Why Ventilation Is The Key To A Healthy Home
Why We Ventilate
By Wendy Thomas, Residential Product Manager, August 2017
The drive towards building more energy-efficient homes has encouraged builders to significantly increase the airtightness of their dwellings in a bid to meet building regulations and ensure low energy bills in the longer-term. However, building airtight properties without adequate levels of ventilation can and does have a negative impact on indoor air quality, and that’s an issue that needs to be highlighted.
By sealing up our homes to keep valuable heat from escaping, we effectively seal in the moisture produced by everyday activities like washing, drying, bathing and simply breathing. The average family produces up to 10 litres of moisture per day, and, if this moisture isn’t extracted, the high levels of humidity encourage condensation which leads to mould growth and an increase in dust mites. These airborne allergens can trigger and even cause asthma and lead to other respiratory problems.
Also trapped within the indoor air are the pollutants produced by burning fuels; cooking; using cleaning, beauty and DIY products, and smoking. Added to these nasties are the external pollutants that enter the home via open doors, windows and natural leakage points - including pollen and, in many parts of the UK, harmful Radon gas. The ‘drying out’ period for new build homes can increase both moisture and pollution levels for many months.
A recent report from the Royal College of Physicians revealed some alarming statistics on the impact of indoor air pollution on our health. It states that indoor air can be up to 50 times more polluted than outdoor air, containing up to 900 potentially dangerous chemicals. This increases our chances of developing serious illness including lung cancer and heart disease.
So in the transition towards airtight building methods and energy improvements, adequate ventilation is now more necessary than ever. Choosing the correct ventilation strategy for your home will not only keep it free from condensation and mould, it will ensure your indoor air quality is at an optimum level: fresh and free from pollutants.
Most Effective Methods of Ventilating Your Home
If you’re planning a self-build project, remember that there isn’t a one-size-fits-all solution for ventilating a home. The most efficient strategy will be based on the size and layout of your home, as well as how you plan to use it.
The most energy-efficient and effective method of preventing condensation and cleaning up your indoor air is whole-home ventilation. A continuously-running mechanical system is ducted throughout the home, extracting stale, moisture-laden air from all the wet rooms.
A continuous mechanical supply and extract system with heat recovery, or MVHR, will help you save energy and offers the best levels of controllability. An MVHR system combines supply and extract ventilation via a balanced system where the incoming air is filtered to improve air quality. It works by transferring heat from the humid extract air into a heat exchanger. This heat is used to pre-heat the incoming, fresh air which is ducted to habitable rooms. It does not mix the air, but simply takes the heat and uses it for the incoming, fresh air.
Our MVHR systems offer some of the highest available thermal efficiencies, so a typical system will recover up to 95% of the heat being extracted, offering homeowners significant energy savings combined with very low running costs. The ability to pre-heat the property when needed, and to utilise free summer cooling, gives homeowners the flexibility they now require to continue saving energy through the changing seasons. This kind of intelligent control is very appealing right now.
Within our MVHR range we offer options for wall, loft and ceiling-void installation, in sizes that have been designed to ventilate all types of properties, so the MVHR system is only as powerful as is needed.
An Alternative Method to MVHR
An alternative to MVHR that still ventilates the whole home is Continuous Mechanical Extract, or MEV. Today’s MEV systems are easy to install and require little energy to run. Nuaire’s MEV has a lower-profile and can be mounted in any orientation, which helps make installation easier. It can also be installed at either first or second fix stages for extra flexibility. A low-watt motor provides high performance ventilation which will keep your property free from condensation.
PIV is a Trusted Alternative
Within the self-build market, a somewhat lesser-known method of whole-house ventilation is Positive Input Ventilation or PIV. This strategy works by providing a continuous supply of fresh, filtered air into the house through a fan mounted in the loft.
The gently warmed air enters the home through a ceiling diffuser, creating a positive pressure effect that reduces humidity levels and forces out air pollutants, improving indoor air quality and helping to minimise the entry of harmful Radon gas.
Nuaire invented the strategy back in 1972 and today PIV is a trusted alternative to MVHR and MEV which, due to its BBA certificate, still meets building regulations. Its ease of install and low running costs are hugely appealing to self-builders.
Prevent Polluted Air Entering Your Properties
While bringing fresh air into the home is the essence of ventilation, the quality of the outside air must be taken into consideration. Air pollution has been much discussed in the media this year. A report from Royal College of Physicians has revealed that up to 50,000 early deaths each year are the result of poor air quality.
Nuaire has considered air filtration as an important enhancement to its MVHR range, and recently launched the new Q-Aire Carbon Filter. This simple solution provides increased filtration of the air brought into homes via MVHR systems, so is perfect for properties built in urban, industrialised areas. It filters harmful carbon dioxide as well as nitrogen oxide, and helps to reduce noise within the duct.
Getting It Right From the Start
Getting design advice early on from your ventilation manufacturer can help you navigate your way painlessly through Building Regulations. They can give you advice on compliance and the best design of your ducted system to ensure optimum performance.
Approved Document Part F and Part L1A are the sections affecting ventilation and the conservation of fuel and power. Part F dictates which methods or ‘systems’ should be used, and recommends ventilation rates for each room based on intermittent extract and continuous extract systems. It states that fixed mechanical ventilation and controls must be correctly commissioned by a competent person.
Part L1A dictates that all new build homes must achieve a minimum level of energy-efficiency, and gives a minimum level of heat recovery efficiency that an MVHR system should achieve, which is more than 70% efficiency.
Building Regulations can seem complicated, which is why the free design services offered by Nuaire and many other ventilation manufacturers can be particularly helpful. Aside from meeting regulations, getting advice early on can help you avoid pitfalls and ensure you make the right choice in your ventilation system and it’s layout within your home.
Written By Wendy Thomas, Residential Product Manager