the energy prices go over the next 5-10 years. So, we are now tending towards @Nickfromwales suggestion of a high flow combo combined with buffer tank for the UFH. Having lived with a (probably undersized) combi in a previous house, I'm a bit wary of baths taking a millennium to fill or underpowered, lukewarm showers Some of our showers for the house have very high flow rates of 24l/m and I notice that the combi Nick recommended does "up to" 20l/m hot - I appreciate with blending this comes down, but presumably it wouldn't manage with multiple outlets at once. Would anything though? My questions: - Will the Valiant 938 cope with very high flow showers? Should we go for something higher powered? - What size buffer would we need for the UFH and how would this be linked up with the combi? - Is there a way to retrospectively connect any PV to a combi? Perhaps another buffer with a PV coil? Or is that adding another layer of unnecessary complexity? Thanks again for all your help - in answer to a previous question, we haven't been connected to the water yet (long story....) but the local pressure at the point we are hoping to connect was approx 10 bar, I think. Don't know about flow rate, but nothing was mentioned about it being problematic. We are next to two blocks of flats, so hopefully the supply is reasonable. Thanks all - off to pick up the wee one, so will catch up later. Cheers, dj

Nope. Well, the skylights, but they already have the EPDM bonded to the upstands. They literally stuck down the last piece last Wednesday! The edging hasn’t been done though, so perhaps under there? We’d have to drill through the MBC kit though.

Roof is complete and watertight .....

Right. So, our sparky is also an installer, so I will talk about it with him. Assuming you lot have won the PV argument, how does this affect my flaming plumbing? @Nickfromwales, thank you for the explanation of the TS argument, I like that it is a simpler install and am reassured that it wouldn't run out of DHW if paired with a big enough boiler. Are the issues about thermal stores running out of HW normally due to a too-small boiler then? So, what on earth do we do with the PV output that relates to a thermal store?

Oh, you lot! Buggeration. What are we looking at in terms of cost here? The available roof space is prob about 100 sqm - large skylights plus no panels within 1m of the edge of the roof.

Ah ok, this did not come up during our original thinking about PV. I take it this makes the install more expensive? I think they would have to be set flat tbh. Next question - can they be installed on top of an EPDM roof? Also - there hasn't been any structural allowance made for this potential install - is this a problem?

I had a quick google and it looks like the same regs for scotland tbh. So, if we were to install the panels flat, how do mitigate the partial shading? I thought that any shading on any of the panels basically took out the whole array? Is that wrong?

Does that apply in Scotland too? OK OK, so say we did go for PV eventually, as we have no cash for the foreseeable - could we mount the panels flat? Or would they have to be at an angle? Having them at an angle would pretty much ruin the look of the house (I know, I know) as you would see them on approach to the single storey section.

Ha! Our planners do not lower themselves to talk to members of the public who have questions about planning. How utterly ridiculous. I can try and get hold of someone, but it's just another task on the so-long list. I was hoping this would be straightforward. Or at least not as nightmarishly complex as every other sodding thing has been. Can you explain why @ragg987 suggestion of a UVC + buffer + blending valve would leave me out of DHW? Could I just upgrade the size of the cylinder?

It's highly unlikely that we would get planning for them tbh - it's taken us 5 years to battle through planning for the house. Even if we did - surely the payback time just wouldn't be worth it?

I thought I had this all sorted out!! I am so confused now Do I really need to read up about Thermal stores again? Nooooooo

@Nickfromwales The PV issue has a few aspects: - conservation area and notoriously nightmarish planning - flat roof -surrounded by 3/4 storey blocks of flats which cast extensive shadows on our roof, there is very little of the roof which is not overcast at some point in the day.

Hmm, that is quite a major issue - we're already trying to mitigate potential over heating problems from our large glazing, so really don't need to add any more potential heat sources.

Thanks for your reply @le-cerveau - to answer some questions.. We have the space for a large UVC - presumably this would mitigate the risk of running out of water mid-shower/bath? I understand that the recharge time would be shorter with a smaller one, but we're fairly unlikely to have lots of showers/baths back to back. From my understanding, a buffer tank is recommended for low temp UFH to avoid the boiler short-cycling trying to provide DHW at a higher temp and water for the UFH at a much lower flow temp. My issue with a TS would be the lack of pressure - we have german fittings throughout and would worry that a non-pressurised system would deliver an extremely disappointing shower experience Also - with an ASHP, there would be an additional cost on top of having to buy a boiler, and I'm not sure it's something we can justify. Definitely worth considering though - I'm reading through the threads and making notes as I go along. I have so many notes!

Hi all, We're still on the plumbing/plant room arranging, so the next purchase needs to be the boiler, UVC and buffer tank. So, I'm on the scrounge for advice again I understand from my reading of other threads in this section, that when we're talking about low energy houses, the main requirement for boiler size is ensuring an adequate DHW supply. I've done Jeremy's spreadsheet and the total heat loss power at 20 deg inside and 0 deg outside is coming out at 2.5 Kw. House has a lot of glazing, a non-optimal shape and 240 sqm total area. The current plan is a UVC, buffer tank (for UFH) and a system boiler. 4 occupants, 2 young children, all very keen on baths and excessively long showers. Showers are high flow, rainhead-type. Mains gas, no PV or prospect of any in the future. This is our forever house, so we will at some point have 2 teenagers, with their associated showering habits. So, questions: - Any boiler recommendations. Do I need to think about whether it modulates to a low enough temperature for the UFH if we've got a buffer tank? - What size of boiler do we need? - How do we size the buffer tank and what should it be? Direct, indirect, what tapping points, stainless steel/copper. pressurised? - We were considering a 300-350ltr UVC. Does this seem reasonable? I have a horror of running out of hot water for a bath, having lived with inadequate heating systems in a few houses. Thanks for pointers to any particularly useful threads or direct advice. Cheers, dj

They are great to deal with as well, very accommodating and helpful when we had to change their plans for a pain-in-the-arse building control guy.

Thanks for all the replies on this, very helpful, chaps. Spent an eye watering afternoon yesterday pricing up Aquapanel, Hardiebacker and Marmox boards. I assume 12.5mm is the thing to use? Some above I notice have done a mix of Aquapanel and MR plasterboard in less "at risk" areas. Is this reasonable, or should we really just do the whole lot in Aquapanel/hardie/marmox and then tank over everything? Cheers, dj PS: If anyone has seen any good deals on this stuff, I'd be most appreciative