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Air Tight Homes Still Need to Breathe

Dear Wendy

By Wendy Thomas, Residential Product Manager, July 2014

I am planning on building an energy efficient home as air tight as possible. Will this have a negative effect on the indoor air quality?

Building More Energy Efficient Homes

The drive towards building more energy efficient homes is making the built fabric of the home significantly more airtight. This can have a negative impact on the indoor air quality within a dwelling and the health of the occupants. Some of the impacts on the health of occupants are indoor air pollutants such as CO2, volatile organic compounds, nitrogen dioxide from gas appliances and smoking. High levels of humidity will encourage condensation, mould growth and also increase the dust mite allergen. All of these pollutants can have a detrimental effect on the occupant’s health which can cause potential health problems. The most common health problems are allergic and asthma symptoms, airborne respiratory infections, irritation and fatigue.
The transition towards air tight homes means that purpose –provided ventilation is now more necessary than before. The most effective way of combating these issues is the use of mechanical ventilation with heat recovery. MVHR is fast becoming the most common method of whole home ventilation for new build properties.

Wendy Thomas, Residential Product Manager says "Historically homes have not been constructed with air tightness in mind. Traditional features such as chimneys, combined with leaky construction ensured that homes were well ventilated and the issue of indoor air quality was not considered or questioned".

MVHR offers year-round, whole home ventilation that will remove condensation and pollutants, significantly improving the indoor air quality. These systems work by combining supply and extract in one unit. Moisture-laden, stale air is extracted from ‘wet’ areas, such as kitchens and bathrooms. The heat from this extracted air is recovered via a heat exchanger, and this tempered air is filtered and delivered into the living areas of the home creating a healthier living environment for the occupants.

Providing the ventilation system is designed, installed and commissioned correctly, and takes into account how air-tight the building is when it is designed there is no reason you should have to compromise on the indoor air quality of air-tight, energy-efficient homes.