TL;DR - called for emergency furnace repair on a Saturday afternoon, he was at our house within 30 minutes and had fixed the issue (wiring that had degraded over time) within an hour of the original call, for ~$150. Would absolutely use again. Longer version: Around noon on a Saturday, realized that the our digital thermostat was off, which is not ideal during the first snow of the winter. It's powered by the HVAC system directly, so no batteries. Checked the breakers, flipped them on and off, detached & reattached the thermostat, checked the furnace for anything obvious (to me, at least). Called Kosta's, he gave me some initial troubleshooting tips on the phone (all of which were included in the steps I had done, but appreciated that he tried to help me avoid a service call) then said he would be at my house in 30-45 minutes (which was also greatly appreciated). Checked out the thermostat, then the furnace, pulled off a panel, and must have seen something in one of the wire splices, because he tapped it and there was some immediate sparking. Flipped off the circuit breaker, cut off the bad wire, stripped and spliced, flipped back on the circuit breaker, and voila! We have a heat pump, so it takes a few minutes before the heat fully kicks in, which he waited to ensure came fully back online. Put a sticker on the furnace with his contact info and told me to call him if there were any more problems. Managed to have the entire repair taken care of within an hour of the time I had called him, which was I was very thankful for, and thought that $155 for an emergency repair on a Saturday afternoon was more than reasonable. Will absolutely use him in the future.