I woke up in a sweat the other morning and couldn’t figure out what the problem was. I didn’t have heavy blankets covering me. My heating, vent, and air conditioning unit was on and making the usual noise that tells me it was operating. However, my home was too hot for the temperature I keep it at. I checked the thermostat, thinking I had moved it or it had magically slipped upward, but it was where I keep it. I know now from experience that the next step is to check the filter. I removed it, brushed some dust from it, and replaced it. I searched online for tips, and had to pass over some of them that weren’t applicable to my situation. The unit was receiving power outside. The circuit breaker had not been tripped. Stumped, I telephoned the HVAC maintenance company whose fridge magnet I have up. They confirmed that I had not had my HVAC unit serviced this year, and stressed that this was a very important aspect of keeping a home together. We made an emergency appointment, and the HVAC maintenance person came out that afternoon to investigate. He discovered the interior coils were filthy and cleaned them, along with the rest of the HVAC unit. We went back inside when he was finished and had assembled the machine, and turned it on for a test. Sure enough, I had cold air blowing into my home immediately. The solution was as simple as cleaning out the unit, but I would have blown the whole thing up if I had let it go another week without service. In the end, it cost me more to service my HVAC than it would have cost to prevent the problem with seasonal maintenance. I’ll never make that mistake again.