I feel so stupid. My husband and I bought our new house a few months ago. Since then, we have had a lot of learning to do as a lot of small things seemed to start going wrong. There were plumbing leaks, a roof leak, and then the air conditioner stopped working. Both of us just decided to tough out the A/C issue because we simply couldn’t afford another repair on top of all of the other expense. When another month past, and the temperature started climbing, we finally broke down and call out and air conditioner technician. But first, we called around and found an HVAC company that takes payments because we were expecting the worst. Reading online, it looked like we might have a repair that cost a few thousand dollars and would require completely replacing, or almost completely replacing our air conditioning system. So when the technician arrived, my husband and I both held our breaths as he looked our machine over. He then went out to his truck, came back with a battery, pulled the thermostat off of the wall and replaced the battery that had been in there. Within second, our air conditioner started working again. I had to laugh, we could have replaced the battery a month ago and had our A/C working. The technician explained this sort of thing happens all of the time. I assumed that the thermostat was wired into the wall. I had no idea it had a battery. We just had to pay a small service fee but it would have cost us only a few dollars to have replace the battery ourselves.