We try to support family owned small businesses but I cannot emphasize enough to PLEASE PLEASE PLEASE DONT GIVW THWM YOUR MONWY. My dad had his HVAC serviced less than 2 weeks ago for the winter and Bret didn't realize that a pressure switch needed to be replaced. We don't know what was actually done for service. So instead we had to pay a different HVAC technician to come and fix it on one of the coldest days this winter. We called multiple times and left many messages with no follow up. We understand it's busy and we need their help because we aren't hvac technicians ourselves - but this isn't how to treat customers. They wouldn't appreciate their friends and family being serviced this way, so why should we? read more

I found him via Yelp and called and left him a VM. He called me back promptly and was at my home and had diagnosed my problem within an hour and 15 minutes of returning my call! He explained several things to me and showed me a couple things; including what was wrong with my furnance. Best part...he had it fixed quickly and correctly (havent had any issues), AND he gave me a great price (which required part & labor). I appreciate & respect that he didn't try to take advantage of me financially. I wouldn't hesitate to call them in the future, or reccomend him to others. Based on my interaction, he seems to be one of the "good guys" to work with. read more

Brett Gremillion is one of a kind. He cares about people, not his bottom line. He is very reliable and is very sensitive to emergency situations such as the AC/heat going out in the hottest/coldest parts of the year. I have been using his services since 2015. As a satisfied customer, I feel good knowing that Gremillion Mechanical is one phone call away. No need to shop around, just book Gremillion Mechanical and you will be very satisfied. Furthermore, this company operates with integrity and that is rare these days. read more

I used Gremillion Mechanical to design a heating system in an effort to heat my hot yoga studio to 95% with 60% humidity. This was no easy task; nonetheless, Brett and his team worked incredibly hard and got the job done. I could not be more pleased with their work. From the start to the end of the job, the team was nothing but professional and incredibly hard working. They went above and beyond the call of duty to ensure the job was completed and everything was running smoothly. I highly recommend Gremillion for any heating/cooling needs you may have. They are cost efficient, very hard-working, timely, and an overall fantastic company. read more

Great service and affordable pricing. Brett came out on short notice to trouble shoot our failing furnace. He was able to readily diagnose and repair the problem. Our furnace is 10+ years old and it's working now better than it has in the last 3 years. We are extremely satisfied with the repair and the exceptional customer service. read more

We've had Brett - Gremillion's owner - out to our walk-up apartment twice, once to fix our furnace, the second time (today) to fix our AC. Both times, he was able to come on short notice, was pleasant, friendly, and extremely knowledgeable, and fixed the problem quickly and at reasonable expense. He's responsive (via text or phone), which is one of the nicest things about Brett - when you have an HVAC problem, you don't want to sit around for hours and wonder if someone is going to get back to you, or if you should try someone else. Don't try someone else - just call Gremillion. read more

Called after a very hot weekend. He came as soon as he could. Only did what was needed. Thought he was honest and fair. Will use him again. read more

We are so pleased with Gremillion Mechanical! They are attentive, efficient, and reasonably priced! Thank you so much for helping us out with our air conditioning! read more

If your heat or air conditioning is out call Gremillion Mechanical. Brett is extremely knowledgeable and is easy to talk to. Brett answered my call right away and set up an appointment that day. The problem was fixed and it didn't cost a fortune. He came over last summer when my AC went out and had it up and running in no time. I'm writing this review because he has now been to my condo twice and it has been nothing but a pleasant experience. read more

I've had the guys from Gremillion over to my place a few times for various AC and heating issues. They are always quick to solve the problem at an affordable price. They're honest and easy to work with. I highly recommend them. read more

Couldn't be happier with my experience with Gremillion (Brett). I am a repeat customer and most recently had an issue with my AC unit. I described the situation over the phone to Brett and he was able to quickly diagnose the problem. Instead of charging me a service fee, labor fee by having to come out and fix my AC ... He talked me how to fix the issue over the phone! He spent 10 minutes (patiently) instructing me how to remedy the situation. Integrity goes along way and in this case... It's certainly appreciated. Brett even called me back 1 hour later just to make sure things were still running smoothly. I'd give 6 starts if I could!!!! Thanks again read more

Brett said he would stop by when we asked during the middle of a heat wave, and he did just that. For that alone, we are greatful.

Brett replaced two radiator valves at my downtown Chgo office last week, and came back without charge to tweak them due to a minor leak in one of them. Professional, pleasant, easy to deal with service. read more

I don't like leaving reviews for anything, and the last time I reviewed a place on here (and my first Yelp review for anything), Yelp deemed it a not recommended review and moved it down. Stupid. Anyway, Brett impressed me so much, that I felt I NEEDED to leave something good for him. So the heat appears this week, and I turned on our system. Nothing. It took about 90 minutes for it to cool our place down two degrees on Tuesday. I started calling around. No one wanted to come to the South Side (really), or they already had too much work, or they didn't feel comfortable being thirteen floors up. I finally called Brett, explained the situation, and he said he worked on the South Side (YAY), and that he would be there Thursday afternoon. Not an hour later, he called back and said that someone had cancelled and he'd be by at 3pm the same day. Excellent. He showed up on time, and it took him maybe an hour to diagnose and repair what was wrong. Our apartment went from 77 to 75 in about 20 minutes. More work will be required on my a/c in the future, but he didn't pressure us to do it immediately, and he gave us the prices for it upfront. He also had fair pricing for the work he had to do that day. So if you need your air conditioner looked at, give him a call. read more

Gremillion Mechanical was very helpful in giving me an assessment of what was going on and also gave me options on how to repair and maintain my unit. Brett was very thorough and it was great that he explained everything and even took pictures to document his work. Very pleased with the service. read more

Good stuff, fixed my heater: increased blower power and replaced ignitor while providing a tutorial/overview of my particular furnace. Also wired the humidifier that was attached but not being used. Called a few days afterwards to check up on performance. Reasonable prices read more

I had the exact same experience as Elizabeth G! The first time we used Gremillion we thought he was great. This weekend, though, we called him on Friday and asked if he could some on Saturday to fix our AC, which would not come on. We have a 10 month old daughter and it was supposed to be 90 so we had some urgency for the repair. He set up an appointment with us for between 9:00 and 10:00 AM Saturday then failed to come or call or respond to any of our messages. We ended up calling Besco Air who came and fixed the problem Saturday afternoon. We will never use Gremillion again. Totally unreliable and unprofessional. I wish I could give zero stars since he didn't even show up. read more

I've been calling on Brett for four years, usually to fix my furnace in an emergency (like last week's cold). He comes out within a day, and we're all warm and comfortable again. His rates are reasonable, and his work is guaranteed, so it's great. He teaches me, too, which I always appreciate. read more

I love these guys! I don't know where my husband found them, but they are reasonable, professional and on time. Brett has fixed our air conditioner and now our hot water heater, and he did a very good and thorough job. I highly recommend him! read more

Brett was SO NICE. He was able to come to my home within 2 hours of call. He even called back to make sure I wasn't being overcharged by anyone. I will definitely call him first next time. read more

This guy is Great ! I had been ( I felt) screwed over big time on two boilers by three major boiler repair services and was thinking the whole industry was a scam. I called Brett after reading a few reviews. He fixed everything for less money than I spent on the supposed big outfits before realizing that it comes down to the engineer that actually does the work. not the size of the company. He is personal, really knows his stuff and explained what was going on. I trust this man. A+ read more

My boiler stopped working last night, just hours before a cold front was due to come through with -30 degree wind chills. I called the people who installed it 1.5 years ago and they could offer nothing except a promise to come by in the morning. I called Brett, with whom I had never worked before, and he talked me through what might be going on, suggested some options, did research on my boiler and even emailed me the PDF of the manual. He said he could come over that night, but unless the problem was one specific part, he would not be able to fix it. Just when I was about to resign myself to spending the night with friends and potentially returning home to frozen pipes, he made one final suggestion: check to see if one of the vent pipes was blocked from blowing snow being sucked inside. I put on three coats, went outside, and sure enough, that was it! I cleared the snow and the boiler fired up without a problem. Amazing service. I will be calling him again. read more

I went on Yelp to find someone for AC repair. Brett with Gremillion Mechanical came quickly (the next day), was on time, fixed the problem with an affordable price. Very professional and easy to work with. Will use him in the future if necessary. read more

same experience as sarah p - he never showed up for an appointment and hasn't responded to messages.

I thought these guys were really great at first-- They were very nice and always replied to me promptly. When my furnace wasn't working they came to assess it and told me I needed a new blower motor. They replaced it for about 600 dollars, but it still wasn't working and my apartment was freezing. I tried to get them to come out to fix it but they didn't get back to me quickly enough during one of the coldest weeks of the year- so a different company came out and I had to pay them to tell me that Gremillion had installed the $600 blower motor in improperly. I contacted Brett on multiple occasions to let him know that this happened and he told me he would pay me back for the second company's visit. He told me to email him a copy of my invoice and that he would happily refund me for the second company's work. This was months ago and I haven't seen a penny. I'll take my future HVAC needs elsewhere. read more