Bifold doors are becoming more popular fixtures in homes, since they give homeowners the option to merge their exterior spaces with the interior–which is useful especially with smaller interior spaces. They work well both open and closed, providing lots of natural light and a remarkable view to the outside. However, in order to fully enjoy the benefits of having bifold doors, consider the following factors before making a final decision to purchase them:

1. Panel thickness

Begin by sourcing for frame/panel sizes from potential suppliers to get an idea of the thicknesses available. Bifold doors are primarily meant to enhance your view of the outside, and having more panels adds up to more solid material, which interferes with view continuity. In addition, more panels add up to more material to be used in constructing the frames, which becomes costlier. Consider having fewer larger panels for less cost and better views.

2. Odd vs. even

The truth is that your bifold doors will be closed more often than they will be kept open, therefore it's worth considering the number of panels on your doors. When you have odd-numbered panels, you can open up the first panel like a traditional door when you want to walk into the garden, which is more convenient. With even-numbered panels, however, you have to move the first two doors, which essentially shifts the entire door.

3. Security features

Security is a major consideration, especially where your bifold doors are used as a main entrance to the house. Therefore, ensure that your manufacturer has insurance-recognised and accredited locking systems according to recommended standards. The door cylinder is usually the weakest part of the locking system; look out for cylinders that can resist picking, snapping, bumping and drilling. The best options are those with integrated multiple-point lock systems, including shoot bolts and hooked locks.

In addition, the quality of materials used should be considered, as it contributes to overall security. Try to look for internally glazed doors, since it's possible to remove the double-glazing and beads on externally glazed versions to make them easily penetrable by intruders. You can add custom blinds for privacy when desired.

4. U values

The U-value measures the degree of insulation on building materials, with lower U-values indicating better insulation. When browsing around, you'll find these three U-value measurements:

  • Ug – the thermal transmittance on the glazing or the centre pane
  • Uf – thermal transmittance on the frame
  • Uw – overall thermal transmittance (Ug and Uf). This is the most important number to consider unless you're buying your frames separate from the glass/glazing. Another measure, the PSI or Edge Value measures the edge/spacer effect of the unit, which improves the Uw measure.

Bifold door U-values can be affected by the number of panels/leaves, size of door and opening configuration (Does it open one or two doors at a time; towards the inside or outside?). Consider these when assessing the U-value as well.