[Gibbon1]

My few thoughts on insulation.

The problem with insulation is retrofitting it is expensive and carries a huge risk because older houses are designed around the idea that they breath.

The current practice of insulating inside the envelope is just so blindly stupid I can't wrap my head around why people think it's a good idea. If you work it out, insulation should go on the outside of the envelop. Think insulated siding and roof panels. Granted I'm now seeing that,

And with insulation you quickly run into the problem that the benefits rapidly diminish while the cost is linear. R30 doesn't save you three times R10.

At some point it's be cheaper to put solar panels on the roof to run a heat pump than add more insulation.

[ClumsyPilot]

> retrofitting it is expensive and carries a huge risk

Because construction industry is shockingly incompetent and corrupt.

Lived in a few newbuilds, they are full of fuckups - walls aren't straight, the hole for a fire sprinkler is not where the sprinkler is, so in case of fire it won't actually work. The hot water plumbing was not up to spec and has discharged a swimming pool of boiling water into someone's apartment, they are lucky no-one died.

They will not get something as complex and humidity control right.

[Gibbon1]

I'll add I'm suspicious of insulation since all the modern stuff is foamed petroleum. I feel that's both a fire hazard[1] and has the potential to be classified as toxic waste. See lead paint and asbestos.

[1] https://en.wikipedia.org/wiki/Grenfell_Tower_fire

[defrost]

Know your products, I've built houses from scratch and added insulation to existing houses, extensions, sheds, and always used glasswool:

https://www.bradfordinsulation.com.au/information-centre/how...

https://insulation.com.au/product/pink-batts-insulation/

It's recycled glass.

[bafe]

I can't speak for other countries, but here (Switzerland) insulation is primarily mineral wool or else it must be fireproof