Double and triple glazing for bi-fold doors—how to choose between them

Choosing glass for your aluminum bi-fold doors means deciding between double or triple glazing. Both are excellent options but they do each have their benefits and drawbacks.

In this guide, we:

• explain the benefits of double and triple glazing for bi-fold doors
• tell you which factors are most important when choosing between them

• Why have double or triple glazing?
• Double glazing or triple glazing—which do you choose?
• Energy efficiency
• Soundproofing
• Cost
• Installation
• View and sightlines

Why have double or triple glazing?

The point of having double or triple glazing in your bi-fold doors is to:

• make your home more energy efficient
• block out noise from outside
• keep your home secure
• add value to the property

Double glazing does this with two panes of glass, while triple glazed units use three.

Double glazing or triple glazing—which do you choose?

Energy efficiency

The energy efficiency of glazed folding doors is measured by a figure known as the “U-factor”. The lower the U-factor, the more efficient the doors.

The table below shows U-factors for different types of glazed panels. As you can see, triple glazing is the most efficient option, although modern double glazing isn’t too far behind.

Triple glazed bi-fold doors do provide better thermal efficiency. In the winter, they are more effective at stopping warm air escaping through the doors and cold air getting in. In the summer, they do the opposite—preventing warm air from entering, and keeping your home cool.

Whether you choose double or triple glazing for thermal insulation, make sure to insulate the walls, roof and floor to the same level as your folding doors. If you don’t, you won’t get the glazing’s full benefit and see as much of a fall in your energy bills.

Read more about thermal efficiency on this page.

Soundproofing

Because triple glazed doors have that third pane, it’s thicker and so better at noise reduction. This is particularly helpful if you live near a busy road or in a noisy urban area.

With both double and triple glazed doors, the size of the gap between the panes can make a significant difference to the level of noise insulation—the larger the gap, the better.

And noise can be further reduced by having the gap between the glazed panels filled with a heavy inert gas such as argon or krypton, although this typically adds to the cost.

Cost

Triple glazing can cost up to twice as much as double glazed units, and this isn’t solely down to the addition of the third pane.

The glass itself has to go through a more complex manufacturing process, and is also much heavier to transport. These extra costs make the product more expensive.

As a result, you need to consider whether the higher cost of triple glazing is worth paying. The doors will likely add value to your property, but that might not matter if you don’t intend to move for a while.

If you already have double glazed panels, the small improvement in performance that triple glazing brings is probably not worth the outlay.

Installation

The extra glass in triple glazed bi-fold doors makes them considerably heavier, which means one van is limited in the number of units it can carry in a single delivery.

Because the installer can only carry so many units, they may need to make more journeys to your home, delaying the installation as a result. This is particularly true for aluminum bi-fold doors.

If you’re leaning towards opting for triple glazed bi-fold doors, make sure you take these possible costs and delays into account.

Read more about delivery and installation on this page.

View and sightlines

Bi-fold patio doors provide superb views onto your garden and surroundings, as well as allowing natural light to flood into your indoor living space. The best ones combine slim frames with the strength to accommodate wide glass panels to really emphasize these benefits.

Because triple glazing is heavier than double glazing, there’s a limit to how big the panels can be—they would be too heavy to operate otherwise.

If an extra door is needed because of the smaller panel size, the door panels would be closer together, meaning there’s more aluminum frame obstructing your view.

However, the sightlines of triple glazed bi-fold doors are still impressive, and the benefits triple glazing offers help lessen the effect of these drawbacks.