Passyfier Conservation Sleeved 230 Vent

Health & Safety Considerations

Plan the work from a safe platform with suitable access and lighting. Wear safety goggles, gloves and a dust mask when cutting or drilling masonry. Survey the chosen wall section for live services, structural lintels and the damp-proof course before any openings are formed.

Control dust and debris, protect internal finishes, and keep bystanders clear. Use lime-compatible repair mortars on traditional masonry where required and handle sealants in line with the manufacturer’s guidance. If you are not confident with through-wall work, engage a competent builder.

Site Preparation

Choose the room that shows persistent condensation or mould and select a position on an external wall at high level. For best performance set the top of the vent no more than 12 inches, about 300 mm, below the ceiling so it intercepts the warmest, moisture-laden air that pools high in the room while keeping any felt air movement away from occupant level.

Where possible pick the colder, stale corner furthest from the door and avoid hiding the internal grille behind curtains or furniture. Confirm the wall thickness. The standard telescopic sleeve suits 240mm-340mm; where walls are deeper, plan to use a compatible 230 Extension Sleeve purchased separately.

Assemble the necessary tools, fixings and a lime-compatible mortar if you are working on historic fabric. In kitchens and bathrooms retain or install mechanical extract; the conservation vent is intended for continuous background moisture control in habitable rooms.

Limitations And Good Practice

This is a passive dehumidification device, not a substitute for rapid mechanical extraction at moisture sources. Do not use it to supply combustion air to gas, oil or solid-fuel appliances.

Maintain a slight fall to the outside through the sleeve so that any incidental moisture drains outward. Where the sleeve crosses an open cavity, form a continuous internal mastic seal to prevent bypass draughts.

Treat any visible mould with a quality fungicidal wash before redecorating so the installation starts with clean, dry surfaces. On heritage façades take care to preserve features and use colour-matched pointing for making good.

Step-By-Step Installation

1. Mark The Position From Inside The Affected Room: Set a high-level location with the top of the vent no more than 300 mm below the ceiling. Check there are no hidden services and that you will not cut into a lintel or the damp-proof course. Drill a fine pilot hole through the centre of the proposed opening to establish the datum to the outside.
   
   

2. Create The External Opening: Working from outside, mark a neat rectangle sized to accept a nominal 225 x 150 mm opening, which corresponds to a standard 9 x 6 inch airbrick aperture. Carefully cut the outer leaf and remove debris. If the wall is rendered, use a firm template to keep edges true.
   
   

3. Form The Internal Opening: Cover the cavity to catch debris, return indoors and cut the matching 225 x 150 mm opening through the inner leaf using the pilot hole as the centre. Dress the edges so the internal grille will sit flat.
   
   

4. Dry-fit The Assembly: Offer the telescopic sleeve into the opening and adjust to the wall thickness. Check that the stainless-steel external airbrick, supplied pre-fitted to the sleeve, and the internal slider duct are aligned level with each other. Set the main duct with a slight outward fall so that any moisture drains outside.
   
   

5. Bed The Unit: With the duct acting as a former, bed the sleeve into place using a suitable mortar, keeping faces flush and square to the masonry. Avoid distorting the sleeve during bedding. Where you are repairing or packing on older masonry, use an appropriate lime-based mortar to suit the substrate.
   
   

6. Seal The Cavity: In open-cavity constructions apply a continuous internal mastic seal where the slider tube crosses the cavity. This prevents air bypassing the mineral-wool core and maintains the draught-limiting performance.
   
   

7. Fit The Internal Grille: Once the bedding mortar has taken an initial set, fix the louvred internal plastic grille with integral flyscreen using the supplied screws and plugs. If making good or skim finishing is required, delay final fixing until surfaces are ready, then secure the grille without distortion.
   
   

8. Make Good And Clean Down: Finish reveals neatly, remove dust and waste, and wash previously affected areas with a fungicidal wash before redecorating. Externally, check that the iron-effect stainless-steel airbrick sits neatly and that joints are well pointed to match the façade.

Handover And Everyday Use

Explain that the vent is entirely passive and has no controls or electrics. It works continuously by allowing moisture vapour to migrate outdoors while limiting draughts, and should remain unobstructed at all times.

Remind occupants to use mechanical extract in kitchens and bathrooms during moisture-producing activities and to keep internal doors closed while cooking or showering, then open for cross-ventilation once steam has cleared.

Maintenance

There are no moving parts. Once or twice a year wipe or lightly vacuum the internal grille and flyscreen to remove dust, and check externally that the stainless-steel airbrick is clear of debris. In exposed locations a quick visual inspection after storms is sensible.

If signs of condensation reappear, review housekeeping, heating patterns and extract-fan use before assuming a fault.

Aftercare

If rooms previously suffered from mould, wash down affected walls and ceilings with a fungicidal wash and allow to dry fully before repainting, ideally with a mould-resistant coating.

For larger open-plan rooms consider two vents on opposing walls to even out the effect. Maintain steady background heat in cooler months so indoor air can carry moisture without reaching saturation on cold surfaces.

Other Information

One vent typically serves a room up to about 20 m² in normal domestic conditions and can transmit up to 2.3 litres of water vapour per 24 hours.

The standard sleeve range is 240–340 mm; a 230 extension sleeve is available separately for deeper walls and preserves the warm-sleeve principle through the thickness of the wall.

Always site the unit high on the wall with the top within 12 inches of the ceiling, maintain a slight outward fall, and form a continuous cavity seal where applicable.

The conservation model features a stainless-steel external airbrick with an iron-effect finish to blend sympathetically with heritage façades while delivering the same passive moisture-control performance as the standard Sleeved 230 Vent.

Q) What is the Passyfier Conservation Sleeved 230 Dehumidifier Vent and what problem does it solve?

A) The Passyfier Conservation Sleeved 230 Dehumidifier Vent is a heritage-sensitive, through-the-wall passive vent that reduces condensation and black mould in traditional homes and conservation settings. It uses a mineral-wool diffusion core inside a warm telescopic sleeve to allow indoor moisture vapour to migrate outdoors continuously without fans, electrics or noise. Because the mechanism is vapour diffusion rather than free airflow, draughts and heat loss are kept to a minimum, so occupants remain comfortable and are far less likely to block the vent. The conservation model features an iron-effect finish over a stainless steel external airbrick so the installation blends with period façades while delivering the same performance as the standard sleeved unit. One vent typically serves rooms up to 20m² and can transmit up to 2.3 litres of water vapour per day in typical domestic conditions, making it a practical, fabric-friendly way to stabilise indoor humidity all year round.

Q) How does the Passyfier Conservation Sleeved 230 Dehumidifier Vent work without a fan or electrics?

A) The Passyfier Conservation Sleeved 230 Dehumidifier Vent relies on the natural vapour-pressure difference that exists between warmer indoor air and cooler outdoor air, especially during the heating season. At the heart of the unit is a dense mineral-wool slab housed in a warm sleeve. This structure is effectively transparent to water vapour molecules, which diffuse outward along the pressure gradient, yet strongly resists bulk airflow that would create a noticeable draught. The result is silent, continuous background dehumidification at zero running cost, with very modest heat penalty compared with open vents. By steadily trimming indoor humidity towards a healthier band, the system helps prevent surface condensation on glazing, cold corners and thermal bridges, which in turn discourages black mould growth and protects finishes. There are no moving parts to service and no controls to adjust, so performance is consistent and occupants simply fit and forget.

Q) Where should the Passyfier Conservation Sleeved 230 Dehumidifier Vent be installed for best results?

A) Best practice is to install the Passyfier Conservation Sleeved 230 Dehumidifier Vent high on an external wall in the room that exhibits condensation or mould, with the top of the unit no more than about 300 mm below the ceiling. Warm, moisture-laden air pools at high level, so a high-level position maximises vapour diffusion while keeping any slight air movement well above occupant level. Choose the colder, stale corner furthest from the doorway where practical, and avoid hiding the internal grille behind curtains, wardrobes or tall furniture. In open-plan spaces, two vents on opposing external walls improve distribution and overall stability of humidity. The conservation model suits solid masonry, cavity walls and timber-frame constructions within the supplied sleeve range. In kitchens and bathrooms, retain compliant mechanical extract to remove short-term moisture peaks, then let the Passyfier manage background humidity in the adjacent habitable rooms.

Q) What room size and performance can I expect from the Passyfier Conservation Sleeved 230 Dehumidifier Vent?

A) Under typical domestic conditions a single Passyfier Conservation Sleeved 230 Dehumidifier Vent will serve a room up to about 20m² and can transmit up to 2.3 litres of water vapour per 24 hours. Performance is tuned for habitable rooms such as bedrooms and living spaces, where steady background control rather than rapid extraction is required. If a room is larger than 20m², has complex geometry or remains persistently damp, consider installing a second unit on the opposite wall to improve distribution. As with any passive system, the actual rate varies with indoor and outdoor conditions, occupancy and housekeeping. You will see the greatest benefit when the vent is sited high on the wall, when mechanical extraction is used in wet rooms, and when normal heating patterns are maintained so indoor air can carry moisture without condensing at cold surfaces.

Q) Will the Passyfier Conservation Sleeved 230 Dehumidifier Vent cause draughts or noticeable heat loss?

A) No. The Passyfier Conservation Sleeved 230 Dehumidifier Vent is specifically designed to minimise draughts and heat loss by using diffusion through a tortuous mineral-wool core rather than allowing free jets of outdoor air through the wall. The sleeve and core resist bulk airflow while remaining permeable to water vapour, which means occupants typically do not feel any direct draught and are not tempted to block the vent. Because heat is not carried away by strong air currents, the energy penalty is much lower than with open airbricks or trickle vents left wide open. Installed high on the wall, any slight moderation of air is well above the occupied zone. This is one of the main reasons conservation officers, landlords and householders favour the Passyfier approach in heritage settings where comfort and sympathetic detailing are equally important.

Q) What makes the Passyfier Conservation Sleeved 230 Dehumidifier Vent suitable for heritage and conservation façades?

A) The Passyfier Conservation Sleeved 230 Dehumidifier Vent pairs proven moisture-control performance with an external assembly finished in an iron-effect coating over stainless steel. This delivers a discreet, durable face that sits comfortably on period brickwork and stone while resisting corrosion. The geometry suits a nominal 250 mm by 175 mm opening so the external airbrick presents a traditional proportion on the façade. Internally, a louvred plastic grille with integrated flyscreen provides a clean finish and generous cover for tidy retrofits. Because the unit operates silently and has no visible fan, there is no modern mechanical aesthetic to jar with traditional architecture. For listed buildings and conservation areas, the sympathetic look combined with passive operation helps satisfy both environmental performance and visual sensitivity, subject to local consent where required.

Q) What are the aperture and wall thickness requirements for the Passyfier Conservation Sleeved 230 Dehumidifier Vent?

A) The Passyfier Conservation Sleeved 230 Dehumidifier Vent is sized for a nominal 250 mm by 175 mm wall opening and is supplied with a warm telescopic sleeve adjustable from 240 mm to 340 mm, which covers common solid masonry, cavity and timber-frame constructions. During installation the sleeve is set to a slight outward fall so any incidental moisture drains safely outside, and care is taken to keep the sleeve straight and undistorted within the wall. Where the wall is deeper than the standard range, a compatible extension sleeve for the 230 format can be specified separately to preserve a continuous warm sleeve through the full thickness. Maintaining continuity avoids bypass draughts and is important for reliable diffusion performance. Always check wall thickness and set-out carefully before forming the opening, especially on heritage fabric.

Q) Does the Passyfier Conservation Sleeved 230 Dehumidifier Vent replace extractor fans in kitchens and bathrooms?

A) No. The Passyfier Conservation Sleeved 230 Dehumidifier Vent manages background humidity in habitable rooms by continuous passive diffusion, whereas kitchens and bathrooms generate short, intense moisture peaks that require rapid mechanical extraction. The correct strategy is to retain or install compliant extractor fans in wet rooms, use them during cooking and bathing, and close doors until steam has cleared. The Passyfier then trims the residual moisture load in living rooms and bedrooms, stabilising indoor relative humidity between peaks. This complementary approach protects the building fabric, reduces window streaming and black mould, and maintains comfort without introducing noise or energy costs into habitable spaces. When used together, mechanical extract and the Passyfier deliver a whole-house moisture strategy that suits both modern airtight homes and traditional properties.

Q) What maintenance does the Passyfier Conservation Sleeved 230 Dehumidifier Vent require over time?

A) Maintenance is minimal because the Passyfier Conservation Sleeved 230 Dehumidifier Vent has no moving parts, motors or filters. Once or twice a year, lightly vacuum or wipe the internal louvred grille and flyscreen to remove dust and cobwebs. Externally, carry out a quick visual check to ensure the iron-effect stainless steel airbrick remains clear of debris, especially after storms or heavy leaf fall in landscaped settings. If you have made good around the external face, inspect pointing and perimeter seals periodically and renew as required to maintain weathering. If signs of condensation reappear, first review housekeeping and extract-fan use before assuming a fault, then check that the internal grille is unobstructed by curtains or furniture and that the vent has not been covered inadvertently during redecoration.

Q) Are there any limitations or situations where the Passyfier Conservation Sleeved 230 Dehumidifier Vent should not be used?

A) The Passyfier Conservation Sleeved 230 Dehumidifier Vent is a passive background solution and is not a substitute for rapid mechanical extraction at sources of steam. It must not be used to provide combustion air for gas, oil or solid-fuel appliances, and it is not intended to ventilate commercial kitchens or high moisture industrial processes. Performance is reduced if installed low on the wall, if the grille is obstructed by furnishings, or if cavity bypasses are left unsealed during installation. As with any conservation work, avoid cutting into structural lintels or damp-proof courses and seek consent where required. Treat any existing mould with a quality fungicidal wash before redecorating so the installation starts with clean, dry surfaces and the vent can maintain conditions rather than overcome entrenched contamination.

Q) What practical tips will help me get the best performance from the Passyfier Conservation Sleeved 230 Dehumidifier Vent?

A) Site the Passyfier Conservation Sleeved 230 Dehumidifier Vent high on the problem room’s external wall, keep the top within about 300 mm of the ceiling, and select the colder corner furthest from the doorway. Maintain a slight fall to the exterior through the sleeve, and if the sleeve crosses an open cavity form a continuous internal mastic seal so air cannot bypass the diffusion core. Keep the internal grille free from curtains, pelmets and tall furniture, and use extract fans in kitchens and bathrooms whenever steam is produced. Maintain steady background heat in colder months so indoor air can carry normal moisture without reaching saturation at cold surfaces. In larger open-plan rooms, fit two vents on opposing walls. Finally, complete the job by washing any previously affected surfaces with a fungicidal wash before repainting.

Q) How does the Passyfier Conservation Sleeved 230 Dehumidifier Vent differ from the standard sleeved Passyfier in appearance and specification?

A) Functionally, the Passyfier Conservation Sleeved 230 Dehumidifier Vent uses the same diffusion principle, sleeve range and room-size guidance as the standard sleeved model. The key difference is the heritage-sensitive external specification. The conservation version is supplied with a stainless steel external airbrick finished in an iron-effect coating so it sits discreetly on traditional façades and in conservation areas. The nominal wall aperture is 250mm by 175mm, providing a conservation-appropriate proportion, and the internal louvred plastic grille with flyscreen is sized with a generous cover to simplify making good during retrofits. Moisture transmission capacity, up to 2.3 litres per day, and the recommended room size, up to 20m² per unit, are the same, so selection between the two is usually driven by visual requirements and planning context rather than performance differences.

Technical Data Sheet

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