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Comment by jwr | Hacker News Reader

While 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 small homes that are similar in structure to the ones in CA: wooden frame, drywall inside. But the ones here have walls that are 25cm thick because of insulation (mineral wool) and use advanced modern membranes as well. Together, these things do wonders, and maintaining warmth in wintertime using a heat pump (AC) is easy and doesn't cost an arm and a leg.

In other words, you can get 80% of the benefits with 20% of the effort — just design thicker walls with insulation and use modern materials.

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>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,

This is the legacy of historical low energy prices coupled with a historically mild climate.

Now, both of those things are changing. Energy prices are rising because of global warming accelerated risks, and simultaneously the climate is getting hotter and dryer.

The result is that it can start making sense to build to a higher standard like passive house in CA - I just did and my HVAC energy usage dropped 75% and is now more comfortable.

However, there needs to be better code enforcement - i.e. air leakage for new homes should be closer to 2.0 ACH50, not the totally unenforced 5.0 ACH50 on the books today - and also better education of buyers so they can start demanding better built and more efficient homes.

"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.

Of course nothing has changed, he’s talking about the exact same housing stock.

Echoing the sentiment, it cost significantly more for me to heat a studio to 65F in CA than to get a 2/1 up to 72F in ND (or rather, to maintain those temperatures).

Both units had electric baseboard heat and were top floor apartments, but the CA unit didn't have double pane windows, had enormous gaps at the doors and windows, and for all intents and purposes didn't have any insulation. If it was warmer than 0F or so outside the ND unit would have more than enough heat just from cooking. If it was colder than 50F or so the CA unit needed the heaters to actually be on.

Don't forget to mention that insulating roof is just as important. Otherwise, heat will happily escape over your head.

Yes, I wasn't stating the obvious: you need to insulate the floor and roof as well. For example, reinforced concrete foundation slabs are usually placed over XPS foam boards here. There are many ways to do this, my point was that you don't have to go to extremes to get impressive benefits of modern insulation.

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.

I even prefer this to a complete passive house. To be honest I don't like the air from ventilation, although that probably depends on the system.

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