![](https://lemmy.ca/pictrs/image/6e29ed11-fb39-48ad-a959-19aeebcfbe65.png)
I think there’s a lot of opportunity for reducing wasted energy in many buildings. Even the term “waste heat” is indicative that energy is typically exhausted when it could be used for space or water heating. Obviously mechanical modifications would be needed, sometimes extensive, but it’s a good option for reducing energy use.
Nice, I have much the same setup in my house!
I visited the recently Passive House certified student residence buildings at the University of Victoria, and the heat recovery there is quite interesting. Passive House requires a very low heating load, so they recover all the heat they can from the commercial kitchen (the presence of which is rare in a Passive House because of high ventilation requirements) processes such as ventilation hoods and refrigeration systems and put it into the DHW system.
They had to get a bit creative with the design, but it’s really not that complicated. More just not doing things the way they’ve always been done.