Have a look into Passivhaus principles.

In your case I'm surprised that a new build did not have all the heating/cooling aspects calculated. How would you even dimension your HVAC if you don't know the numbers?

There are easy and not so easy solutions:

1. heat recovery ventilation - equalizes the incoming and outgoing ventilation air temperature so you don't have to heat or cool the inside as much but still get a lot of fresh and filtered air.

2. solar shades positioned in a way that shades the sun when it's high i.e. summer time but lets sun in when it's low during the winter.

3. proper insulation and air-tightness .. a hard sell for a house that just came online.

4. ground loop heat-pumps instead of air source.

Other than that I like your house, especially fond of the integrated catwalks/doors!

> How would you even dimension your HVAC if you don't know the numbers?

Well the people setting up the HVAC definitely ran the numbers accounting for windows, insulation, etc. The resulting system does successfully heat/cool the house.

What I'm a little unclear on is whether it was always expected to use this much power in the process. I've been struggling to get info out of my HVAC contractor, may need to hire someone else to come in and look at it.