The Active Trickle Vent: a window that breathes in and out.
A passive trickle vent or an open window only lets air in. The Active Trickle Vent uses the wind to move air both ways from a single unit: fresh air in, humid air out. At 0mph it works like a standard vent; once the wind picks up, it ventilates actively, without the heat loss of an open window.
Price on request · 2+ per window · Landlord or developer? Portfolio pricing
Most vents only let air in. This one moves it through.
Removing humidity needs an inlet and an outlet. That is what makes the Active Trickle Vent different from an ordinary background vent.
Real installations, real homes
Fitted to windows in bedrooms, dormers and loft rooms, the spots where condensation and mould take hold first.
Designed to support Part F background ventilation
Approved Document F sets out background ventilation for dwellings so that moist indoor air is replaced. The Active Trickle Vent is designed to support Part F background ventilation at the window (equivalent area to be published), and once the wind picks up it actively cross-ventilates rather than waiting for a draught.
It complements the Active Weep Vent, which ventilates the wall cavity: one helps the rooms breathe, the other helps keep the cavity drier.
Why airflow, not sealing, matters for damp
How trapped humid air condenses on cold surfaces, and how cross-ventilation helps.
Read the science → The researchThe evidence behind ventilation
GOV.UK, WHO and UK Building Regulations on damp, mould and why homes need ventilation.
See the evidence →Room ventilation that can't be switched off
Damp and mould now carry legal deadlines for social landlords under Awaab's Law. Because the Active Trickle Vent needs no power and has no switch, it is a straightforward way to add background ventilation to rooms. Damp also has other sources, such as leaks and plumbing faults, which a vent can't fix.
Simple to fit. Priced for your windows.
How many?
We recommend a minimum of 2 Active Trickle Vents per window, so each window can bring fresh air in and move humid air out. Manufactured in Cardiff by an ISO 9001-certified manufacturer.
Easy installation
Designed so a homeowner or builder can fit it: drill a 16mm hole through the window frame, insert one section from outside and one from inside, and they click together in the frame. Each vent is 15mm in diameter and 75mm long. No wiring, no fan, no electrician.
Price on request
Online ordering for the Active Trickle Vent is coming soon. Tell us how many windows you have and we'll send you a price, or arrange fitting for you.
Get a price →Complete the whole-house system: pair Active Trickle Vents in your windows with Active Weep Vents in your cavity walls. The Whole House Pack of 50 covers a typical terraced or semi-detached home.
Further reading
- Awaab's Law Awaab's Law Record-Keeping: A Defensible Compliance Trail
How social landlords can build a clear Awaab's Law record trail: what to log at each stage, the 3-working-day written summary and keeping tenants updated.
- Awaab's Law Tenant Lifestyle Myth: Fixing Root Causes Under Awaab's Law
Why blaming damp and mould on tenant lifestyle no longer works under Awaab's Law, what guidance says on root causes, and where ventilation fits in.
- Awaab's Law Awaab's Law Phase 2 Rollout: 2026 and 2027 Hazard Expansions
What is confirmed about Awaab's Law Phase 2 and Phase 3 as of October 2026, which hazards are expected to be added, and how social landlords can prepare.
Useful pages
- Active Weep Vent →
The wind-powered weep vent with a removable insert you can inspect and keep clear.
- For homeowners →
Damp walls, streaming windows or mould: what is going on and what helps.
- Awaab's Law hub →
The statutory damp and mould timescales, who they apply to and where ventilation fits.
- Weep vent calculator →
How many weep vents your home needs, using Approved Document C and NHBC spacing, and what they cost.
One range, every part of the building
The Active Trickle Vent helps rooms breathe; the Active Weep Vent helps keep cavities drier. See the full range, or talk to us about the right combination for your property.