Why Ventilation is Important
Modern homes have become increasingly energy conscious. To save energy, we have blocked our chimneys, added wall and loft insulation, draft-proofed, double-glazed, and turned our homes into sealed boxes.
An average family home creates 16 pints of moisture a day from general everyday activities.
But where does all this moisture go? Without the correct ventilation, this will leads to higher humidity and moisture levels which are unable to escape, creating condensation which then leads to damp, mould, and overall poor indoor air quality.
Did You Know
- 1 in 5 UK homes suffer from mould and condensation problems. Unless the problem is dealt with professionally, it will cause problems time and time again.
- You won’t solve a mould problem with bleach and household cleaners. Mould will keep coming back unless you deal with the root cause. What’s more, it can also affect your health and immune system, causing headaches, breathing difficulties, nausea, fatigue and even triggering respiratory problems and asthma.
- The effect of not having good-quality air in the home is dramatic. The average person spends 90% of their time indoors, and 70% of this time is spent in their own home. Therefore, the indoor living environment is crucial to the health of the occupants.
- Most people don’t associate health problems with the air in their homes, yet as many as 900 toxins pollute our indoor air. Certain indoor sources, such as pet dander and VOCs from cleaning and aerosol products, have negative health effects and can lead to serious health issues.
- Mould and dampness are caused by excess moisture. Moisture in buildings can be caused by leaking pipes, rising damp in basements or ground floors, or rain seeping in because of damage to the roof or around window frames. Everyday activities can lead to condensation on internal surfaces leading to mould growth in the property.
- Condensation is formed when warm, humid air meets colder surfaces such as windows and exterior walls. When there is good airflow through a building, temperatures are evened out, providing a better mixture of air.
- Good ventilation systems also help manage airflow in and out of a building. Extractor fans in “wet” rooms such as bathrooms and kitchens, where there is more moisture from bathing and cooking, extract the damp air at the source to the atmosphere and prevent humidity from spreading to other rooms.
- The installation of ventilation systems is now considered a controlled service. You need to be a competent installer with the correct qualifications to install ventilation products, providing notice to building control. Taking specialist accredited courses will give contractors and installers a good understanding of the different ventilation strategies and installation requirements, helping them to become more competent. This certification is a requirement for contractors and installers wishing to join a competent person’s scheme.
- You can reduce the amount of condensation in your home by taking a few simple steps in daily life. For example, you can use pan lids while cooking to reduce the amount of moisture that is released into the air when water is boiling, and furniture can be moved away from walls to increase airflow in your living space. Small things like wiping down cold surfaces to remove moisture and opening windows in the warmer months also help to reduce condensation.
- In most cases, damp and mould originate from condensation. When temperatures drop, the air can no longer hold as much moisture and will migrate to the coldest parts of the house, where it condenses on windows and walls.
- Relative humidity measures how much water vapour is in the air compared to the maximum amount the air can hold. The warmer the temperature, the more moisture the air can hold. When the temperature drops, the air can’t hold as much moisture, so relative humidity will rise, which can lead to condensation, dampness, and eventually mould.
Types of Ventilation Solutions
- Positive Input Ventilation (PIV) is a whole-house air ventilation system that draws filtered air into a property from outside. By supplying filtered air into the property, it dilutes and displaces indoor contaminants, helping create a healthy living environment.
- Extractor fans are a functional and practical solution for controlling excess humidity or unwanted odours. On a basic level, any extractor fan draws out the moisture at the source. This creates a negative pressure in the dwelling, allowing the extracted moisture-laden air to be replaced by external air.
- Mechanical Extract Ventilation (MEV) systems can be either whole-house centralised units or decentralised fans. The centralised MEV systems are typically located in a loft space or hallway cupboard. Multiple ducts run from the unit to the kitchen, bathroom, en-suites, and other wet rooms of a property to simultaneously draw moisture-laden air from these wet rooms to control humidity levels. Decentralised systems continuously run extract fans in each individual wet room. Continuous running extract ventilation is a more controlled and energy-efficient to ventilate a dwelling than a traditional on/off fan.
- Mechanical Ventilation with Heat Recovery (MVHR) systems are sophisticated whole-house ventilation and condensation control units. The systems extract stale, moisture-laden air from wet rooms such as bathrooms, which passes over a high-efficiency heat exchange cell before reaching the atmosphere. Simultaneously, filtered air is drawn into the unit from outside and is warmed by the heat exchange cell before being delivered through supply vents into the living, dining and bedroom areas.
Key Advice
Whether you’re a homeowner or a landlord, it’s vital to have a full property survey before purchasing a ventilation system. This will help you get the right solution for your situation and improve indoor air quality.
The NHIC wishes to thank WG2 | Consumer Voice members for contributing to this guide.
Please note that this guidance document produced by the NHIC was correct when published. However, information and regulations may have changed since then. Therefore, it is always advisable to seek the most up-to-date information and expert advice before deciding to ventilate your home.
