MikeGrahamT21

Yeah, I thought 1.5KW sounded very optimistic too. Annoyingly today the clouds are out in force, while i was out yesterday it was a perfect day, in which we generated 4.5kWh. I've got a firmware upgrade to do on the inverter today, no idea what it fixes as they haven't included release notes, after i've done that i'll see what data I can drag from Sunny Explorer. T21 doesn't have any gliding significance, its just the first three letters from my car registration plate! Not very imaginative i know...

It does indeed, I’ll get those figures off and post them. Shame I’m not in today as it’s a lovely day. Also worth noting there’s no trees or other high objects nearby to shade us at any point in the day.

Hi we have an east west split 50/50, 2kwp on each, and a sunnyboy string inverter with each side of the roof on a different circuit. Now our generation in December and January has never been great, usually around 50kwh each month, and I’ve never really thought there was anything wrong with that, however my suspicions were raised when speaking to a battery supplier the other day. the west side is main concern, it faces slightly more north than south and roof pitch is around 35degrees, so less than ideal at this time of year id say. Yesterday afternoon we had full sun in the back, around 2pm, I was speaking to the battery person and he said you must be generating about 1.5kw (which I thought at the time was a bit optimistic), when in fact we were generating 220w. Does this sound about right. December and January we peak at around 1kw of power at best, generally in the morning. if this doesn’t seem right I’m thinking of getting a local company out to inspect it all (our installers went bust and ‘forgot’ to register our insurance based warranty) and give them a clean at the same time (hardly much more money over inspection alone). what do people think?? regards mike

Hi has anyone used blauberg for their MVHR unit? Came across them whilst looking for an activated carbon nox box, theirs is well priced at £200. Their MVHR units look good on paper, but wondering how they are in real life? regards mike

They do look pretty cool, plenty of sensors on board too. Be wary though, POE switching is expensive and power hungry!

Any of the Blueair Range, these are rated the best air purifiers in the world, and filter down to 0.1micron, much smaller than most HEPA which do to 0.3micron. We have two Blue Pure 411's which are classed as entry level, but as far as we can tell do a good job (hard to really know), and also come with a small amount of carbon to absorb smells/gasses: https://www.breathingspace.co.uk/air-purifiers-c1/blueair-blue-pure-411-air-purifier-with-combination-filter-p232 Obviously the more expensive units with SmokeStop are better for getting rid of smells and gasses, all depends how much you want to spend. EDIT: Just changed the filters for the first time today, done every 6 months, and my god were the old filters black! New filters are £20 each, so not stupidly expensive.

Sounds sensible if you want to get the MVHR turned back on ASAP, longer you can leave it the better though. Dehumidifiers and heaters lower relative humidity causing the plaster to give off its moisture too quickly, and in turn weakening it. MVHR will have the same effect, especially at this time of year. Best thing to do is just leave a window slightly open in the rooms being plastered, this way you can guarantee a slow dry, and the air temperature will also be reduced.

Leave it a couple of days until the plaster is visibly dry, remember the slower the plaster dries the stronger it will be, and you want it to last a lifetime ideally, with the heating on at this time of year it won't take more than a couple of days. Also gives chance for plaster dust to settle, and you to clean it up, as its very fine, will clog the filters up well.

So getting someone to actually install this stuff is almost impossible, so I've been having a think. We have a single large wall onto the party wall (master bedroom) which I am going to be renovating potentially next year. What effect would knocking all of the plaster off of that one wall, parge coat and then some insulated plasterboard? I'm assuming that would pretty much negate the effects of the party wall bypass?

The poured walls will be airtight for sure, just concentrate on junctions. Any blockwork, 5mm parge coat and wet plaster if you can, or dot and dab with continuous ribbon of adhesive around edges

dont forget though, waterproof doesn't necessarily mean not-breathable, though solid concrete would have a lower vapour permeability figure (i.e. be quite resistant to the passage of water vapour). On a block work house, a parge coat would generally be applied to the inner side of the inner leaf, or it would be wet plastered. What exactly is the construction type of your property?

Ahh sorry must have misread. As long as the materials are vapour open on one side, then i don't see a problem with this, normally the membrane nearer the living space would be the airtight vapour membrane, and the outer membrane could be more like a breathable roofing membrane, however you would want it to be airtight to more than 50pa (Tyvek is ok to 50pa) to avoid cold air blowing in the void. I'll let someone else more qualified answer though, one thing you could try is simulating it: https://www.ubakus.de/u-wert-rechner/?

Is dot and dab ever truly airtight? You would definitely need to do the airtighting before the dot and dab if thats the way you are going, parge coat on block work (5mm min) (cheaper than blower proof), and tape all f the junctions. Another method would be airtight membrane and wall battens to create a service void, which is a much nicer solution. If you are wanting to ensure tightness, before you board in either method, get an air test to confirm tightness. Airtightness and moisture diffusion are two very different things also, which aren't particularly related.

So i've been on the lookout for some Smart TRVs to go with our Tado system for around a year now, waiting for them to come up on offer, and finally the other week i bought some. Arrived yesterday, got the attached and linked up to the Tado app, but they just don't seem to work well at all. Because they sit so near to the radiators, the temperature is massively out when the radiator is hot, Tado say to use the offset, but this only works when the rad is hot, the offset would be completely variable, so thats not do-able. Has anyone had a positive experience with these type items? The only real solution would be to buy an additional thermostat for each room where the is a smart TRV, thats another £600 which i'm not willing to spend! The main issues i was trying to over come was that the back of the house is always colder than front, as the original stat is in the living room, which is fine until we watch the TV which heats that room up and turns the heating off. I wonder if just buying one additional stat for the back of the house would be a better idea, and do away with these TRVs, go back to the old fashioned ones I took off to attach these. Getting in touch with Tado regarding these see what they have to say.

Be very careful at this stage, we had someone do first fix and then disappear, and now we can't get BC sign off, because the person who is being certified needs to have both designed and installed the electrics. Basically it all needs ripping out and re-doing, but its plastered now. Hopefully they are still visible, in which case another firm could easily take over and assess what is already there.

Ahh should be OK then, my mistake was buying from random people off eBay!

We've been through 2 centra's in the utility now, with the latest one dead, yet the bathroom is still on its first. Picked them up for about £35 on ebay luckily, so haven't lost much. Going to replace utility with a greenwood cv2gip which are also reasonable to pick up on ebay and the web, and look fairly nice, center parcs use them, so i'm guessing they will last a good amount of time

We used an AVCL over the top of the joists, and its surprising before you seal it to the walls, just how much airflow there is, even when you have fitted the insulation very tightly, and sealed everything with expanding foam! Bottom of the joists is of course open, and the benefit of the AVCL is reduced moisture flow downwards, and the airtightness actually gives an increased airflow between air bricks under the floor, since less of the airflow is breaking into the living space.

Its a very good idea, as you say for circuit isolation, but don't be fooled, it is very expensive! I've just put a manifold in for wall hung radiators, 7 circuits, whole project cost me around £500 (excluding the new rads I needed).

Definitely needs BC, and be careful as if you renovate a certain amount, you have to do your entire property to current standards, which includes electrics and everything else. PP only required if you are changing the look of the building, if its going to look the same, then no PP required.

For the small amount i've done in EPS (13m2), i'm happy as it is, there is nothing over doorways anyway, so the drip effect isn't an issue, but for any future projects I think i'd lean toward rockwool, even though its not as thermally efficient, there is the added benefits of fire resistance and sound reduction.

Yeah thats right, i've had a sample from EWI pro of both the EPS and Rockwool systems, and when complete there is no different to toughness. The slabs are called duo-density. Yes the non-combustability is appealing, though i tried to set fire to EPS system too, and it just melted, PIR on the other hand does set alight and burn, until it carbonises.

Well, we finally made it, 3 years from when i first started! Just got some blinds to go up at the windows which haven't come yet, but otherwise done and dusted. Just wanted to say thank you for all your help, both from this forum and ebuild (thats how long its taken me lol!) The room itself is performing as expected, with an average temperature of 21C and humidity of between 40 and 50% (with hardly any ventilation at present, just the vents in the roof windows). The radiators I put in were massively over-specced, but at the time it was hard to imagine the room being easy to warm, indeed the calcs were correct and they rarely come on, even on the coldest of days, though it hasn't had its true test yet, but overall really pleased with this.

Yeah thats potentially the main issue here, i'd have to put planning permission in for anything other than brick finish (we would use resin brick slips like i used on the rear extension), ideally i'd prefer timber or a timber and render combo, I think we'd get it, just a lot of hassle getting there, plus we don't get on with our neighbours which helps greatly lol. What would you do for fire breaks in larsen truss? With EPS you have to have a rockwool section between floors, and though technically we don't have another floor, we do have a large uninhabited loft. Also what is the minimum depth of this system? I was thinking of using 100mm insulation (EPS/Rockwool) in the usual EWI fashion. Next year I plan to renovate the main bedroom, rip up the floor, replace all of our woodwormed timber, and replace, insulate and airtight, and then monitor the heat loss. This room has the largest area of unfilled party wall cavity, which potentially is the main source of heat loss in this room once the floor is done, but there is a chance we may not even require EWI if the heat loss is acceptable. I've been very pleased with the performance of the small bedroom which has had the above done, with no EWI (external wall makeup is approx 0.5U).

I was thinking simple timber, this look very similar to those i-joists but with gaps along, so yeah the thermal bridge side of things should be smaller, but still worse than EPS overall, and would be a more expensive system to install since you'd have a requirement for a render carrier wouldn't you?