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tahir
Joined: 28 Oct 2004
Posts: 45421
Location: Essex
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tahir
Joined: 28 Oct 2004
Posts: 45421
Location: Essex
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kGarden
Joined: 01 Dec 2014
Posts: 178
Location: Suffolk, UK
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 Posted: Mon Dec 01, 14 4:54 pm Post subject: |
 
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In case my experience is relevant / useful:
We have a solid-built house constructed in 1960. Originally with flat roof made of concrete, as is 1st floor. uPVC double glazed replacement windows fitted by previous owner about 10-15 years ago when a pitched roof, and loft insulation, was also added.
We have sought to reduce our energy usage over the last 7 years and amongst other things filled the cavity and increased loft insulation.
Latterly we started looking at improving the thermal properties of the building. Turns out that it's as hard as a hard thing  Build a new outer skin wall with celotex type insulation, move all the windows further out so the insulation layer is "continuous" (as well as replacing with more thermally efficient windows), significant difficulty insulating the floor, and enough of the new outer skin walls' footings, vertically, to prevent cold-bridging. The new join between top of outer skin and roof is also a tricky detail. Must be no cold-bridging between inner-and-outer walls, and the building must be very very airtight (mechanical ventilation is then used, with heat recovery, to provide excellent air quality)
We were lucky that our house was already relatively air tight (2.5 ACH [air changes per hour], 5-10 is more common for existing housing stock) probably because of the amount of concrete used. Starting with a house with joists / floorboards that was a lot more leaky would be even harder.
The South end of our house was just the garage, and an upstairs corridor window. No, I have no idea why they designed it like that either!
We didn't want to move, so, instead, we demolished the garage and built an extension [only recently finished] on the South end, built to full Passive House standards, and taking advantage of orientation and solar gain. Its also benefit from the existing house sheltering it to the North, and includes kitchen, snug and bedroom/bathroom above. Sufficient for Mrs K and I to hibernate in for the winter.
Passive House build needs almost no heating (dunno how little "almost" is as yet, but the bedrooms are 19C and have had no heating at all yet this (mild) winter). I have put some heat into the kitchen floor, but only when we have lit the boiler to heat the old part of the house, which we are now maintaining 2C lower than before. The UFH in the extension is probably getting 2-3 hours boost once every 2 - 3 days (yeah, I know that's not how it is supposed to be run  we have a log burning central heating boiler for the old part of the house, so being a batch system it lends itself to heating the thermal mass periodically rather than continuous heating).
Other thing we have done is to put sophisticated home automation. I was in two minds about whether that was actually going to be something that would turn out to be a real benefit as I don't see myself in the Footballer's Wife category of colour changing mood lighting etc. but my acid test is if Mrs K thinks it is fault-free and Grandma can get the TV on and find some Tennis to watch  Works find on all counts.
Retro fitting lots of CAT6 cables to the existing building, rewiring (not strictly necessary, but the lighting is not well thought out, and there are only one / two power points per room, typical 1960's spec) would have been a major upheaval.
So ... summary:
I think there is a huge market for someone to figure out how to retrospectively upgrade existing housing stock, but we aren't there yet. Living in the house during that refurbishment may well be impossible - extra cost / hassle of moving out for, say, 6 months.
Bunging a hibernation-extension on has worked for us, if that is not an option for you then my advice is demolish & rebuild, if affordable / sensible / etc., or failing that then new-build on a greenfield site (in which case there is the option to live in old house until new house completed)
I am a huge fan of Passive House. Incredibly comfortable, and it means that our fuel costs, into retirement and dotage, will be a fraction of that for a conventional house. Some extra cost of insulation and air tightness during the build, save the cost of a boiler and wet heating system, in return for negligible heating costs for the lifetime of the building.
We now have a modern building, with modern control systems and no faffing about making-do-and-mending.
Passive House info:
https://www.passivhaus.org.uk/
a quote from that site:
"with fuel prices continuing to rise the low heating demand of Passivhaus Buildings of less than 15kWh per square metre per year means that annual fuel costs are reduced by a factor of 5-10. For example a household living in a 70m2 Passivhaus with gas heating could spend as little as £25 on space heating each year."
For anyone interested I can recommend the Passive House handbook. It contains technical information, but in a way that can be skated over if not of interest whilst still providing a soup-to-nuts education. Sorry, but its not a bargain basement purchase
https://www.greenbooks.co.uk/Book/426/Passivhaus-Handbook.html |
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vegplot
Joined: 19 Apr 2007
Posts: 21301
Location: Bethesda, Gwynedd
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BahamaMama
Joined: 21 Sep 2006
Posts: 2315
Location: Away with the fairies
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tahir
Joined: 28 Oct 2004
Posts: 45421
Location: Essex
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wellington womble
Joined: 08 Nov 2004
Posts: 15051
Location: East Midlands
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