New building standards don't affect existing buildings. And they're not optional, so the tax isn't an option for non-compliance.

Forcing existing landlords to retrofit to new building standards isn't even done for safety purposes, so it certainly isn't going to happen for energy efficiency.

And calling for this to now be a thing, well, I can't think of a better way to get entrenched interests to suddenly lobby hard against every single new building reg.

> New building standards don't affect existing buildings.

No, but habitability standards do (or, technically, in general affect the legal ability to charge rent for units in existing buildings.) So, user those of your concern is recalcitrant landlords.

> Forcing existing landlords to retrofit to new building standards isn't even done for safety purposes

Yes, this is done (not always, but it does happen), through habitability standards beifn updated along with building standards (or referencing them.)

I just went and looked at habitability standards, there's no way to get energy efficiency out of that mechanism, at best you could make landlords install ceiling fans.

And the only example I can think of for the latter was for asbestos. If being as horrible as asbestos is the bar you have to clear, regulation isn't a viable option and we're stuck with market solutions.

They could, but then the costs will just be passed down to the tenants (i.e. increased rent).

Even with the cost of insulation upgrades added to the rent, that's still cheaper total.

Depends on how much the costs of insulation upgrades are blown out of proportion by being mandated.

For something that has to be done to most houses, I would expect a pretty large and competitive market.