What is the Most Energy Efficient Ventilation System

Ventilation in your home is essential in improving airflow. Good ventilation in bathrooms and kitchens helps to reduce humidity from bathing and cooking and stops condensation from forming on walls and ceilings that could lead to damp or mould. With energy bills at record highs, and the need to make our homes as efficient as possible at the front of our minds, choosing the most energy efficient ventilation system is important.

What is ventilation

Quite simply, ventilation is the process by which stale air in an environment is replaced by fresh air – usually from outdoors. In a home you might have some areas which are passively ventilated or actively ventilated.

Passive ventilation can be achieved simply by opening a window or using the natural flow of air through the fabric of your home – air bricks, vents, and other spaces.

Active ventilation is achieved using a ventilation system. This might be a single room extractor fan mounted on a bathroom wall or a whole house system that uses a central unit and then distributes air throughout the building.

While passive ventilation does not require the use of a power source, it may not always be the most energy efficient choice. Uncontrolled airflow, particularly on chilly days, may result in the loss of warmth from your property which will require additional use of your heating.

How different ventilation systems work

All mechanical ventilation systems work by means of a fan in one of two ways:

• Extract ventilation – blowing the air out of the building
• Input ventilation – drawing the air into the building

Extract ventilation is the most common system in the form of single room extractor fans but there are also whole house options known as “Mechanical Extract Ventilation” or MEV. Whole house systems involve the installation of vents in multiple rooms that pull the air through a central unit and expel it outdoors. MEV systems can be designed to include heat exchangers that use the warmth of the outgoing air to heat up fresh air as it is drawn into the home. These are known as “Mechanical Ventilation with Heat Recovery” or MVHR. The nature of whole house MEV and MVHR systems means that they are not normally installed in an existing property unless as part of a full restoration.

Positive Input Ventilation systems (PIV) work in the opposite way to MEV. Rather than pushing the air out of the property, they actively draw it in through a central unit and then distribute it around the house. This fresh air displaces the stale or humid air which vents naturally though air bricks and vents in the envelope of the building. Some PIV systems include a heater that warms the incoming air which can be switched on or off depending on the time of year.

Which ventilation systems are most efficient

Modern ventilation systems, whether single room or whole house are designed with energy efficiency in mind. Fan and motor design, and the use of sensors that detect what power level is required to reduce humidity mean that the ventilation systems can use minimal power to function.

One way of looking at efficiency is the amount of money different systems will cost you to run them over the course of a year.

A simple extractor fan in your bathroom such as the EnviroVent Cyclone 8 does not run continuously and automatically adjusts its power level in operation so that when the room is most humid it works harder and when less power is required, it slows down. This means that it is highly effective at reducing the amount of water vapour in the air while using minimal power. With average usage over the course of an entire year, a Cyclone 7 will cost less than £4.50 to run.

Positive Input Ventilation Systems (PIV) are more effective at protecting your whole home from condensation, damp, and mould than simple extractors. They do run continuously to circulate air, but thanks to their efficient design, they are quite cheap to run. Without using the heater to warm incoming air, a PIV system such as the ATMOS Air will cost less than £10 over 12 months. If the heater is used on cold days, the cost rises to around £74 – about £0.50 per day.

In an average house, with three extract terminals, an MEV system such as the MEV 160 costs less than £21 to run for 12 months.

MVHR systems which use a heat exchanger require slightly more power operate than a standard MEV system, but a substantial amount of that cost would be offset against your heating bills because they are highly efficient at retaining heat in the property. In a typical house, the energiSava 400 system would cost around £55.

Which system is right for you

When choosing the right ventilation system for your needs, it is important to speak to a specialist. EnviroVent have ventilation experts across the country who can visit your home to conduct a FREE home survey. During the survey, they will assess the different sources of water vapour in your property and the size of different rooms so that they can recommend an appropriate solution that is both effective at preventing condensation and efficient in use. To find a ventilation expert near you, simply enter your postcode below.