Connection of a hood on a wall facing outside - advantages and disadvantages

Connecting a Hood to an Exterior Wall – Advantages and Disadvantages

A kitchen hood can be installed in various ways and locations in the living room or kitchen. Here’s a look at the pros and cons of connecting a hood to an exterior wall of a home or flat.

Ways to Connect a Kitchen Hood

The connection method depends primarily on the hood type. Let’s outline the main differences based on where the hood is installed:

• Wall-mounted (chimney hoods) are mounted on the wall above the hob

• Island hoods are installed above the hob on the kitchen island, mounted on the ceiling (either structural or suspended)

• Ceiling hoods are mounted in the ceiling (structural or suspended) directly above the hob

• Integrated hoods are installed in an upper cabinet above the hob

• Telescopic hoods are also fitted in a kitchen cabinet above the hob (unlike integrated hoods, they activate when the front panel is extended)

• Countertop hoods are installed in the kitchen counter beside the hob or integrated with it

Connecting a Wall-Mounted Hood

This article will focus on connecting a wall-mounted (chimney) hood. It can be connected in two main ways:

• As a recirculating hood – with an added carbon filter (sometimes two), allowing the hood to operate in a closed circuit, absorbing moisture – the carbon filter should be replaced every 3-6 months

• As an extractor – connected via a duct to an external vent, which removes vapours and moisture outside the kitchen (open circuit)

We recommend the second option (extractor) as it allows the hood to work more efficiently and quietly. The recirculating option is recommended when extraction isn’t possible due to construction limitations (e.g., no dedicated ventilation duct) or when using a decorative island hood with only a recirculating mode.

Connecting a Hood to an Exterior Wall

The location for installing a wall-mounted hood is usually determined by two factors:

• Hob placement (the hood should be directly above it)

• The location of ventilation ducts

Theoretically, a hood can be installed on a different wall from the ventilation ducts, but we advise against it. This would require longer ducting with more bends, increasing noise and reducing efficiency. The exhaust duct should be as short and straight as possible for maximum performance and quiet operation.

There is another way to connect a wall-mounted hood as an extractor – by mounting it on an exterior wall, venting moisture and vapours outside the building.

Is this a good idea? Let’s find out.

Connecting a Hood to an Exterior Wall – Pros

1. Quiet and efficient operation – a hood correctly connected to ventilation operates more quietly and effectively. Additionally, with an external motor (if supported), the hood will be nearly silent in the kitchen, with only a gentle airflow noise.
2. Short duct section – only a short length of duct is needed to connect the hood to the wall’s exterior, eliminating bends and maximising airflow.
3. Easy cleaning and maintenance due to the duct’s short, straight structure and accessible location.
4. Option for an external motor (façade mounted) for even quieter operation.

Connecting a Hood to an Exterior Wall – Cons

1. Noise emitted outside through the duct.
2. Construction work – drilling through an external wall and sealing the hole to prevent rain ingress.
3. Reduced sound insulation from outside noise.
4. Need for a backdraft damper near the outlet, which could jam over time.
5. Air vent could expel directly into a garden, causing inconvenience nearby.
6. Condensation forming inside the duct.
7. Sloping duct required through the wall, increasing the risk of stains on the façade.
8. Thermal bridging evident in thermal imaging.
9. Condensation increases the risk of mould and mildew within the duct.
10. Insects may enter through the duct.
11. Air reversal from outside through the hood.

Summary of Installing a Hood on an Exterior Wall

As shown, the disadvantages of connecting a hood as an extractor to an exterior wall significantly outweigh the benefits. Before making a decision, it’s advisable to consult professionals and consider an optimal solution.

To conclude – the comparison highlights four advantages: quiet and efficient operation, short duct length, easy maintenance, and the possibility of an external motor. We can also achieve these advantages without drilling through an external wall.

Connecting a hood to an external wall could lead to numerous drawbacks, potentially causing inconvenience and additional costs.