Having our old 1930 house insulated has far and away been the best investment we've made in our house. We've lived in the house for over 40 years and were used to sweaters and sweats in the winter and during our hot days spending more time in the cooler downstairs. We now leave the thermostat set at 64 for a low and 74 for a high and the heater rarely goes on. Today (9/9/2026) we think the AC might actually go on later today. Yesterday the house never even reached 74. We had building efficiency do the insulation almost 2 years ago and have gotten so used to our house being in a comfortable range all the time we rarely even think about it. This latest heatwave has reminded us of how glad we are that we did it and that we should give them a plug again! The process itself is fairly disruptive but doesn't take too long and Building Efficiency was very profesional and helpful in minimizing the disruption. Our only regret is that we didn't do it long ago. read more

Building Efficiency evaluated the property and educated us thoroughly before providing a competitive to install a heat pump and water heater. They communicated well, kept a clean work site, and the staff was professional and efficient. We've been very happy with the results. read more

This is long overdue, a number of years ago we had building efficiency come out and assess our home, I felt like they were so knowledgeable, professional, and informative - it was truly a pleasure. The pricing also seemed extremely reasonable. We ended up doing insulation in our ceilings, such a seamless experience and they supported with the rebate process, had finances not been a limitation we would've done walls. Highly recommend, in fact writing this review has inspired me to loop back with them about their suggestion that our furnace is waaaaay overdue. read more

Installed my furnace in 2018. They moved my furnace in wall to attic which makes it hard to reach. In December 2025 Co detectors fired up twice. Since the furnace should be still under warranty I contacted them by email and phone but no response. Don't be fooled by the yelp ratings. This business is hard to work with after the initial purchase. read more

Incredible team, professional, terrific communication and great clean work. Absolutely recommend.

We requested a number of quotes for heat pumps, and Building Efficiency was by the far the most knowledgeable and trustworthy, with fair and transparent pricing. Dave also found a creative solution for the location of our air handler that saved us a ton of space in our garage, and greatly improved the overall air flow and efficiency of the ducts. His team was knowledgeable and hard working, and Dave worked with us through to the end to get all of the details right. The house is so comfortable now, our energy bills have gone down, and the air filtration is a great perk as well. I highly recommend this company. read more

From start to finish, Building Efficiency was a pleasure to work with. Very professional, reliable, excellent workmanship in all phases of my project including attic insulation, weather stripping, installation of a heat pump water heater and a heat pump furnace. They were helpful in the rebate process and kept me informed throughout all phases of the work. My only regret is that I don't have any other projects for them to work on! read more

David and his team installed a heat pump and heat pump water heater in my home several years ago, and I have been very pleased with them and Building Efficiency's ongoing support. When my garage was flooded in late 2022, David and his team helped troubleshoot the heat pump and made sure everything was running smoothly. More recently, I had plumbing issues that required another service visit, and the team was just as responsive and efficient as before. I highly recommend you go with Building Efficiency for your HVAC needs; they are an excellent value! read more

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Dave and Building Efficiency were the most knowledgeable contractor which I interviewed for our project to install a Heat Pump system in our house. Unlike, several others, Dave sized the system accurately and had clear expertise in the technology. He included improvements to our ducting system which others did not. The pricing was very competitive. Although we had a long wait for our installation, when it occurred, it went smoothly and efficiently. The crew clearly was well experienced and expert at the work. They were prompt, communicative, and cleaned up thoroughly each day - making room in our garage so we could move our cars in at the end of each day. read more

I worked at Nest on the thermostat and energy algorithms for over seven years, and so I'm picky when it comes to HVAC contractors. When I look for an HVAC contractor, I don't just want one who shows up on time and cleans up after themself; I want one who understands building energy efficiency and cares about it! I first worked with David and his team at Building Efficiency when I was in charging of selecting and coordinating an HVAC contractor to perform an energy upgrade for my church. The energy upgrade included installing heat pumps for two different buildings, along with performing a total ductwork replacement and attic insulation upgrade for one building that serves as an office and preschool building. The Building Efficiency team was great to work with, and we love having the heat pumps! Replacing our old fossil fuel-burning gas furnaces with heat pumps that can run on clean electricity was a win for the environment and a win for our comfort. Having been pleased with how the project at the church went, I referred Building Efficiency to a neighbor of mine and also hired them to upgrade the attic insulation in my own home. Lalo and the crew who did the attic insulation and air sealing work were fantastic, and I appreciated that Lalo went the extra mile to do things like loan me some drywall patching compound so that I could fix a pre-existing hole in my garage ceiling before they blew in the new insulation. I'm very happy with the new cellulose insulation, both because I got rid of all of the old fiberglass insulation and because my home stays warm much better in the winter and cool much better in the summer. I wouldn't hesitate to recommend Building Efficiency to a friend or neighbor, and I look forward to working with them again in the future. read more

Building Efficiency - One of the heat pump units installed by Building Efficiency that keeps our preschool tentants nice and comfortable! - Heating & Air Conditioning/HVAC Near Me - San Francisco, California

David and team have been instrumental in helping us to upgrade our old furnace and ducts. They did a full assessment, provided several options with pros and cons of each and walked us through making a durable decision, making our home more comfortable, while staying within the budget. They were dependable, efficient and did exceptional-quality work on a pretty tight timeline. Would highly recommend for anyone in the city, looking for a fair assessment of options available on an older house or condo. BE is the best! read more

David and his team were a pleasure to work with. I contacted them via Yelp and was scheduled for an initial intake by Russell who discussed my project needs which was followed up by an on-site visit. There was no effort to upsell things I did not need. My job was basic: my home was uninsulated so I needed wall and attic insulation. I accepted the estimate which was in line with other estimates and work was scheduled. They explained the entire process and what to expect in great detail. As explained, the insulation process was very dusty and they had a professional cleaning company to clean up afterwards. The install itself was seamless, there were no surprises, and the work was completed within the projected timeframe promised. Now my home is insulated and the difference is noticable; my bathroom is much less cold, it is less drafty all around, and as an added benefit the street noise is muffled slightly. I would definitely recommend them. Thank you! read more

David and the team at Building Efficiency were a joy to work with. He walked us through the process of installing heat pumps and how it all worked. Fun fact - with heat pumps you get a (sorta) cooling system as well as the heat. Great for those two heat wave weeks a year in San Francisco. Everything was clear, on time, and works. Couldn't ask for a better experience if you are electrifying your HVAC. BTW heat pumps are faster, quieter, and work better than our old forced air system. read more

The Building Efficiency team installed 2 heat pumps (1 of them shown in the photos, the other is in a crawlspace that's a little hard to get to), heat pump water heater (shown), new ducts, and attic + kids' room insulation in my 75+ year old home. They did this quickly and efficiently (in under 1 week despite needing to re-duct our home and the random space constraints you'd expect with a 75+ year old home), helping us get the rebates we qualified for and making sure what they put in fit our home. We now have air conditioning (increasingly necessary in the Bay Area) and just better comfort (esp in my kids rooms which used to be too hot or too cold) and the knowledge that everything is electrified (and pairs nicely with our solar installation). They've also gone above and beyond in being responsive to our questions after the install, coming in to rebalance the air flow, answer our questions about air filters, and even troubleshooting a manufacturer's defect. I can't recommend them highly enough! read more

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Replaced our entire HVAC system and insulation for our house. Incredibly responsive, helpful and flexible to meet our scheduling needs. Would recommend to anyone in need of home energy related issues. read more

We hired Building Efficiency to design and install a heat pump system for our top-level apartment in our 120-year-old Victorian building in San Francisco in 2023. Getting the project started and ordering all the components took longer than we'd anticipated; supply-chain issues may have been at work, but also this is a small company that does high-quality work and has a lot of demand (as other reviewers have noted.). HOWEVER: the work they did was top notch. We had a difficult installation, as there is no easy roof access, and we have very narrow attic crawl space. BE solved all the problems. After six months of operation the system has worked flawlessly. We are comfortable AND power-positive (with the solar power system that was installed by Albion Power at the same time.). The owner David H obviously treats his employees well. read more

Excellent work. On time and very good finishing / cleanup. Seeing the benefits of the upgrade immediately. read more

Building Efficiency installed insulation into my 1800 sf San Francisco house (which had no insulation prior) at the end of 2021. Insulation was installed both into the exterior facing walls (via holes in the interior drywall) and into the very low clearance attic crawlspace (maybe 1.5-2 feet of clearance). They were willing to crawl in the very small attic crawlspace to get the insulation installed - which was impressive b/c the clearance was so low. Day-to-day life in the house is completely different. The temp is actually regulated. Heat no longer dissipates immediately after being run. The house also doesn't get super hot when the sun shines on the walls. In the dead of winter we used to sleep with wool hats on - no longer! (We've never run the heat at night at still don't.) I actually only use a light sheet when sleeping at night now - even when it's cold. It really is the single best thing I've ever done to this house and I should have done it much sooner. It's as life changing as anything you can do to a house can be lol. I was concerned about having holes drilled in the drywall but they matched the texture of our drywall (skip trowel texture) and you absolutely cannot tell at all that there were ever holes in the drywall. I also got my BayREN rebate timely to help offset some of the cost. All in all a great experience. read more

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These free "consultations" are limited to offering paid services provided by the company - they are not about maximizing the energy efficiency of your home. In addition, after a month of waiting for an appointment, I had my consultation was told that an estimate would come in a week. After two months of waiting for an estimate - and several unanswered phone calls and emails - I still have not heard back from the company. If the company was too busy , unable or uninterested to provide services, they could have simply written an email to inform me. Instead, I have wasted months of my time when I could have sought help elsewhere. read more

We wanted to do energy efficiency upgrades, but didn't know where to start or what we needed. David helped us put together a long-term plan and figured out what we needed. They put in wall insulation, redid the attic insulation, removed our gas furnace and air conditioner in the garage and installed a heat pump in the attic, and installed a heat pump water heater. At some point we'll have them get our crawl space in order too. We are finally on the verge of being 100% electric and removing our gas line! He teams handles all the permits and rebates, and has been patient through all of out delays with PG&E. I don't know anything about this stuff, but the building inspectors have been impressed with both the equipment and the installation work, so I take that as a good sign! read more

I had Building Efficiency insulate my home. They did an amazing job - really professional, kept to their schedule, was really tidy and covered all the furniture (they even helped me move some of the furniture) and cleaned up each day. I also had them paint our interior which was even better than before. So glad we had this done before winter and makes a big difference (our home is warmer each morning) and we even got an energy rebate. Would highly recommend these guys to anyone. Great price and really professional. read more

Building Efficiency - Play room during insulation work - Heating & Air Conditioning/HVAC Near Me - San Francisco, California

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Our heat exchange system had been damaged by another company during some electrical mods to our solar panel breakers, and David Hamburger and crew showed up to quickly and efficiently diagnose and repair the problems, which gave us back our heat during a very cold winter's week! Couldn't recommend Building Efficiency more highly----very professional service! read more

This is a bit delayed, but I worked with David last July/August to insulate my 1960s house, with blown in insulation on the exterior walls and in the attic. Overall, I had no major issues and think everything was done professionally to a good standard. The house was built without any insulation and that made winter/summer miserable since the house temperature would swing so much to match the outside the temperature. I knew that I wanted insulation going into things, but I think the insulation projects they recommended were the right recommendations (they didn't oversell me anything) and they did fix my problem: my house is now much warmer in winter and more comfortable! Random thoughts on other things: the pricing was fair and competitive, the scheduling and communication was responsive (usually getting back to emails within a day and most scheduling for the work was within a few weeks) and the quote and instructions had plenty of details around what to expect. The work took about 5 days (one week monday to friday) and the work crew was always starting on time around 8AM and finishing by 4ish. They some random questions by me well and took good care of my house and with cleanup at the end. For the work of drilling the holes into the exterior wall and blowing in the insulation, they helped me a bit moving furniture around and did a great job taping plastic down to limit dust/debris. And David did specifically schedule a time to come by after everything was done to inspect things and checkin with me, which is good. read more

David and his team are incredibly professional, experts in their field and very easy to work with. They insulated the attic, installed a heat pump with all new duct work and also installed a heat pump water heater. My 110+ year old SF house has a new lease on life! read more

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David runs a wonderful service, whose efforts I enjoy every minute I'm home. We have a decent-sized house built in 1937 with minimal insulation. Basically, this consisted of outdoor cladding, wood framing, about 6 inches of open void, and then drywall. That meant our home was chilly whenever it was cold out and scorching whenever it was hot because the house has no adequate way to maintain temperature. David personally came over and did the project estimation, which included adding blown-in eco-friendly insulation into all the exterior facing walls and the ceilings. He also scoped out a new, much more efficient furnace for our home and redoing all our heating ducts. Communication was prompt and courteous, and the pricing seemed very fair, considering the scope of the project. The Building Efficiency team included about seven very courteous people divided into the insulation and furnace work. They took a lot of time to carefully cover areas from dust and cleaned up every day during the project. The entire job took about a week and a half. They even loaned us a pile of space heaters so we wouldn't be uncomfortable while the furnace was being replaced. Now our house feels practically tropical during the winter. We can set a temperature on the heater, and the house holds that temperature effortlessly. We've experienced some cold nights this winter down to 45 degrees, but we're nice and toasty. As a bonus, the new insulation also does an excellent job of dampening the outside sound. We're warm and peaceful inside now. As a final bonus, we received a rebate from BayREN for making our house more efficient, which knocked another 15% off the final tab. You spend a lot of time in your home, so why not make it as comfortable as can be? Thanks again Building Efficiency! read more

Highly recommended. David and his team are all very professional and knowledgeable. From the virtual review of my project all the way through to completion, everyone was helpful as I navigated the very complex topic of electrifying my hot water and heating system. All members of the team were friendly and patient with my numerous questions. They also were responsive every time I reached out and they completed the project within the timeframe they estimated. If you are doing any energy upgrades or electrification projects, I highly suggest you reach out to Building Efficiency. read more

They promised a quote within 7 days, but it took 12 days. They did not keep me updated, and their [former] office manager stopped responding to my emails. When I finally did get the quote, the price was fair, but it was too late. Their competitor delivered a quote after only 1 day. read more

We used Building Efficiency to make our house more energy efficient. 5 stars for the following reasons: Tailored approach: We wanted to undertake a project and Building Efficiency gave us two options, one that suited our immediate needs and was more budget friendly. The other approach was comprehensive and more expensive. We didn't feel pressured / they did not try to upsell (unlike other vendors). They did not provide the most competitive quote, and the quote included the energy rebates (which we were not aware of). While building efficiency wasn't the best price, we decided to move forward with them because we liked them the most. They were very responsiveness: I reached out to building efficiency for an initial consultation/estimate and they responded within a day. My husband and I had multiple questions throughout the process and David was very patient and answered all of our questions. We wanted to move fast and they were able to fit us into their schedule. We ran into a few hiccups where we had to stop and they were very accommodating. Communication was easy: it was very easy to reach David and Alex via email, text and phone calls. Again, we had a lot of questions (both technical and logistical) and they answered all of them. Direct and honest: we ran into a few hiccups where we had to delay the work for electrical work. David was more than helpful, recommending an electrician and telling us what his other clients did. There was a mix-up with the billing, and David was honest and upfront with us. We understand that mistakes are made and appreciate that he was honest, accepted responsibility, and suggested a solution that worked for both of us. Great work: my husband is happy with the quality of the work. I'm happy with the crew. They arrived at 8am every day and left the house in the same way they found it. They cleaned up and locked up after themselves. Overall, we are happy with the work and would highly recommend them. read more

The HVAC upgrades Building Efficiency did on my home last February -- high-efficiency furnace, all-new ductwork, and R44 attic insulation -- have made a huge difference! For starters, I was considerably cooler inside the house on hot summer days; I didn't even realize the weather was hot until I stepped outside. As for the cooler seasons, PG&E sent me an email in early December to say that I used 49% less energy during the last billing period than I did during the same period last year. Of course, it all depends upon how cold it was this year vs. last year, so I'm continuing to keep an eye on the difference ... but it appears the savings are substantial. I am a very happy -- and far more comfortable -- camper! I highly recommend Building Efficiency for your HVAC needs. read more

I've hired Building Efficiency on several occasions for energy upgrade related projects for my home, and they've never disappointed me. They are always responsive, on time, on budget, and do exceptional work. read more

Had my house insulated and David and Alex were always very professional. They worked with our schedule and did everything in a timely manner. Would recommend! read more

I contracted Building Efficiency to install a central AC in my house. The company is a member of BayREN (bayren.org) which makes some of their services eligible for rebates. David, the company owner, is very knowledgeable and can help with a variety of additional services such as duct layout, leak testing, permitting, etc. However, you need to do your own research to figure out what services you really need. Their installer guy, Beto, is the best. He installed my AC like he would in his own house. For example, he ran the electrical line in the crawl space rather than in the attic because he felt it would look nicer. I did not insist on that because my crawl space is really tight but he wanted to do it that way. He patched every hole and calked every gap, not only adding new equipment, but improving on what I already had. I wish every contractor worked like Beto. All in all I had very good experience with Building Efficiency. The only negative is that it took a little while to get initial response from them and schedule the job. They are a small company that does very good job so they are pretty busy.  However, once they gave me the starting date they showed up on time and finished the job on schedule. read more

I want to echo the many positive comments that have already been made. Building Efficiency were initially one of the more responsive contractors that I called, and David Hamburger came round to have a look at our house. He also sent a colleague for another free consultation at my request because I really didn't know what I needed at the beginning. In the end, we decided to do much more than simply replace an existing furnace. Instead, we upgraded the electrical (which they don't do, but they recommended another great company who did: Wells Electrical) to accommodate a heat pump to replace our two(!) old furnaces, removed and remediated the old asbestos ducting (which was sub-contracted very cheaply and efficiently), added all new ducting, a new heat pump hot water heater, and insulation. Throughout the whole process, there was no stress, rush, or forced decision-making. We're still working on the finishing, so I can't comment on that yet. Overall, I really felt like David was trying to help me navigate my options, rather than trying to sell me on something I didn't really need or want. I know a lot of folks try to do that, but very few succeed so well. I would strongly recommend getting a quote from Building Efficiency - they put themselves in the customer's shoes even though they really know what they're doing. Here are things I really appreciated: 1) The estimate was really well itemized, with all my options laid out so I could pick and choose the right thing for me and my family. There were no big surprises, so they came in right on budget, despite waiting for a supply chain issue that took longer than expected. 2) The start of work was delayed (see above) and in the end we had to substitute for a different heat pump, which had different electrical requirements, but it was all resolved very smoothly. 3) Once work started, it was quick, pleasant and clean - all over in less than 2 weeks. The crew were really nice and seemed very efficient. 4) The results have been dramatic: Our house is much more comfortable AND quieter. No more forced air alternating bouts of sweating and shivering, just comfortable all the time. read more

I have an old multi-unit building that we discovered had no insulation in the top floor attic. There was minimal access and only about 30" of height to work in. Building efficiency figured out all installation issues, the best type of insulation to use, and did the work at a fair price. The installers were on time (actually early), respectful of tenant concerns, cleaned up and completed the job earlier than anticipated. I was most impressed with their full assessment of the larger and more complicated issues (heat, furnaces, duct work and more) and the thorough written estimate that included various options. The insulation might be only the first step. Once I assess the impact of the insulation on gas usage, I suspect I may need more work done and will, of course, call building efficiency again. read more

We have a 1939 Sunset mass produced home. Up until we talked to David and Building Efficiency, we had an original gravity furnace and no insulation, meaning if we wanted our bedrooms at 65F, the front of the house (and garage) were 80F, and we were spending $300+ a month on natural gas in the winter. Now, we're spending $45 a winter month on natural gas, and the home is comfortable. David's team took just over a week, and put in insulation in the attic, above the garage, and in the walls. They also replaced our gravity furnace with a modern furnace. The work was done on time, as described, on budget, with great communication. We also got a strong PG&E rebate. I recommend insulating your home, and Building Efficiency is a great company to do it. read more

Building Efficiency replaced our furnace and upgraded the duct work in our house, and we couldn't be happier. Dave was easy to work with, gave an honest assessment on our project, never tried to upsell us, worked within our parameters, and was great at communicating. His crew was also fantastic, working quickly and doing a thorough job while keeping our place tidy. The project took place during covid-19 shelter in place and while we were working from home, but we barely knew they were around. And Alex, the office manager, made the contract and paperwork easy. I highly recommend Building Efficiency to anyone considering getting any HVAC or insulation work done. You won't regret it! read more

I had David and his team come in to replace my old gravity furnace with a high efficient, two-stage hanging furnace. They handled everything from coordinating the asbestos abatement to installing all new ductwork and hanging the new furnace. Everything was on time and the final work was clean and very professionally done. They also helped do the PG&E energy rebate, which included doing the energy audit and helping file all the paperwork needed for me. Overall, excellent work and I would highly recommend them again. read more

Buliding Efficiency did an A+ job. I just bought a 100 year old house and needed a new furnace as well as new ducting. They also installed a flue for my water heater. It was a big job. They were incredibly professional and very responsive. I was well informed throughout the entire process. They were also able to get me a significant rebate from PG&E because my home was a lot more energy efficient. I did a ton of research on different companies and found them to be the most affordable as well. (You'll find that a lot of HVAC companies are also pretty non-responsive and don't follow up) After a week, the fuse on my furnace blew and wasn't working. It was a foggy and cold night and I didn't know how to replace the fuse. I called David up and he came over at 9pm to fix just so that my family would have heat. He went above and beyond. In short, super happy with them. read more

We just had a home energy audit done by the people at Building Efficiency. If you're thinking of making any major modifications to your house in the near future or you just want to save some money on your energy bills, then you should get this audit done by Building Efficiency. They will help you determine where it is best to spend your money and they will also tell you the little things that you can do yourself. David, the analyst who came to our home was bright, professional and friendly. He was careful of our things and didn't mind my two little kids asking him lots of questions and following him around the house. He was extremely thorough from the moment he walked in the door. He explained everything that he was doing and invited me to tag a long a few times to see some of the places that my house was leaking hot air. At the end, he sat down with me and talked about all the areas that were causing the most problems with heating and cooling our house. (A report is to follow). Some of the other companies that I called took more than a week to get back to me, while others just didn't want my business because I live in the south bay. read more

Last year I attended a informational meeting about the rebate program offered by PG&E and the city of San Francisco to make our home more energy efficient. We have the typical 90 year old home with zero insulation. We chose Building Efficiency as they are one of the license contractors who work with the rebate process and know how to get he most bang for your buck with the process. The process itself is not much fun. They poke holes all over your home and blow in insulation, the dust and mess that ensued was simply overwhelming to me. This process lasted about a week, they tried as best they could to clean daily but it's an impossible task. At the end of it all, they bring in a professional cleaning crew to take care of the rest. These guys did an amazing job. They were super communicative during and after the entire process and even did some things they didn't have to do to make my home both safe and more energy efficient. My first gas bill after the installation was already $100 less and that was just for 1/2 of the month. While there's no way to get around how messy and disruptive this process is (unless you stay in a hotel for a week!), I'm glad we chose to have it done and do not hesitate in recommending this company to be the ones to do it. read more