Thinking about reducing that energy bill by improving the efficiency of your doors and windows? We all know that double glazing makes a significant difference to our homes but is it worth going the extra mile (and expense), to install triple glazing?

Instead of two panes of glass, a triple glazed window requires three.

This improves the u-value of the window, which is how the product is measured in terms of energy efficiency. The lower the u-value, the better. 

Factors that contribute to the efficiency of this window are the use of inert gas between the glass panes, low emissivity coatings and aluminium spacers.  

Naturally, the more panes there are, the more opportunity to add each of these elements.

Triple glazing doesn’t mean you have to compromise on design.  The extra pane of glass can be incorporated into whatever style choices you make.  

Triple glazed windows and thermal efficiency (u-value)

As already outlined, triple glazing ensures an impressive u-value of around 0.3.

This can be of great benefit if you have rooms that do not receive much direct sunlight or rooms that are difficult to heat.

The thickness of a triple pane window unit is roughly 36 mm but this can be increased to a maximum of, somewhere in the region of, 52 mm, providing even greater value efficiency.

The addition of an extra pane of glass means that the internal temperature of the glass is closer in match to the temperature of the room.  This means less cold spots which in turn, creates a more comfortable, snug environment.  

Triple glazing looks pretty much identical to double glazing so the beauty of this is that you can mix and match.  

Rooms that don’t need triple glazing can be fitted with double glazed windows yet still retain the same look to ensure continuity throughout the home.

Triple glazing for security

The security of triple glazing is significantly increased due to the extra pane of glass

Double and triple glazed profiles are made with toughened glass and as such, is extremely hard to break, meeting all relevant Building Standards and Regulations.  

It is important to remember that by installing double glazing into our homes, we are already making them infinitely more secure than single glazing.  It would take some force to break a double glazed unit.

In the unlikely event of an object hitting the outside of a window, the inside would not be broken.  It is worthwhile remembering then, that to replace a triple glazed unit would be more costly than replacing a double glazed unit.

Features such as sturdy frames, internal beading, locks and professional fitting techniques are what makes the replacement windows secure.

Is noise reduction better with triple glazing?

Glass is a bad conductor of sound given it is a rigid material. 

If there is considerable noise pollution outside your home, any increased glass thickness or spacing in between the glazing will be key.

There is a natural assumption that triple glazing, compared to its counterpart, will offer better noise reduction simply due to its extra pane of glass.

It is worth noting that a good quality double glazing with high spec sealed units and gaps between the panes of around 16-20mm  will be the most thermally efficient and produce the best noise protection. 

If triple glazing were to improve upon this, the gaps between the panes need to be no less than 16 mm, otherwise they will not match the efficiency of double glazing.

Should I Get Double or Triple Glazing?

Does the extra pane of glass increase efficiency and noise reduction enough to warrant the higher price tag of triple glazing?

Let’s look at the u-value in more detail.  The u-value of a standard, brick house wall is about 0.8.  

By comparison, the installation of single glazing will provide a u-value of around 5 – shocking!

However, thanks to the invention of double glazing, a u-value of between 3 and 1.6 (depending on how long ago it was installed) can exist in our homes.  

Finally, triple glazing will rate at around 0.3 and well on its way to banishing weak efficiency of a building.

Because of the more demanding weather conditions, many Scandinavian countries, already provide triple glazing as a standard practise, whilst in the UK, the debate between the two goes on.

Homeowners will need to check the specification and measurements of the manufacturer’s glazing units to ensure paying extra for triple glazing is really worthwhile.  

If the chosen units are a thickness of 44mm or more, for instance, then you can expect a 40% increase in insulation.

That said, the extra thickness of glass you would require for triple glazing to be worthwhile will also impact on the weight of the unit.  

Making sure the hinge technology lives up to any extra weight is another area for consideration.

The next question ought to be about what the gaps are filled with?  Krypton gas is more expensive but works better on smaller spaces than argon gas.  

Wider units will also have a bearing on the type of bead detail, again a personal choice but worth checking if you have specific ideas on aesthetics.  

So, clearly there is much to consider and it is certainly not a cut and dry case of triple glazing being superior to double glazing with so many variables. 

The triple glazed door

All the benefits afforded to glazed windows will of course extend also to doors.

The higher u-value; thickness of glass to achieve an ‘A’ energy rating and the three panes offering extra strength and durability can all be beneficial to your external, patio, French, bi-fold and sliding doors.  

Many people gain peace of mind, knowing that the largest opening into the (often hidden) back of the house is made of high spec, triple glazed units and therefore, more secure.  

Additionally, the sheer amount of glass area which potentially allows heat loss may be your reason for choosing triple glazing even whilst other windows in your home are double glazed.  

Whilst there may be some limits in terms of style, most glazing manufacturers are able to install all of their door products with either double or triple glazed units.

As with windows, it will be necessary to compare the cost of both types of glass and weighing up the benefits, before making a decision.

Triple glazing prices

The money-minded homeowner needs to be well-informed when weighing up the choice between double and triple glazing

As a rough guide, each window made with triple glazing will cost around £100 more than the same in double glazing, based on one square metre of glass – an average 4 ft window.

Yes, the cost of triple glazing is much higher and, unless you live in a particularly cold climate or experience high noise pollution, you may want to think about how long it would take to claw back the finances of a high quality triple glazing compared to the slight increase in efficiency.

On reflection…

We’ve talked a lot about glass but frames are equally important.

Ensuring the window frames of your double or triple glazed units are well insulated requires reflection too as this is a major heat loss area.

Thicker, window furnishings and keeping them closed at night is surprisingly helpful when it comes to efficiency and of course, at little extra cost.

Deciding which type of glazing – double or triple – is best for your property, lies in a conversation with your installer. 

They will take everything into account; what issues you currently have with your windows, the environment of your home, your design choices and provide you with recommendations and a like-for-like price comparison.

Only then, can you decide if triple glazing is worth the extra ‘pane’!

Matt James
Matt James

Hi, Matt here! I started out almost 20 years ago as a teenager working in the family business fitting doors, windows and conservatories. I now run this website to share the best tips and advice for anyone looking to get a good deal on double glazing.