How to build homes with virtually no heating (2020) • Hacker News Board

Re: How to build homes with virtually no heating (2020)

#221

Post by liveoneggs » Tue, Jan 18, 2022, 1:30 PM UTC

osobo wrote: post #9

SenHeng wrote: post #6

I'm in the middle of building a PassivHaus. The building itself is mostly done and we're working on the interior. There are still a few gaps that haven't been plugged and the heat exchangers have not yet been installed. I'm above 800m elevation, snowstorms every weekend. It's cold here. My house also actually faces West instead of South, so I'm not getting much heat from the sun. This was a surprise to use because th…

I'm looking into making a house sustainable right now and the windows are actually a point of contention. One side thinks super-high insulated (triple pane) windows are a waste of money, the other swears by them. Assuming the frame doesn't leak, does triple really make that much of a difference?

they are worth it in cold climates if you use fixed or very fancy casement windows with maintained seals. Double-hung will just leak around frames and sides.

Also ensure you use a good brand which will be around when you need a replacement and hope to get an actual match.

Re: How to build homes with virtually no heating (2020)

#222

Post by Retric » Tue, Jan 18, 2022, 1:50 PM UTC

jaclaz wrote: post #209

empiricus wrote: post #158

Earlier quoted context omitted.

Not only "philosophical", better insulated houses are also more comfortable.

Sure, but not all houses are built for "you" to live in perpetually. You build a house according to the minimal requirements of your local codes/norms. If you next year go to another city you may either sell the house or rent it (at average market value). You build a "passive house". If you next year go to another city you may either sell the house or rent it. Do you believe you can easily get 30% more rent or sale p…

It’s rather pointless to go through the effort of building a house if you don’t expect to live in it for very long. So, the minimum standards should only be relevant to people building homes for sale.

As to insulation, it’s very cheap to add some form of solar heating outside of the arctic but cooling always takes energy.

Re: How to build homes with virtually no heating (2020)

#223

Post by Mvandenbergh » Tue, Jan 18, 2022, 1:50 PM UTC

alkonaut wrote: post #163

KaiserPro wrote: post #107

TLDR: point one: you need insulation _everywhere_, along with some thermal mass to make sure there is some inertia to keep temperature even. This means that putting a jacket around the outside of a brick/cement structure is generally better than putting it inside. You need to insulate under the floor. External wall insulation is not overly expensive. Its about 50% more expensive than a standard silicon render (in the…

> Standard double glazing How is the code still allowing new construction with windows having U of 2 (such as double glazing)? A more restrictive code would reduce a country's CO2 footprint, companies would sell more expensive products like windows, and no one except the few constructing new homes would be economically impacted - and obviously only short term, while the economic gains are reaped by everyone. So how i…

Effectively it isn't allowed since the whole building has to meet a minimum efficiency standard which would be impossible to meet with U=2 windows throughout.

My double glazed windows have a U value of 1.2 and typical for triple is 0.8 so the improvement isn't that big between good new double glazed and triple.

Re: How to build homes with virtually no heating (2020)

#224

Post by Dylanfm » Tue, Jan 18, 2022, 1:52 PM UTC

rogalian wrote: post #156

ricardo81 wrote: post #119

Earlier quoted context omitted.

Yes, it's one of the top recommendations (internal wall insulation) on my EPC and have had a survey. 60mm PIR boards would be used. Turns out I wouldn't have to sacrifice much space but would have to pay a bit extra replacing the cornices. There are some regional grants in the UK that can cover a large portion of the amount. For me, it is £7.5K, with the quote I received at £9K. This would not have covered the kitche…

Had to sign up for this. Take extra care to use appropriate materials for a house this age or you'll create more problems than you solve. Solid stone walls need to breathe! Make sure you've spoken with a surveyor specialising in heritage property too. PIR boards are almost certainly unsuitable. https://www.victorian-house.co.uk/ (be sure to pick up a copy of the Haynes Victorian House manual, it's a gem) https://www.…

Another good resource is https://www.neighbourhoodconstruction.org e.g their page on Thermal Envelope > Bio aggregate https://www.neighbourhoodconstruction.org/bio-aggregate/

Re: How to build homes with virtually no heating (2020)

#225

Post by tpxl » Tue, Jan 18, 2022, 1:52 PM UTC

dx034 wrote: post #124

patrickk wrote: post #96

Earlier quoted context omitted.

Modern air or ground source heat pumps tend to be quiet, even silent, at least according to some deep dives down the Youtube rabbit hole on passive houses. Check out the "Moonstone house" on Youtube for example. https://youtu.be/sSE8PurhfQs

My neighbour has a air heat pump for a ~200m2 house with good insulation, but not a passive house. It's at the edge of his property so I regularly pass it. I'd say you need to be less than a meter away to hear it at all, and even then it sounds like a fan. There's absolutely no vibration or so. However, the house is new, let's see how it the unit sounds in 5-10 years.

We have a heat pump from ~2008 about a meter away from the outer wall of the house and I don't recall ever hearing it from the inside. You'll hear it from a few meters on the outside, but it has never been a problem. It's able to heat a ~250m2 house in -10°C weather.

That being said, do yourself a favor and do not get a heat pump connected to 'the cloud'. Our heat pump can't be fully controlled locally (some functionality is web only) otherwise I'd put it offline. They unnecessarily performed repairs on the heat pump to the tune of 500€ because their servers had issues.

Re: How to build homes with virtually no heating (2020)

#226

Post by Mvandenbergh » Tue, Jan 18, 2022, 1:54 PM UTC

lbriner wrote: post #143

I 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…

>Bearing in mind how much profit a lot of home builders make, increasing the regulations is likely to add at least £20K to a basic house, significantly more if you include mechanical ventilation, triple-glazed windows and heat pumps (perhaps +£50K), which is some cases will be 50%+ of the original cost!

The sales price of houses in the UK (and elsewhere) is driven by the market and there is a low amount of released, buildable land and a lot of demand in the Southeast. The land value (a large component of the value) is not actually set in an independent market but is based on the expected sales price minus construction costs and development costs. Therefore increasing the built cost of properties will decrease the value of land likely to receive planning permission without affecting purchase price by much.

The marginal cost of thicker walls is also very low (especially compared to retrofit costs) so the impact on construction cost is nothing like £50k.

Re: How to build homes with virtually no heating (2020)

#227

Post by madaxe_again » Tue, Jan 18, 2022, 2:00 PM UTC

phillc73 wrote: post #135

madaxe_again wrote: post #87

Earlier quoted context omitted.

We’ve just built a 45m2 log cabin to passive standards here in Portugal - heavily insulated in walls, floor, roof, lifted off the ground on concrete columns, double glazed, only heat source is a 2.5kw log stove. Everyone here (who all live in uninsulated concrete houses heated by open fireplaces) said we will freeze in the winter, roast in the summer. We situated the house on a north facing slope, to minimise sun exp…

It would be very interesting to learn more about this build. Was it something pre-fabricated (I've seen "kit" log homes advertised) or something completely custom?

Pre-fab, although loosely so - about 1000 me-hours to make it into a functional home. I unfortunately can’t recommend the outfit I bought it from, as they screwed up and shipped only part of the order, sent me defective parts (bad and/or incorrectly machined timbers), and had the worst post-sales service I’ve encountered in anything - but there are plenty of companies out there that make decent kit cabins.

Re: How to build homes with virtually no heating (2020)

#228

Post by thebiss » Tue, Jan 18, 2022, 2:00 PM UTC

lbriner wrote: post #143

I 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.

It's an incentive and delegation problem. I'm in the US, and have been through three large renovations to family homes, and the trades I've worked were (nearly) all HIGHLY skilled, but had zero incentive to exceed energy efficiency goals required by code. The small business contractor needs to complete your project, get paid, and move on to the next. The best ones don't have any extra time - they're prospecting clients and building estimates for the next big project.

Re: How to build homes with virtually no heating (2020)

#229

Post by throw0101a » Tue, Jan 18, 2022, 2:01 PM UTC

bluGill wrote: post #208

throw0101a wrote: post #186

Earlier quoted context omitted.

> What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds. Here's a 500 sq. m. (5000 sq. ft.) house built with heating equipment that uses 1800W (the equivalent of a hair drier): * https://www.youtube.com/watch?v=_vul4vMFdkA The same person building his own…

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.buildingscience.com/documents/insights/bsi-001-t...

* https://www.buildingscience.com/documents/building-science-i...

However, AIUI, using 2x6s reduces the number of studs needed and so would generally reduce the cost on average from both a material and labour perspective (even if 2x6s are slightly higher each).

* https://www.buildingscience.com/documents/insights/bsi-030-a...

* https://buildability.ca/wp-content/uploads/2017/05/M400-Adva...

* https://www.energystar.gov/ia/home_improvement/home_solution...

* https://www.protradecraft.com/article/advanced-framing-dos-a...

And it's not like it's a new technique: it's been around for (at least) forty years.

Re: How to build homes with virtually no heating (2020)

#230

Post by HPsquared » Tue, Jan 18, 2022, 2:03 PM UTC

mnw21cam wrote: post #220

markvdb wrote: post #167

Earlier quoted context omitted.

Be super careful internally insulating an old house. This can cause _a lot_ of humidity problems if not done _exactly_ right. Very often, there is no way to do it exactly right! I would recommend you to consider breathable internal insulation materials, combined with breathable finish layers of course! Some hints. Roof (or attic floor) insulation is the most important. I imagine those have been done properly already.…

The one key rule that you should always follow is to have your water-impermeable layer on the warm side of the insulation. So, I'd recommend against breathable internal insulation, because that will make your solid wall (water-impermeable layer) colder, but still exposed to the humid inside air, and this could cause condensation on that cold wall. As an example of this, I have rubbish double glazing, and when the tem…

Agreed, houses with insulation have a vapour barrier behind the plasterboard for this reason: counterintuitively, the warm internal air carries a lot more moisture than the cold air outside. The partial pressure of water vapour is higher inside the house than outside, so the dew point of the internal air is higher than the outside temperature (dew point depends on water content).

If there's a way for that moisture to diffuse through the wall from inside, through the insulation, to the cold structure (which would be colder than before due to the internal insulation), the conditions are right for condensation to form. Those conditions are: surface temperature ≤ dew point.

Condensation can be prevented by a combination of:

1. Reduce the rate of moisture diffusion from the interior (seal the rooms and use a vapour barrier)

2. Lower the dew point of the air in the "cold" structural areas by ventilating the cold space to outside, so the moisture can exit (this is why houses have air bricks, vents in the roof, etc.)

3. Prevent the building structure from being colder than the internal dew point (i.e. use external insulation)