There's the passive haus highly insulated stuff. Guess that might work?

Full on certified passive house looks very silly with solar this cheap, and frankly the math used to figure out a lot of the requirements is basically faulty.

2025 Code minimum is pretty decent if it's actually complied with, and 'net zero' middle ground with triple glazing is a worthwhile upgrade.

If you wanna spend 2-3x more, yes. Otherwise solar or grid battery is cheaper.

Try 30-50% more.

It's so obviously better to reduce your need for heating and cooling than it is to increase your panel. battery, and HVAC size.

30-50% over 500k build is 10x more than 10k solar or 5k worth of batteries.

I've just setup electrical heating for my bedroom (HA PID sensor). Uses about 450KWh - $90 NZD worth of grid power per winter. Heat pump would take 20+ years to pay itself. Double glazing probably 30-40 years.

To make same amount of solar power per year I need a single $130 NZD panel.

That's an interesting way of looking at it. I remember in the 70's baseboard heaters were very common. They use a lot of electricity, but electricity was super cheap back then. It would be interesting to compare baseboard+extra solar to heat pump+less solar. The baseboard is more reliable, so potentially would last longer.