Do replacement windows need trickle vents?
Usually yes. If the old windows had trickle vents, the new ones must have vents at least as large. If they had none, Approved Document F requires 8,000 mm² equivalent area in habitable rooms and kitchens and 4,000 mm² in bathrooms, unless building control accepts an alternative.
What if the old windows had no vents?
- Fit trickle vents of 8,000 mm² (habitable rooms and kitchens) or 4,000 mm² (bathrooms)
- Or fit continuous mechanical extract and give each habitable room at least 4,000 mm²
- Or show building control another route that is no less effective
Which vents do not count?
Combustion air for open-flued appliances is separate and does not count towards Approved Document F. A night-latch position on the window does not satisfy the rule either.
How do you order them?
Check the equivalent area stated for each vent on the product data and specify the number needed per window. Agree any shortfall with building control before ordering. Our supply-only windows can be made with vents fitted. Keep the vent data sheet with the job file in case building control asks for evidence.
Need a trade price? Call the trade counter on 01903 262 636 or visit us at Unit 1, Friar Walk, Worthing. We offer free delivery within 30 miles.
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