Gartner has done a fair amount of work for me in the past several years. They removed an aging steam heat system (removed boiler, radiators, baseboard heaters, and all the piping) and installed a new high efficiency gas furnace and central A/C along with installing all new the ductwork and floor registers in a 90 year old house. They did a good job as evidenced by the positive comments a plumber and a remodeler made upon seeing the ductwork. They also replaced a gas furnace in another house with a new high efficiency furnace so they had to put in new exhaust pipes, and they had to slightly modify the ducts to fit a furnace that was a slightly different size and shape. This major work was done well at a good price and I liked that they gave me a range of options without pushing the most expensive option even though it is what I chose for the higher efficiency (trying to use less energy to contribute less to global warming).
I was surprised that the company was so booked up this fall that the routine maintenance had to be scheduled a full month after my call, but I figured that they were probably busy fixing furnaces that didn't work once the weather had actually gotten cold enough to need to heat. The reminder phone call the day before confirmed a "10am-12" arrival, so I was not expecting the crew when they arrived 1.5 hours early at 8:30am. At least I was home and it was OK for them to just do the serving early, but I would have preferred to have been given notice if they were going to arrive that far out of the window of time given.
As with my past experience with this company, the workers were friendly and polite and told me exactly what they checked and did. I asked them to replace the humidifier pads since the thermostats had been saying they needed changing for a few months. They said they "probably" had the right pads in their truck, although I had specifically requested new pads when I placed the service call to make sure that they came with the right pads. But they did have the needed pads and changed them. A minor quibble is that they did not properly reset one of the thermostats after the service was complete, so it gave me another "reminder" that the pad needed to be changed a couple days later. It was easy enough to reset it myself, but it's a detail that was missed.
Overall, Gartner is a very good local family-owned business. They are honest and straightforward and do good work. They could be a bit better with attention to small details, but I do wholeheartedly recommend the company to friends.