A green space is a space that is built with the local climate in mind. Our country is a tropical climate. And one of the major difficulties of tropical climates is cooling interior spaces
Cooling a space mechanically generally takes up as much as 50 percent of the electricity bill. By cutting down on your use of the air-con, not only do you save energy and money, but also any greenhouse gases that may have been emitted by the production of electricity. This series looks at the various ways of being comfortable without turning on the energy.
Natural ventilation is one of the most efficient ways to cool the interior space. It involves creating internal air movement, just strong enough to feel comfortable but weak enough not to blow all the paper around. By circulating the air inside the space, the hot air is pushed outside and the cool air is carried inside.
Last time, we tackled the proper orientation for your desired space. There are two important directions to consider for our country: northeast and southwest. Generally, at any time of the year, prevailing winds travel from these two points. Northeast monsoon (hanging amihan) occurs during the cold months and southwest monsoon (hanging habagat) starts during the summer months. PAG-ASA (Philippine Atmospheric, Geophysical and Astronomical Services Administration) even has localized data on prevailing wind directions specific to cities and municipalities. By having ample windows and openings facing these directions, we can have guaranteed air movement to enter the space.
To maximize ventilation, one also needs to maximize the openings. Having large operable (that you can open) windows is ideal. Increase the size of your windows. Lower the height of the window sill while extend the height of the window up to the ceiling line. Old ancestral houses even have window openings at the top and bottom of regular windows called ventanillas to allow as much air as possible. These can have louvers or screens instead of unobstructed openings to preserve the privacy of the users.
The optimum type of window to specify is the one that maximizes the opening; that means it can be fully opened 100%. Sliding windows for instance can only have a maximum opening of 50%. Awning-type windows have 60-70% openings. Casement types (swing-out like cabinet doors) have 100 percent openings. Jalousie windows or louver types can also have 100% openings, plus having the distinct advantage to adjust the air flow by manipulating the panels.
To screen or not to screen? Common insect screens restrict air flow by as much as 50 percent. There are imported types that impede less, but they are generally more expensive. If the space is not that critical or located atop a high-rise building, I suggest opening up your windows. Use screens only on sensitive areas like bedrooms and nurseries. Besides, there are house plants that deter mosquitoes and other insects.
So maximize natural ventilation for your spaces and minimize your energy costs for cooling.
Previous: proper orientation
Tags: conscious living, green design, insect screen, natural ventilation, passive cooling, tropical design, windows
Posted in conscious living | 1 Comment »