Older buildings which may have a poor design or craftsmanship, with inadequate insulation, can result in a faulty building envelope that does not perform well with today’s energy efficiency requirements. Even for newer builds, most of our clients at Energy Rating Perth feel like once they have achieved a 6 Star energy rating, their building will now be energy efficient, have an optimum thermal performance and give save them thousands of dollars for years to come. While a 6 Star rating is a minimum requirement it is not a guarantee for energy efficiency, as the efficacy of the construction practice is the ultimate deciding factor. Our energy assessors urge our clients at Energy Rating Perth to ensure they avoid poor construction practices that result in building defects which are both expensive and cumbersome to correct.

One such building defect is condensation which occurs when warm air carrying moisture comes in contact with a cooler surface, the water vapour leaves the air and condenses as mist or droplets on the cold surface. We breathe out moisture into our environment and activities like cooking, showering, and the use of hot water results in a rise of moisture of our interior spaces. This however, is not the only source of moisture, porous building elements, air leakages and opening your windows on a humid day brings most moisture into our homes. Depending on our interior temperature, the building envelope, and the ventilation of the home this moisture gets trapped inside the home and is absorbed by building elements like insulation, wooden floor boards, porous walls, and collects on our window panes which causes many other building defects. This cause staining, damage to wall and floor coverings, slip hazards, mildew/mould growth etc. It can also reduce the thermal performance by hampering the efficiency of thermal properties of construction materials. For instance, damp insulation does not function as efficiently and may reduce the thermal resistance of the wall/roof/floor assembly. Similarly, reflective glass is required to be clean and free of condensation to function properly.

The key factor in avoiding condensation is to improve ventilation by encouraging cross ventilation. If there is inadequate ventilation, then the use of mechanical ventilation is important. The following steps are to be taken to control condensation:

  • Reduce appliance/activities that cause moisture. For example, replacing flueless gas or oil heaters, water radiators and avoiding drying clothes indoors, ensure bathing areas are well ventilated, ensure tumble dryers are properly vented.
  • Increasing indoor air temperatures.
  • The use of dehumidifiers.
  • Improve ventilation through either natural or mechanical ventilation. Opening windows may not be the best idea as depending on the climate; it may introduce further moisture into the space. On the other hand, the use of exhaust fans and ventilators in roof spaces or ceiling fans on slow speed in the rooms creates a positive pressure system eradicating excess moisture from the air.
  • Maintaining a constant internal temperature (that is not too low) while increasing surface temperatures, by improving glazing and the use of insulation.
  • Where there is a direct connection between the inside and outside through building materials that are more thermally conductive than the rest of the building envelope, a thermal bridge is created and cold thermal bridges create condensation. These must be avoided by using thermal breaks or ensuring proper insulation and sealing.
  • The use of vapour barriers (vapour control layers), which prevent moisture from diffusing through the building fabric to a point where temperatures might be low enough to reach dew point.

 

If you would like any further information on condensation in building or any other energy efficiency topic, please give one of the friendly assessors at Energy Rating Perth a call today!