They need to build more high density housing downtown. That requires government intervention to force buy the land and tell the NIMBYers and people that want endlessly increasing housing prices to fuck off. That way there is alternatives and people can get modern homes that are actually at market value rather than artificially inflated. The huge amount of immigration is just making things worse.

A LVT like Wales are bringing in would also help.

We live in a pretty mild climate very little heating is actually required to keep mould away it just requires proper ventilation and insulation.