A version of this article appeared in the Southern Highland News, 7 August 2013, under the title “Dry Homes — warmer and healthier”. More articles from the CANWin column.
We’ve barely begun to see how we can use the sun to make our lives healthier and more comfortable. It’s not just about solar hot water or solar power. Ready to use sun power is waiting in many unexpected places.
For example, have you ever climbed into the ceiling on a cool day and noticed how warm the space is? Now if you could just get that warmth down to the living room…
The technology to do this is called Heat Recovery Ventilation (HRV). It’s fairly new in Australia, but it’s been used in America and Europe for many years.
Window condensation is a sure sign you have a damp home. That dampness in the air which is slowly attacking your new paint job on the window frames is also costing you and the environment 2/3 more energy to heat and cool than dryer air.
Cooking, showering, breathing, etc. adds about 30 litres of water vapour to the air in an average Australian home every day. This is good for mould and dust mites, but not so good for people. The World Health Organisation recommends homes should have a relative humidity of 30-50%. Most homes have a relative humidity of 80-90%.
Mould spores are the number one trigger for Asthma and Allergy sufferers. Mould can also lead to coughs, colds, ear infections, low energy levels, and even depression. Dust mites love a damp environment. Next time your sheets feel damp remember there are billions of dust mites pooing and shedding their skins in your bed. Dust mites are the second biggest trigger for Asthma and Allergy sufferers.
How it works
An HRV system consists of a temperature-controlled fan, a medical-grade air filter, ducting from the fan to the rooms, and a control unit. It has no heater or heat exchanger. Its job is to move air that’s already at a useful temperature to the places where you want it.
The system creates a slight positive pressure inside the building as it pushes the roof air down. This forces air outside, through the spaces where it normally escapes, and with it go moisture, mould, and mites. The air is cleaner, drier, and easier to heat.
The only electricity the system uses is to run the 80 watt fan. The real power of this system is from the sun.
Disclosure: Claire Burniston is the owner of Fresh Heating & Cooling, a supplier of heat recovery ventilation systems.