How to Choose the Right Ventilation Fan at Home (Manrose Guide)

When it comes to domestic ventilation, we all need help; thanks to Manrose, we now have a guide on, How to Choose a Ventilation Fan at Home.

We read their guide and we would like to present the main points recommended by this ventilation fans manufacturer as it relates to ventilation at home. Ventilation is absolutely necessary, and it is good to know the following matters related to ventilation at home:

• What are the Problems caused by Poor or No Ventilation?
• What do Regulations say about Ventilation at Home?
• Where should we Install a Ventilation Fan at home?
• What Ventilation Fan is Required for the Minimum Air Changes Required per Hour?
• How to Choose the Right Ventilation Fan at Home
• What options are there for Ventilation at Home?

If the ventilation fans are not working or nonexistent, or if there is poor ventilation in a home, there are a few problems that may arise.

First, there is the stale air which we all hate. Stale air can be caused by things such as cooking smells, odours remaining in the bathroom, a general lack of ventilation around the house, smoking, and a damp atmosphere.

Stale air is not good for health and is very unpleasant to breathe.

Stale air can cause a certain level of discomfort and poses a risk of respiratory illness and general poor health.

Condensation is another problem caused by poor ventilation at home.

When the steam from the kitchen or the bathroom spreads in the house and finds cooler surfaces around the house, there is condensation.

We may try to conserve heat by sealing the windows and keeping them closed, therefore reducing natural ventilation; this causes more condensation.

The consequences of condensation in a home include mould growth, peeling wallpaper, and even severe structural damage such as wood rot or dampness. 

According to the Building Regulations Document F1 (2006 Edition), we know the importance of ventilation.

Furthermore, these regulations stipulate that mechanical ventilation must be installed in kitchens, bathrooms (or showers), and toilets.

The ventilation fans installed need to meet or exceed the current Building Regulations so that humidity is removed at the source before it can reach the cooler part of the dwelling.

In particular, what is recommended and even required by the Building Regs are as follows:

Intermittent fans - they operate on an "as required" basis and are turned on or off with the light switch or via other control (such as a pull cord switch). These are the regular fans installed on the wall or ceiling that provide high extraction for a short period of time when turned on.

In the bathroom or shower room, the regulations require a fan capable of extracting min. 15 litres per second when installed.

In a toilet, separate from a bathroom, the regulations require a fan capable of extracting a minimum of 6 litres per second when installed.

In the kitchen, the regulations require a fan capable of extracting min. 60 litres per second when installed.

And in the utility rooms, the regulations require a fan capable of extracting min. 30 litres per second when installed. 

Continuous Fans - they work all the time to extract excess moisture and stale air at low extraction rates throughout the day, and they have a boost function when humidity levels rise.

They are becoming more common, for they ensure better indoor air quality while using less energy than intermittent fans, thus being more cost-effective to run.

The Regulations regarding these in terms of air extraction rates are as follows: in the bathroom or shower room - min. 8 litres per second, in the toilet (separate from a bathroom) min. 6 litres per second, in the kitchen - min. 13 litres per second, and in utility rooms - max. 8 litres per second.

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The location of the ventilation fan is very important; it is of utmost importance to site the fan correctly.

A ventilation fan needs to be always sited in the furthest window or wall from the main source of air replacement in order to avoid short-circuiting the airflow.

Also, it needs to be located as high as possible in the window or wall nearest to smells or steam, but not directly above eye-level grills or cooker hoods.

If a room in the house contains a gas boiler or any other fuel-burning device with a non-balanced flue, it is imperative that there's enough replacement air to prevent fumes from being drawn down the flue when the fan is extracting to its utmost capacity.

Furthermore, according to the IEE Regulations in the UK, conventional mains voltage fans in a bathroom or shower must be located in places where they cannot be touched by a person using the bath or the shower, as well as away from any water spray.

SELV fans (Safety Extra Low Voltage Fans, 12V fans) are specifically designed for safe ventilation of toilets, bathrooms, and shower rooms.

They can be fitted within the area with splashing water (see their full specs) without any risk of electric shock. 

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When considering where and what fan to install in a particular room at home, we need to know what is the minimum air changes required per hour.

In order to calculate the correct air changes required for a room, you need to know the room volume in cubic metres, which is basically the length x width x height of the room, which needs to be multiplied by the number of air changes required.

According to the current Building Regulations, here are the minimum air changes required per hour:

• Bathroom & Shower Rooms - 3 air changes/h
• Bedrooms - 2 air changes/h
• Cafés - 10 air changes/h
• Canteens - 8 air changes/h
• Cellars - 3 air changes/h
• Changing Rooms with Showers - 15 air changes/h
• Conference Rooms - 8 air changes/h
• Garages - 6 air changes/h
• Hairdressing Salons - 10 air changes/h
• Halls & Landings - 3 air changes/h
• Hospital Rooms - 4 air changes/h
• Laundries & Launderettes - 10 air changes/h
• Living & Other Domestic Rooms - 3 air changes/h
• Meeting Rooms - 4 air changes/h
• Offices - 6 air changes/h
• Restaurants & Bars - 6 air changes/h
• School Rooms - 2 air changes/h
• Shops - 8 air changes/h
• Sports Facilities - 6 air changes/h
• Store Room - 3 air changes/h
• Toilets – Domestic - 3 air changes/h
• Toilets – Public - 10 air changes/h
• Utility Rooms - 15 air changes/h
• Workshops - 6 air changes/h

In light of all the requirements and specifications above, we need to find out in particular how to choose the right ventilation fan at home.

When we choose the right ventilation fan, we need to bear in mind the types of air extractor fans and the types of switching/turning on for the fans available. 

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Type of Air Extractor Fan for Home

Axial Fans - the axial fans are designed to move air over short distances of up to 2m ducting.

For example, you need an axial fan if you install it on the wall, the window, or the ceiling and the exit is straight through or the ducting is under 2m long.

The axial fans come in 4-inch (100mm, the most popular ones), 5-inch (125mm), 6-inch (150mm), and larger sizes.

Centrifugal Fans - these are designed to move air over longer distances, performing well against the pressure caused by longer lengths of ducting and resistance by grilles.

They are not as popular as the axial fans but sometimes are recommended to use.

When ducting vertically, it is recommended that a condensation trap is used. 

Type of Switching On/off for the Ventilation Fans

Standard ventilation fans: the standard model fans are wired to the wall switch for remote switching through either a wall light or a separate switch. They are the most common ones. 

Timer ventilation fans: the timer models have a built-in adjustable time delay operated by the light switch. The time delay can be adjusted at installation, and these are suitable for locations where you need some extra ventilation even after the light is turned off. 

Pull-cord ventilation fans: the pull-cord fans have a pull-cord switch to be turned on/off when needed via this means. 

Humidity ventilation fans: the humidity models with built-in adjustable sensor turns the fan on when a certain threshold of humidity is sensed. They are automatically turned ON or OFF when the humidity sensor detects the humidity levels. 

PIR or Microwave Sensor ventilation fans: the PIR models are sensitive to movement. When someone enters the room, the fan turns on, and when presence is not detected, it is turned off.

On our website, we have a wide range of ventilation systems available, and the three main manufacturers we distribute are Airflow, Manrose, and Envirovent.

For further information concerning what ventilation fan you require at home, do not hesitate to contact us.

You can also visit the dedicated sections for Airflow Extractor Fans, Manrose Extractor Fans, and Envirovent Extractor Fans.