If two or three tenants in a row move out and cite sky high power costs due to poor insulation as the reason, the landlord will notice and do something about it. One tenant is a fluke, several all saying the same thing over a few years is a problem that will get dealt with. Nothing costs a landlord money like high turnover. But departing tenants DO need to communicate that as the issue, otherwise the landlord would never really know since s/he isn’t the one paying the bill.