Passive house thinking comes from an era of peak oil concerns, no solar, and no heat pumps. None of those conditions holds anymore. Further, passive houses are notorious for overheating and because they’re so airtight they require expensive mechanical ventilation and make-up air systems unless you want indoor air pollution problems.

People building houses today are much better served by spending their money on solar + battery + heat pumps than going passive.

Solar is still not free or unlimited. A well designed house will be more comfortable and save energy over its whole life while costing a fraction more than a badly designed house.

It's better no matter the heat source really. And it allows you to do without central heating and/or complex heating techs which are more annoying to maintain and replace

> expensive mechanical ventilation

A top of the line heat recovery ventilation unit cost the same as a shit tier air/air heat pump and has no moving parts besides the fans, which are cheap and easy to replace.

You can even make reasonably efficient heat exchangers at home with corrugated plastic sheets...

But any modern house is too airtight and essentially requires ERV.

Which brings us to next interesting problem - you would think that ERV should be built-in into modern cooling/heating systems, but it’s no the case.

you need FAR less solar+battery for passive house tho. And AC in summer is essentially free. Of course, it all depends on area, if winters barely have any snow and summers are very hot the benefits of very insulated house are much slimmer

The old houses didn't overheat because the floor wasn't insulated all that well so the cold came from below. We could do something similar by just mounting heat pump ground loop under the house, before it is built, but today house developers want it cheap and quick so you pretty much can't find much of that and would have to do it on your own.

Other interesting system is using underground as a way to cool house air intake, just running pipes underground for several metres to get it to cool down in summer and heat up a bit in winter. But again, expensive thing compared to "just add more solar panels/battery storage and let AC handle it"

> because they’re so airtight they require expensive mechanical ventilation and make-up air systems unless you want indoor air pollution problems.

Most modern homes have this issue. Building science has driven them to be air tight bubbles. Look at blower door tests on current construction and a lot of "building science" driven construction.