I hate that I have to answer this. Coming from the biggest energy conservationist in the east coast. 17.5 seer
My house hold one is 21 seer and I'm also picking up another mitsu 12k that's 26 seer. You do get what you pay for with these. The long term benefit is in higher seer but this is a 1-2 year plan here so 17.5 fits the bill.
It's like buying cobs for a single grow. Not worth it one bit. The guys who are in this for the long haul and plan on numerous harvests get paid back quickly.