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Double Glazed Units

Replacement Double glazed units.

Replacement Double Glazed Units.

Foggy or misty draughty glass units need replacement double-glazed units when condensation forms between the glass panes. This indicates a failed seal, which, due to its unappealing appearance, requires immediate attention.

Broken sealed units can occur due to various factors. These include thermal stress, impact damage, age-related deterioration of the bitumen sealant, or material failure inside the existing spacer bar. Traditional aluminium spacer bars are tubular and are filled with an anhydrous material called desiccant, which is generally put in the two most extended lengths or all four bars and absorbs moisture from the space between the panes. Over time, when this material fails, it leads to moisture ingress and reduced insulation. This often results in the need to replace the damaged or “blown” unit.

Aluminium spacer bar.

Aluminium spacer bars are available in various colours and bar thicknesses. Tailored to each glass unit’s specific installation requirements, glass type 4mm-6mm or laminated safety glass is required.

Glass Manufacturers.

The results are the same with automatic line insulation machines for larger companies, hot melt gunned units, and two-part application sealants for smaller companies. The goal is hermetically sealing the edges to trap the air inside the unit. During manufacturing, workers trap air when sealing the unit. This air inevitably contains a certain amount of moisture that they cannot eliminate. As a result, when external weather conditions are damp, particularly during the morning when the home’s interior is warm, the trapped air’s temperature will decrease. This phenomenon leads the desiccant inside the aluminium bar to absorb water droplets. Over time, this may ultimately result in its degradation.

By comprehensively understanding these factors, property owners can effectively manage their insulation systems. This helps prevent heat loss and mitigate increases in energy costs.

If the glass units were manufactured at the same time, other units nearby would likely malfunction soon. Therefore, we recommend replacing all of them at once if one window shows several non-functional units. This approach will help you maximise cost savings in the long term, ensuring a secure and lasting investment.

We recommend that if one window displays several non-functional units, it may be financially prudent to replace all of them simultaneously. This approach will help to maximise cost savings in the long term and ensure a secure and lasting investment.

Our team expertly manufactures new double-sealed units using an insulated spacer bar and a double-seal process with argon gas. These units come with a ten-year manufacturer’s guarantee. This allows you to avoid costly service calls and enjoy upgraded insulated glass units that surpass the performance of your previously installed broken-down glass units.

Replacement Unit cost.

We have set a minimum requirement of four units to ensure a smooth replacement process. This is due to the associated costs of replacement units and the expertise needed to determine the exact sizes and specifications of the new units. Additional features like leaded coloured lights or Georgian bars also factor into this process.

We have set a minimum requirement of four units to ensure a smooth replacement process. This is due to the associated costs of replacement units and the expertise needed to determine the exact sizes and specifications of the new units. Additional features like leaded coloured lights or Georgian bars also factor into this process.

Use the calculator below to get an instant guide price for your job — we’ll confirm the exact cost after a survey

Replacement Glass Unit Calculator

Add each unit you need — glass type, width and height — for an instant guide price, inclusive of VAT.

Sample pricing — placeholder, update with your own rates

Units required

Location Glass type Width (mm) Height (mm) Thickness (mm) Argon Patio/ Door Units Price £ (inc VAT)

Extras (applied across all units above)

Supply only?

Select a glass type and enter a size to see a price.
All prices shown are a guide only, inclusive of VAT at 20%, and are based on standard sizes. Minimum charge applies per unit (0.25m²). Fitting includes survey and removal of the old unit, charged at £180.00 per m² (i.e. a 1.000m × 1.000m unit costs £180.00 to fit), subject to a minimum fitting charge of £45.00 per unit. Toughened glass, non-standard combinations, and specialist products are priced on enquiry. Final price is confirmed at survey. Delivery costs for supply-only orders are estimated from postcode-to-postcode straight-line distance with a road-distance correction factor, and are a guide only — always confirm exact delivery cost before invoicing. A van delivery surcharge applies automatically on supply-only orders when any unit exceeds 1m in width or height, as these can’t go out on a standard courier/car delivery. A two-man lift surcharge applies to any unit over 1.8m in width or height, whether fitted or supply-only, to cover the extra handling required. All glass units are subject to survey to confirm exact sizes and any site-specific requirements. Any glazing below 800mm from the inside finished floor level is a critical location and must be toughened or laminated safety glass — tick Patio/ Door on any affected unit so this is applied automatically. This calculator is for illustration — figures must be replaced with Southeast Windows’ own supplier rates before publishing.

Want to know More?

Call us today for your FREE, no-obligation quotation or fill out our Contact Form! For complete home Comfort Replacement, Double-Glazed Units are Designed to Keep You Warm, Safe, and Secure.

Alternatively, call your local number below to arrange an appointment.

East London Double Glazing: 020 8472 4088 (head office)
South London Double Glazing: 0203 856 6667
North London Double Glazing: 0203 856 6669
Epping: 01992 940 809
Chelmsford Double Glazing: 01245 208 058
Romford Double Glazing: 01708 202 457
Great Dunmow Double Glazing: 01371 704 771

Upgrade your existing double-glazed glass units today!

Southeast Windows Ltd place picture
4.9
Based on 31 reviews
Callum profile picture
Callum
2 months ago
Professional and friendly service from Roy and team throughout when fitting replacement windows for first floor flat! Competitively priced too
David Luck profile picture
David Luck
3 months ago
Brilliant job by Roy and Rob. Very professional standard. Front Door and side and Transom windows fitted to perfection 😇
Paul Cvecka profile picture
Paul Cvecka
3 months ago
Lads have been more than amazing!
Our house is wonky as matchbox, so this house was a real challenge!
Guys sorted everything out, did absolutelly splendid job.
So sorry you had to went through the headache with our old “cottage”.
Southeast fitting team have been absolutelly professional, helpful and very knowledgeable.
You have been absolutelly amazing!
Thank you!
If I ever see you in pub around, round is on me!
You have been amazing!
Brian Porter profile picture
Brian Porter
8 months ago
Arranged a visit/quote and Roy turned up on time and gave us a non-pushy estimate and details for us without his wider window knowledge.
Gave us a very decent quote and went with them.

Arranged the date & time and Roy kept us up to date with any developments by email.

Arrived on the day on time, did a great job fitting two windows in the morning and left the place clean and tidy. You can't ask for more really.

5/5 Stars. Would recommend. 👍
huong Luc profile picture
huong Luc
2 years ago
The team was led by Peter - great comms, double glazing patio door to insulate the ground floor bedroom, replaces single glaze door. After installation there was a slight problem but it was resolved in good time. Thank you.
Laurence Radford profile picture
Laurence Radford
2 years ago
Roy and team did an excellent and professional job replacing 3 front windows, making the change unnoticeable from the outside. They were worked with challenges getting large frames into the upstairs room and were courteous throughout. Would recommend.
Kate Cleaver profile picture
Kate Cleaver
2 years ago
Really happy I chose Southeast Windows to fit my UPVC back door. Roy was friendly, professional and helpful at every step of the process. I was very happy with the workmanship and it was done so efficiently and with so little mess. I definitely recommend for a first class service !
Derek Wong profile picture
Derek Wong
2 years ago
I would like to express my heartfelt thanks to Southeast Windows for their exceptionally good service. From the moment I reached out to them, their team demonstrated professionalism and efficiency that truly impressed me. The installation process of double glazing was remarkably fast, allowing me to enjoy the warmth of the new windows brought sooner than expected.

Moreover, I was particularly impressed with the cleanliness maintained throughout the whole installation project. The team took great care to ensure that my home remained tidy, leaving no mess behind. This attention to detail speaks volumes about their commitment to customer satisfaction.

Besides, the quality of the windows is outstanding. The windows not only enhance the aesthetic appeal of my home but also provide excellent insulation. I am thrilled with the results and would highly recommend Southeast Windows to anyone in need of window services. Thank you Roy and your team once again for your hard work and dedication!
Marc Jones profile picture
Marc Jones
2 years ago
Amazing company and service. High quality work at very good price. Very efficient with great communication throughout. Would 100% reccomend.
David Gridley profile picture
David Gridley
3 years ago
Excellent work from Roy and his team. He installed our windows quickly and with a minimum of dust etc. They also took away the old windows which was a great help.
Arnold Cabanus profile picture
Arnold Cabanus
3 years ago
We recently had all our old windows replaced and installed by Southeast Windows. Everything, from the survey to the installation day runned smoothly .We are delighted with the excellent window installations that they did and left our house clean and tidy after. This company is very trustworthy , professional and courteous. If you need an honest and efficient windows installation company, definitely Southeast Windows Ltd is highly recommended.
Leah Corney profile picture
Leah Corney
3 years ago
We chose southeast windows to replace our old upvc windows
from initial survey company were very informative explaining different options available fensa warranty fire regs etc
quotation was very competitive detailing all widow specifications everything what we was getting including removal of all rubbish
So glad We went with triple gazing option not that much extra
guys arrived early every morning we’re courteous and professional at all times did a fantastic job of installing windows clean and tidy
windows look fantastic house is so much warmer and noise reduction really please we choose this company would definitely use again
Highly recommend
Steve Clare profile picture
Steve Clare
4 years ago
Roy replaced all the windows at the front of my house three years ago. This time I got him to replace a couple of blown windows in my kitchen. As before, he was efficient, courteous and excellent value for money. Communication was also outstanding. Very happy with the job and strongly recommend Roy.
Hilary Armstrong profile picture
Hilary Armstrong
5 years ago
Roy and his team fitted new windows and French doors in our house earlier this year (we wanted to live with them for a while before reviewing!). We are really pleased with the quality of the windows and the service from Roy. He's a real gent to deal with and is punctual and professional. His quote wasn't actually the lowest but he was the only one to supply full details of materials, give fire safety and security advice, send a detailed quote etc. Thank you Roy
Megan Monaghan profile picture
Megan Monaghan
5 years ago
I got quotes from a few companies however Peter was the only one who followed up to my questions on email so I decided to go with Southeast Windows. I am super glad I did, as Peter was professional and I am really happy with the work done in installing a new PVC backdoor and replacing glass in several windows. Peter was knowledgable, friendly and didn't take advantage of my lack of knowledge of window and door installation like some other builders have, being a first time home owner.

I wouldn't hesitate to recommend Peter and Southeast Windows, I will for sure be using them again if I need. Thank you Peter!