Simon R

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Simon R last won the day on May 6

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About Simon R

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  • About Me
    Retired form the computer industry. Like getting involved in projects, between my wife and I we have restored cars, built a boat, a done limited house renovation, new electrics, central heating and plumbing.
  • Location
    Lee on Solent - Hampshire

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  1. Just thought I would throw in my pennies worth. We're not passive, but designed from the start to minimise inputs. Our calculated structure value came in a 68W per degree. In practice this means we need about 2.5kW for maintain a 20 degree difference. The input is so small we don't have an ASHP and rely on a small gas boiler to heat two towel rails and provide hot water on demand. What is easy to get wrong is solar gain. All our SAP calculations looked good but we soon found out that our east facing glazing was causing overheating and we have had to add solar film to the windows. We're not alone in this it has caught out several builders on the forum including Mr Harris. More importantly by designing to minimise input you get a very comfortable living environment, and tiny bills. Our gas used this week works out at about 75p a day, and we have had a couple of frosts. We are now looking at adding a small 2.5kW air-con system to provide summer cooling which hopefully we'll run from PV. We used a very good service from 'SAP Box' that cost just £120 for design stage calculation, money well spent.
  2. I had intended to remove the units fan on the grounds the that the flow rate from the MVHR should provide more than adequate cooling. It was proving hard to get the information on fan flow rates for the unit to verify my assumption though. Going the aircon unit is so much simpler, found an entry from Mr Harris with some very useful stuff
  3. It does sound odd, but given the our MVHR installation it's easy for me to install the ashp in the MVHR exhaust to scavenge a little more energy. That way all the mods are in the same area and pipe runs are kept to an absolute minimum. Our mvhr has frost protection and so would protect the AG unit. However as has been pointed out by @Iceverge , the simplicity of going the inverter heat pump route rather than modifying the mvhr ducting and putting in water pipes makes a lot of sense. The only down side of this approach is that the heating/cooling is in a single area and will have to dissipate through the house rather than being distributed to all rooms by the mvhr.
  4. Ah, I think you're absolutely right. Why complicate life when there is an even simpler solution. Just got to love the build hub for a second opinion! Many thanks
  5. Good point, the plenum box is right next to the MVHR which has a condensate drain.
  6. I had figured as it would be inside the house the 10+ should not be a problem. Regarding the flow rates .45lt/s is 'normal' for 22mm which equates to about 1.6m3 an hour and more than the units required flow rate.
  7. Good point, the MVHR has a shut down temperature so should protect it. You can also get central heating inhibitor/anti freeze for central heating on boats.
  8. Our house is very well insulated and our heating requirements are tiny, in the range of 2.5kw for a 20 degree temperature difference. At the moment we heat the house with two towel rails, that are fed from a gas boiler. I'm considering installing a matrix heat exchanger in the flow plenum of our MVHR fed with water from a small ASHP to effectively replace the heating from the towel rails. Having looked at the available ASHPs and came across a suitably sized unit the 'AG Mini' intended for pools at less than £500 it looks a good option. It needs a pumped flow rate of about 1.3m3 and hour. Does anyone have any experience of these AG Mini units or spot a problem with what I'm proposing. The plenum box is plenty big enough for the heat exchanger not to cause flow volume issues. Potentially I can also run it in reverse in the summer to provide a little cooling (would only use available PV power for this).
  9. We had a few problems but nothing as serious as poor guy with the stroke. Our raft looked smooth and level but we still ended up using a self levelling resin screed to make the surface suitable for a karndean floor. We did the screeding ourselves, it's not perfect but it's a self build. The stuff we used was the Mapei ultraplan, mixed up a bag at a time with and electric stirrer. It goes off very quickly so you need to have everything ready before you start.
  10. Could try these, nice and simple As it happens we have one of these going spare as it didn't work for us...
  11. Sorry to hear you've had such a torrid time so far. A self build is stressful enough when things go reasonably well. One additional point not mentioned is CIL exemption. Do you have this in place, you really need to have it in place before you even start clearing the site. If you don't have it contact your council and plead your case, they may be sympathetic. On our project the architect was probably the least value for money, mainly down to high hourly fees and poor communication. I've just used a architectural draftsman who's been really good value, handled planning, structural calcs etc, ( he's on the south coast so may not be able to help you. Google 'Architectural Services' for your area for people providing this kind of service. You do need to get the design and planning sorted before going forward.
  12. We've got the Blauberg SB 550 which is a tad larger than the one BCP recommended at 690 m3. Very happy with the unit and support. The 5 bed kit cost £2046 (not including VAT) in 2019. They also do the system design for free. If you do go that route make sure you say you're a builder when you create your account on their system to get trade discount (the Blauberg sales guys told me to do this).
  13. Yes, several, I installed them on top of 11mm moisture resistant MDF which I've found to be very stable even in damp conditions. see:
  14. it's the Divertron 1200x, Anglia Pumps have it at £227 which surprisingly is less than the 235 I paid quite a while back. We would not have gone the rain water harvesting route if we had had the option of a mains connection. In our case the surface water connection was prohibitively expensive. For a private dwelling rain water harvesting systems save no carbon and give you additional maintenance.
  15. Another one not to be overlooked. they do a huge range and allow you to provide your own images, which surprisingly reduces the cost.