AC is a luxury that should be banned outright - maybe except in all-glass office buildings.

You obviously don't live in a desert climate.

While there are building techniques that can achieve some measure of passive climate control in true deserts (much of Southwestern US, Mexico), no passive system can adequately cope with 100F+ heat. Then there's the problem of cooling inefficient pre-existing housing stock. Even if the law mandates strawbale, cobb & earthship construction going forward, can we replace tens of $Trillions worth of perfectly good structures overnight (and tear-down historic buildings as well)? I don't think so.

In the eastern USA high ozone on hot summer days can be deadly to asthmatics like me. I had a very close near death experience on one of those days back in the 1990s. Just a few years ago thousands of vulnerable people died in France do to lack of A/C. It could be reasonably estimated that 100 times as many were sickened enough to be life threatening.

Houses in climates that need A/C generally use less energy overall than houses in colder climates. So I guess you would have us ban heating as well. What about banning refrigerators while you're at it. They consume as much energy as A/C.

Metal cool roofs work extremely well. Asphalt shingles absorb more heat because of the coarse texture.

I just put new metal shingles on my 70 year old farm house this last year and I get a very sizable discount on my homeowners insurance as a result of putting on insurance company approved metal shingles.
So the insurance companies are on board (At least State Farm is).

Metal roofing is widely used along the Gulf Coast. It has much better hurricane resistance than asphalt.

My homeowners association refused to allow me to use the most energy efficient color; however I was able to get a gray with 38% reflectance, which qualified for a $500 tax credit.

I think retrofitting (making energy efficient) old houses may be difficult, and this may be a problem. What is needed and what can be done varies by region.

Sealing leaks is described by some around here in NH as the FIRST thing to do, even before insulating. It is more than just "leaks"... vertical passages in a house, from basement to attic, exist e.g. the plumbing vent pipe, electrical wiring, chimney "chases", hot-air-duct passages and the like. These passages set up an air flow called the "stack effect" or "chimney effect", with momentum and with cold air coming in downstairs to replace air we've paid to heat that is exiting upstairs. Taunton Publishing has a good book "Insulate and Weatherize" (or vice-versa!). In my old house we had all of these, plus the natural gas water heater vented freely into a chimney, sucking additional air out of the basement even when the gas was not "on". We also had a lovely old coal fireplace which we sealed by holding a dry-cleaner bag over the iron cover, allowing the air pressure in the room to press it against the cover and hold it in place, 24 x 7, just based on the chimney effect.

You have to seal a house darn good to worry about toxins. An old house, you'll probably never be successful to the point of suffocating... :-)

We built a new house that is seriously tight, and we're tightening it more. We have an air exchange system with a heat exchanger that salvages some heat and humidity while swapping bad air for new air. When it's 60 degrees inside and 20 below outside, we are so lucky we get fresh air that's between 10 and 20 above... When the sun is out, we ignore the wood stove (Jotul #3) which is our sole source of heat. Front (south) windows have a glass invented by Livermore Labs I think and probably used in Canada (and which is far better than the standard "low E" which is designed for the south and southwest and blocks 50% of incoming solar energy) and has a film of silver that reflects "far infrared" back into the house while allowing nearly 100% solar energy in. The house is about 1800' plus full basement.

If we need more room we can add a wing that is cheaper to build and not as warm - the house as it is now is a suitable "core" for winter. One idea for old houses is to identify a core within the larger house and set up a thermal boundary around that core. Give up on fixing the whole thing... I am interested in this problem and the more I learn the more difficult it all seems.

Usually, older homes are so drafty that sealing many of the main leaks might bring them to 1 air change per hour (ACH). Newer tight construction, or a really good renovation might require a heat recovery ventilator.