<prompt> Human: I recently bought my first house. I had an inspection done and there were no red flags related to cooling. The seller provided a receipt showing the AC was serviced about a month prior and there was one small issue with it that they gave me credit for. I was satisfied with this and wasnt too concerned as they also paid for a home warranty which will cover the AC if it breaks.I move into the home, and its immediately noticeable within the first two days something is wrong: it runs all the time, and it only cools the home down to about 80 degrees during the day, and about 70 at night. I live in Arizona where its normally 100 to 120 outside during the summer.I installed a Nest thermostat and this confirmed that it runs all the time - normally during the day I see that it never shuts off between 10am and 6pm. This obviously has resulted in a super high energy bill - about 300 a month, when I expect the unit running properly would cut that in half to around 150. Its a relatively small house.I called up the home warranty, and after having a company come out about 6 separate times replacing the same part on 4 of those trips, they finally figured out whats wrong and told me that the indoor coil needs cleaning. They showed me pictures of how it was all blocked and restricting air flow which is making the house not cool enough and it needing to run constantly to keep it cool.The catch? While the home warranty covers mechanical breakdowns, they dont cover cleanings. I will have to pay for it myself which is going to cost 900 for the type of unit I have. I dont have that kind of money to spend right now. If I did it, I would have to put it on a credit card. I stupidly spent all of my savings on the downpayment for the home so have basically nothing left and about 2k in credit card debt.So I can either pay the 900 now and put it on the credit card, which will save me about 150 a month which I will then put right back as payments to the credit card. Or I can keep saving and pay for it in cash in about 6 months. I can live comfortably at the temperatures my home is at currently and were moving out of summer and into winter soon as well. I did invest a little into putting UV blocking tint and blackout curtains on all the windows. So should I just keep paying the high energy bill for now and pay for the cleaning when I can? Or should I get it done now to save money on the energy bill, but pay interest on a credit card while I use the energy savings to pay it off?  <response>: My first suggestion would be to look on YouTube and learn how to clean the coil yourself. I bet you could do it. If you dont want to do that, I would save up. I live in the desert too, and we should only have a few more weeks of unbearable heat. 