> On an individual household scale, I've always wondered why nobody has come up with basic drain heat exchangers to capture most of the heat coming out of shower and washing machine wastewater before it leaves the building.
I have had one of those installed in my home recently. A QB1-16 from Q-Blue https://www.q-blue.nl/en/products/q-blue-showersave/
Supposedly it saves about 50% of the loss heat. Since I dislike hasty showers, I figured that would save me plenty.
> I'm amazed at how little district heating is used in northern climates
In my country we can pick our own electricity and gas provider, but for district heating you're tied to the provider for your area. Consequently, people with district heating get fleeced. When buying a house, I gave preference to the ones without district heating.
I have had one of those installed in my home recently. A QB1-16 from Q-Blue https://www.q-blue.nl/en/products/q-blue-showersave/ Supposedly it saves about 50% of the loss heat. Since I dislike hasty showers, I figured that would save me plenty.
> I'm amazed at how little district heating is used in northern climates
In my country we can pick our own electricity and gas provider, but for district heating you're tied to the provider for your area. Consequently, people with district heating get fleeced. When buying a house, I gave preference to the ones without district heating.