NetZero Insulation

I feel lucky we found these guys. Very approachable, thorough and absolute professionals. We used them for blow-in insulation and whole house fan removal. They were more affordable than other companies we vetted and they did an amazing job!

NetZero was a tiny bit more expensive but by far worth every penny. They were thorough, professional and easy to work with. The work was completed on time and we can't believe the change in the comfort of our house. They took the time to prep everything and protect our belongings. The crew was polite and friendly. We highly recommend them.

Would definitely recommend this company. They encapsulated my crawlspace and did a fantastic job from start to finish, including cleanup. There was a slight issue with the curing of the closed cell foam in one of the spots and I called them and they came back within a couple days and fixed the issue right away. Loved the work they did at my previous house that I hired them to fix some things in my new house...specifically with issues related to two bedrooms over a garage that were cold in the winter and hot in the summer. Since the work was completed, the rooms are much more comfortable now!

Cannot say enough good things about this company and team. Extremely professional and knowledgeable throughout the process, from initial consult to final cleanup. Really appreciate their explaining energy audits and handling the rebate, too. Having worked in and with the trades most of my career, this is one of the best teams I’ve worked with. Strongly recommend NetZero to anyone needing their services.

I contacted NetZero to get a quote on updating the insulation in one part of my house. I received a detailed quote from Ryan that included my original ask, and an update to the other attic spaces in the house including air sealing that was cheaper than just the one service due to Ryan's comprehensive knowledge of the rebates offered by Xcel and the federal govt. Ryan and his team completed a full update to all my attic space insulation (knee walls, air sealing, updating to R60 insulation) for the same cost as me finishing one space DIY. His large team came in and finished the improvements in one day and cleaned up so well it was like they weren't there. One month later, my electric bill is down 29% and my gas bill 10%. Best home improvement purchase I've made to date!

Used NetZero for a crawlspace encapsulation (before getting radon mitigation). DJ and 5 dudes came out, cleaned out the entire crawlspace (~200sqft), fully encapsulated it, AND CLEANED UP AFTER within 2 hours. I can't state enough how painless the process was and how easygoing everyone was. Easily the best company for the job!

From start to finish. NetZero was an excellent company to work with and the results were outstanding. From removal of the old, sealing the attic, and then adding the insulation to all communications. Done right the first time.

We had an excellent experience with Ryan and his crew at NetZero Insulation!! 10/10, I would recommend them to everyone! We had 3 insulation jobs completed - 1) attic, 2) crawl space and 3) sunroom ceiling. We had the 2-4” of old rockwool insulation from the 70s removed, the attic air sealed, and installed 20” (R-60) of fiberglass into our attic to receive the rebates from Xcel Energy. For the crawl space, they insulated the rim joists with spray foam and installed R-19 blankets along the foundation wall. Finally, they blew in fiberglass into each joist into our sunroom ceiling. Not only was NetZero 1 of 3 companies that give the rebate up front, he was the only company that gave the accurate rebate amount based on the complicated formula Xcel requires, saving us thousands!

Over the summer of 2025 I took bids on re-insulating the attics of my 70s house. Excel Energy was offering bonus rebates so a good time to get it done. I got four bids and all were within the same ballpark. However, none of the other bidders wanted anything to do with removing the old insulation or dealing with the Excel rebates. Net Zero’s bid included both of those items for the same price. On work day they showed up with a LARGE truck with all kinds of gear and a crew of 5. They were totally professional throughout the process and did a great job of protecting the interior of the house. I am so glad I chose Net Zero for this project!

Delivered as promised! Thank you NewZero.

We had a great experience with Ryan and team. From the initial quote, to the execution of the project. The team was very thorough, took the time to explain the before and after and left it spotless. Highly recommend them!

Ryan is the best home contractor I've worked with. He is incredibly thorough with his explanations of what is needed, priced fairly, and stands by his work. I'd highly recommend NetZero if you need any work done.

NetZero air sealed my attic/garage and installed new insulation lat week. I was skeptical on how much we’d really notice, but the temperature difference of my top floor and rooms over the garage has been incredible. Ryan and team were incredibly clean, professional, and quick. They operated in unison with each of the 7 workers knowing exactly their role. Very impressive company/staff. Highly recommended!!

We used NetZero Insulation for our previous home in Lone Tree and were incredibly impressed with the pride their team has in their work, as well as their competitive pricing. They installed insulation in my parents' home in Castle Rock, and in our new home in Castle Rock. They finished last July, our Nest noted that we used 80 hours less AC in August compared with July. Our home is SO much more comfortable, and the noise insulation has increased dramatically as well. Our family highly recommends Ryan and his team at NetZero.

Ryan and his crew did an amazing job sealing up our very complicated crawl space for a radon mitigation project. The team was polite, efficient and some of the hardest working folks I have ever seen. Ryan was super communicative and provided perfect customer service from start to finish. Highly recommend!

Sean and his team did an amazing job removing and installing new attic insulation. The house was built in 1959 and the attic insulation was a mess. After removing the old insulation and sealing and blowing in new insulation, the house is more comfortable than ever. No more cold drafts and I expect to see my energy costs drop. I got bids from multiple companies and Net Zero was more than fair and quick in every response. Couldn't recommend them more!

Ryan and his team did a great job. Exceeded my expectations. All the work that was done very timely. My home is So much more comfortable now, and it Will be even more efficient with the new Energy, saving furnace I installed recently. Thank you To the net zero team for doing such a wonderful job. I highly recommend them for any insulation work that needs to be done.

Great professional service from the initial estimate all the way to completion of the project! The humidity is don and I’m already seeing a difference in the amount of times my heat turns on! Thanks again

I asked NetZero to let me know if they noticed any issues in my attic between removing and installing insulation. They said everything looked great! Forgot to mention mold and TERMITES. Fast forward to a year late I’ve had to remove all the insulation to remove the extensive web of termite nests throughout the eaves of the attic, the worst parts are where NetZero air sealed exhaust vents to the nests. !! How could they not have noticed these giant “mud piles” throughout the attic when they were face first with them?

These fine folks did a great job and I highly recommend them for your insulation needs. They were punctual, communicative, and respectful of the property, all while maintaining affordability!

Net Zero recently finished a garage project for me and it has made a significant improvement to my uncomfortably hot 1929 vintage garage. This is the second insulation project since 2021. The first was attic insulation in my 1929 bungalow which has made the house more comfortable in the summer and winter. Owner, Ryan Donnell is a pleasure to work with. His experience and knowledge were invaluable in making decisions about how to approach an insulation project. He is honest, dependable, and friendly. Ryan was always available to answer any of my questions and was able to recommend another contractor to add drywall to my garage project. Both insulation projects were completed efficiently with the highest quality materials. I highly recommend NetZero and Ryan Donnell for any insulation projects.

So fortunate to have found Ryan, Shaun and his team at NetZero. In our 25-year old house we had severe air leakage and inadequate insulation. NetZero completely transformed both attics and took care of both the air and insulation issues left by the original home builder. Couldn’t be more happier with the team’s knowledge, professionalism and the ability to fix the problems correctly. They know what they’re doing!

Editing to add that I've used NetZero again in 2024 for my new house. Excellent work by Ryan. THANK YOU!! Original post 5 years ago: We had a wonderful experience working with Ryan and Sean and their team to seal the attic, replace attic insulation, and install a whole house fan. It was clear that Netzero cares about their work and cares about their customers. Strongly recommend.

We highly recommend NetZero Insulation. Ryan came to our home and gave us a detailed description of the process they would use to upgrade our insulation in our upper and lower attics. We received his bid the same day. Other insulation companies did not compare to Ryan’s knowledge and expertise. Ryan’s team arrived on time and they were pleasant and professional. They protected our floors and cleaned the work area before leaving. We are very pleased with the results. Ryan took care of the rebate process through Xcel Energy and the rebate amount was deducted from our payment.

Ryan and his team are amazing people and very good at what they do. I have used them on numerous projects and have always had fantastic service.

Fantastic company. Work was done professionally in the timeframe they said. The owners explained everything to us and were super helpful and communicative throughout. Thank you

Very happy with the job that Net Zero Insulation did. They were cost competitive and did a clean professional job.

We used NetZero to reinsulate our attic. The quoting process was easy, pricing was very reasonable, and the entire team was both professional and courteous. They made this process very easy and we could tell the difference within days.

Ryan is an amazing human. He has gone above and beyond in ways that have been incredibly beneficial to me. He is a knowledgeable, kind, professional businessman and I am beyond thankful I found him!

NetZero did a thorough job replacing our home's attic insulation. We contacted them initially to set up a quote and Sean came out to see the home. Despite not having attic access Sean properly assessed the current inadequate insulation and prescribed a reasonable plan to address the situation. Within 24 hours I received a quote where local Xcel rebates were already applied and would be handled by NetZero. Their quote was in line with other businesses but I felt assured by the thoroughness of Sean's walk-through and the details of the job we discussed. We set up the job for two weeks later. Sean arrived with his crew right on schedule in the morning. He reviewed the work with the crew and lead and reviewed everything again with me. The crew laid down floor protection and covered up furniture and equipment in the room where they were working. Throughout the day the crew lead, DJ, was communicative and friendly and everyone was working like crazy. A little after midday they had completed the work and walked me through everything they'd done in detail by showing me pictures of all the sealing, duct connecting, foam, and blow-in insulation they added. The work looked sharp and thorough. I was worried that there'd be some clean-up, especially since they were cutting two attic access points, but when they left everything looked as clean as before they arrived. Even the work on the attic access cuts was clean and looks good. Finally, immediately we've been able to tell the difference with our home holding temperatures much more steadily. We used to fall into the 50s every night and now the house holds a much higher average temperature. We can already see lower usage on our utilities online tracking and the furnace kicks on much less often. Highly recommend NetZero insulation! Thank you Sean, Ryan, DJ and team.

Thanks to the Steve's and Mya we have a warm house! Great work, definitely take pride in what they do, highly recommend!

I cannot say enough good things about this company. Professional, honest, more than a fair price, excellent work ethics, on time, polite, did a great job and cleaned up afterwards. Ryan and his crew were wonderful. I will definitely recommend this company to friends and family.

Netzero did our air sealing and attic insulation - they were great! Ryan was super helpful and knowledgeable including giving tips on other ways to make our home more comfortable and efficient.

I'm in the early phases of exploring improvements to my attic sealing and insulation. Ryan came out to evaluate my home and make recommendations. Having myself had years of mold-related illness and being more aware than average about indoor air quality (IAQ) and how important it is for optimizing health, Ryan blew me away with his knowledge. He is the real deal, and I feel very happy to have found him to assist me with improving my own air quality. Update: Ryan's team sealed and re-insulated my attic. They were a well-orchestrated machine working together seamlessly. I wish every vendor was as skilled and professional as they were. They even vacuumed after they were done and worked in my home as if it were their home. I can't say enough about how impressed I am.

Ryan (NetZero) is one of the best vendors we've had the pleasure of working with. His professionalism is matched by his extensive knowledge in the field and building science. I couldn't recommend them more for all your insulation work, this is not your typical insulation company. His team is top notch.

I looked at close to 10 different insulation contractors before coming across this team. They do great work and are very knowledgeable. They take care of your home as if it were their own and do exactly what they say they are going to do. I would highly recommend!

Doug and net zero insulation is the best Clean and prepared to work. Great job.

I had my attic insulation removed and re-insulated by Netzero. I do a lot of research before I hire anyone to do a project, and Netzero checks all the boxes. The owner, Ryan Donnell, showed up at the scheduled time to look at our project, and he was very professional and knowledgeable. We received the quote within 24 hours, and it was reasonable for the amount of work that needed to be done. He put me on the schedule, and he contacted me a day before the project. They showed up on time, and D.J. and his crew did a remarkable job. I was amazed by the whole process from start to finish. The almost 70-year-old rock wool attic insulation was no doubt the nastiest stuff I've ever seen, and they efficiently removed all that nasty stuff. When they were done with the removal process, they air sealed the entire attic. D.J. wanted me to check out the work, and all I can say is they all really take a lot of pride in their work, and it shows in their attention to detail. Even when they sealed up the attic access wall, they didn't like the way it looked, so they covered it in sheet foam. Now that our house is insulated to the correct depth and air sealed, it feels much more comfortable. Also, we used to hear a lot of road noise from the nearby highway, and the noise level has dramatically decreased. Thanks, guys, for making our house comfortable again.

Called the company, left message and filled out contact form. No answer.

The NetZero boys just finished encapsulating my crawl space and did an outstanding job. I have two separate crawl spaces, about 1300 Sq Ft in total and they knocked out the job in about 6 hours. The work included the vapor barrier install and insulation of the rim joists and foundation walls. The crawl space is clean and now can be used as proper storage. I'm really glad I found this company as they provided both great work and really good value. All that really has to be said now is, Yes, I would hire them again.

NetZero? They showed be called NetPlus ! Best Insulation Company in Denver metro area !! Ryan the owner showed up on time for the bid and job ! All the guys were great to talk with ! They were honest, hard working and cleaned up very well ! Even took pictures of the work they did ! Not all company's do that !! My house is much more comfortable ! Hiring these guy's anytime I need anymore work on my house !

No matter how many times you call they never answer their phone.

From initial contact to saying goodbye to the crew after install working with NetZero was a net plus. After the Marshall Fire we needed to have our insulation removed and then replaced: Ryan, the owner, was polite and professional but more important to me is that Ryan had excellent communication and was so respectful of our family's particular mitigating circumstances. I have to give a particular shout-out to the crew who came to do the work in our large attic ... in July. They arrived early and worked quickly, cleanly, quietly. To a one they were sweet and totally respected that we have a medically fragile child and indoor-only cats. Ryan and DJ, the foreman, were also proactive in filing all the paperwork, making less work for me (which I absolutely appreciate!). Without reservation would I recommend NetZero.

NetZero removed all of my old attic insulation (70 years old), air sealed, and blew in new fiberglass insulation all in just over 3 hours. Ryan and his team were excellent to work with from start to finish and the pricing was fair. I would highly recommend working with Ryan and NetZero for any insulation projects.

I can't say enough positive things about this company. Over the past 2 years we've asked them complete 3 different projects. 1) add blown-in insulation and foam seal our attic; 2) foam seal our basement; 3) add blown-in insulation for soundproofing. First, they are very competitively priced. Also, they always arrive on-time, are extremely professional, and quickly respond to my many questions. During the estimate phases, Ryan always does a great job explaining, in layman's terms, the benefits of different options. DJ, Javon, Christian, and Kike always do a great with installation, so much so that we received the highest possible rebate from Xcel Energy upon completion of the attic project (a nice surprise and unexpected because our house is 26 years old). Prior to having the attic done, our furnace or A/C would run as much as 10-12 hours a day (there were times it would literally run all day). Now that the foam sealing and blown-in insulation has been installed, the A/C only runs 4-5 hours per day (on hot 90 degree days) and the furnace only runs for 5-6 hours per day (on cold 10 degree days). We were debating between remodeling our bathroom or foam sealing and insulating. A year later we're SO glad we had NetZero make our house more energy efficient and comfortable. Our gas and electric bills usage has gone down 25-30%, and we don't have drafts like we did before. It's so nice to live in a comfortable house. As a side note, I learned at the end of the job that Ryan has an engineering degree.

I reached out to Ryan at NetZero Insulation to address some insulation issues with our attic and crawlspace areas, and he responded quickly and professionally. Proposal was provided the next day and was very thorough and reasonable. Communication has been great even throughout the holidays. Would highly recommend NetZero Insulation for any insulation needs. -Robert M

I can't say enough good things about Ryan and his team. Absolute class act. I had them install a vapor barrier in my basement and add more insulation in my attic and add spray foam. It's been a few years since they installed everything and the house has been noticeably warmer in the winter and cooler in the summer. I have no doubt we're saving a lot of money on our electric bills as a result. And recently I noticed the vapor barrier was coming off the wall in an area in the basement where some other workmen had walked on it, and Ryan and his team came back and fixed it for no charge. It's hard to find people that stand behind their work like Ryan does. Definitely don't hesitate to have these guys do the work for you! Thanks again Ryan!

NetZero sealed and added insulation to the attic and encapsulated the crawl space in one day. Ryan the owner was there to get the job started and the crew knew what needed to be done and had everything required. I would definitely recommend NetZero to anyone looking to make their home more energy efficient.

Ryan and his crew at NetZero were amazing! They installed insulation in our attic. Our house was built it 1901 and was very drafty. With all of the work that NetZero did. We are able to keep our home comfortable. It stays cooler in the summer and we're positive it will stay warmer in the winter. Ryan explained what our house was needing and the solution options we had for fixing it. He is very knowledgable and shared his experiences. We would recommend this company to anyone!

We solicited bids from two contractors to seal and add insulation to our attic spaces. Ryan at NetZero, and all his employees, were professional, knowledgeable, efficient, and considerate. NetZero’s quote was detailed, comprehensive, and clearly explained, and his price was the best. Ryan allowed us to pick and chose work items from his quote that we felt best met our needs and budget. You will enjoy working with Ryan and his team!

We are extremely happy with the professionalism and care Ryan and his team worked with from quote to install. The team you could tell cared about their work even vacuuming up after themselves. We had them do the attic and crawlspace, very glad we ended up adding on the crawlspace. They had pictures of the whole process, and were very detailed with all the info and items we should follow-up with. Couldn't be happier!

My construction company was finishing a large basement in Lone Tree and we used Ryan and his team at NetZero to fill in all the ceiling joist cavities, soffits, and bedroom walls in order to control sound between the floors and bedrooms. Ryan's team was there on time, did what they said they were gonna do in an unbelievably timely fashion, and cleaned up when they were finished. In addition, the communication during the weeks leading up to the project was stellar in order to make sure things happened when they needed to happen. You won't be disappointed in the quality and professionalism of NetZero.

The MOST professional company you will find! Ryan educated us on all of our options, services were well explained and they delivered beyond expectations. The entire team was friendly and respected our home like it was their own. Thanks again!

Top 3 contractors we've ever worked with! Ryan and everyone on the crew was a pleasure to work with. They were fast, efficient, clean, and the quality of the work was top notch. With how old the house was, removal ended up costing a decent bit, but after seeing how much trash they sucked out it made sense. They removed everything on a Wednesday, and came back there next week to install which gave me time to take care of some issues before everything got sealed up. The quote we received was the most detailed and specific I've ever seen. With our attic they had to seal up the vertical walls for the finished part and sealed it up tight as can be. They also blew in about 20 inches of insulation everywhere else. The air sealing they did cut our air exchanges per hour down in half. We ended up with great results. House is now quieter, cooler, and we're hoping this winter for it to be warmer and less drafty. During the peak summer days. Exterior temps we're over 100 degrees and we noticed the inside temperature stayed 5 degrees cooler (no a/c). The upstairs room went from getting up to 105 or higher to really no more than 90 degrees. Very noticeable. Would recommend NetZero to anyone and I would encourage you to get a quote. We are very happy with the results.

I worked with Ryan and his crew replacing the insulation in the attic of my mountain house. Even when issues were discovered that caused it to have to be broken into multiple jobs he was always willing to work with me to get the job done. The crew was very friendly and the job was top notch. If ever I have to do more insulation work they will be first on the list of folks I call, and I’d recommend they be someone you evaluate also!

Can’t say enough good things about this company. Sean, Ryan, and their crew were very informative, professional, and responsive. I had insulation and air sealing done back in January, and I’ve been monitoring my energy bill since then. Wow... what a HUGE difference blown-in insulation and air sealing made. We are saving big time on our energy bills. Don’t think twice about going with NetZero Insulation.

Ryan's team was professional and lightning fast with their insulation installation.

Ryan at Netzero is very knowledgeable and professional. We had our house reinsulated in October and the work quality was outstanding. Made a huge difference through the winter. Then in May, when doing renovations, his team came back and insulated newly opened areas. Knowledge, professionalism, responsiveness and quality are exceptional! Highly recommend.

Very impressed with Ryan and his crew. They were hard working and professional. Prices were reasonable considering the quality of the work done. Customer service was top notch...Ryan even returned to address an issue (which turned out to be nothing at all). Would recommend their services to anyone.

I can't say enough positive things about Sean and Ryan. They and their staff are incredible. They arrived on-time, were extremely professional during every interaction, quickly responded to my many questions, and left my house cleaner than when they arrived. During the estimate phase, Sean did a great job explaining, in layman's terms, the benefits of adding foam sealing and blown-in insulation to our attic. He, then, backed up his explanations with facts and figures. Ryan was on-site working alongside and supervising the crew. The guys did such a great job foam sealing and insulating that we received the highest possible rebate from Xcel Energy (a nice surprise:), which was unexpected because our house is only 26 years old. Prior to having the foam sealing and new insulation installed, our A/C would run for 12-13 hours a day (it would literally run all day). Once the foam sealing and new insulation was installed the A/C only ran for 3-4 hours a day and that was on 90 degree plus days. The furnace has never run more than 7 hours in a day and that was during the coldest part of winter (-10 degrees at night and 5 degree highs during the day). We were debating between remodeling our bathroom or foam sealing and insulating. 7 months later we're still so glad we had NetZero make our house more energy efficient and comfortable. Our gas and electric bills have gone down 25-30%, and we don't have drafts like we did before. It's so nice to live in a comfortable house. Sean, Ryan, and their team are best-in-class...a top notch company. As a side note, I learned at the end of the job that both guys have engineering degrees.

We are tremendously impressed with Ryan and his team's professionalism and expertise throughout the process. NetZero completed our attic insulation (including the necessary sealing, etc.) and crawl space (vapor barrier and insulation) with the utmost quality and timeliness. We give NetZero our highest recommendation. Truly exemplary.

Excellent work quality. Their team moved quickly and they were flat impressive in accommodating the unique requirements of our project. They were also technically adept, so we felt that genuinely understood how to make the right decision(s) for our home. They installed sound isolation insulation inside our home, and they also insulated our garages.

Had a very good experience with Net Zero Insulation. Sean and Ryan (Donnell) were both very good about explaining what would be done based on the need of adding additional insulation in the attic and sealing all necessary air leaks and putting in vent baffles for air circulation. The crew also was very good. The additional work qualified for Ecel Energy rebate and they took care of all the necessary paper work. The cost was also reasonable.

Left multiple voicemails and never got a callback.

We had our basement, crawlspace, rim joists, cantilevers, and attic properly foam sealed and insulated to code. One of the two owners was here the entire time. They took pictures and guided us through every aspect including the rebate. They did a thoroughly complete job for a very reasonable price. Dealing with Sean and Ryan was an extremely pleasant experience!

Netzero insulated both my crawlspace as well as attic, which included attic sealing. The owners were onsite during the work and available for questions. The crew was very professional and the owners were very responsive. During the site survey, the owners identified work that other estimators missed and were able to finally remediate issues that have been a longstanding concern. As a result of the work, my natural gas bills were reduced by 10% but, more importantly, there is a noticeable greater comfort level throughout the house...it is less drafty. I highly recommend NetZero!