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About Benjseb

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  1. Sept 9th the install starts. If they can get the old 500l hot water tank out of the room! 😂 no PV yet but we’re converting a garage into a holiday let later this year and it’s got a decent East/West roof so planning on adding some to that. Weve asked for a buffer tank with an immersion so we can divert to DHW or buffer tank if we’re lucky enough to have excess at the right time of year. I think we can either fit a 6kw system on single phase or 9kw on 3 phase. But trying to avoid using 3 phase as it will mean we get to consume less of the electric we generate.
  2. We don’t actually have any condensation issues at all, not even in the bedroom if the windows are closed overnight the thinking behind PIV was that our humidity is over 70% currently (usually about 60-65%) and I just want to ensure the air is as fresh as possible for health reasons. With an old stone house there’s always going to be moisture in the air so it’s more of a way of proactively managing this I guess. But as usual it’s a balancing game as don’t want to be pushing all the warm air out.
  3. Thanks @ProDave @JSHarris Very useful insights I think I’ll start off running it when we’re in and need it and then extend the running time as/when needed if the low flow temp can’t reach heat during that period. The house does does tend to keep its temp quite well due to the insulation and some exposed stone and brick so hopefully we won’t need to keep it running 24/7. Especially as I can’t stand it hot, so would rather it be slightly chilly than too warm. 18c is toasty in our house! Do you think PIV would have a negative effect on energy consumption? Or be balanced out by the reduction in humidity and therefore less wasted latent heat? Cant wait to rip the dirty old oil boiler out!
  4. So after months of deliberation between an ASHP and a GSHP we’ve decided that paying £15000 for boreholes doesn’t really herald a decent enough increase in COP to warrant the extra outlay. Also it seems quite a risk that if they aren’t sized correctly you’re rather stuck, vs worst case with an ASHP is upgrading the unit. Our next toss up was between a northern European brand of ASHP and one of the more mainstream/air con manufacturers We’ve decided to go with a Mitsubishi Ecodan, for 2 reasons. 1. Maintainability - we don’t have to find a service partner that’s familiar with a unit primarily used overseas and 2. Advances in refrigerant technology seem to be better with the likes of Mitsubishi. Ecodan was also about £8k cheaper with same RHI return. We have a fairly big old house, 250sqm, probably 1800s built but it’s fairly well insulated and draft free for its age. We did ponder about waiting and doing more insulation first but we’d already done all the internal walls, some floors and recently all the ceilings so were at a point where additional changes were going to start getting expensive and take more time. Our peak heat loss is currently about 13kW (from survey) and this was before doing some floor insulation and we’re going to be replacing some doors and windows at some point in the next few years. So, a 14kW Ecodan incoming (would have gone smaller but... MCS!) Id love to hear people’s tips on running it effectively. I’m already planning on keeping the water temp as low as possible and using our 7kw wood burner to topup on the colder days. Have people found running it at night on E7 works well for an older house or just gradually 24/7 better? What sort of set back temp works best? Do people time the hot water (as we currently do) or set the DHW to keep a constant tank temp (seems the norm on ASHP, we have one at work and quite hard to time it) we've just installed UFH in half of the downstairs but left the rads on the walls for now. Undecided if we’ll keep them running and then hopefully be able to run a lower water temp overall or decommission them. Any tips much appreciated. Ben
  5. Has anyone experiences with the Nuaire FlatMaster (or similar?) as I’ve seen lots of reviews of the Drimaster but not sure how the FlatMaster performs?
  6. Good to know, thank you! We're looking at getting an ASHP to replace an old knackered oil boiler. All the heat loss calls add up, but adding UFH was also a way of increasing the emitter size so we could run the water temp lower. Combining 45m2 of UFH with 5 rads should hopefully achieve this, and we can then play with the mix between UFH and Rads if needs be. I'm hoping that the ASHP being on 24/7 rather than the up/down of oil will also help in our old building and stabilise humidity, etc due to less temp fluctuations.
  7. Understood. We only heat two rooms with UFH, kitchen/hall so these tend to stay at 18c on the stat - so yes, the floor temp will obviously be higher than that, but we're not using it in rooms where we hike the stat up high. Much of it was for comfort as the floor felt cold with Amtico so we were worried that with limestone it'd feel colder. It's much better now, but haven't had a winter yet to test the full effects. We actually still have all the radiators on the wall in those rooms which had already been oversized, so I'm hoping to use all in combination so we can run things at a lower water temp on the UFH.
  8. Approx 0.6 according to a heat loss calc we had done for heating system.
  9. @JSHarris the specs for the XPS are: Thermal Conductivity: 0.033W/mK
  10. Love the way you’ve done that Ferdinand. We literally have no voids though. It’s wall then roof so the only way to make that work would be to add a false ceiling and go out of the roof, but if doing that we may as well just go out the wall and box it in somewhere discreet.
  11. Its stone built so no external insulation possible walls are 600mm sandstone, cavity, brick inner leaf then either 50mm or 150mm internal celotex/EPS depending upon which room.
  12. Not sure I’m following the figures completely. There no doubt would have been heat loss if we’d not added any insulation at all... Even without the UFH on there’s a noticeable difference now with the insulation under the tiles, maybe just because there’s less of a thermal bridge.
  13. Thats awesome thank you. Yes I guess that ceiling work and skimming probably has tightened things up quite a bit. We also had all new skirting that was foamed behind too During the works we found our stove flue had been installed by a cowboy (there was a 6” gap!!) many years ago, so had to get that replaced so not had the wood burner working which is great at reducing levels of humidity. That’s now sorted as of last week so may crank that up to pull some air through the house and dry things off first and see how we get on. I’m really keen to make the air quality as good as possible as I have a tendency for allergies. PIV has been on my list, it’s a big house (250sqm) so think we may need two but unfortunately no loft so will have to try and use something like the Nuaire FlatMaster and box it in. A pain as well have to drill some big holes in the external wall. Thats put my mind at rest a bit so thanks.
  14. It’s a retrofit so all we could fit in. When I asked around quite a few people said it worked well, we will see!
  15. Hi all We live in an old stone built house, which was renovated/insulated in 2005. At the start of this year we had our internal upper floor ceilings (no loft) torn down, and 50mm celotex installed (gaps between rafters sealed with expanding foam) then reboarded and plastered. We also had about 5 new velux windows added and most internal walls skimmed. A month ago downstairs we had the horrible plastic karndean pulled up and limestone tiles laid (with UFH + 25mm XPS insulation below). The concrete floor has a DPM and was dry to touch. Previously our humidity levels were about 60-65% (expected to be a big higher as old house, no DPC). We'e noticed since about April (roughly when the ceiling work was finished) that our humidity levels have been above 70-75% on many days. I'm fully aware that adding insulation/increasing air tightness can increase humidity, but seeing as this house is probably fairly leaky, I didn't expect much of a shift when we did this. We've also added more ventilation from the velux vents. We have 3 decent DMEV trickle extractors which are running on boost mode 24/7 at the moment as the higher humidity levels are setting them off. As its summer, we often have the velux open (the velux are only even closed to 'ventilate' mode at worst, and often open all day). As it's been quite wet here (North West UK) with the humidity levels outside often 80%+ I'm hoping this is just due to inside/outside temperatures being the same (or often lower inside due to the stone keeping it cool) and so the internal humidity being the same (or more) as outside Do you think it could be the weather currently, or think we've created an issue with the work we've had done?