Eco Happy (Solar Expert)

Published February 28, 2024

The most common reason for installing double glazing is its ability to better insulate your home and reduce your energy bills. In fact, the Energy Savings Trust estimates that your home loses 25% of its heat through windows and doors. So, it makes perfect sense that better insulation means lower costs.

However, the average price of basic double glazing starts at £250 per unit. Even taking into account the UK’s rising energy costs, this still doesn’t fully make up for the price of installing the product in your home.

But the fact is, there are many additional benefits of double glazing that make these windows well worth it.

In this article, we will break down the top six ways that double glazing more than makes up for its cost. This includes raising your property’s value, reducing sun bleaching and so much more.

We will also briefly touch on what affects the cost of installation and explore how replacing old panes with today’s product still makes economic sense.

The Top 6 Ways Double Glazing Is Worth It

Let’s dive into all the ways you get added value when you replace old glazing for your windows and doors. This will also help you understand a bit more how double glazing works.

1. Energy efficiency

The main selling point for double glazing is the promise of a more energy-efficient house compared to those with just single-glazed products. Continued advancements in green technology have made modern glazing even more energy efficient than products of just a few years ago.

Some key advancements in recent years include:

  • Low emissivity glass (Low-E) reflects more radiation from the sun while allowing more visible light to pass through, compared to untreated glass.
  • Advancements in window spacer technology deliver superior reduction of thermal transfer.
  • Aluminium and composite material frames further improve energy efficiency, compared to double glazing using standard unplasticised polyvinyl chloride (UPVC) windows.

How will double glazing save me money on my energy bills?

According to the Energy Saving Trust, when you install secondary glazing, it can reduce your annual heating bill by over £150.

Double glazing helps your home stay cooler in summer by reducing the amount of heat transferred from outside your home to the inside. It also helps reduce the amount of UV radiation that enters and heats your home during the longer summer days.

2. Increased property value

If your home has double glazing installed, it will directly affect your property value. The material costs involved play a huge role in the market value. It also positively influences the buyer’s perception as they know they won’t need to make additional renovations or perform regular maintenance.

Double glazing gives your home a high energy rating on your property’s Environmental Protection Certificate (EPC). The EPC is an evaluation of your home’s total energy efficiency and it ranks a property on a scale from G at the lowest end to A++ on the highest end. Completing this certificate is part of most building regulations.

The higher your home’s EPC energy rating, the more attractive that property becomes for prospective buyers. It means that the buyer would not have to incur additional costs to improve the EPC rating or endure any disruptive construction work.

How much value does double glazing add to my home?

Installing double glazing adds between 5% to 10% to your home’s value. This percentage can vary depending on the size of the property and the number of windows.

The Energy Saving Trust estimates that installing A-rated double-glazed windows costs around £15,000 for a semi-detached home. If we look at the average semi-detached house price, it runs to about £300,000.

This means that even if your double glazing only adds 5% to the value of the house, that would be a £15,000 increase in the price. The installation has paid for itself.

3. Noise reduction

Double-glazed windows offer increased soundproofing for your home since the window has two sheets of glass to buffer against noise.

When sound waves move through the insulating gas or vacuum between the two panes of glass, the change between the mediums greatly reduces the energy of the sound waves. 

Double glazing is invaluable for homes that experience excessive outside noise. This includes a home facing a busy road or flats on the high street.

4. Reduced sun bleaching

Double glazing reduces the amount of UV light that comes into your home from the sun by more than 90% when compared to single glazing.

This greatly limits the level of photooxidation in your home, protecting carpets, furniture, artwork and more. This means that you won’t constantly need to replace these items when they become sun damaged, which alone makes double glazing well worth it.

 5. Reduced condensation

Condensation on windows is caused by warm air inside the home meeting the colder glass surface on a glazed window or door. The temperature differences cause water to condense on the surface of the pane inside your home, which can cause mould to form on your window frames. It will also cause water damage to wooden frames.

Double-glazed windows guard against condensation due to their fundamental design. The air-tight gap between panes can’t transfer heat as efficiently as a single glaze pane.

As a result, there is a much more gradual temperature difference between the inner pane and the outer pane, which drastically reduces condensation on your windows.

6. Enhanced strength and security

Due to the two panes of glass and stronger overall construction, secondary glazing offers extra protection from impact compared to single-pane windows. This can include damage from debris blown during a storm as well as accidental impacts.

On top of additional physical safety, double glazing is also much more resilient to thermal stress cracking caused by the temperature differential between the inside of your home and the outside environment.  

Cost Of Double Glazed Windows

The cost of double glazing is directly tied to the type of glazing used, the frame materials and the size and design of the windows or doors.

When buying double glazing, always check for the ‘Energy Saving Trust Recommended’ or a British ‘Fenestration Rating Council’ logo. These guarantee that the product will deliver quality and value for your home.

When To Replace Old Double Glazing

Double glazing is a specially manufactured and professionally installed fixture for your home that can work effectively for many years without the need to replace them.

It is not immediately necessary for anyone to replace old secondary glazing, as long as the units are still intact and properly sealed.

So, when should you replace double-glazed windows?

The current condition of the windows

If your old glazing has any damaged or deteriorated seals between the glass panes, or you are experiencing a draught coming from the window, it means it is time to replace them. These issues will defeat the entire purpose of installing secondary glazing.

You can spot damaged window seals by checking for condensation on the glass panes. For a draught, use a match, candle or stick of incense to check:

  1. Close all the doors and windows in a room.
  2. Light the match, candle or incense stick.
  3. Hold it near the panes, moving slowly along the frame.
  4. The flame or smoke will be an excellent indicator of any draughts coming through your double-glazed windows, indicating a gap in your sealed unit.

Improved energy efficiency

Advancements in green technology have provided improvements in window and door insulation over the last few years. One new development is low-emissivity glass, also referred to as low-E glass. This special coating reduces heat loss from within your home, while also blocking heat radiation from outside.

This means your home will stay warm in winter and cool in summer. Replacing outdated double glazing with modern glazing will mean a more energy-efficient window which translates to savings on your energy bill.

Consider your warranty

You may not need to replace your old window glazing yourself if a manufacturing fault has occurred to the unit. Many manufacturers offer up to a 10-year warranty on their products, such as Velux, Everest and Safestyle UK. This covers the cost of both materials and workmanship required for new windows.


How do I check the efficiency of my double glazing?

You can check the energy efficiency of your doors and windows by looking at the U value of the product you have installed or wish to install. The lower the U value, the more efficient the windows are at preventing heat loss from the interior of a room to the exterior.

Standard single-glazed windows have a U value of around 5. Double glazing, by comparison, has a U value of around 2.6 but can be even higher depending on the materials used.

What are the disadvantages of double glazing?

The cost of double-glazed windows is one of its biggest disadvantages. It is a more expensive product than single glazing and requires a professional to install it properly. This also means that homeowners will not be able to make any DIY alterations or fixes to their windows without compromising them.

Over time, the seals between the two panes of double glazing can degrade and fail. This lowers the ability of double-glazed glass to stay optimally energy efficient.

What is A rated double glazing?

A rated double glazing means that the windows or doors are very energy efficient. Glazing has an energy rating from A through G, which categorises it on the level of insulation and its carbon footprint.

A rated windows and doors are on the highest tier of the rating scale. They will help ensure even temperatures throughout your home. These windows also help lower energy bills as they are much better at preventing heat from escaping, compared to single-glazed windows or lower-rated, outdated double glazing.


Double glazing offers great value for money when you consider all its benefits. Reducing your heating bills and meeting building regulations is just the tip of the iceberg. If you want even more advice on how to further reduce your energy bill, you can read our comprehensive article.

If you need further advice on heating solutions for your home, Eco Happy is the place to start. Our quote comparison service is the simplest and most convenient way for you to find the best value services in the UK. Contact us today to get started on your efficient heating journey.

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