Nationwide Coverage

uk icon

Made in the UK

40 year icon

40 Year Heritage

unique icon

Unique Patented Products

warranties icon

Extensive Warranties

Advanced acoustic & insulating secondary glazing for your Sash Windows

Preserving the unique heritage and charm of period timber windows really is a priority to us, which is why we offer industry-leading secondary glazing products as an alternative for listed buildings, conservation areas, and other properties subject to restrictive improvement regulations. Tailored to a wide range of property styles, we have over 35 years' worth of experience crafting and installing quality secondary glazing designed to enhance thermal efficiency and security and reduce noise pollution.

Secondary Glazing Features

What makes our secondary glazing unique?

noise icon

Reduced noise levels up to 80%

heat icon

Reduced heat loss up to 65%

ruler icon

Bespoke traditional & heritage styles

drawing icon

Custom fit to your property with care

van icon

Local expertise, national coverage

Secondary Glazing 1080 x 1080

Preserve your building’s unique aesthetic with quality secondary glazing

Enlightening, discreet, warm & tranquil

Secondary glazing consists of a fully independent internal window fitted on the room side of an existing window.

This technique creates an extra layer of insulation, providing various advantages such as:

  1. Improved Thermal Efficiency: Secondary glazing significantly reduces heat loss, enhancing the energy efficiency of your home.
  2. Noise Reduction: Experience a quieter and more peaceful indoor environment by minimising external noise intrusion.
  3. Enhanced Security: Strengthen your window’s security with an additional barrier, offering increased protection against intruders.
  4. Preservation of Historic Windows: Safeguard the original features of your timber windows while enhancing their performance.

Made from lightweight, slender aluminium frames, enjoying the sunshine and making the most of far-reaching views, whilst preserving your property’s exceptional character, is a straightforward process with secondary glazing installations by Ventrolla.

Find Out More
tall sash window

Secondary glazing windows in two period-style ranges

Designed to seamlessly blend with the style of your property, our secondary glazing is purpose-built to suit all property and window types, and is available in six diverse variations;

  • Horizontal Slider
  • Vertical Slider
  • Hinged Unit
  • Fixed Unit
  • Lift Out Unit
  • Bespoke & Arched Units
Secondary Glazing Brochure
close up aluminium window

Traditional Secondary Glazing Features

  • Slim, discreet aluminium profile
  • Minimal sightlines
  • Easy access to primary glazing
  • A popular choice with homeowners

Heritage Secondary Glazing Features

  • Slightly thicker, heavy-duty aluminium profile
  • Perfect for small to large-scale commercial installations



Our Process



The Ventrolla journey begins with a discussion with a member of our team and/or a detailed home or site design survey, to explore your ideas & devise a bespoke plan of action.



Once our team have finalised the plans, we will provide a comprehensive estimate for your works. Enquiry to estimate typically takes between 5 and 10 working days.



Ventrolla fuse traditional skills with modern technology. If you require new joinery, creating your unique product begins in our UK-based manufacturing facility, and takes between 6 and 10 weeks.



The utmost care is taken to deliver quality products and renovation works that exceed our customers’ expectations. Varying from area to area, Ventrolla lead times depend on how busy we are, and the work required. On average, our installation team will be on site between 6 to 18 weeks from the date your order is placed. We will advise guide installation dates when you place your order.



Our customers come back time and time again – when they move or if they’ve phased their works – all thanks to our exceptional customer service and after care. In the unlikely event that your Ventrolla products require expert attention, we’re always on hand.



Renowned for delivering outstanding quality, all our work comes with a minimum 5-year guarantee (subject to terms), for absolute peace of mind.

What our customers are saying

Ventrolla were able to beat all the other quotations that I received and answered queries quickly and informatively, making changes as required promptly and without fuss. I was kept informed throughout of lead times and manufacturing times. The real stars of the show were Rob and James who worked tirlessly and brilliantly as a team to repair sash boxes where required and install our new sashes. Thank you!


Everybody I dealt with has been super friendly, informative, and helpful. I received emails with updates on what was happening, etc. It has been a great experience from start to finish.


I used Ventrolla to renovate my sash windows over to years ago. When two of them finally collapsed, including a bay window the size of three full sized Georgian windows they were my first contact. The office staff, surveyors and the three fitters that did an amazing job installing them in less than two days were all excellent. The quality of workmanship and the standard of installation were first class, and the new windows look amazing. I will definitely be using them again as more of my windows will need replacing over the next few years.


This is the second property Ventrolla have restored my windows for me, and the this job was every bit as good as the first. 14 sash windows in a Grade II listed building installed/refurbed without a hitch in week. The team of 4 installers were lovely chaps, super efficient and tidy. All round another fabulous job done – thank you the Ventrolla Team


nbs partner
builders profile
british safety council
safety first
disclosure and barring service
Responsibly Sourced Timber Tree heart

Frequently Asked Questions

I live in a listed building / conservation area / AONB - can you work on my property?

In these cases, secondary glazing is an ideal alternative. We have completed lots of work over the years on listed properties and those within conservation areas and Areas Of Outstanding Natural Beauty (AONB). Working closely with local conservation and planning officers, English Heritage, Historic England, Historic Scotland, and Cadw, you can trust in Ventrolla to reinstate and sustain unique architectural features whilst simultaneously heightening historical value too.

Will secondary glazing reduce outside noise levels?

Independently tested and proven to significantly reduce sound intrusion, our high performance secondary glazing can reduce noise levels up to 80% and heat loss up to 65%.

Do you offer an installation guarantee?

Yes, our work is guaranteed for 5 years.

What is the average cost of renovating a window with secondary glazing?

It all depends on how much work each window needs. For a more accurate estimate, please call us on 0800 0277 454 to arrange a free, no-obligation survey.

How long does it take to install secondary glazing?

The time taken will vary depending on the result e.g., your survey and the work we identify is needed. Typically, we work to a one-window-per-day time scale, although this can be adjusted, if necessary, to suit your requirements or our schedule.

Varying from installation to installation, our average timescale targets are

  • Enquiry to quote: 5-10 days
  • Quote to order: 30 days
  • Order to installation: 10-16 weeks

Can you put secondary glazing on sash windows?

Yes, it is possible to install secondary glazing on sash windows. Secondary glazing involves adding a second layer of glazing to an existing window, creating an insulated airspace between the two panes of glass. This can help to reduce noise, improve energy efficiency, and increase security.

Secondary glazing is a popular solution for historic or listed buildings, where replacing the original windows may not be allowed. Sash windows can be particularly suitable for secondary glazing, as they often have single-glazed panes that can be easily upgraded with a secondary glazing system.

What is the lifespan of secondary glazing?

The lifespan of secondary glazing can vary depending on several factors, such as the quality of the materials used, the installation method, and the level of maintenance.

Regular maintenance can also help to extend the lifespan of secondary glazing. This may include cleaning the windows regularly with a non-abrasive cleaner, lubricating moving parts, and checking for signs of wear or damage.

It’s important to note that secondary glazing is not a permanent solution and may eventually need to be replaced. However, with proper installation and maintenance, secondary glazing can provide long-lasting benefits such as improved energy efficiency, noise reduction, and increased security.

Got questions that haven't been covered? Visit our FAQs or speak to our friendly team today:

get in touch

What to do next

Subscribe to our Newsletter

Stay up to date with the latest news and tips from our Knowledge Hub.