Architectural Aluminium Windows & Doors in Hertfordshire
Elevate your home with bespoke Cortizo glazing, combining ultra-slim sightlines, energy efficiency, and beautifully bright living spaces. Expertly installed with over 20 years of local craftsmanship.
No obligation. FENSA registered. Direct fitting team
Benefits of
Aluminium Windows and doors.
Advanced manufacturing metrics built for modern residential architecture.
Slim Frames
Maximise natural light with narrower aluminium profiles.
Exceptional Strength
Ideal for larger openings without bulky frames.
Powder-Coated
Durable finishes that resist fading and corrosion.
Thermally Efficient
Modern thermal break technology keeps homes comfortable.
Sliding DoorsCortizo Cor-Vision
Cortizo Cor-Vision
Minimalist Sliding Doors
"Continuous floor-to-ceiling glass with near-invisible frames."
Interlock Sightline
Ultra-slim 20mm visible profile.
Maximum Glazing
Up to 2.5m wide x 3.0m high per sash.
Smooth Operation
Heavy-duty stainless tracks (up to 320kg).
Configurations
Concealed tracks, open-corner, pocket doors.
Sash Casement WindowsCortizo Cor 70
Cortizo Cor 70
Hidden Sash Casement Windows
"Sleek, flush exterior profile engineered for maximum insulation."
Sightline
Hidden sash design hides the opening frame inside the outer track.
Thermal Strut
24mm–32mm polyamide thermal break preventing heat loss.
U-Values
Down to 1.2 W/m²K (double glazing) and 0.9 W/m²K (triple glazing).
Tilt and TurnCortizo Cor 70
Cortizo Cor 70
Tilt & Turn Systems
"Dual-function functionality for optimal airflow and easy cleaning."
Acoustic reduction
Up to 44 dB for city or roadside noise dampening.
Multi-Point Locking
PAS 24 certified security in both open modes.
Technical Deep Dive
Detailed engineering specifications and the benefits they provide for your home.
| Feature | Cortizo Engineering Specification | Customer Benefit |
|---|---|---|
| Thermal Performance | Uw ≥ 0.9 W/m²K (Triple Glazed) / 1.2 W/m²K (Double) | Exceeds UK Building Regs (Part L). Cuts energy bills and keeps living rooms warm year-round. |
| Security Certification | PAS 24:2022 & Secured by Design Approved | Maximum Security. Multi-point locking and hardened frames engineered against levering. |
| Acoustic Insulation | Up to 41–44 dB sound attenuation | Silent Indoors. Blocks external traffic and urban noise. |
| Weather Proofing | Class 4 Air Permeability / Class E1800 Water Tightness | Tested for UK Weather. Keeps wind driven rain completely sealed out. |
| Color Customisation | 200+ RAL Colours + Dual-Colour Finishes | Complete Design Freedom. Match internal interior design while maintaining exterior home requirements. |
Trusted by Homeowners Across
Stevenage, Hertfordshire, & North London
Design A View installs bespoke Cortizo architectural systems in Stevenage, Harpenden, St Albans, Hitchin, Letchworth, Barnet, and surrounding areas..
| Product | Material | Maintenance | Energy Efficiency | Ideal Property | Investment |
|---|---|---|---|---|---|
| Composite Doors | GRP Composite | ★★★★★ | ★★★★★ | Any home | ££ |
| uPVC | uPVC | ★★★★★ | ★★★★★ | Modern & family homes | £ |
| Aluminium | Aluminium | ★★★★☆ | ★★★★☆ | Contemporary homes | £££ |
| Bifold Doors | Aluminium | ★★★★☆ | ★★★★☆ | Extensions | £££ |
| Sliding Doors | Aluminium | ★★★★☆ | ★★★★☆ | Luxury & scenic homes | £££ |
| Flush Casement | uPVC / Timber | ★★★★☆ | ★★★★★ | Traditional homes | ££ |
| Sliding Sash | uPVC / Timber | ★★★☆☆ | ★★★★★ | Georgian & Victorian | £££ |
| Timber | Engineered Timber | ★★★☆☆ | ★★★★★ | Heritage properties | ££££ |
| Porches | Bespoke Build | ★★★★☆ | ★★★★☆ | Home improvements | £££ |
Investment key: £ = Most affordable · ££ = Mid-range · £££ = Premium · ££££ = Luxury heritage
Tony W.
1 month ago
Great company, very efficient and professional. Used them for some complex projects and their work was brilliant. Highly recommend!
Diego de A.
2 months ago
We checked several companies, compared the quotes they offered. Lee offered by the most reasonable price. We trusted positive feedback on internet and weren't disappointed! Guys were very professional, polite, did all the work and cleaned everything up. Well done!
Mahesh N.
2 months ago
We’re extremely pleased with the new aluminium windows Lee installed for us in Hitchin. From the initial consultation through to the completed installation, Lee was professional, reliable and easy to deal with.
The new windows look fantastic and have completely transformed the appearance of our home. The quality of the windows and the standard of workmanship were excellent, with great attention to detail throughout.
We would definitely recommend Lee to anyone considering new aluminium windows in Hitchin. The whole experience was smooth from start to finish, and we’re really happy with the final result.
ANIL S.
2 months ago
We’re extremely pleased with the work Lee carried out installing our new bifold doors in St Albans. From the initial consultation and quotation right through to the completed installation, Lee was professional, reliable and attentive throughout.
The workmanship was excellent, and the finished result looks fantastic. It’s clear that a lot of care and attention went into the installation, and we couldn’t be happier with our new doors.
We would definitely recommend Lee to anyone looking for high-quality bifold door installation in St Albans.
Jody M.
3 months ago
Couldn't fault Lee from start to finish. He was knowledgeable and took time to understand our requirements. Good attention to detail making sure we knew what work may/ may not be required ahead of time.
Installation went smoothly and in no time at all!
He went above and beyond and purchased a new additional latch (toddler proofing) to make sure everything was 100%. We didn't ask or expect it but it was a wonderful, thoughtful touch. Thanks Lee!
Praveen N.
3 months ago
Lee was exceptionally professional right from the beginning. He arrived at the promised time, helped me pick the right door, patiently answered all my questions, and helped me navigate the local approvals. Lee is very responsive and patient. The fitters arrived EXACTLY at the scheduled time, and the door looks fantastic! Pictures attached.
I would highly, highly recommend Lee and the Design A View team. All my future window/door work will go to them as well.
Gareth B.
4 months ago
Lee and the team were brilliant. Really quick to come and quote and helped us make decisions about what we wanted for our budget. The work was done quickly and professionally and we are pleased with the work and it was completed with a high quality finish. Thanks Design a View
Dina M.
4 months ago
Thank you Lee We have just had our new composite front door installed, and had our bedroom window fixed by Paul and George, what a great team of guys, professional cleaned up afterwards
We are very happy with the new door would highly recommend
Cam G.
5 months ago
Great quality service from Lee. Lee spent time explaining different options that would suit our budget. Really pleased with the finished result and would highly recommend.
D4SH
6 months ago
Lee and his team delivered exceptional service from start to finish. Lee provided a prompt quote and completed the work efficiently. This is a highly professional company that I strongly recommend.
Madeleine W.
7 months ago
Lee and his team are fantastic!! Lee helped us with the complete design and installation of all our new windows and doors as well as our new extension windows and doors. Lee listened to what we wanted to achieve with endless endless patience, giving knowledgeable professional advice, going above and beyond to get our order right(Timberlook). On installation day, Lee and his team were reliably on time and made a very daunting project to us a very joyous experience with their great sense of humour and cheerful disposition, taking the greatest care with attention to detail, minimising dust levels and achieving a very high standard of finish internally and externally to brickwork/decor. Would 100% recommend to anybody needing window/door installation.
Edmund K.
8 months ago
We couldn't be happier with the work Lee and his team carried out on our 50s refurb. They took on a full exterior wall refurbishment on one side of the house—stripping back the old cladding, re-insulating, and fitting some absolutely fantastic windows.
What really stood out was how they went the extra mile; when we hit a snag with a shortage in our cedar order, they didn't let it slow things down. They personally drove out to collect the extra materials to ensure the project stayed right on schedule. The attention to detail is top-notch, the house is noticeably warmer, and the windows are honestly in a league of their own.
If you’re looking for a brilliant, reliable team, I can't recommend them enough!
sam H.
8 months ago
Lee at Design A View was brilliant, from initial quote through to installation of my window and door unit. Would highly recommend to others.
Om P.
8 months ago
I recently had new windows and doors fitted by Design a View in Stevenage, and honestly, I couldn’t be happier with the result. From the start, Lee was friendly, professional, and really knew his stuff. He gave us great advice on what would work best for our home without being pushy.
The quality of the work is excellent. The new windows and doors have made such a difference, both in how the house looks and feels. Everything was done on time, with minimal mess, and Lee made sure we were happy every step of the way.
Aduragbemi A.
11 months ago
Lee did a fantastic job replacing all our single glazed windows as agreed. He was prompt and ensured the work was finished timely before the cold snap begins. Having had lots of bad experience with trades people, I can attest that he is a breath of fresh air and trustworthy. The pricing was competitive and did other stuffs without charging at all.
Kim M.
11 months ago
Passionate About Perfection
Its so refreshing to see the whole workforce taking pride in their work. Lead by Lee, his team Lenny and Rory completed a very professional job on our soffit's, fascia's and bedroom dormer cladding. Cannot comment on the longevity of the products as only installed last week but the instillation was completed in a very timely and tidy manner and all the team made us feel like a special customer.
Holly W.
12 months ago
Lee was recommended to us through a mutual friend and we couldn’t be happier. Lee and the boys were friendly, professional, polite and done a great job changing our back and front doors.
Thanks Lee!
Julius A.
12 months ago
New porch built
Lee has carried out porch renovation project from demolition of old to completion. Site was fully managed and tidy, materials turning up when needed and it took no time to finish.It was done to the agreed price also. He had all trades in team so I had nothing to worry about.
Also if you call or text him, unlike most builders, you can reach him!
Would deffinately use him for other parts of home, so highly reccomended.
See phots of before and after!
Jordan
1 year ago
We were introduced to Lee and his team through a garden room company,
He transformed the house inside and out with all black windows and bi-fold door, and the garden room all matching too,
We opted for bottom opening windows in the bathrooms, and when Lee saw our young children he fitted extra safety hinges,
Lee was friendly, professional and hardworking.
Highly recommended!
Vinay krishna Y.
1 year ago
We recently had our windows and doors installed by Lee and his team in Harpenden, and the results are outstanding. From the initial consultation to the final installation, the service was professional, friendly, and efficient. The quality of the windows and doors is exceptional, and they’ve truly transformed the look and feel of our home.
Lee was punctual, tidy, and incredibly knowledgeable. he took the time to explain every detail and made sure everything was finished to the highest standard. If you're looking for reliable, high-quality windows and doors installation in Harpenden, I can't recommend Lee enough. A five-star service all the way!
Vishal V.
1 year ago
Lee has done my windows and door installation recently, and I’m really impressed with the quality of his work. He was professional, quick, and cleaned up after himself. Everything is working perfectly now. Highly recommend him for any installations in the Stevenage area!
vamsi B.
1 year ago
I couldn’t be more thrilled with the work Lee did on my UPVC windows and doors in Hertford. From start to finish, his professionalism and dedication to top-tier quality were evident. Not only did he work quickly and efficiently, but he also went above and beyond to ensure everything was perfect, leaving my home spotless! Lee’s attention to detail and reliability make him stand out in a league of his own. If you’re looking for someone who truly cares about the job, look no further. I wholeheartedly recommend him - absolutely brilliant!
06_ B.
1 year ago
Great UPVC Windows Service in Stevenage
Had UPVC windows installed by Lee in Stevenage, and I’m really impressed. The windows look great, improve warmth, and cut down noise. Lee was professional, efficient, and left everything clean. Highly recommend!
iype B.
1 year ago
Excellent job and great value, clean and punctual. Will be using again in the future.
Angela M.
1 year ago
DESIGN A VIEW first came to my home to replace my patio door/window. Lee was very professional, polite and his work is exceptional. On that visit I asked him to do the windows on the front of the house. Which were single glaze wooden framed. They were beyond repair and had panes missing!
Once again the communication, quote and professionalism throughout the whole process was exceptional. They removed and replaced, cleaned and left the premises spotless.
He is coming back to do the rear of the house soon and I couldn’t honestly ask for better. 10/10. Thank you to Lee @ DESIGN A VIEW. Images of before, during and after.
Dinko M.
1 year ago
I would definitely recommend this company.
The windows look great, the people are honest and reliable.
The price was reasonable.
The fitting has been done with care and attention to detail.
Jamie R.
1 year ago
Lee and his team cut an opening out and installed a new door on an out building for us.
I must say Lee was extremely professional from the onset. He turned up early each time, explained all that he was going to do and executed the work perfectly. He throughly protected the surrounding areas, didn’t leave a trace of dust and took away and disposed of all the removed bricks and left the site impeccably clean.
I’m 100% using lee again on future projects.
Glenn S.
1 year ago
I was recommended by a friend to use this company, and the results are outstanding, completely blown away, the moment Lee came round explained the procedure,I knew we was in safe hands with design a view.100% will again👌
Complete perfessional
Ipek Gomec M.
1 year ago
Lee and our family’s roads crossed 3 years ago when me and husband expecting our baby and I was rushing to get our porch done. I had terrible experiences with builders in the past hence finding someone like Lee who is reliable, comes on time and as promised, trustworthy just when we are so close to our deadline due to baby’s arrival was the best feeling ever! Lee is someone who knows his stuff really well, extremely detail oriented, amazingly talented with coming up with ideas when he comes across to unexpected issues due to structural issues with the building etc. He built the most beautiful porch and pathway to us with a beautiful design with his flawless and meticulous work in 2022 which made us say “yes, he is our man next time we need anything.” We got our whole house windows replaced by him after and recently ( only 2 weeks ago) we completed exterior cladding of our house. All these jobs were big, complex jobs but he and his team said we’ll come this day and time and yes, they were there on time EVERY SINGLE DAY! No delay, no slacking - just pure hard work bang bang bang! They started and finished as planned. We requested extra things after we started, despite we caused trouble by coming up with ideas in the middle of the job, they accommodated and still worked so hard to get it done in timeline! They are fast as they focus, they dont mess around! With Lee, you also know he charges just the right amount - i didnt even need to ask other companies to see what it cost as i know i’ll %100 decent job with Lee. I honestly didnt question. He gave me a price and i said “you got it” as he is trustworthy! They just get the work done! 3 yrs down the road, 3 big job, all top notch workmanship! They are the BEST! I highly recommend! Thank you Lee and his team! You have an extremely happy customer! (We see him and his team like a family now after working with them 3 years and knowing how great, reliable people they are! Thank you! Thank you! Totally deserved review this is!
Natalie L.
1 year ago
Would highly recommend Design a View. Lee and Lenny completed a third job for us on Monday and as usual the work was high quality at a competetive price.
Friendly, reliable, tidy and with great attention to detail. Their experience and pride in doing a good job really shows.
Whether it's a straightforward replacement like the French doors we've just had, or an innovative design like the Origin Soho porch they completed for us a few weeks ago, Lee works with you to bring your vision to life.
I genuinely wouldn't use anyone else (although I've run out of glazing projects for the time being 😟)
alasdair M.
1 year ago
Lee replaced our old, rather tired looking uPVC porch with a fantastic new metal framed one. The quality of work is excellent. The finish is incredibly high standard, with careful attention to detail, including filling and shaping the ceiling around an odd toothed-edge lintel to retain the shape while still finishing the edges for painting. He and Lenny were great to have on the job; thoroughly decent blokes who took care to keep everything tidy and did a great job of cleaning up when it was all done. Price-wise, he was really competitive with other quotes. We wouldn't hesitate to recommend Design a View to anyone (we've already booked him to come back to fit new conservatory doors).
FAQ's
Aluminium windows and doors
Yes, modern aluminium windows and doors are highly energy efficient. They feature advanced thermal break technology and double or triple glazing to help reduce heat loss, improve insulation, and lower energy bills.
Aluminium windows and doors are extremely durable and can last for decades with minimal maintenance. They are resistant to rust, corrosion, warping, and fading, making them ideal for UK weather conditions.
No, aluminium windows and doors are low maintenance. Unlike timber, they do not rot, peel, or crack. A simple wipe-down with mild soap and water is usually enough to keep them looking new.
Yes, aluminium frames are naturally strong and are fitted with advanced multi-point locking systems for enhanced home security and peace of mind.
Absolutely. Aluminium windows and doors are available in a wide range of colours, finishes, and styles, making them suitable for both modern and traditional properties.