My air conditioning system stopped working on a weekend. I called Windy City Air Conditioning & Heating at 11 o'clock, and I got the answering service. By 2:30 that afternoon, I received a callback and they said that they had a technician out and about and that he could be at my house as soon as he finished his current call. The technician arrived within a half hour and did the repairs within an hour. It turned out the system was low on freon and the capacitor was going bad. I really appreciated the quick service as the temperature had spiked into the 90s. I'll definitely use them again.