Query: We're spending much more time indoors as a family during the restrictions, and have become aware of how our home can feel either stuffy or Baltic. How can we make improvements to our air quality and maybe save energy too?
Answer: While Ireland doesn't have a particularly cold climate, it often feels quite damp here and putting in a heating system has often been as much about drying a room as raising the air temperature, especially if ventilation is limited or the building occupancy is high. This characteristic is measured as indoor air quality (IAQ).
Traditionally, the solution to poor air quality or ventilation was to open the windows in good weather - as long as there are no concerns about security, road noise and air pollution.
Otherwise, a trickle-vent, either on a window or through the wall, which is humidity-sensitive, is very useful. We have tested these in situ, and they have been shown to let in minimal external noise and air pollution while still admitting fresh air. Nor are they expensive to have retro-fitted.
More recently, mechanical ventilation systems have been installed in more energy-efficient homes, but it's not often realised that these can lead to increasingly poor indoor air quality if the air is delivered through dirty filters or ducts. That problem is exacerbated if the house was designed to rely on a ventilation system but the occupants switch it off, maybe because it is too noisy or to cut the energy bills associated with running the fan unit.
Before starting alterations or improvements, it is advisable to consult a registered architect, as they will look at your home holistically, as a living system. Think about the following:
AIR QUALITY IN NEW HOMES
Higher Building Regulations standards now require a newly-built home to be fitted with a ventilation system for energy efficiency, reducing heat losses to outside as well as uncontrolled air infiltration. This obviously improves the Building Energy Rating (BER) of your home. Usually, an electric fan draws the stale air from the living rooms through the bathroom to outside. Simple controls allow you to adjust for humidity, air temperature and carbon dioxide levels.
There are different types of mechanical ventilation systems. Some also supply air, usually preheated fresh air, to the living rooms, using a second fan. A heat exchanger recovers the warmth from that stale air to preheat the fresh air coming in, known as Mechanical Ventilation with Heat Recovery (MVHR).
The downside is that the energy use involved in running the double-fan circuits of MVHR can use 60pc more carbon than that of other systems such as demand-controlled, passive stack or other types of extract ventilation systems, where the indoor air is supplied to each room through ducts.
AIR QUALITY IN OLD HOUSES
To increase energy efficiency, even in an older building, we are encouraged to improve the air-tightness of the house's external envelope, whether at the junctions of the ceiling/ wall/ floors or around the windows and doors.
However, air-tightness needs to be balanced by providing an adequate fresh air supply for the occupants, separate to that which will be consumed by a fireplace or stove. 'Combustion air' needs to be available to solid fuel appliances, and brought directly from outside to the hearth, where an efficient closed stove can be inserted into an existing fireplace.
Thoughtful design can then avoid any unnecessary draughts between or across rooms that are typical of traditional chimneys and conventional wall ventilation grilles.
One simple and cheap solution for old houses can be to leave a window open by a fraction so as to provide a trickle of fresh air from outside, or to use ventilation fittings with sensors, for example, on roof lights, which adjust for rain or high winds, and adding security hardware to suit.
We have tested these approaches and they also reduce noise nuisance and other pollution entering from outside.
ALL ABOUT MAINTENANCE
When any ducted air ventilation system is fitted, it is important to have it regularly serviced by specialists. Unfortunately, occupants are often not familiarised with or aware of the installation in their building, which could have serious implications for their health.
For instance, one facilities manager in an apartment building reported recently, when responding to complaints about black mould forming on bathroom ceilings, that the residents had switched-off the ventilation fans.
Spores in the air find the cooler surfaces making condensation inevitable, and that can lead to the proliferation of mould and bacteria. These can cause harm and trigger allergies for those who suffer asthma or have other underlying respiratory problems.
SICK BUILDING SYNDROME
We have all become, at this difficult time, acutely aware of the prevalence of respiratory diseases from asthma to lung cancer (many airborne pollutants are toxic). In a typical year in Ireland, respiratory deaths attributed to poor housing conditions alone equal those caused by road accidents.
Where air is supplied through fans, the constant noise of air movement associated with some MVHR and low indoor air quality are two factors implicated in Sick Building Syndrome, according to research published since 2011. Symptoms are found more often in mechanically, rather than naturally, ventilated buildings, ranging from throat irritation, concentration problems, nasal irritation, dizziness, fatigue, eye irritation to headache.
HOW TO IMPROVE AIR QUALITY
Fresh air smells sweeter, as you can tell by 'sniffing the difference' when a window is ajar, or even when you just release the catch on a window to a open 'snib' position. Some people like to use fans or air purifiers that 'filter' the air. While they have their uses, they don't provide any fresh, oxygenated air from outside.
IAQ is often overlooked in the drive for energy efficiency. There is no specific grant available from the SEAI, although there is for an exhaust air-to-water heat pump which might form part of an energy retrofit system design. If you are planning a deep retrofit, the Tipperary Energy Agency's 'Superhomes' grant scheme considers these elements as essential.
If you're building from scratch or adding an extension, where possible, choose internal finishes of timber, untreated textiles, hemp fibre, lime and other natural materials which absorb and release moisture, or 'breathe'. Controlling indoor humidity reduces house dust, mould, stains and dampness.
And if you've moved into a new build, it's worth buying house plants that humidify the air, such as succulents, aloe vera and spider plants to process some off-gassing from new plastics, carpets and the dye from textiles.
If you are considering changes to your home, work with a registered architect. Find one on riai.ie, the registration body for architects in Ireland.
Sally Starbuck, BA BArch (Hons) RIBA MRIAI, is an accredited client adviser and environmental architect with Gaïa ecotecture; gaia-ecotecture.eu
Do you have a design dilemma we can help you with? Email firstname.lastname@example.org. Advice provided is for guidance only and readers are advised to seek professional assistance for any proposed project.