David repaired our A/C unit a couple times (once was a "turn it off and back on situation ) and then after the unit had given us 25 years of service, he replaced it for us. When the AC unit in our daughter's house started leaking, she called a company she saw in commercials. Their quote was astronomical and i could tell there was som BS going on. We called David to come take a look. Of course there was an out of season heat wave and he was very busy but was able to come out in just a couple days. He was able to repair the system rather than replace it and for a fraction of what the other company wanted. He even was bantering with the grandkid while working. He is a life saver. Prompt, professional, knowledgeable and not trying to sell you something you don't need. Thank you David!!! read more

David Burnett runs his business with integrity and offers a reliable, dependable and high quality service. He upgraded my house with a 90 percent efficiency system in my house, including the duct work and two ductless units in my downstairs units. His work and service are superb. I trust his work and expertise. If you are looking for a person who is honest in his work and reliable. He is your guy. read more

"Grumpy" is actually David, a seemingly nice man who blew off my first appointment and had to come back. He said he'd help me with my existing cooling system that uses Freon and then a few days later told me he won't work on anything with Freon after agreeing to come next week. I tried to patiently explain to him that existing units were fine and could be serviced until 2030 in California and he started mocking me and telling me to do the job myself because I know it all. He doesn't know anything about state law and I patiently tried to educate him, since he didn't attend law school and was completely incorrect. I cited the law so he would know, but he lost it. Obviously, this "grumpy" doesn't want any new business and will probably not show up to give you a quote. He stated a nasty message exchange with me and probably needs a number of psychotropic medications and therapy. If people want to threaten me, they don't want new business. What irritates me is that I tried to help him so he would understand and was very patient. This business should be renamed "Grumpy Rage" HVAC. read more

I had David install a heat pump for me last year, replacing 2 furnaces that had been added during remodels. It was a fairly crowded attic installation, but David did a fabulous job, was very considerate of the house and was very clean. I later had some minor problems that he came out and fixed under warranty. He was very responsive to the problem and took them seriously. I highly recommend him for any HVAC work you need. read more

Our AC unexpectedly stopped working, so I called David to take a look and to also give us a quote for a new AC if needed. He was prompt, professional, and courteous. He quickly diagnosed the problem and got it working again so we don't need to buy a new AC (yet). I really appreciate that he didn't try to upsell us to buy a new system. Such an honest guy. He has transparent and reasonable pricing for repairs. It was a great experience and I plan to call David when we finally do need to get a new AC read more

We found Grumpy's HVAC through a colleague of ours. We reached out to David since our AC was not functioning as expected. David was able to accomodate our schedules and was super responsive with text/call. After the initial inspection, he mentioned to us that the entire unit would have to be replaced since it was almost 25 years old and the compressor was busted. He explained to us all the nitty-gritties about what was broken and what it would take for installing a new unit. He immediately responded with some quotes and told us that we would need a crane job since the unit had to be installed on the roof. His quote was very competitive and he explained to us about the various brands of the AC unit and their associated costs. He promptly got all the permits from the city and was able to do the installation very efficiently in under a week's time. He promptly arrived at the set date and time for the install, got everything set up and was infact ahead of schedule! He did the job brilliantly and very efficiently and got our AC unit working in no time. Throughout the process, he was very responsive, very easy to communicate with, friendly and it was truly a pleasure to work with him! We are super happy with the new unit and would highly recommend Grumpy's HVAC!! Thank you! read more

I highly recommend Grumpy's HVAC. From the first conversation to job completion, David was honest, thorough, and competent. We badly needed to install central heating and air in our 1950's home, and cannot be more pleased with the workmanship and outcome. Everything was arranged with precision, the installation went brilliantly with no fuss. The skill level, attention to detail, timeliness, and cleanliness were very appreciated. Call Grumpy's for a job well done! read more

Grumpy's HVAC - David and Antonio, Grumpy's HVAC, installing heating & air. - Heating & Air Conditioning/HVAC Near Me - Sunnyvale, California

David was excellent to work with. I came to him needing a second opinion as another HVAC firm tried to push me to replace my unit claiming it needed a refrigerant that was not readily available. Turns out they misdiagnosed the issue altogether (surprise) and it just needed a capacitor replacement. David was an excellent communicator and very above board. He came highly recommended from a neighborhood forum and I can attest he lives up to this reputation. His repair pricing was very fair. read more

We initially contacted David to install a new thermostat for us. He was able to accommodate our schedule and is very responsive through text. Then a little while later, our heater wasn't turning on. We called David to come back to check it out and on the same day, he was available. He was able to teach us how to re-lite our furnace. Free of charge! Such a different experience than the other HVAC company we had worked with previously. We have known for a long time that our furnace and AC unit needed to be replaced. We decided to hire David for this project. Throughout the replacement process, he has been very responsive and always keeps us notified of all changes. Our furnace and AC unit was replaced quickly and efficiently and both are now in great working condition. It was not an easy task as our units were both from the 1960s and there was a huge storm this past week. We are so happy we found Grumpy's HVAC and highly recommend his services! read more

If I could give more stars for David and Grumpy's I would. 2022 was a year of projects for our family, with full kitchen, bath, electrical, and interior renovations including a new heat pump and ducting. Grumpy's was far and away the BEST company we worked with throughout the process. David was responsive, friendly, professional, and knowledgable about all aspects of the work. David helped pull our permits with city of Oakland, and was patient with us and persistent with the City as needed to complete the project. From start the finish we never had to worry about the quality of follow-up on David's work, and the work was fantastic! The new heat pump works great, the pad was installed perfectly, and the ducting installation was clean, precise, and a major improvement. Again, can't recommend Grumpy's enough, thank you! read more

I had a great experience with David who is a pleasure to talk to and not grumpy at all ;) He offered us a good quote for a flat-fee HVAC maintenance, was available within a day and came on time. He is licensed (it was not clear from the Yelp profile) and very knowledgeable. His approach is no-nonsense, efficient, minimal "upsell" which I really appreciated. Our house had a problem with the first floor getting super heated, and the second floor to be cold, even when the main damper appeared fully open. His fix worked - he adjusted the dampers and explained to me the problem spots he found. I waited some time before writing the review, but I can attest the situation definitely improved and the heat level seems more balanced. Were very happy to use Grumpy's HVAC - Thank you David! Highly recommended! read more

David was amazing to work with, he worked around our schedules, provided competitive quotes timely, was very trustworthy. He is a perfectionist - His craftsmanship is excellent (based on my research, HVAC brand is not as important as much as the workmanship). He has much better warranty period than the other vendors we looked at. He answered all of our questions patiently and promptly. So happy and grateful to have worked with David! Highly recommend. read more

We reached out to David to help us with an unresponsive Nest thermostat, as well as conducting a check-up of our AC unit and furnace. David arrived on time, and was able to quickly debug and resolve the issue (blown fuse), as well as give us his professional opinion of our home's HVAC system. He was knowledgeable about the different types of refrigerants (ours is no longer manufactured) and gave us recommendations on how to proceed if the AC unit stops working in a few years. David also helped us power wash / clean our AC compressor given the amount of dirt it had collected over the years. The work he did was high quality and very thorough. David is experienced with a couple decades under his belt, and we were thrilled to support a small business (he finally decided to be his own boss) - literally, a one man show! read more

We found Grumpys through his van as he was working on another project, and happened to need a new furnace! We were doing a full home renovation, so we have lots of data points on contractors, and David was the most amazing partner we had in our home journey. He was always punctual, very communicative, always respectful, very professional, and made us comfortable each step of the way. The price was very competitive compared to other quotes we received. We're so incredibly happy with our choice to go with David! read more

Having never had to request HVAC service since moving to the south bay area, I was concerned about choosing someone who was skilled, honest, affordable, flexible, and had obvious pride in work. Well, now I know David and Grumpy's, and I will never contact anyone but Grumpy's if I need HVAC services in the future. I had a unit with a coolant leak, and with some coaching from David over the phone, we were able to confirm this problem by my trying a couple of simple tests on the unit. Once this leak was confirmed, he instructed me not to use the unit until it was fixed and we set up an appointment. He arrived on time and inspected the unit to determine the location of the leak. Once that was done, he explained what he'd have to do, what the cost would be for labor and coolant, and how long it would take him. He completed the work in less time than estimated, tested the unit and left the whole work area so clean and buttoned up that I could not tell anyone had worked in the area. Why would I ever call anyone else but Grumpy's? read more

We hired David to fix a flaky furnace on the home we just moved into. He arrived on time and was very methodical in his debug process. After two hours work, the furnace works flawlessly. Just so you know, we checked YouTube for the symptoms, and NONE of the videos showed the correct answer. All the YouTube videos pointed to a dirty flame sensor, none pointed to clogged combustion tubes. That's what experienced guys like David are for. read more

David was fast and efficient in installing refrigerant lines for me. Everything worked perfect the 1st time. He is very experienced and highly recommended. read more

Dave repaired our ancient gas furnace about a year ago for next to nothing, warning that it would at most get us through one more Winter. He also informed us that because parts were no longer available it would be "new furnace time" when the fix failed. Well, he was right. A year later our old furnace died for good...but thanks to Dave's advance warning we'd saved up for a new electric heat pump. We called Dave again. Not only had he earned our confidence, his bid was extremely competitive. Throughout the process he was professional and communicative. He showed up on time and cleaned up every day. Now we have a wonderful system that's quieter, more efficient and much better for us and the environment. Dave is experienced, responsible, and we highly recommend him. read more

Available, honest, straight to the point. My kind of business owner! Thanks Dave read more

David is referred to us by our general contractor. He arrived and immediately jumped on locating the gas leakage on recently installed wall heater. He was able to address the issue and replaced the leaky pipe. He took his time in repairing the leaky gas pipe and did not skip any necessary steps. Besides his work quality, he brought a floor cover and was wearing booties around the house. He also repaired the gas pipe going to the outdoor grill. Definitely recommend him when you need a high quality work at very reasonable cost. read more

Great service with a smile! David was the only one to respond to our request for repairs to our heater. He found our part needed quickly and was here before the storm predicted. He is reasonably priced and a pleasure to work with. Thank you David! Not grumpy at all!! Gerbers read more

We were fortunate to find David Burnet of Grumpy's HVAC!! We've called him 2 times for service and both times he was able to come right away and did a very thorough job! This last time he reconnected our roof flues after we replaced our roof (the roofers did it incorrectly!!) and he also cleaned and replaced our furnace filters (duplex). He is very knowledgeable & trustworthy and his prices are very reasonable. I'm spreading the word to all my co workers & friends because it is hard to find great HVAC companies! thank you David!! read more

Good professional service, quick repair of my A/C in Sunnyvale. I'll definitely be calling back for any future HVAC work.

He really helped me out. Found my parts and repair my A/C uint. And he got it fixed the same day. Thanks.

Our AC's drain pipe sprung a leak in the attic and it was Friday evening. I called around and David picked up and offered to come the next day. He was early, very professional, identified the issue right away and fixed it. Highly recommend David and Grumpys HVAC. read more

Of course my heater would go out on one of the coldest days ever. I went to Yelp and asked for help. Grumpy's was the first to respond and stated he'd be in my area the next day. We set up the time and he was there. Found the issue and was more than reasonable. Thank you Mr. Grumpy who was so helpful with advice. Nice to have someone who is not trying to collect and leave. Thank you!!! read more

After a power outage our very old heating unit wouldn't turn back on. I called Grumpy's, and David came out that afternoon. He quickly diagnosed the problem as a broken transformer and swapped a new one in fixing the broken unit. He was very friendly, quick to respond, and also very capable to get the job done! I will recommend Grumpy's to anyone who asks. Great service. read more

My relatively new electric furnace stopped working on Thanksgiving day, which also happened to be the coldest day of the year. After a freezing night, I called around to find someone to fix it--including the contractors who had installed it--but no one seemed to think a lack of heat was a priority, so I couldn't get an appointment sooner than a week out. I saw David's positive Yelp and NextDoor reviews, so I gave him a call and he came right out! Texted me his ETA, showed up exactly when he said he would, and didn't even get upset when he found that the "broken" furnace had actually just been unplugged by the plumbers who had replaced my water heater a couple of days earlier. David is professional, friendly, and efficient; I will absolutely call him when I really do need HVAC service in the future. read more

Dave came out to fix our heater and it turned out to be a simple job. Yet was so kind, wonderfully responsive; he didn't charge me anything because he said it was under warranty. For the trouble of driving out to my property in bad weather, I am so grateful and appreciative of his service. read more

What a find! I couldn't be happier with David and the work he did for us after another company (Hussey Bros) massively screwed up the installation of our brand new, very expensive Mitsubishi system. David is responsive, knowledgeable and reliable. Showed up on time every day and worked with us on the final adjustments needed to make everything work perfectly. read more

David fixed our problem very quickly and was exceptionally prompt and very friendly, and has a great sense of humor. I would not hesitate a moment to hire him again. In fact, I plan to, to upgrade our HVAC system. You can't go wrong with a Grumpy HVAC guy. read more

David installed a super quiet and efficient all electric heat pump system that we are super happy with. We had nothing but a 1940's original gas floor furnace, so this was a full system install. After discussing ducted and ductless options with him, we decided to go for a ducted central system. They went above and beyond with the ductwork, working in difficult spaces to get the vents to the ideal locations with perfectly balanced air flow. He was great to work with and he's obviously very experienced at this kind of work as everything went super smooth--highly recommended. read more

We recently hired David to replace the 20+ year old furnace in our house in San Francisco and add central air with dual zones. After getting several bids David came in with a detailed estimate at the best price and was responsive and pleasant to work with through the entire project. He is also the owner and works on every project himself so you know your project will be in good hands. read more

Davis is FANTASTIC! I am an interior designer and I work with a lot of contractor's in the industry. David is a true pro, easy to work with, thorough, and entirely reliable. He replaced my AC unit and I could not be happier with the outcome. I highly recommend Grumpy's! read more