We realized that the A/C stopped working around 3PM. The temp in the house was 84 degrees. We contacted Bryan. He was in Brea. He said he will stop by in half an hour to take a look. By 4:30PM, he was done. A/C was fixed. We got lucky as we know how busy Bryan gets. He definitely is a master at what he does, experienced and knowledgeable. We certainly appreciated his quick response! read more

McMaster Mechanical - Heating & Air Conditioning/HVAC Near Me - Diamond Bar, California

Came out at the spur of the moment being that he had a job near us. That was great cause he scheduled us for the next day but getting it done quicker was definitely appreciated. Brian was very friendly and quickly determined that our AC unit had a contact burnout. He had the replacement part on his truck and fixed the problem in about 30 minutes. He is now our go to for any HVAC services. read more

Fixed my immediate issue and gave a detailed rundown of other issues my system has. I'll be calling him back when everything blows up.

I have used McMaster Mechanical in the past at my residence to diagnose an issue i was having with my AC losing freon. Bryant came out and was very knowledgeable and helpful. I also have a rental property that needed an upgrade to AC/furnace that was over 35 yrs old. Bryant came out and was very thorough in measuring and estimating the best unit for my rental needs. I had other estimates from tech's that tried to up-sale me to go to a 3 ton unit that would require new ducting as well for additional cost. Bryant inspected my existing ducting and said I would save a lot of money to stay with a 2.5 ton unit and use the existing ducting, that was still in great shape. Bryant knocked the project out in one day, saved me thousands. My tenant is happy, I'm happy and i highly recommend McMaster Mechanical for your AC/Furnace needs! read more

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Bryan was highly recommended by my neighbor and lived up to his reputation. Definitely very knowledgeable and honest about what he was able to do. I have an AC system that is ancient. Going on 45 years old. He was able to revive the system and is pricing was very fair. I will be definitely be keeping him on my Rolodex of keepers for future use. 5/16/25 read more

Wow,what can I say. These guys are wonderful. I called around none and explained my problem. A few hours later I got a call back and they said they would be there in 10 minutes. Gary showed up, diagnosed the problem, told me what it needed, did the work and got me back to having cool air upstairs. Courteous, friendly and reasonably priced. I will definitely call them for any future issues I have. I would definitely; recommend them. read more

Bryan is the man! My knight in sweaty armor. The bread to my butter. The salt to my pepper. He and David are like Thor and Mjolnir. With a little wiggle of their fingers, magic starts to happen. I called Bryan with my pleas for help to make the heat go away. He asks, "What's the problem?" To which I reply, "Kind sir, my just-out-of-warranty unit has stopped working." He asks for some details, I divulge what I know, and he comes back with, "I think I know what the issue is" and proceeds to lower his sunglasses. Out of nowhere The Who theme song starts playing in the background, and I'm like... this guy is good. Well, at least that's what I pictured in my head during the initial phone call. Fast forward a few days and he's inspecting my unit. Straight away the cause of the leak is revealed, and Bryan's hunch was right. He goes around inspecting the rest of the HVAC system and proceeds to complement how big my unit is. But with a twinkle in his eyes he winks and says, "Brosef, bigger isn't always better." At this point, I have to make a life altering decision: do I patch things up with the way things are or do I go through with the procedure of shrinking my unit? The cost differential was minimal, so I made the tough decision to go with the HVACtomy for the better efficiency. Bryan makes a few calls to order the parts and leaves to go do another job. To my surprise, he was able to return to finish the job later that afternoon. McMaster Mechanical to the rescue. A few hours and some chicken tenders later, I have a band spankin' new AC unit with the matching evaporator coil. I even got a proper gable attic fan to get rid of the old one that would vibrate the whole house. Once the system was confirmed to be leak free, it was recharged and the sweet bliss of cool breeze oozed through the vents. If it weren't for the tag team of Bryan and David, I wouldn't be sitting here cool as a cucumber writing this legendary review. Thanks for the hard work fellas, now I get to dodge this heat wave. read more

Find Bryan on Yelp after I've been told from Home Inspection Company that my two A/C systems need to be replaced. I actually called 3 companies for price comparison, one of them didn't show up, another came first and took like 20 min to do the inspection, and then he showed me his Yelp account has over 200 five stars, and every job he has done before was very clean, very quality etc. and then he gives me a very high quote which I can not afford it. I'm assuming that he is a very professional A/C engineer, so for my 2 A/C systems(3 ton for downstairs, 3.5 ton for upstairs) he can figure it out very quick that how much this gonna cost and how long this gonna take. I don't know, just feel like realy? 20min? BTW, he spent almost a hour trying to convince me and my wife to accept his price. And then Bryan showed up and spent almost 3 hours on inspection, you may don't know, this was a free estimate and he spent nearly 3 hours! and then he told me every details about what is he going to do on my project. and importantly, even though he's price wasn't the lowest, but I can afford it! so for me , that's the reason why I choose him to do this project. At the next coming 5 days, he usually came at 8:30am and left at 4pm. working hard and not much talk. as you can see the pictures I've posted below, shows how it looks like, before and after. He finished an amazing job with a very fair price, I would like highly recommand him for all kinds of the A/C system, weather repair or replace! As you can see, my English is very limited, can not describe more details about how he's done this job, but if you're looking for a professional A/C engineer, you should definitely give him a call. read more

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Bryan is awesome!!! He's honest, thorough, responsive and knowledgeable. I reached out to Bryan since he's the go to guy for ACs on my city's Facebook page. He was very responsive and we scheduled for him to take a gander at our AC unit. He actually squeezed us in because he was so busy and the next time he would come out was in 3 months. There was nothing wrong with it, at least that we knew of. It was working fine and we wanted to make sure it was in tip top condition for the coming summer. Bryan took apart our AC blower and it was disgusting! I mean it was covered in dust, dirt and who knows what else. No wonder my allergies are horrible!!! This would be a good few hours to clean. He suggested we get a new filter and he would be back to clean that abomination when the filter came in. Once we got the filter, I let Bryan know it arrived. He came in and cleaned that bad boy out. He was very thorough and made sure it was clean. He also checked other parts to make sure it was good and it looked like everything was in working order. I'm so glad he was able to clean it. Since then, my allergies have been A LOT better. I can't thank him enough. I don't sneeze and get itchy eyes as much! Bryan is definitely your go to guy for AC/HVAC units! You won't be disappointed! read more

We were so happy that Bryan fit us in his schedule on a hot Sunday in July. All the five star reviews are true. Bryan provided us tremendous service for a very good price. Someone else had "fixed" our air conditioner and it stopped working on the same day. Bryan fixed that problem and was also able to diagnose another problem that was about to happen and fix that as well for us. If we can get an appointment with this company, we will not use anyone else. read more

Very responsive to calls. Air conditioning unit was not running. Found the problem quickly and repaired. The cost was reasonable for service provided. Overall I was pleased with the service and cost of repair. I would highly recommend this business. read more

Bryan Heer is the go to guy! He came after hours and got the job done. Our heater kept tripping off due to overheating and he knew exactly what to do. He is extremely knowledgeable and well versed in his craft. He was kind and the cost was reasonable, especially for coming after normal working hours. If you need help, start here. read more

Bryan was great to work with and knows his trade. He came recommended by a friend, and we will be sure to recommend him to others. Not only was his work great, but he was motivated to get it done no matter what it took...and our 1957 home definitely gave him a few tests! He was on time, paid attention to detail, honest, client-focused, and worked harder than most. We will defiantly keep in touch with him for all our heating and AC needs. Highly recommend McMaster Mechanical! read more

Bryan is the only contractor my husband has ever been happy with. He installed a Bosch a/c with heat pump system over 3 years ago. When we turned on the air last week, the house was not cooling off. We called at 3:pm on Friday afternoon, and he was here already at 4:30pm. He ordered the part on the spot which was still under warranty but his labor wasn't. He installed the new part today and didn't want anything for his time and trouble. We would highly recommend him and the way he responds in a timely matter. We will always call him for help and highly recommend his company. read more

Bryan was able to come out and figure out what was wrong with my air conditioner and fix it. Appreciate his hard work, transparency and knowledge (along with humor). Would use again in the future if needed. Highly recommend! read more

Professional, detail-oriented, honest, timely, fair, trustworthy, funny, respectful, and diligent are just a few of the traits Bryan possesses. From the moment we first discussed our request for an AC unit and furnace, he asked various questions to get an idea of what my wife and I wanted and potentially guide us in the right direction. We set up a quote with him shortly after that phone call. During the quote, Bryan arrived on-time and was very diligent and truly analyzed everything to make sure that it, was first off, something that can be completed, and second, provide an accurate quote and also a timeline of when the job can be completed. The quote was very professional, timely, and detailed. Once we agreed to have Bryan help us, he was on-time (once again) every morning, left everything clean, and continuously educated my wife and I on the unit that we are getting. He's nerdy like that, to educate us on what he's doing, but I truly appreciate that, since I am one that likes to know the details. I like to think I know a little about HVAC/AC equipment, because Bryan was so patient with explaining things. The pictures of the new equipment show how organized and clean Brian leaves everything. He completed the job in the time he stated and we were very happy with the work he did. However, Bryan was not. There was something that Bryan felt he could have done better and he ended up coming back to fix what he thought needed fixing. That goes to show the type of character Bryan has. He does things as if it would be his home and to someone that is a new homeowner, it was extremely appreciated. I will always look to Bryan for help with ANY of my HVAC/Air conditioning needs and would recommend him to any of my friends and family. read more

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I can't say enough good things about Bryan. I'd been dealing with home warranty contractors for over a year because my AC wasn't blowing cold air. They kept "testing" the lines with compressed air, then come back 2-3 weeks later to check them. They finally determined that my condenser needed to be replaced. This was supplied by the home warranty company, but it took 3 weeks for the contractor to go get it. They finally swapped out the condensers and I had cold AC...for 2 weeks. This was followed by months of different home warranty contractors doing the same tests and determining that there was still a leak in the line set. After meeting with 3 different home warranty contractors including the one who did the initial installation, they all said that they wouldn't touch it. I live in a lower unit condominium so we were extremely limited as to the route to take from the one side of my unit where the air handler is to literally the complete opposite end where the compressor was, outside my unit. Only option was through the ceiling where I have no attic space. After inspecting and exploring Bryan agreed to take it on. I was done with home warranty....it's been over a year at this point. Bryan was very methodical in the way he went about this job. He worked REALLY hard to do as little damage to the drywall as possible. This is also when he discovered that the original line set ran through the foundation and not the ceiling as we had assumed. He discussed my options with me giving me the pro's and cons with every choice, never trying to up sell me. He totally nailed a not so easy 50' path through my kitchen, hall closet and across the master bedroom to the outside wall where the condenser sat. He also did this with a SINGLE piece of copper, through the bends and turns in the ceiling! He was determined and he did an AMAZING job! He's also SUPER clean! His pricing is very fair and, OK...he's a pretty cool guy. I would totally recommend Bryan and McMaster Mechanical. No BS! read more

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Bryan was very professional and very nice guy He knows what he is doing. Me and my husband we're so happy we chose Bryans company. If you need a honest person to do your air conditioning give Bryan a call he is honest and great costumer service!!!!! read more

The service was great! On time, honest, conscientious, friendly, very fair price, a real people person. He truly enjoys being of service. My old air conditioner is working great now! read more

Our air conditioning unit started making an abnormal buzzing sound in the midst of summer. I initially called a well reviewed HVAC company local to Walnut and got charged for a "diagnosis" fee and was simply told I needed to replace the whole A/C unit. I then contacted Bryan for a second opinion and he showed up the next day and presented different options to us on repair vs replace. Turns out, our 30+ year old unit has not been maintained and just needed some maintenance and TLC. Bryan swiftly completed the job the same day and saved us the hassle and price of replacing an AC unit which I know we will eventually need to replace but with Covid and supply shortage, he recommended to wait for rebates and better unit availability. He was upfront and honest about pricing for different options which is rare to find nowadays. I'm happy to give Bryan five stars for honest and hard work! read more

If you are looking to replace your heating and air conditioning, Bryan Heer and his assistant David are your guys. I had a 34 year old HVAC system that I replaced with a Bosch heat pump a few weeks ago. At least 4 other mechanical contractors bid this job. They all took some kind of short-cut/back of the envelope guess at what I needed. Only Bryan took the time to make a thorough inspection, figure out how to keep my equipment out of my unconditioned attic (and in my garage where an old guy like me can get at it for periodic filter changes), and to increase the amount of my return air by 1/3 (All of the others said I had too little return air flow, but none of them had a fix.). Bryan and David were very diligent, and worked hard to replace my whole HVAC system (including new ducting throughout the house) over the course of three days. The finished product is meticulous, like a fine watch movement. Both the city inspector and the Title 24/HERS tester said "Wow" when they first saw the installation. The city inspector complemented Bryan, telling him his work was "excellent." To top it off, the price was fair, especially considering the work done. My wife and I could not be any happier. read more

Bryan is our go-to AC technician! He is honest and reliable. He responds in a timely manner, is honest in telling us what is wrong with our unit, and gives us options on solving the problem. Bryan got our AC unit running just in time before the heatwave arrived and before my grandson's baptismal party. read more

Bryan is a rare find in the HVAC industry. He communicates extremely well. He will respond to urgent matters same day, works long hours on weekends, holidays, and especially during high-demand heat waves that we've recently experienced here in So. Cal. Although Bryan is extremely busy everyday, and well-deserved, as he is quite popular in our local community, he is still able to squeeze in appointments on short notice to accommodate individual emergencies. He is also a giving man, as shown in his past charitable donations in our local community. Finally, he's an honest pro in the HVAC field who provides options and delivers efficient and effective solutions. I highly recommend Bryan and his company! read more

We have called Bryan three times, once to check our AC, once to fix our furnace and most recently last month to move our AC and then reinstall after redoing our hardscape. Every time he has been thoughtful, informative, and above all has done beautiful work. I wouldn't call anyone else. read more

Bryan did an inspection and service on our HVAC.... replaced 2 capacitors that were weak - even showed me the specs and the readings on his measurement equipment. Made some valve setting adjustments - again showed me everything and explained what was wrong and why. He found all other equipment in proper working order - no attempt to distort or expand. Also measured for carbon monoxide - very thorough - no problem found. However, he did observe an improper vent pipe that was done incorrectly 15 years back... showed me the photos and explained everything. We agreed for him to replace it - work was done well and complete. Summary: very knowledgeable, very professional, great explainer and communicator, reasonable pricing, and very pleasant and personable; Highly Recommended. Will use again as needed. read more

Thank you to Bryan who came out and took care of my heating/ac system. He was very Professional, prices were very reasonable, service was great! highly recommended .VERY TRUSTWORTHY & HONEST! read more

Bryan fixed my dad's air conditioner and replaced the air conditioning/heating unit, updating the system, in a 30 year old condo I recently purchased. He is very knowledgeable and puts in lots of time and effort to complete the job in the best way possible. He is very thorough and dedicated to his work. I would definitely recommend Bryan! My dad also loves Bryan and he is 75 years old, super fussy and knows good work when he sees it! read more

Bryan was very helpful in fixing my heating issues. He took the time to explain why it wasn't working properly. He was on time and very personable. I will definitely be recommending him to friends and family. read more

Bryan came out to our house the same day. We phoned late and he was nice enough to come before going home. He was very thorough and showed us every issue that we had. We were outside with him the entire time. He gave us options and was all around very helpful and genuine. We highly recommend him. read more

My AC stopped working at my house recently and a friend of mine referred me to McMaster Mechanical. Bryan came out to my house and was able to get my AC up and running again. I don't put up many reviews, however Bryan promptly responded to my house, clearly explained what was actually going on with my air conditioner and gave my options on how best to proceed. Bryan sounded very educated, but was able to explain my issues to me on a level where I understood what was broken on my AC. I know that I was getting the best deal for my dollar and that he stood behind the quality of his work. I would definitely refer McMaster Mechanical and Bryan to any friends and family. read more