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How to build homes with virtually no heating (2020)
281–290 of 335 posts
Re: How to build homes with virtually no heating (2020)
#282Earlier quoted context omitted.
I work on energy systems modelling and how domestic thermal performance interfaces with that - the UK has not just "one of the oldest in Europe" it actually has the oldest in the world. Many European countries had a lot more post WWII construction so at least have cavity walls (even if in many cases not filled until later).
My understanding was that cavities should actually not be filled, since they allow water to drain out. Is that incorrect?
The issue is will the cavity system allow water to penetrate to the inner leaf which is bad and will cause internal dampness.
Cavities can be carefully partially filled with some type of insulation which allows the water soaking through the brick to evaporate and drain back out.
The standard technique is to use blown in EPS beads which allow for drainage downwards, reducing the chance that any water loading will make it through the insulation layer and to the inner leaf of the wall.
Problems with cavity insulation are often caused by:
-Treating walls which have a large amount of debris in the cavity, leading to water bridging
-Over-filling cavities which also leads to water bridging
-Treating walls with very large amounts of rain exposure, especially to driving rain for extended periods of time since this will lead to saturation of the cavity insulation system which may be unable to dry for months at a time. These walls should be externally insulated and clad instead.
In the UK context for example, houses in Wales and parts of the English South coast, the whole Southwest, the East of Scotland, and most of NI are in zones 3 and 4 in terms of wind driven rain exposure.
In zone 3 and 4, installers are required to carry out an assessment of site conditions and of cavity thickness as well as exterior wall finish. Older houses might have 50mm cavities, new properties often have 100mm or 150mm cavities. Obviously that reduces the changes of water soaking through.
Approved Document C allows a full fill of insulation for a 75mm cavity on a fully rendered wall and on a 50mm cavity if clad with rain impervious material but requires 150mm for bare masonry.
Re: How to build homes with virtually no heating (2020)
#283Earlier quoted context omitted.
"About the only part of a Californian house you can't put your foot through is the front door." 'The Big Sleep', Raymond Chandler (1939). Good to see nothing's changed!
Oh, this is so very true! In addition, said front door is protected by a flimsy deadbolt that sits in a dinky thin door frame. The whole thing breaks and opens with a kick and offers symbolic, rather than practical protection.
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Re: How to build homes with virtually no heating (2020)
#284While this is at the extreme end of the spectrum, there is a much easier way to save lots of energy: just build modern well-insulated homes. I lived in California and I was appalled at the monstrous energy waste: houses are generally made pretty much from cardboard. You need to cool them in summertime and heat them in wintertime, and the energy expenditure is enormous. I now live in Poland and have recently built sma…
Coming from a decidedly unsexy post-industrial Midwestern city, I was very surprised to learn that for all the wealth and splendor of California, most of the buildings here seem horribly impoverished.
Re: How to build homes with virtually no heating (2020)
#285I've also built a simple and small (99sqm) PassivHaus in Romania, 5 years ago. Everybody, and I mean everybody from family to friends called me nuts, but I've got my payback this winter when the energy prices went trough the roof and I'm just slightly affected. The house is elevated from the ground on 12 concrete columns so that I can insulate under the foundation beams using glass foam, insulation on walls is 30 cm…
So with home solar panels and storage getting cheaper and cheaper and better and better, where is the optimization point of investing in better insulation vs just buying more solar panels?
Especially if the solar panels may produce profit on sunny mild days about 40-50% of the year if there is reverse metering and the like?
Re: How to build homes with virtually no heating (2020)
#286I think this is one of those things where people generally agree that better insulation and lower energy costs is a good thing but who pays for it? In the UK, there is a constant demand for "affordable housing", which is caused by governments not controlling the housing market from either foreign investors or also people using the housing bubble to buy up loads of properties over time forcing others to rent. Bearing…
> Another major problem is the quality of building in the UK, mainly driven by a lack of tradespeople, and simply not having the skills to install to the quality levels required by thermally efficient houses like installing a membrane with zero holes in it, using the correct tapes, designing, installing and maintaining heat pumpes and various other things.
I agree with the sibling comment this is an incentive problem rather than a skill problem. If house builders can cut corners they will. If they can sell a house for the same cost without the fancy new insulation gear they will.
This is why your bit about regulation is needed because otherwise the things you list won’t happen. Home chargers are a good example which the govt deemed necessary for new builds, the skill will be there for that and without the regulation I’m not sure most builders would have bothered, leaving people to retrofit one further down the line paying a higher cost. The skills for heat pumps will organically grow as regulation kicks in too.
> why governments aren't keen to make large improvements in energy-efficiency regulations.
The govt have been consulting with various business and institutions on future building standards you can view their response here: https://www.gov.uk/government/consultations/the-future-build.... But from it we've already had EV charging point requirements, ban on gas boilers, new homes in England will have to produce around 30% less carbon emissions, plus raising the standard for insulation.
Re: How to build homes with virtually no heating (2020)
#287Reminds me of 'Earthship Houses' that are completely off grid, recycle their waste water to grow crops, are built using repurposed car tires and grow their own food. There is a community in New Mexico https://www.youtube.com/watch?v=wgUkjbMhF18 And even some in Canada https://www.youtube.com/watch?v=EAvY5JeMz9w&t=62s
Ha, I volunteered to build Earthships in New Mexico in 1995 during my orientation week at college. Fascinating community.
Thanks for the reminder.
Re: How to build homes with virtually no heating (2020)
#288Earlier quoted context omitted.
The next most effective thing to do is External wall insulation. However that'll mean that you'll loose the whinstone look. (unless you pay a _lot_ to get whinstone like shims put on after) The alternative is to have internal wall insulation: https://www.insulationsuperstore.co.uk/product/vacutherm-vac... This is as effective as ~150mm of rockwool, but only 20mm thick. So this can be stuck behind plaster/plasterboard…
I followed your link, but am confused and/or doubtful: how do you replace 150mm of rockwool with 20mm of anything other than a good vacuum? It says that they are 'very low internal pressure' - but if it contains any kind of gas (which i presume it must do - air if nothing else) then the conductivity does not depend on pressure until the mean-free-path has increased to be > the width of the container. Is this product…
https://en.wikipedia.org/wiki/Vacuum_insulated_panel Looks like the thing. So, yeah, very good vacuum. It's apparently decades for the lifespan, but much of it boils down to the materials being used.
Re: How to build homes with virtually no heating (2020)
#289Earlier quoted context omitted.
Modern codes have moved back to 2x4, then they put continuous foam on the outside of that to make the total the width of a.2x6 wall. Wood is not a great insulator and you have to have some
> Modern codes have moved back to 2x4, then they put continuous foam on the outside Codes do allow for only external insulation, but it it also possible to have some exterior "continuous insulation" with the remainder being in the wall cavity. The thicker the exterior insulation, the trickier it can be to attach it to the wall and then also have mechanical fasteners for your external cladding. * https://www.buildings…
I should have said modern building and not codes. there are a lot of ways to satisfy good codes, 2x4 tends to be cheapest for single family houses, but others are not far behind and may be worth it in the long run. Consult a proper engineer if you are building a house of course.
Re: How to build homes with virtually no heating (2020)
#290Any tips for me? I live in Northern California in a house that (1) has an empty space below it, (2) single-pane windows, (3) an inefficient fireplace with no steel stove, (4) a big, cavernous room with high, un-insulated ceilings on one half of the house.
Obviously we could spend a zillion dollars to insulate everything and fix all of the problems I identified above (and probably more), but what is critical?
One thing we started with is putting a thermal curtain between the big, drafty room and the rest of the house so that the thermometer doesn't get triggered by the big room sucking the hot air out of the rest of the house.