HVAC reviews in Gaithersburg, Maryland

This company is full of un professional, un skilled handyman collection. If you look at their website they look like a great company who can do any job as far as HVAC is concerned. But they are a bunch of handyman looking to tighten a screw and rip people off. I don't recommend this company for people who need a professional clean service.

This is the worst firm I have ever worked with. They were hired by my contractor to do all of the vent work and HVAC system in my addition. They did the work but did NOT pull a permit as required by law! They held up my close in inspection because they could not do the J calculations necessary. They claimed that the regs had changed recently but the county told me they were in effect for 2 years at the time. Then they told me that they did not have the person on staff to do these calculations. I had to wait 3 weeks to get it done. All the time the 2 brohters that owned the place told me this would not have happened if they had known sooner. But they were useless in getting it completed. They would assure me I would get the calculations the next day then the next and so on.

The technician that did the work "Chuck" would show up apparently when it suited him. I set up 4 appointments with him and never showed up. I had to point out errors to him. It took 2 discussions with him boss also named Chuck to get him to show up.

Then the HVAC unit kept shorting out. I looked at the system and clearly marked on the side called for 60amp fuses. "Chuck" the tech used 50amp's. I didnt want him back in my home but was told he was the only guy who was running their "NEW" residnetial division. So he came back to complete the hook up on the vent to the furnace. Instead of hooking up with vent cut in the wall he decided it would be better to cut a vent in the furnace itself and put a return vent cover. It was another example of sloppy have baked service. I caught him as he was walking out and told him to fix it. He said he thought it was "good enough"! I took pictures in case you cannot believe this is true.

Now because of all of the trouble they caused me and the additional 3 WEEKS I had to wait to move ahead with my project they promised to add at NO COST 2 humidifiers that I was originally going to purchase. These were recommended to me by them and were high end Aprilaire steam models. Owner Chuck said he would pay and install for free these units on both of my furnaces. Well when they got to my home they were not the high end models but very simple water based units that cost $190 dollars on line. Okay I thought let them install these and be done with them. I should have known better. One unit was installed in the wrong place with standard copper tubing that in order to change the filter every 3 months the copper tubing would have to be wiggled. Anyone who has ever dealt with copper tubing, like an HVAC tech, knows how sensitive it is at the junction. It leaked after 3 months.

The unit installed on my other furnace was not checked properly and the condensate pump did not work. When I discovered, I am rather handy but by no means and expert, I called and asked Diversified to come out immediatly to fix it. They sent a new tech out to do the job. I am sorry i cannot remember his name as he was very polite and capable. He told me the work done by the other 2 techs were wrong and he apologized. He got a new condensate pump and hooked it up.

Imagine my shock when I got a call to pay for the work done. The tech didnt mention any of this and since it was part of their promise for the many headaches I was floored. And it wasnt just a bill in the mail it was a constant barrage of calls. Faxes sent to my office with remarks in the top line that said "Be a man and pay your bill"! They still did not stop and over a 3 day time I recieved 11 calls with 4 messages. Needless to say I am done with this firm.

I sent them a nice letter explaining that a condensate pump is part of a humidifier and therefor free under our original agreement. The letter also included the quotes of 3 very reputable firms to correct the varios mistakes their tech "Chuck" had made. I have not heard from them since. When I saw an ad for their services in a mailing I decided to post this email. This firm is a nightmare to deal with and their workmanship is HORRIBLE!

I called them on weekend to repair my heater. Their technician came and spend less than 30 minutes. And he wanted to replace a part (at a cost of $1000) but couldn't guarantee that would fix the problem. I told him that after spending $1000 i would have thought he would know. He said it was somewhat of a guess. I told him a guess wasn't good enough and that i would need to have a second estimate -- he said fine and charged me $580. I asked why so much since he did NOTHING and he said for weekend calls they charge for 3 hours of work automatically. Oddly enough i wasn't informed of this in advanced. Total incompetence and an insane charge. Avoid them!!

They don't even deserve one star! They recently replaced a roof top unit on my office building and the entire experience was a disaster! After they wired the unit up improperly (even had the air handler running backwards) without even knowing it, they had to return over 10 times to my office to attempt to repair the problems that they had caused, but were unsuccessful. Their staff and techs were totally unprofessional and blamed the problems on us! They would never admit that they had caused the problems with our system or that they were unable to fix them. I had to call in a second HVAC contractor to make repairs to our system that cost me over $1400 because of their incompetence. (BTW- the new contractor had the system working perfectly in only about two hours!)
When I called the owner to discuss the issues and complain, I asked if he would make it right. He only made excuses and insisted that the repairs needed to fix the problems that they had created were my problem, and that I should have to pay for those repairs since I had to call in someone else to fix them.Terrible experience!! I would NEVER recommend them to anyone for service, repairs or installations.

Service Tech was great. But I'm not paying a fee to pay your company for driving to my house to do work, I'm expected to pay for. Not paying a 3% fee to pay by credit card. $147 for first 30 min and 137 an hour. I chose this business on a recommendation. I won't be forwarding advice for future solicitations. If my unit is not working or fails to work correctly...I'm Calling, and Paying for SERVICE from another vendor.

After enduring weeks of uneven temperatures, I finally have consistent comfort thanks to their expert ceiling ventilation repair. The team displayed impressive knowledge and efficiency, wrapping up the job in about an hour. I'm thoroughly impressed by their professionalism and will definitely call them again if needed.

Professional repair with noticeable improvement in performance.

I would not let anyone other than Elmer Slack ever touch my HVAC. Not only is he highly talented, experienced, capable and conscientious, and watching out for my wallet, he is also warm and personable and a very good person to have in your "back yard." He is so good that he is entertaining, and makes an art of science while he makes everything right. I cannot recommend him highly enough. In fact, I hope no one ever reads this, because I consider him a well-kept secret.
Dave Tabor

Elmer is fantastic and professional. He installed a heat pump for a brand new second zone and replaced our 33 year old gas furnace for the main level. He explained everything he was doing along the way and truly taught me a lot about my home's HVAC and how to care for it. Highly recommend working with Elmer as he is a true craftsman and his attention to detail shows in his work.

Replaced worn fan belts on our older commercial rooftop unit. Tech brought the exact OEM belts and adjusted tension perfectly. Quiet and efficient operation restored.

Trustworthy and efficient, the technician ensured our A/C ran smoothly with meticulous attention to detail. Arrived promptly and completed everything within an hour. Highly recommend!

Having a thermostat professionally installed was a game changer. The technician was prompt, arriving within 20 minutes of the scheduled time, and was incredibly knowledgeable. Now, my home feels perfectly cozy with minimal effort on my part.

Excellent, prompt, reliable and clean service.

Great job. Done on time, Thank you

Honest and knowledgeable.
I highly recommend this company.....

Excellent service. Professional. Would recommend.

Too expensive for a townhouse owner. Unreasonable markup on top of manufacturer prices.

Very dependable and efficient service provider. I am a delighted customer of 20 years!!!

Couldn’t be more pleased with the quality of product as well as service we received. Ronen was very knowledgeable and professional. Would highly recommend to others.

I have been very satisfied with the service provided by ADI for the past 6 years. He goes above and beyond to be helpful and is very responsive!! Thanks so much!!

Ronen and his team were excellent! I would recommend ADI for all your heating and ac needs!