Malaysia is a hot and humid country, with a capital HOT. And believe it or not, our modern rumah batu is not really optimized for our climate. The bricks/batu/stone retains heat absorbed during the day, and the heat is released at night, mostly inside the house.
As a result, many resort to the easiest way to cool down, which is the AC. A 1HP AC consumes about 0.7-0.9 KWh per hour of operation. 10 hours each night & 51.6cents per KwH and you can spend up to RM139 per month for that 1 AC alone depending on the duty cycle. If you have 2-3 units, you can see where this is going.
My trick? Simple. Electric Ventilator Fan to cool down without AC.
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| Window Type Ventilator. |
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| Ceiling Type Ventilator. |
I can almost hear you say "Wait a minute, cannot be that simple". Some of you may even say.
"I have done that la. Useless one".
"Its still too hot"
"Cannot la, Mosquito.
Well, bear with me for a while.
Although weather in Malaysia is hot, it does cool down at night. Yet, many people still sleep with their AC on at night. So what gives?
The job of a ventilator is to suck air out from your room. This causes outside air to be "sucked in" to replace the air that was sucked out. It is this air that is sucked in that cools and freshens the room. But how come this practice is not common?
The problem is most ventilators I have seen are not placed in the right position. Installing a ventilator in a sealed room or right next to an open window will yield you ZERO benefit. Yes, Nada!!! The small gap between the door and the floor is not sufficient.
You will need to consider where is the fresh replacement air coming from. I experimented with different placement before, & the best by far is to place the ventilator across the room from a window with the occupant in the middle. A picture speaks a thousand words.
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| Only Top Right Window Pane Is Open. The rest are closed shut. If you zoom in, you can see the black velcro strip used to hold the mosquito net in place. |
Depending on your window type, there are 2 types of DIY mosquito net. Magnetic type and velcro type. I used velcro type as it is the cheapest. Can be quite tricky to install especially behind the grill, but 1-2 hours of work+some cussing, all done.
As for the ventilator, get one that can change the volume of the entire room at least once every 3 hours. Take the surface area of the room in feet^2 times the height in feet, then divide by CFM to get minutes. You can get the CFM from the spec sheet. Also choose one that is quiet ( 20-30db ). You do not want to sleep next to a "jet engine" do you?
Links to ventilators that I would use.
If you install a ceiling type ventilator in a room upstairs, you shouldn't need ducting because it expels air into the attic space above. If you are doing this downstairs, or you live in a condo, ducting is way too much trouble. Just get the window type & install at a window ( My Picture Above ). Be creative. My living room ventilation needs are taken care by a window fan ventilator in the kitchen.
Also, unless you are an electrician, get a qualified person to install the fan for you. Shouldn't cost you too much, & there should be a return of investment via savings in electricity bills.
There will be certain days, where it is still too hot. So what should I do? Install 10 ventilators? No man. In this case, just switch on the AC. No choice. I still use my AC on average 1-2 nights a month when it gets way too hot compared to almost everyday before this. Need to run the AC from time to time too. If not rosak or the gas will leak out. Off course, if you use your AC, switch off the ventilator.
Pros and Cons?
Pros:
- Cheaper Electric Bills. Save the earth. Reduce your carbon footprint.
- Fresh air. Our furniture, wooden flooring, paint especially new ones emit dangerous chemical compounds called VOC over time. VOC buildup inside living spaces is an issue worldwide especially in air conditioned confined spaces. With a ventilator, the air in your room is constantly refreshed, preventing the VOC from building up.
- Wake up every morning feeling refreshed. Its a completely different feeling compared to waking up after a full night sleep in an air conditioned room. Don't really know how to describe this. I used to have migraines & this pretty much solved it. Not saying it will cure your migraine or sinus, but there is a health benefit to this.
Cons:
- $$ to install fan and mosquito net. Mosquito net can be DIY at less than RM50 depending on the size of your window. A small one will do. Don't have to do all.
- Dust. Be prepared to vacuum your ventilated space a few times a week. With great power comes great responsibilites. With fresh air comes dust.
Update 1: I received several comments from eagle eyed readers that 1HP should be 746watt, not 700 to 900 watt, with the focus completely changed to that.
Let me explain why i used a range rather than 746watt. The 1 HP rating in aircon is only a rating, and in practice, they do not consume exactly 746watt. To get something accurately, you need periodic calibration and I don't think any AC manufacturer calibrate their AC compressor to consume exactly 746 point zero-zero watt. Age, state of the compressor, gas charge, temperature differential between hot and cold side, efficiency of the motor, etc all affect the real life consumption. Install a wattmeter like this and you will see exactly what I mean. I have one upstairs.
An AC will not be on all the time. Once it reaches a certain preset temp, it will shut down the compressor. The total time the compressor is on vs the total AC operating hours is called the duty cycle and it is mentioned above.
Update 2: 1 Reader commented about his house facing west, hence the wall feels like a stove. He already has trees, special curtains, etc. You say the bathroom is cooler. Which makes me suspect you have wooden/laminated flooring in your room.
I'm not an expert in building insulation, and won't claim to be 1, but I would try the following if I were you.
i) Install reflective tint on your windows facing west. Some expensive ceramic nano super duper ultra mega non reflective tint may be better in terms of heat rejection, but the same performance can typically be achieved with a cheaper reflective tint. Not legal in automotive applications, but for home use, this might be your best bet. My condo faces west, and the tint only cost me RM80. Made a huge difference. Can DIY somemore. All you need is a sharp knife, water spray can and a few old credit cards to "screed". Just make sure you are not reflecting into your neighbour's living room, or the main road, for instance.
ii) Heat rejection paint. Since your complain is on one side, paint that side first. You can DIY or get someone to paint for you if you think its too difficult/dangerous. Follow the instructions to the letter. You may need an undercoat. Some examples below;
Heat Rejection Paint 1
Heat Rejection Paint 2
iii) If you have extra budget, Radiant Barrier and/or heat rejection paint on the roof.
It should be much better now. Even if you still have to on your AC, it should be easier to cool.
Feel free to comment on the comment section below and we can discuss here. Lots of things we can discuss. Yet to talk about attic ventilators, ceiling insulation, tinting, that kind of things. Thanks for reading.
