tenant complaints about heat cost- can anything be done?

[Marci Stein]

Finally found a tenant who pays her rent on time,

but now she wants to move out when lease is up due to  heating cost.

 It's her first winter there and

propane heat costs 2 tanks a month ($230 a tank).  there is also electric heat

 but that's even more costly.  Plus,  she does not like it warm so keeps the heat low.

 will more insulation help?

I really would like to have her stay .