All about Air Conditioning

OK, maybe not ALL about it since I’m only talking about the cooling part. In this post, I’m just going to talk about how to choose an air-conditioner and how to maximize its usage while minimizing energy consumption.

There are a few things that affect how cold aircon feel so take note of these points when buying your next air-con.

1. Blower speed – The higher the better to circulate the air & draw out the heat & humidity. Setting your blower speed to AUTO is the best. When you first switch on the aircon, the blower will be high but as the temperature approach the set temperature, the blower will slow down. If you use a fan to circulate the air, it’ll work even better! But after the walls & furniture cool down, the fan should be switched off because fan/blower noise is irritating & distracting especially when watching a movie.

* Remember, the aircon will cool the walls/floor/ceiling first due to larger surface area.

2. Temperature (inside the room, outside the compressor) – Inside the room, depends on what you’re cooling. If you always have party with many people + you have a big amplifier, set lower (see heat capacity). The thermostat will try to increase cooling power (for inverter) and turn the blower on ‘high’ longer. I set mine to 27’C when watching a movie on my home theatre & it’s cool enough if the blower is directed at the sofa.

Outside the compressor, if the weather is really hot, the compressor need to turn on the fan higher to exchange heat more efficiently and this increases power consumption. My compressor is facing the evening sun so I got 2 compressors that can handle 100% of the BTU load.

3. Humidity – this is the reason we feel stuffy, high humidity reduces our skin ability to cool down from evaporation and makes our lungs work harder to extract oxygen from the air. A good aircon can extract an insane amount of water from the air. My aircon can probably fill a bucket in an hour.

4. Direction of flow – self-explanatory. Want to feel COLD NOW? Stand in front of the aircon blower. Ladies should stand aside to avoid the cold air and dry skin.

5. Blower heat capacity (also compressor wattage for multi-split) – calculate the amount of heat (in BTU) that you expect the blower to extract. This depends on room volume. Budget in extra 10% in Singapore for hi-res HDB/Condo, or 20% if there’re many windows. Budget in 30% if you always have parties. People generate a huge amount of heat.

For compressor, it depends on how many blowers you have. With 3 blowers or more, always go for inverter. I used to have a non-invertor System3 for my old 3-room HDB, it seriously uses tons of energy but it was cheap. Now I have 1 System3 + 1 System2 to cool 5 rooms. Both are invertor systems and even though my room size has doubled, my current air-con actually uses LESS power on average! Based on this calculation, I should breakeven in 5 years.

Correct calculation of heat capacity will ensure you feel cool & save power since the compressor don’t have to struggle to exchange heat. For compressor, ensure you have at least 80% of the wattage required for extracting the Total BTU the blowers can sustain. This is because for invertor system, most of the time, it wouldn’t be operating at max capacity (if you do your math right).

For non-invertor multi-split, when any blower is on & temperature is above thermostat setting, the compressor is also ON FULL. On a hot day, the compressor is always on, maxing out on exchanging heat even though my 1 blower isn’t able to extract that much BTU. So to save some energy, buy up to 80%. Your room wouldn’t cool as fast when ALL blowers are on but it wouldn’t cost so much money to operate.

6. Room size/shape – depending on room size & shape, placement of the blower should be as near to where the people will be as possible. If you have odd shape room like an L-shape or has different segments, consider a blower in each segment. My living room is conjoin to my dining room so I have a 12000BTU blower for the living room & a 9000BTU for the dining room.

To calculate your BTU budget, use this calculator.

7. Room insulation & how many windows – make sure your doors have as little gap as possible to reduce air movement. Large windows are nice but also allow more sun in and trap the IR inside the room. If you don’t have IR film on your windows, increase your BTU budget, especially if you have evening sun. Curtains & blinds will help by reflecting some of the IR back outside the house and create an air buffer.

8. Coolant & Drainage piping – This is usually neglected but making sure the refrigerant flows smoothly to/from the compressor to the blowers without leaking and without choking at the bends is very important.

Just as important is making sure the drainage pipes for the water extracted from the air is piped out without leaking & causing a mess especially if everything is buried in walls & ceilings.

Make sure you have a reputable contractor to install these pipes! Some brands insist on using their contractor, like Fujitsu Singapore. Go for it! Make sure your interior designer or renovation contractor can work well with the aircon contractor. This will ensure a good installation, an efficient aircon & no trouble in the future.

I hope this has helped you in choosing the correct aircon. If you have any comments or suggestions on what to add in this article, please comment below.


Workaround – Lumia 920 screen can’t turn on while taking call

UPDATED (30/05/2013)

Recently, after owning the Lumia 920 for about 3 months, I noticed that I can’t turn the screen on while taking call. During that time I’ve updated to Portico & dust started accumulating in the front facing camera (FFC). So I googled the problem & came up with this thread at Nokia Forum.

This is a problem since launch & appears to be related to dust in the FFC lens. It’s a known problem that the FFC lens housing is not completely sealed.

The solution for me is to use the front camera a few times with different light source, just like how you need to calibrate the front camera to get the correct screen brightness adjustment, you need to calibrate it for calling as well. I’ve tried to get rid of the dust in the FFC lens by vacuuming, didn’t work. Will try a lens blower next if not, I’d just have to open up my Lumia 920.

Apparently either the proximity OR the FFC will switch off the screen. Why not just use the proximity sensor only? My Lumia 800 had no issues when I place the phone to my face when calling. Unless Nokia telling me the screen wouldn’t switch off in the desert…

Anyway the situation seems to be better now that I “calibrated” the FFC.

1308 Update

I got the 1308 update almost 2 weeks ago which completely solved the problem for most people. As far as I can tell, when the dust covers about 30-40% of the lens, the “calibration” technique will fail because not enough light falls onto the sensor. The 1308 seems to switch on the FFC longer to get a more accurate “averaged” reading thus solving the dust blockage issue.

Of course, the ultimate solution is to send the phone in for cleaning & replacement of the FFC casket.

Food & Cooking

My Quest to cook more like Heston Blumenthal



So what’s better than finding a great place to sample great food?

Finding great recipes & cook it myself!

My Culinary History

I love to create stuff for others to enjoy, which is why I was a programmer & now a blogger. Cooking is just another way for me to express my creativity.

Unfortunately, I have no formal training & my experiences have always been trial & error. After a few tries, I do eventually gets it & make the recipe my own.

I make a pretty good Cheesecake & I can do a restaurant style scrambled egg with runny center & caramelized skin.

However, these are based on others’ recipes which I’ve perfected by tweaking.

Which is why I find Heston Blumenthal’s way of cooking so fascinating!

Heston Blumenthal

If you don’t know Heston Blumenthal, I don’t blame you. Unlike Jamie Oliver & Anthony Bourdain, Heston don’t do TV much until recently. However, his restaurant, “The Fat Duck”, has 3 Michelin-stars & has been voted “Best Restaurant in UK” many times.

I chanced upon Heston Blumenthal in 2009 after trying the Ramen @ Ippudo Mandarin Singapore. My wife & I were exploring the new Mandarin Gallery (shopping center) when we come across an open-concept café with an interesting menu & concept. It was a café that sells exotic ingredients, cookbooks & many of their dishes uses these exotic ingredients.

I don’t remember having anything there but I came upon this book called, “In Search of Perfection”.

In Search of Perfection

Inside the book were crazy recipes that uses crazy equipment that process crazy ingredients that were next to impossible to recreate with my average home utensils. I managed to watch the TV series that the book was based on & while inspiring, reinforced the idea that I can’t attempt these creations without putting serious time & money.

It was very educational & entertaining though because Heston’s idea of cooking is based on Science & not myths. He prefers to experiment to remove any guesswork from his recipes. This inspired me to enhance some of my current recipes & try new techniques.

New series with home-cooks in mind

Recently, while searching for Heston on Youtube, I came across a new BBC series called “How to Cook like Heston” which was aired in 2012. These recipes were much more approachable, uses simpler ingredients which are easier to source (dry ice versus liquid nitrogen) & uses every day kitchen utensils + a thermometer.

This motivated me to try something that’s really nice that most restaurant got it wrong.

Roast Chicken!

The Process & using local ingredients.

You can watch the video below.


Recipes are here.

Living in a HDB apartment in Singapore where space is limited, I’ve made some changes to the recipe to allow for tighter space.

For home-cooks, you need to buy an oven thermometer (your oven thermostat isn’t accurate enough,) a meat thermometer & plenty of cheap coarse salt. The washing bowl is replaced with salad spinner bowl (or any bowl that’s deep enough) & the UK chicken is replace with whole Kampong Chicken.

Other than these changes, Heston’s recipe should be fool-proof enough for anyone who’s had some experience in the kitchen.

For novice or noob, try something simpler (like Heston’s foolproof scrambled egg) because this recipe takes almost 4 hours to complete excluding the brining process (19 hours including) & you need to process the whole chicken (chopping off & ridding internals.) It can be devastating to spend so much time to fail.

The result was fantastic! The best roast chicken I’ve ever tasted! Move aside Kenny Rogers!

Brining the Chicken in 6% salt solution, making sure the whole chicken is covered.
Brining the Chicken in 6% salt solution, making sure the whole chicken is covered.
After buttering the chicken, it's ready for slow bake.
After buttering the chicken, it’s ready for slow bake.
After slow bake, the skin should look raw.
After slow bake, the skin should look raw.
After a quick blast of hot air, the skin will separate from the flesh & brown.
After a quick blast of hot air, the skin will separate from the flesh & brown.

The process continue because I’ve saved the carcass for the next part, Chicken Stock, which requires milk powder & pressure cooker.

I’d post that next time!