Jump to content

jack

Members
  • Posts

    6795
  • Joined

  • Last visited

  • Days Won

    35

jack last won the day on February 26 2023

jack had the most liked content!

2 Followers

Personal Information

  • About Me
    Considering a move to Octopus Energy and want to help BuildHub?
    https://forum.buildhub.org.uk/topic/36891-considering-a-move-to-octopus-energy-and-want-to-split-a-%C2%A3100-bonus-with-buildhub
  • Location
    SE England

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

jack's Achievements

Advanced Member

Advanced Member (5/5)

2.1k

Reputation

  1. The Passivhaus standard sets, among other things, a maximum annual energy budget for heating off 15 kWh/m2. On that basis, it's reasonable to expect that heating will be required. The standard says nothing about how the heating is supplied. If your son rarely turns the heating on, what sort of temperature does the house usually sit at during winter? Passivhaus works particularly well in places where there's a lot of winter sun, which doesn't generally describe the UK! As a point of comparison, our house temperature stabilised at about 14 degrees when we went away for a month over Christmas a few years ago. That was no people, no appliances, no cooking, and no showers for a month. In comparison, some of my friends live in Victorian houses, and during cold weather struggle to get parts of their homes to 16 degrees even with the heating running flat out for hours. I know which I'd rather! Have you read that for houses that meet the Passivhaus standard? One other point: when you say you're building a Passivhaus, do you mean a house that's been designed and modeled to meet all the requirements of a Passivhaus? Or are you building using Passivhaus principles such as using lots of insulation and good airtightness? It does make a difference. I don't think our house would meet the standard due to the size and location of our windows, for example. If it's been modelled, you should know how much energy it will use for heating in a year, and you can then easily work out how much it will cost to run an ASHP to supply that heat.
  2. Our BCO actually accepted the original design document. I did the measurements just to satisfy myself that the as-installed settings were about right.
  3. Aesthetic, agreed. If you don't have an out-of-sight place for one, they are generally pretty ugly. We're lucky that we were able to site ours on the far side of our attached garage, where it's out of sight unless you walk along that route (and there's generally little reason to do so). I'm less sure about comfort. There are lots of reports about how noisy GSHP pumps are, to the point where it's sometimes recommended they be sited in their own sound-insulated housing outside the main building envelope. I can't hear my ASHP when it's running unless it's a very still day and I stand pretty close to the unit. I'm not saying there are no use cases for GSHP, just that the economics rarely make sense if you can choose between one or the other (as appears to be the case with OP, since he mentioned both).
  4. Definitely worth checking with your BCO before relying on this unit, although I haven't heard of any of the nearly 30 people who've used our uncalibrated unit having had an issue with building control.
  5. ... and find a way to make 100% sure that the insulation is installed properly. Pointless having a load of insulation in a wide cavity if there are gaps everywhere allowing for thermal bypass.
  6. (PS: I'm going to stop replying on this topic, as we've hijacked the OP's thread)
  7. £30k was the total system cost, which was a guess on my part (added a bit to my vague memory of £20-25k for a typical slinky-type system). Quick search found: https://www.greenmatch.co.uk/ground-source-heat-pump/borehole: Or https://www.imsheatpumps.co.uk/blog/ground-source-heat-pump-borehole-cost/: Given your property has relatively low heating requirements, it'll be at the low end of that range, so probably around £25k. You need to add to your numbers above the periodic replacement of the heat pump itself - maybe £10k every 10-20 years? Not sure. TBF, you probably need to replace an ASHP at least as often, but they are a lot cheaper. Plus a few hundred quid every few years to replace the fluid.
  8. Yes, that's the one. I've heard horror stories about badly implemented slinky systems. I'm sure there was someone on BuildHub a couple/few years ago who had problems with the ground over their system freezing towards the end of winter. My main point is that there are only very limited situations in which a GSHP will make sense over an ASHP.
  9. That's true. Still, in a town centre, you'd probably need to use vertical boreholes, which add significantly to the cost.
  10. Interesting looking build, hopefully you can share more details in due course. I think we've probably reached the point where GSHP is simply not a cost-effective option compared to ASHP. There might be the odd special case where you have a large field next door that you were going to massively dig up anyway, in which case GSHP might approach price competitiveness. But in general, GSHP setups are at least double to price of an ASHP of the same output. If properly done (and that isn't always the case), the GSHP will have slightly higher efficiency, but not enough to ever pay back the price difference.
  11. Awesome news. Despite not having a programming background, I found the programming side very satisfying.
  12. I think we ought to be encouraging larger tanks. They store the same amount of energy at a lower temperature (suits ASHPs) in the colder months, and allow greater usage of diverted PV power when the sun is shining.
  13. Welcome @Allyzap The forum search is a good start, or you can Google "subsidence site:buildhub.org.uk" for slightly better results. If you want to post something, the "Foundations" sub-forum is probably a good place to start: https://forum.buildhub.org.uk/forum/73-foundations
  14. Very useful, thanks for reporting back @Ultima357
×
×
  • Create New...