MikeGrahamT21

We have the infamous east west split, and we did around 3250kwh both 2016 and 2017. The west ones don't do so much in the winter. We do have south facing space for those (2kw) now, but its almost impossible to find anyone who will move them.

As said above, the fact that most of the appliances use more power than the solar pv can provide, even at its best, the battery will get heavy use. Even when we do have the oven on, we rarely just have that on. There is several fridges (cerca 200W each) for medical storage, oxygen concentrator (500W), my work equipment (100W), background load (up to 100W), boiler in cold times (2-300W), so we will use more than the current 4Kw solar PV we have, hence why i believe the storage would be a good thing to have, to top us up during the day, and provide the background load during the night.

We are further north than you, but out of curiosity how many kwh did you generate last year?

Yeah the winter generation can be pathetic, i monitored it this winter and we averaged about 2kwh a day, so clearly wouldn't be getting full battery use. I think maybe to think about this less as the full charge and discharge cycle, the major benefit for me is the ability to top up existing generation, which rarely is enough. For example on a hot sunny day in summer, we'll generate a reasonably static 2.2-2.6kwh, which barely scrapes running things like oven, washing machine singly. The ability to provide another 3kwh from the battery on top of this 2.2-2.6, gives a lot more scope for flexibility, and of course it costs nothing from the grid.

Specs for the Pylon Tech batteries have just been improved to 90% DoD with a full 10 year warranty, used to be 80%, however their materials have improved I believe.

I totally agree with this, i really do, but there is something about more self sufficiency which can't be put into money terms. For example, having a UPS setup, for us would have key benefits. Our electric rate is 12.8p, on a 4.8 capacity thats 61.44p saving per day, however, in a day we could charge and use that capacity numerous times, so you can't just use 4.8 a day, and of course it would top up the generation if it wasn't quite enough, so I reckon the saving is actually a lot more than the simple calculation, but of course theres no way you could work that out. And of course, theres energy costs going up, over 10years, which could be a lot, and also might not be a lot, a bit of a gamble, but i'd say 18p a unit isn't unrealistic. Using 12.8p a kwh, gives a potential saving of £224 a year, so if the kit costs £1800 (which is what i'm aiming for), thats a £400 profit over the 10 years, not a lot i agree, but as said above, I think the saving potential is greater. Now if that electric cost went to the aforementioned 18p, that becomes a £1300 profit, even with the bare minimum saving. Agree the batteries would be more or less useless after the 10 year period, but would still have some good potential even if only at 50% capacity, plus in 10years time, they'll have either broken under warranty (best case scenario), and of course new ones will be a hell of a lot cheaper by then, plus the tech will be a lot better. We can't do water heating, as we have a combi boiler and no water tank, so thats out the question. Electric car i've thought about, but they won't do the range i require for work, unless i buy a tesla, which is far too much money. Ive worked hard on self consumption, and working from home really helps that, but even with my best efforts, the bloody wash basket always fills ready for a cloudy day, and of course the battery would cover this, in terms of a top up. It is a lot of ifs buts and maybes but I'm almost sure its a go-er. EDIT: We would be able to consume the 4.8 relatively easily in a non generation time, we do use a lot of electric which is unavoidable.

Hi, Aside from waiting for the price to drop a bit, I'm all set on getting a Sofar Solar ME3000SP battery AC inverter and a number of Pylon Tech 2.4Kwh batteries to go with it, in the last year a 4.8kwh package has dropped from about £3k to £2.3k, just wanting it to go sub £2k and then i'll consider it properly. I've monitored our solar output throughout the year, and 5Kwh of storage seems fillable most of the year round. Obviously in spring summer and autumn we generate far in excess of this. We aren't on an Economy 7 tariff, i suppose we could move to one and charge batteries via grid on a night, but would mean us having a smart meter more than likely, which im not that bothered about. Question is, if I say for example, bought 2 addition batteries to take us to 9.6kwh of storage, which would get used for majority of the year, to save the batteries sat being flat for months, could I unplug them when they were full, and leave them sitting fully charged until the higher output came again? The PylonTech stuff is pretty modular so allows this very easily, and aside from reprogramming the inverter, not much else would be needed. Or should i just stick with the 4.8kwh which I can use all year round? By the end of this year (Year 3), we will have earned around £1600 from the solar installation (not taking into account electricity savings, just from the FiT), and I plan to spend that money on the storage, obviously when the 2 meet in the middle (savings and cost). The plan is to do most of the house improvements in terms of energy saving, based on the money we earn from the PV, which seems a good way of doing it, and there should be more than enough to warrant it, especially when you take into account electricity savings. Regards Mike

@JSHarris Did you manage to come up with a plan for something like this? I've emailed a few more MVHR suppliers, again all say carbon filters, but again none of them can guarantee that it will even work, and at £800, its a lot of money to gamble on. I did have a thought on making any sort of carbon filter last longer, and that was to put a manual bypass, so that when the heating season is over, we can effectively bypass the carbon filter, since we don't live in a high pollution area anyway, but other than that, i'm still in the no-go camp for MVHR, which is still extremely annoying. Its a good job i've got a lot of improvements to make before i get to this stage lol! Reading a few bits online seems to suggest electrostatic will remove the majority of the smoke, which will be the ozone you spoke about. Looking on ebay these type units are really cheap to buy, and I'm guessing you'd just put the carbon brushes into the MVHR ducting and silicone them in?

Just remember to pay maximum attention to airtightness, to ensure as efficient running as possible for the MVHR, its fiddly time consuming detail for sure, but its going to be there doing its job for many years to come, and if you have the opportunity before you get to second fix, get an air test done, to detect any small leaks which aren't obvious, again worth its money in the long run.

If you can do MVHR, do it, as it is far and above any other type of ventilation method. Remember, trickle vents only work on days when there is wind, unless you have a dMEV setup, however this is basically like a poor MVHR which doesn't recover any heat.

Put as many in as you can (obviously keep sensible), its cheap to run, and they have far more uses than just for general networking, can also be used to transmit all types of signals using x-over ethernet converters (where x is what you want to transmit), one such type is HDMI over Ethernet which can be very useful, since long HDMI cables tend to not fare very well. Make sure you pay the extra for good quality cable, LSOH (Low Smoke Zero Halogen), and really ensure you are buying solid core cables, and not stranded!

Not strictly speaking true, but not truly airtight. Something like Tyvek Supro is airtight to 50pa

If its a breathable membrane, that means moisture can pass through, so I'm guessing in this instance it wouldn't be of any use at all. You'll need a full AVCL to stop moisture from passing.

Absolutely, going with the thickest pipe insulation, the water bylaw stuff just to be sure, and to make sure we have hardly any heat loss from the CH too.

In some places they are in outer walls, and in others internal walls. Airbricks are doubles, so they are the same height as the 2 brick sleepers, and the bottom of the airbrick is the oversite concrete, so no room for manoeuvre.

Not thought of that, how about the DPC on the house though, as this is the same level as where the timber is currently sat, plus it would also decrease the air gap underneath the timber to around 75mm, below the 150mm min which is required, which is what its at currently.

Yeah I had also considered this too, sub base is already concrete, so would just need insulation and then screed. I went away from this idea, as all of the heating pipes and electric cables run under there, would make it a large project and a much larger cost, so going to stick with the timber for that reason.

Friction fit, with a bit of expanding foam in any gaps, theres not enough room below the joists to get the screwdriver drill under there to fix anything to the underside, plus the PIR will poke through as below, i've done 1 room already and that worked well, but I didn't know about AVCL's back then. I'm using the AVCL more for the airtightness factor, as you can never seal 100% without one in my opinion. Yeah joists going too, i know the new ones are 95mm, so the PIR will protrude the bottom by 5mm, no point getting 90mm PIR as its more expensive than the 100mm.

If it wasn’t for needing to replace the wood I’d do this, but need to rip it all out, clean underneath and 100mm PIR in between joists, had a look at BG Plank system too, but it makes so little difference to overall u value it’s just not worth the expense. Going to put AVCL under floorboards too and stick it to masonry behind the skirting as an upgrade

This is only single storey house, but no it’s just brick, dpc and then joists, had a look on google earlier and found both variants so I guess it probably varies around the country and each build, which materials they had more of. We’re 68 bungalow. I’m kind of glad there is no wood there at moment as we are still stripping out all of the woodworm damaged stuff!

Yeah I was annoyed by that too, i even rung them about it and they claimed thats how much it costs them, needless to say I didn't order via them. I got it from these... http://munsterhrv.com/shop/index.php?main_page=product_info&products_id=123 The other brand i've used is airstop (https://www.airstop.co.uk/airstop-tapes-c1775), both products seems to do the job well, if anything the airstop stuff is even more sticky but doesn't seem quite as thick.

Yeah there are airbricks to the outside, and you are right, the bottom of the joists will be on show to this. So not much point?? Saves me work i guess if not, just trying to make it the best it can be

Hi, Our bungalow is blessed with sleeper walls, and 100mm joists, and to increase to 200mm joists, would be far too much work digging out. At present the sleeper wall is simply created from bricks, with a DPC, and then the timber joists on top of that. In an effort to get the thermal bridge as small as possible, would it be worth while taking the top row of bricks off of the sleeper wall, adding a new DPC on top of the remaining brick, and installing a timber for the joists to sit on? Regards Mike

I did this again the other day, and ensured that all of the materials had the correct Mu values for water vapour, with a 20mm internal VCL via the Marmox it came down to around 2days of condensate a year, which is absolutely fine, don't think i'll get it any lower than that without losing too much space inside. EDIT: Entered correct details for the Marmox and we are now condensate free, definitely the way to go.

BuildDesk, that was the one I couldn't think of. I ran it through there and it said no risk. BS5250 is the one which building control accept isn't it? Maybe its worth going with the marmox just to be on the safe side, like i say aside from the financial aspect, it doesn't make much difference. Just had a play with u-wurt, that seems quite extreme, even with the vapour check it reckons 55 days drying time per year, and oddly how a house is normally built is even worse!