Design Strategy in Warm-humid Climates

What we have working against us?

1. In warm-humid climates, the nights are usually warm and there is very little diurnal variation (often less than 5 deg C).

2. Evaporative cooling will be neither effective nor desirable as it would increase the humidity.

3. In humid climates, moisture-laden air that entering an enclosure may contact elements below the dew point which can result in condensation within the enclosure, possibly leading to long-term moisture problems.

4. In a hot-humid climate, moisture will flow from outside to inside most of the year.

Design strategies…….

1. The designer should ensure that the indoor temperature does not become higher than the outdoor.

2. Adequate ventilation may ensure this by removing any excess heat input, but this is not enough.

3. Undue increase of ceiling temperature may be prevented by:

· using a reflective roof surface

· having a separate ceiling

· ensuring adequate ventilation of the attic space

· using reflective surfaces both for the underside of the roof and for the top of the ceiling

· using some resistive insulation for or on the ceiling

4. The whole building should be lightweight to allow rapid cooling down at night.

5. East and west walls should have minimum or no windows in order to exclude the low angle east and west sun.

6. They should be reflective and/or well insulated.

7. North and south walls should be as open as possible, to allow for cross ventilation.

8. This requires that the plan arrangement should avoid double-banked rooms.

9. Avoid obstruction of the wind.

10. The openings require protection from the sun and driving rain but also from mosquitoes and other insects which abound in these climates.

11. At times orientation for wind and for sun give conflicting requirements, solar orientation should take precedence, as there are ways of deflecting wind, but no ways of altering the sun’s movement.

12. This indicates that the most important issue in ventilation and window placement is that the path of moving air be at the level of the occupants. Window openings should be roughly the same size on both windward and leeward sides, and should be placed across from one another at the level of the occupant.

Material Properties………..

1. In general, lighter colors and smoother surfaces lead to lower surface temperatures.

2. Low thermal mass construction is typical in regions with low diurnal range.

3. Slab on ground construction is useful for winter heat storage provided windows catch the winter sun; walls should be made of lightweight materials.