People love bifold doors because they change how a room feels. You get more daylight, a wider opening in summer, and that “inside-outside” flow everyone wants. But the quotes can swing wildly, and it’s not always because one company is “ripping you off”. Often, it’s because two door sets that look similar online are built very differently in real life.
Start with daily use. Will you open the whole set often, or do you mainly want a normal door most days? If you’re the “open once, walk through 20 times” type, ask for a traffic door configuration so you’re not folding the entire run just to pop outside. It sounds small, but it changes how the room works.
Then look at sightlines and frame thickness. Slim frames can look incredible, but don’t treat “slim” as a quality guarantee by itself. Ask what’s happening behind the scenes: thermal breaks, corner joints, and how stiff the frame is across wider spans. Big openings demand rigidity. If the system flexes, you’ll feel it in the handles and see it in alignment over time.
Glass is another big one. Lots of people focus only on insulation, but overheating is often the bigger problem for sun-facing rooms. Solar control glazing (and sometimes shading) can be the difference between “my favourite room” and “we can’t sit there at 2pm”. Also ask about safety glass where required, and whether there are upgrade options like laminated panes for extra security or noise reduction.
Threshold detail matters more than most homeowners expect. A flush or low threshold looks modern and is great for moving furniture, but it needs the right drainage and weather detailing. On exposed sites, the “prettiest” threshold isn’t always the smartest choice. A good installer will explain the trade-off instead of dismissing the question.
Finally, be honest about what the quote includes. Some prices quietly exclude making good, plaster touch-ups, electrics, or disposal. That’s how two totals end up looking similar while one becomes an expensive “add-on festival” later.
To get a sensible starting point before you compare quotes, you can rough-price an opening size and spec using the Double Glazing Cost Calculator. It won’t replace a site survey, but it helps you sanity-check whether a quote is genuinely premium… or just vague.