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The Pretty Good House

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Re: The Pretty Good House

#331

Post by HPsquared »

dan-robertson wrote: post #317
HPsquared wrote: post #168

Earlier quoted context omitted.

You'd still have radiative heat transfer, even if there is a vacuum between the panes. For a given budget, you're probably better off adding more regular panes.

Aren’t new windows often coated with something opaque to IR, that way they keep heat in during winter and don’t heat up like a greenhouse in the summer?

Those are low-emissivity coatings. Very effective in reducing radiative heat transfer. This is why the glass in a vacuum flask is silvered: metals have low emissivity. These coatings aim to have low IR emissivity while still allowing visible light through (IR light gets reflected, instead of absorbed/emitted).

My point was only that a vacuum gap is still not a perfect insulator, so it's an economic trade-off.

Re: The Pretty Good House

#332

Post by thih9 »

archontes wrote: post #266
mech987 wrote: post #262

Earlier quoted context omitted.

I think if there is condensation between the panes then the sealed air cavity inside the window has been compromised- you might want to get a new window put in. The large double glazed sliding glass door in one of my previous apartments had that issue, and it eventually became mold trapped inside the glass that was uncleanable.

I think in the context of this conversation, that failure mode is a reason for preferring the primitive option.

Is the failure mode likely to reoccur?

For most residential home scenarios I guess that's unlikely; wouldn't it be more convenient long term to fix the broken glazed window and enjoy its benefits for the next 10-20 years [1]?

[1]: "IG units typically last from 10 to 25 years, with windows facing the equator often lasting less than 12 years. IGUs typically carry a warranty for 10 to 20 years depending upon the manufacturer.", https://en.wikipedia.org/wiki/Insulated_glazing#Longevity

Re: The Pretty Good House

#333

Post by jq-r »

reef84_ wrote: post #330
jq-r wrote: post #272

Earlier quoted context omitted.

I guess in theory that would be true, but in practice ( at least where I live ), there is no accountability. So yes, doctors, lawyers, architects/engineers etc, get all the prestige and social status, without the downsides. There was an exception though, like 10 years ago where the doctor was removing a patient's appendix and damaged major artheries. The poor patient lost the leg and the other one is not functioning…

>Doctors (and similar) don't get insurance against damages at all. Why would they? More sarcasm, I assume?

Certainly. At the same time, completely true over here.

Re: The Pretty Good House

#334

Post by 10u152 »

dalanmiller wrote: post #324
muro wrote: post #182

Earlier quoted context omitted.

I was never as cold indoors as in Australia. The houses have no insulation, it's almost as cold inside as it is outside. Even if it's above 10°C in Sydney in winter, it's about 15°C indoors unless you use AC for heating. Add to that just terrible craftsmanship of walls and windows.

American in Australia - the house quality, even if the building is new(er), is absolutely shocking. I'm contributing to climate change with all the heat/cool bleed from my rental. Where I never even thought about the electricity bill from where I am in the U.S., I'm spending anywhere from $60 to $250 a month depending on season, where the anecdata average is actually 2x or 3x that. Thankfully two or three years ago,…

I think the “quality” actually goes down as you get newer. They are better sealed and insulated yes but…not quality - especially project homes. I own an old house (1890s) and the craftsmanship of the original portion of the house is spectacular. The 80s extensions are horrible though.

Re: The Pretty Good House

#335

Post by maratc »

dan-robertson wrote: post #319
maratc wrote: post #137

Earlier quoted context omitted.

Thermal mass is usually not a factor you're looking at when choosing windows; thermal resistance is. In a nutshell, stone, concrete, metal, and glass are very good at transmitting heat, so the inside of your house will quickly be as hot (or as cold) as the outside. Plastic, wood, and especially air are very bad at transmitting heat (or good resisting to heat transmission) and this is what you want for your house. Bac…

I know how double glazing works but if you put a window somewhere then you aren’t putting a wall there. So I’m wondering if having a much higher % window (is less wall and more glass) will cause the building to have an importantly lower thermal mass. But I don’t really know if modern buildings would want a large or small thermal mass. I’m confused by what you write about stone and concrete being good at transmitting…

> But I don’t really know if modern buildings would want a large or small thermal mass.

This depends on climate.

When the outside temperature changes, the building will eventually get itself to the outside temperature (thermodynamics laws). How fast that change would happen exactly — depends on thermal resistance and thermal mass.

Thermal resistance acts as an amplifier (or rather diminisher) of that changing force: the higher the resistance, the lower is the force, and so more time for the change to take effect.

Thermal mass acts as a momentum against that changing force: the higher the mass, the more time for the change to take effect.

In some climates (e.g. south Europe) the outside temperature is only a problem on winter nights and on summer days. You are only fighting the outside weather for hours on end. And you can effectively make that fight with large thermal mass alone.

In other climates (e.g. north Europe) the low temperatures at winter can come for months, so you want mass, resistance, and inside heating.

Re: The Pretty Good House

#336

Post by dkarl »

acjohnson55 wrote: post #320
dkarl wrote: post #250

Earlier quoted context omitted.

I don't know what to call it on the consumer end, but on the builder side, it's often just laziness and greed. If they don't know how to work with a material, then it sucks. If it's hard to hire subs that know how to build something, then it doesn't meet code and won't pass inspection. If they misbid it, it will never work and needs to be redesigned. In short, building contractors are a lot like software developers.…

To be a bit more charitble, I think there are builders who choose mastery of an older skillset over good enough with an evolving set of new skillets. I don't think that's such a bad thing, to be honest. Compared to software, in a building, it's a lot more expensive if you mess up.

I agree, that's cool, but some contractors take it a step too far and bid projects on the assumption that they can replace unfamiliar techniques, materials, and design details with alternatives they can do more cheaply and easily, and then they make themselves into a problem much later in the project when the client doesn't agree to the alterations.

I think it's something that contractors even do in good faith. They read drawings and think, "Oh, I know a lot of ways to speed this project up, they're going to be super happy with my bid." They can see it'll be easier if they use a different material, move a door twelve inches this way, move the electrical to another wall, replace a difficult detail with an easier one, etc. They've probably worked on projects where those details are chosen without much care, and the client is delighted if they can speed up the project a bit by changing them.

Re: The Pretty Good House

#337

Post by dalanmiller »

sgt wrote: post #327
dalanmiller wrote: post #324

Earlier quoted context omitted.

American in Australia - the house quality, even if the building is new(er), is absolutely shocking. I'm contributing to climate change with all the heat/cool bleed from my rental. Where I never even thought about the electricity bill from where I am in the U.S., I'm spending anywhere from $60 to $250 a month depending on season, where the anecdata average is actually 2x or 3x that. Thankfully two or three years ago,…

Why did you move to Australia? You must be out of your mind. Kidding, just wondering.

I moved for work is the simple answer. Came to find pretty quickly life in Melb is pretty great, possibly one of the greatest places to live.

Re: The Pretty Good House

#338

Post by acjohnson55 »

dkarl wrote: post #336
acjohnson55 wrote: post #320

Earlier quoted context omitted.

To be a bit more charitble, I think there are builders who choose mastery of an older skillset over good enough with an evolving set of new skillets. I don't think that's such a bad thing, to be honest. Compared to software, in a building, it's a lot more expensive if you mess up.

I agree, that's cool, but some contractors take it a step too far and bid projects on the assumption that they can replace unfamiliar techniques, materials, and design details with alternatives they can do more cheaply and easily, and then they make themselves into a problem much later in the project when the client doesn't agree to the alterations. I think it's something that contractors even do in good faith. They…

Yep, I can relate to that.

Re: The Pretty Good House

#339

Post by doctorhandshake »

hgomersall wrote: post #251
doctorhandshake wrote: post #191

Earlier quoted context omitted.

In the US the rating associated with this loss is called Visible Light Transmission, or VLT, and it can be quite low by percentage, especially in ‘Low-E’ windows designed for sunny climates. The nature of our perception of light intensity means that the use of a percentage of transmission might not be the best measure for the effect. I feel like something like the geometric scale of the f-numbers used in cameras woul…

Low-e windows are not just for sunny climes - it's arguably the dominant benefit of modern windows. Interestingly, when you put low emissivity layers on each pane, it doesn't matter whether it's pointing towards the inside or the outside. When pointing outwards, it reduces the propensity to radiate outwards, when on the inside it reduces the propensity to be heated by radiation. More layers are good because that incr…

I don’t think you can generalize quite that much - on buildings in heating-dominated climates, low-e windows and their accompanying low SHGC result in rejected solar energy that could otherwise be used to heat the home by day. Without proper shading, overheating can be a concern in fall and spring for south and west facing windows but in my understanding north facing glazing shouldn’t be low-e in any heating dominated climate.
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