Bifold Windows

Bi fold windows

What are bi-fold windows?

Bi-fold windows are made up of a number of individual sashes (framed windowed panels) that are hinged together.

Most bi-fold windows can consist of a number of sashes and can be opened up in a concertina style to make a large uninterrupted opening with the individual window panels stacking neatly against each other.

The concertina design helps to minimise the amount of clearance required to open and close the window.

How are bi fold windows used?

As a result of the large, wide open apertures, bi-fold windows help provide excellent ventilation. Their versatility makes them ideal for allowing controlled amounts of airflow through a house when its needed.

They are also a great way to make the most of your scenic outlook and can help blur the lines between your indoor and outdoor living areas.

Bi fold windows are often used as servery windows off kitchens or people will use an over sized sill as a bench setup and place some chairs on the other side to create another eating area.

These are particularly useful if you plan on having an outdoor bbq dining setup of using them to create an outdoor bar area.

Bi fold windows can be used indoors and are useful if you want to have a feeling of openness without wanting sound to carry through.


Are bi folds easy to install?

Bi folds can be hinged to either side of your frame. and in most installs are supported by rollers running across a rail system along the bottom of the window frame which allows the windows to be smoothly opened and closed.

Another rail at the top of the window frame is also used to help guide the window sashes.

In some cases windows that are being used as a servery will not include the bottom rail and have the weight of the windows supported entirely by the top rail. This makes for a flat and tidy bench service but it may cost a little but more.

Are bi-folds secure?

For security bi fold windows would typically use a flush bolt and mortice locks either at the top or bottom of the window. Depending on how many sashes your bi fold window is using. You may need to install locks at various points along your windows to ensure they are secure.

Bi-fold window weatherstripping

Having a window that opens up wide to allow serious ventilation might be great in the summer but summer is when flies and mosquitoes are at their worst so some bi-fold windows allow for special roll out insect screens to be installed as well.

In winter windows can cause big problems if not designed to seal up tightly or offer adequate insulation. Good weather sealing around the window sashes is particularly important for bi fold window to prevent draughts and reduce the amount of air infiltration that is allowed. There are various types of seals that can be used although the best bi fold windows normally feature double seals to completely prevent airflow.

Double glazing or other glass and window frames

Glass in windows is the natural enemy of climate control in the house and because bi-fold windows normally have a larger amount of glass it is well worth considering just how much heat they will let out. Double glazed window panes are more expensive than standard glazed window but they will do an excellent job of increasing insulation for both the summer and winter months.

Low E glass or window tint can also be a cheaper alternative depending on your needs.

Window frames can also be problematic. Bi fold window sashes are available in a wide variety of materials of which heat and cold conduct differently. Metal frames are an excellent conductor and will therefore let plenty of hear through. Timber, PVC and fiberglass sashes normally do a far better job of insulating your home.



  • Great, variable ventilation
  • Allows for uninterrupted views
  • Can be used as a bar or servery
  • Can help to open up a space



  • Likely to cost a lot more compared to simpler options
  • Requires good weather protection
  • Large windowed areas may require double glazing
  • More moving parts, greater chance of problems