Design for Natural Ventilation
- Naturally comfortable houses are low energy houses
- Ceiling fans provide low energy cooling if you only use them whilst rooms are occupied
- Light coloured roofs (or zinc alum) reflect the heat
- Use orientation and shading to eliminate direct sun on walls
- Minimise east and west wall areas and avoid windows on east and western walls to prevent low morning and afternoon sun heating up the house
- Correctly sized eaves can provide permanent shade to north and south windows and walls (northern verandas make sense
- Plant tall trees on the east and west sides of the house to shade walls
- Tall trees on north and south shade roof (minimise mid-height foliage to let breeze through for naturally ventilated houses). Consider leaving half roof unshaded if solar panels are to be used
Minimum Insulation Standard
- Use the breeze for cross ventilation through openings in opposite walls and internal partitions
- Maximise the area of windows (e.g. louvres) that can be opened
- Orientate house to catch the breeze (whilst still minimising sun on east and west walls)
- A long narrow floor plan catches the breeze best.
- Trees and shrubs act to cool the air passing through the house.
- Don't use exposed concrete on ground immediately outside the house as it heats the air.
- Roof space ventilation draws the heat out.
- Dirty flyscreens block more breeze. Consider using openable/removable flyscreen shutters
Design for Air-Condition
- Light coloured well ventilated roofs: foil/sisalation
- Other roofs: R1.5 batts and foil/sisalation
- Full shading of wall is much more important than wall R-value. Unshaded, masonry walls store heat and release it well into the night.
- Shelter windows with louvres, canopies, shutters or fixed overhangs - then you can enjoy the cooling effect of rain.
House designs depending on full air-conditioning for comfort are not very suitable for our tropical climate nor environmentally sensitive.
- Energy costs will be high when air-conditioning is running and comfort levels will be low when air conditioning is switched off. Occupants can have difficulty acclimatising to outside temperatures
- The better your house seals and is insulated, and the less glass area, the less energy air-conditioning will use.
- Keep the heat and moisture out and the cool in!
- Shade walls and choose the highest wall R-value(lowest U-value) possible.
Combined Air-Conditioning and Naturally Ventilated Houses
- Medium sized with the greatest possible openable area per window, and placed for cross ventilation, so you don't have to air-condition all the time
- Heavy snug fitting curtains and pelmets prevent cooling energy loss from radiation and air flow against glass
- A square floor plan minimises external wall area and therefore reduces cooling energy loss through walls.
- Exposed heavy construction materials (e.g. concrete and bricks) inside insulation barrier store cooling energy.
Click to view these design considerations in pictures....
- Many houses in tropical regions have some air conditioned spaces and some naturally ventilated spaces or the same spaces are naturally ventilated and air-conditioned at different times
- Design of each area should follow principles for natural ventilation or air-conditioning as relevant.
- Walls separating naturally ventilated and cooled spaces should be insulated and have doors to limit loss of cooled air.