Business Details
22 Years
experience
Expert Window Insulation and Soundproofing Solutions
Castle Window Covers has been revolutionizing window insulation and soundproofing solutions since 2004. Our innovative acrylic window systems, derived from aerospace technology, provide superior thermal efficiency and noise reduction while preserving the aesthetic integrity of historic and modern windows alike. With over two decades of specialized expertise, we deliver cost-effective alternatives to window replacement, serving residential and commercial clients across California and Nevada. Our patented magnetic installation system ensures seamless integration with existing windows, offering energy savings of up to 50% while maintaining 97% UV protection.As industry leaders, we combine technical excellence with customer-centric service, evidenced by our extensive portfolio of historical preservation projects and partnerships with major brands. Our commitment to quality is underscored by our certification with the California Department of General Services and membership in professional construction organizations.
Services
Window Insulation
Soundproofing
Commercial Blinds
Antique Window Preservation
Custom Window Treatments
Details
- Year established: 2004
Highlights and features
- We've specialized in window insulation since 2004 with proven energy savings
- Our patented acrylic system outperforms dual-pane windows at half the cost
- 70% noise reduction using aerospace-grade materials
- Preserve historical windows while meeting modern efficiency standards
- Certified by the California Department of General Services for quality assurance
Associations and certifications
- California Department of General Services
What people say
Noise reduction
Temperature stability
Cost savings
Historical preservation
Easy installation
Services
Window Insulation
Our acrylic window covers create an airtight seal that maintains indoor temperatures year-round. By preventing heat transfer through glass panes, we reduce energy consumption by up to 50% while eliminating condensation issues. The system preserves window aesthetics while delivering performance exceeding dual-pane windows at half the cost.
Soundproofing
Using aerospace-grade acrylic, our soundproofing system blocks 70% of external noise. The vibration-dampening material outperforms traditional glass windows, creating quiet environments in urban settings. Installation maintains window functionality while providing commercial-grade noise insulation for homes and businesses.
Antique Window Preservation
Specialized solutions for preserving historical windows without replacement. Our non-invasive system protects against UV damage and humidity while maintaining original window integrity. Compliant with preservation regulations, this service extends window lifespan and enhances energy efficiency in heritage buildings.
Commercial Blinds
Custom commercial window treatments for offices and retail spaces. Our Draper product line offers solar control, privacy options, and motorized systems. Solutions combine durability with energy efficiency, available in vertical blinds, roller shades, and solar shades for large-scale installations.
Custom Window Treatments
Precision-fitted window systems for unique architectural requirements. From odd-shaped windows to historical preservation projects, our magnetic acrylic covers provide seamless integration. Custom options maintain structural integrity while delivering modern performance standards across residential and commercial applications.
Questions
How does your window insulation system work?
Our system uses acrylic panels with magnetic edges that attach to installed frames, creating an airtight seal that prevents heat transfer and reduces noise transmission through existing windows.
Is your solution more cost-effective than replacement windows?
Yes, our system costs about half as much as replacement windows while providing superior insulation and soundproofing performance, with installation completed in hours rather than days.
Can you work with historical preservation requirements?
We specialize in historical window preservation, offering non-invasive solutions that meet regulatory standards while improving energy efficiency and noise protection without altering original window structures.
What energy savings can I expect?
Most customers experience up to 50% reduction in heating and cooling costs through our system's superior thermal barrier that prevents air leakage and heat transfer through glass panes.
How is soundproofing achieved?
Our acrylic panels vibrate less than glass, absorbing 70% of external noise. The material, used in jet aircraft windows, creates quieter environments in urban areas while maintaining window functionality.
Videos
Reviews (6)
Cameron C.
Jun 04, 2022
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Ken provided excellent service with a really great product. My room is facing an extremely loud street with Muni and lots of street noise outside. These window covers blocked way more of the noise than I was expecting- easily 60-70%. They are fairly easily detachable when I wish to open the windows. The installation was also quite pain-free. My one complaint is that the magnet is not very strong, so on windy days, which happen frequently in SF, there is often a rattling noise from the window covers partially detaching and reattaching. Other than this, I am very satisfied with the product!
Sean S.
Feb 12, 2021
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We live on a busy street in San Francisco. We moved into a early 1900s building and recently replaced all of our windows with the double-paned ones with a sound package upgrade (windows were old and needed to be replaced - but was most excited about new windows solving the traffic noise). Thanks to SF laws/regulations, many many months and a hefty price tag later.we had new windows but still hear the traffic most of the day and night.
A couple of years ago my neighbor recommended Castle Windows as she had done a ton of research, priced out competitors, etc. and was impressed with the results. I spoke to and price-compared some competitors but felt like choosing Castle was a no-brainer given all of the positive feedback and it was a CA company to boot. Kenn & Denis came to measure my windows and only a couple of weeks later - I've got window covers that you barely notice are there and the traffic noise is significant reduced. I highly recommend this company - quality products that really work and look great.
A couple of years ago my neighbor recommended Castle Windows as she had done a ton of research, priced out competitors, etc. and was impressed with the results. I spoke to and price-compared some competitors but felt like choosing Castle was a no-brainer given all of the positive feedback and it was a CA company to boot. Kenn & Denis came to measure my windows and only a couple of weeks later - I've got window covers that you barely notice are there and the traffic noise is significant reduced. I highly recommend this company - quality products that really work and look great.
Terri R.
May 21, 2020
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I highly recommend Castle Window Covers. I live in a 1928 flat in San Francisco, with beautiful street-facing windows. However, the windows are leaky (visible air gaps) and do nothing to reduce noise on my busy street. I looked into having the windows reproduced, and was quoted $20K, not including the city permit. Additionally, the windows would need to be removed and boarded up while the reproduction work was in process. Instead, I went with Castle Window Covers at a fraction of the cost of replacement.
The window covers are virtually invisible, and have drastically improved energy efficiency and noise reduction in my front room. In addition, Kenn and Dennis were great to work with, responsive and speedy. The window covers are a terrific solution!
The window covers are virtually invisible, and have drastically improved energy efficiency and noise reduction in my front room. In addition, Kenn and Dennis were great to work with, responsive and speedy. The window covers are a terrific solution!
Renas R.
Nov 09, 2019
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I live next to the caltrain station and the noise from the trains were unbearable. As soon as I realized what a bad move I'd made I started looking for solutions. I'm glad I found Caste Window Covers. Kenn, Dennis and Ragnar were amazing and they've brought quiet back into my life. They are super friendly and did a great job installing the covers. Will use their services whenever I move to a new apartment.
Poonam K.
Sep 18, 2019
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I live in San Francisco near a noisy corridor and desperately needed a good night's sleep. I found Castle Windows online and asked them to add sound barriers. I am so thankful to Kenn and Dennis for providing customized window treatment with a quality product. These guys are down to earth and very professional. I got a great deal and am very satisfied. Getting a good night's sleep is priceless and something I cherish everyday. I continue to use their services as needed and always recommend them to neighbors and friends who want to maintain the beautify of their homes while benefiting from less noise.
Jessica P.
May 30, 2019
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These did not work in my apartment. I had double paned windows already installed. Before installation of my window covers, the noise in my bedroom was 45-50 dB C on average. After installation of my window covers, the noise in my bedroom is 43-50 dB C on average. These window covers only appear to maybe attenuate some medium to high frequency noise. They are not affecting overall noise levels. Any rumbling from trucks, etc, does not seem to be reduced at all.
I spent over $3,000 for no reason and wish I had gone with more expensive glass window inserts instead. One reason they may not be working is because they are not properly sealed. There are gaps between the inserts and the surrounding frames. When I asked if they could fix this, they told me "no."
I spent over $3,000 for no reason and wish I had gone with more expensive glass window inserts instead. One reason they may not be working is because they are not properly sealed. There are gaps between the inserts and the surrounding frames. When I asked if they could fix this, they told me "no."
