Had a plastic-burning-smell in conjunction with the heater ceasing to operate properly, so look around the attic and notice the power-cut-off box had some melted plastic in it, and some scorch marks. I figured it had been arcing. I send an appointment request to AirTech via their website, and they responded quite quickly. I told them I had pictures so they asked for them, and thereby knew what to bring. This saved both them and me a lot of time and effort. They were able to bring out exactly what was needed, and completed the swap-out very quickly. The service tech was very professional, very efficient, very polite. And the fee was quite reasonable. Highly recommended!