My original experience with Halls was positive. I had a recurring issue with my furnace that they resolved despite them needing to come to the house multiple times.
I have heard positive things about Halls from friends in Guelph.
When my a/c broke down, they could not resolve the issue and guessed that it was our thermostat. This was the result of 2 separate service calls and three hours of investigation.
When I inquired about the validity of charging me twice for an issue that was not originally resolved, the owner claimed that they should have spent that time when they checked the A/C the first time. He was not polite about it.
The third time my a/c broke down, I called them again. The owner showed up to take a look, spoke quickly about filling it up with refrigerant and said he would be back in a few hours.
He never showed up and did not return my calls. While I was polite during a frustrating situation, he showed no similar professionalism.