We put Origin Bi-fold doors in on our new extension and were sold on the low threshold, nice design and ease of use which in reality did not quite deliver. We didn't get a low threshold and have a 5cm lip on the doors which was the first disappointment but one we could live with, especially with the fine appearance, safety features and ease of use. Since coming back in to the cold and windy weather of winter this has highlighted problems. The doors have dropped in the frame, which does happen I believe and we can now see daylight through the frame again so the installers will need to come back for a third time. Our architect specified triple glazed doors for the extra thermal protection but this is quite frankly a waste of time. The biggest issue we have is the long vent which leaks cold air like a sieve would leak water. On windy days especially, a significant draught comes through the vent. The installer is not interested as the vent is as supplied and not incorrectly fitted or damaged. Unlike other, cheaper, vents on our double glazing units the origin vent is anything but trickle. On our other windows in the house with their £5 plastic vents if we choose to close them they are designed in such a way that the wind pressure actually forces them tighter shut. The stronger the wind the tighter shut the vent, simple. With the Origin vent on their bi-fold doors I believe that there is a fundamental design flaw as the stronger the wind the greater the draught in the house. This completely negates the triple glazing. Origin say that the vent is not weather rated but this is a feeble excuse. They were keen to tell me their vent was 10 times the cost of my cheaper vents and the doors were double the cost of what our builder wanted to put in. The installer told me that some people in windier areas tape up their vents. Origin do not seem interested and will not agree there is a design flaw. The design of the vent is such that when the wind blows it easily exploits the gaps. The outside facing part of the vent acts as a funnel and is larger than the inside vent. This in principle would cause a pressure difference I believe. On our cheaper units the vents shut against the airflow and are sprung in the direction of air flow. On the Origin vent firstly it is not sprung and secondly it opens with the direction of airflow, out to in. At present this problem has not been resolved and Origin customer services have stopped replying to me. Poor service from a very promising beginning.