I have a Gree 30kBTU with two units, an 18 and a 12. I bought it due to being on the Mass Rebate list due to Seer rating. Down to about 40 degrees outside I use it almost exclusively. Below that is where the efficiency starts to dive and I have a Navien for heat so I switch to that with Nat gas. My electric bill has not been higher than $120. My gas bill has not been higher than $230 and includes hot water and stove.