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Comment by throw0101a | Hacker News Reader

> 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 personal home up to Passive House standards:

* https://www.youtube.com/watch?v=mBOvflXoWlw

You do not need concrete† and masonry to make homes efficient. Switching from using 2x4s @16" off centre (OC), to 2x6 @24" OC ("advanced framing") would allow for less wood use, less thermal bridging, and more cavity space for insulation.

† It should be noted that concrete creates a lot of CO2 emissions, as does baking bricks. Growing wood on the other hand is a way to sequester carbon.

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I agree, you do not need concrete and brick but you also need to take into account the local traditions. For ex. building a wood house (framing or CLT) would have cost much more than concrete and bricks and was also much more prone to errors because of the builders lack of experience, at least in my area and country.

Recently in Romania it really took of building houses using CLT (cross-laminated-timber) but it costs so much more than a regular brick and mortar house that few people afford it.

When -15 outside and 20 degrees inside, my house requires 2000W to keep the balance. This kind of simulations are done using PHPP package from PassivHaus Institut.

L.E. What I wanted to point out, thermal mass can have a huge impact on the house energy footprint.. to give you an example, today and tomorrow will be sunny days and this will drive my interior temp to about 23-24 degrees, this heat will heat-up the masonry and slabs and then give me back the heat in the next days when there will be no sun.

Wood is fairly inexpensive in North America because there are still many forests (especially in Canada).

There is nothing "inherently better" with one material over another for most applications. A good structure mostly depends on proper drainage and cladding to protect against UV rays and bulk water (precipitation), good air tightness (with mechanical ventilation for filtered, tempered fresh air), and high insulation.

* https://www.buildingscience.com/documents/insights/bsi-001-t...

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.

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.

Moving insulation outside the frame also helps reduce the effect of thermal bridging although with timber that's not so important as it is with steel.

High thermal mass is definitely more energy efficient in the summer, when you can "store the cold" from the night into the next day.

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