Monday, September 23, 2013

HDB Energy Saving: West facing Apartment? Beat the Heat!

In sunny Singapore, the west facing apartments will always face the brunt of the setting sun. Our HDB apartment happen to be one of those.
HDB Flats in Sunny Singapore

In our experience, the late afternoon sun approximately 4pm to 5pm has the biggest influence on the residents' thermal comfort. The discomfort and inconvenience is 2 tiered.

Firstly, the indoor ambient temperature 4-5pm can sometimes can be unbearable and be as high as 35 Deg Celcius. 

Secondly, at about 5-8pm, the wet facing wall would have absorbed sufficient radiation from the sun and starts to emit heat into the room. This is also known as a "hot wall" effect. Air-conditioning cost will increase to cool the "hot wall" down.

What can we do about this?

Creative Passive Solutions:
1.  If you are lucky to have the laundry drying area facing the west, dry your laundry on the west facing side. Although I was told by many seniors citizens that it is better to dry wet clothes in the morning sun. I wonder why this is so... Please share if you happen to know.
HDB Laundry scene

2.  Beat the 4-5pm heat by going to the National Library to enjoy free air conditioning.
National Library of Singapore, Courtesy of nlb

3.  Chill out in a swimming pool 4-5pm for less than 2 dollars at the neighborhood SSC swimming pool.
Chilll out at the Swimming Pool, courtesy of SDSC

4.  Stay on the rooms on the east side.
Now that you have loosened up..... here is the real stuff.

Active Solutions:

1.  On the west facing wall, close all windows, day curtains, curtains to provide maximum insulation against radiation penetration. This was the first thing we did, unfortunately, our curtains were not thick enough to black out the evening sun. The indoor temperature was could be as high as 33 Deg Celcius. Looks like we need to spend some moola to get some comfort. 

2.  Convince HDB to use "cool paint" to repel radiation. 
There are products available in the market to help improve our lives. Can we use it? Are developers looking into this or they are just considering mass production? Check our solacoat, a water based acrylic coating with membrane additive which helps to reflect solar rays. This option is a long shot.... I can't do it alone.

3.  Hang blinds on the west facing windows.
I would have pushed for this if we are allowed to hand the blinds outside the window pane. The blind gets in the way of the curtains which also serves a value aesthetically. 

4.  Apply Solar films on the west facing windows.
High reflective solar films was initially my favorite choice. Until I learnt that HDB has a 20% cap on the reflectance for solar films that can be applied on HDBs. If so, what is the point of applying the solar film??
An associate who applied the solar films on her windows advised us against the solar film as she claims that the film will deteriorate after 2-5 years, turning the window into an unsightly bubble pop. In turn, it was a nightmare to remove the "melted" film which has bonded tightly to the window pane under extreme temperatures.

5.  Apply Black-out curtains on west facing windows.
Surprisingly, these are not common in Singapore, given the all year round summer. This was our eventual solution. The details are coming up in the next posting!


  1. Dynamicshades HDB windows could also be a preferred various for homeowners to manage the amount of daylight and star heat coming back into their homes.

  2. Aesthetically attractive views and more sunlight which helps minimize requirement of artificial lightings. Apart from greatly reducing the need for cooling, window film helps to create a comfortable temperature and environment for the home.

  3. This article is humourous! Made my day:)

  4. This article is humourous! Made my day:)

  5. With newer and more advanced technologies, higher quality solar films no longer face this deterioration problem after 2-5 years. High quality solar film can last 10 years and beyond.

    We are always happy to share more to solve your heat problems for your house.