In Malaysia, most people do not consider passive cooling or natural cooling. What is passive cooling? Passive cooling means cooling your home without using any energy consuming device like an electric fan or air conditioner. Through careful design, use of materials and or certain modifications, you can keep your home cool without using additional electricity.
As Malaysians get more affluent, and air conditioners get cheaper and cheaper, you see that most homes have more than one air conditioner. It is no surprise to see entire homes air conditioned. Once you have more than 2 air conditioners, most electricians will advise you to change your electrical supply to 3 phase power supply.
Do you know why? It is because air conditioners draw a lot of power and if you are on a single phase power supply, using several air conditioners at the same time will cause voltage dips or peaks for your neighbors. It creates an unbalance power supply for the utility company. Three phase power supply reduces this un-balance.
While air conditioners are very effective at cooling the interior of your home, you’ll need to spend a significant amount of money on electricity. For some, the utility cost is a significant amount of income. Even if you can afford to pay the electric bill, the problem with air conditioners it that it needs electricity and the power company most likely is burning fossil fuel that adds to global warming.
You may not care much about global warming, however there is also something called microclimate that affects you. If you walk past the outside unit of an air conditioner, you’ll feel the warm air. This hot air now surrounds your home unless there’s a breeze to blow the air away. This an example of microclimate.
Using air conditioners will eventually make the area surrounding your home warmer & you’ll probably use the air conditioner more often. As more people in your neighborhood use their air conditioners as well, the entire neighborhood gets warmer. Under certain atmospheric condition, the hot air can get trapped above a city causing localized heat wave. Wikipedia has a more detailed explanation on microclimate that can help you understand more.
Whether you live in an urban area like the Klang Valley or other cities, you probably have notice that our climate is getting warmer with each passing year. You can create a cooler microclimate around your home to your advantage and we will look into this later in the article.
One of the reason we need to use an air conditioner is the design of houses today traps heat. For instance, developers build houses with low ceilings to save construction cost. Roofs are also made low to save cost in certain houses.
Most homes today do not have ventilation holes to allow cross ventilation. This is done to prevent dust from entering our houses. It is also built with the premise that the house owner will use air conditioners for cooling. This makes the problems worst as hot air is trapped within the home.
Houses in Malaysia are built with concrete and bricks. These building materials absorb a lot of heat from the sun during the day and slowly release the heat at night when we are at home. This makes the house warm and uncomfortable at night. If you stepped on a part of the floor at night and wonder why it is so warm, it could be the concrete releasing heat it absorbed during the day.
Now that you are aware of the problem, there are several ways you can consider to incorporate passive cooling or natural cooling for your home.
Let’s look at several ideas. We will go from simple and low cost projects that you can implement immediately and then move on to more major changes that require renovation works.
The easiest way is to have trees shade your house during the day. This reduces the amount of sunlight that hits your house and heat it up. When you are in older neighborhoods where the tress are mature, you feel much cooler compared to newer housing developments where the tress are still young.
Trees also release water during the day as part of photosynthesis and this water vapor also cools the surrounding area. If you don’t have any trees in your neighborhood, it could be a good time to plant a few. Try to get the neighbors involved as well for maximum impact. It can take a few years for trees to mature but better now than later.
Trees take several years to grow. For more immediate solution, you can use creepers and potted plants. Get some medium to large pots and select plants that have large leaves. A good example will be this plant shown in the photo. This is easy to plant and maintain. As long as the plants can shade the cement and walls, it will help.
You can also plant creeper plants that can climb on walls or trellis. Using creeper plants is cheap however it will take several months to a year or so before they grow to a sufficient height to shield the wall. The creepers needs to be trimmed once it reaches roof level. It can be quite a task to trim the creeper once it reaches that high.
Malaysians tend to cement up whatever tiny garden space that’s available. Cement is a heat absorber and when the sun is at a certain angle, it reflects heat into the house in the day time. Most people cement and tile up the garden for the following reasons:-
- to reduce maintenance of mowing grass
- to park another car
- to have a cleaner neater area
Instead of cementing and tiling up the little garden space, you can lay honey comb hollow blocks that allow some grass to grow. The blocks are strong enough to support a car so that your shoes won’t get muddy as you exit. At the same time, you car won’t sink into the garden soil over time. Since there is limited space, the grass that grows in hollow blocks tend not to grow as fast. Water in the soil can evaporate through the blocks and keep the surrounding area cooler as compared to a single section of concrete. Consider this instead of cementing the garden.
Below you see an amazing wall that made up of plants. The resulting “green wall” serves several functions providing shading, cooling, privacy as well as security.
If you have already cemented your garden, then what you can do is to place potted plants to shield the concrete floor as much as possible. Plants will certainly help. You can also consider installing awnings to shield the house. You can look at different types of awnings to suit your home.
In part 2 of passive cooling, we will look at other methods you can use to keep your home cool naturally.
Click here to see the next part of passive cooling.