Control of airflow into and through the house is important for winter and summer comfort, we discuss this in this weeks article. Control of airflow into and through the house is important for winter and summer comfort.

 

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Natural ventilation

Natural ventilation is any uncontrollable air movement that enters the home, usually through cracks and small holes in the home. Most commonly today, people will opt to seal these gaps to increase the homes energy efficiency. Though without complementing passive solar design features, the air tight home will not respond to its best abilities without the use of heating and cooling systems or opening doors and windows.

For comfortable conditions to be achieved in winter, there should not be excessive entry of outside cold air into the house through gaps in walls, windows and door fittings. With windows and doors closed, the house should be relatively airtight, with only enough fresh air admitted to meet the needs of occupants and gas (or other fuel-burning) appliances.

Natural ventilation can be unpredictable. Uniformly relying on natural ventilation to cool your home won’t always be successful. In mild weather you would experience a lack of ventilation and during the more extreme weather, your home can become uncomfortable and more expensive to heat and cool with electronic systems.

Spot ventilation

Spot ventilation is the vents used to remove indoor air pollution and moisture at the source, eg. Vents in bathrooms to expel heavy moisture air, or exhaust fans above cooking appliances to expel unwanted odour or heat.

Whole house ventilation

In order to maximise the cooling effects in summer, the house should be constructed with windows or louvres that can be opened to allow prevailing cooling breezes to pass through the house when required.

If natural breezes do not provide adequate ventilation, fresh air can be drawn into the house by large mechanical exhaust fans installed in the roof. These do not require as much electrical energy as air-conditioners, and can ventilate the entire house.

Alternatively, a ceiling fan will create air movement to make for greater comfort within a particular room. Before considering a ceiling fan, make sure that the ceiling is high enough (at least 2.4 metres) to allow the fan to be mounted safely above the reach of occupants. Lights should not be mounted above the fan, as this will cause annoying flickering.

To clear it all up, these are four different ventilation systems you could use in your home:

  • Exhaust ventilation systems work by depressurising the building and are relatively simple and inexpensive to install.
  • Supply ventilation systems work by pressurising the building, and are also relatively simple and inexpensive to install.
  • Balanced ventilation systems, if properly designed and installed, either pressurise or depressurise a house. Rather, they introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.
  • Energy recovery ventilation systems provide controlled ventilation while minimising energy loss. They reduce the costs of heating ventilated air in the winter by transferring heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer, the inside air cools the warmer supply air to reduce ventilation cooling costs.

Your architect or builder will be able to assist you in which would be beneficial to your design.