You can let them know what you paid in rent, if you have their contact information. I’ve seen posts where people have mailed a card to their old address to share rent history so there’s some form of accountability and solidarity. On your way out, you might also be able to share some resources with your landlord about winterizing homes and upgrading efficiencies. Obviously, they may not care because their costs now don’t change from how efficiently your home is able to keep heat or cool. But, with the IRA, I do know there are incentives for homeowners to invest in weatherization, renewable energy, etc. that long term do pay off in landlord’s favor. And of course that’ll help mitigate the incoming tenants utilities. I feel for you!