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4 Things to Know Before Installing Air-conditioners

Air-conditioners are taken for granted. We don’t put too much thought into them until they break down unexpectedly – to which, we respond by flying into a sweaty rage. So unless global warming really does disappear (read: it won’t), chances are we’ll still be reliant on air-conditioners to keep us cool.

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Here’s what you need to know if you’re planning to install a unit in your home/office:

1. Understanding the different types of air-conditioners takes some getting use to

You’ll probably be thinking “What? Can’t be right, thought just install into the wall can already?” Unfortunately, It isn’t that clear-cut. There are various types of air-conditioner units in the market, so it is important to determine which model suits your rooms best.

Wall vs window air conditioners

The most frequently used ones are the wall-mounted and window units. As their names suggest, the former is sealed permanently to, or mounted on, an exterior wall, while the latter fits right in an existing window. Both come with their pros and cons; having a wall air conditioner means that you do not have to give up your window space and are much more economical in the long run. However, the downside is that installation costs may be higher (because you’ll probably need to create openings in the walls).

Do note that if you’re planning to install a wall air conditioner in your HDB unit, you’ll need to get a BCA trained air-conditioner technician to assist you. In addition, you must submit an installation report to your respective HDB branch within 14 days after installation.

On the other hand, window air conditioners are easy to install without professional help. They come in a variety of sizes, which can fit vertical, horizontal or sliding windows. Regardless of the configuration, the most important thing to note before purchasing one is to be sure to take accurate measurements of your window so that it fits perfectly.

Inverter vs non-inverter

You’re bound to come across these terms if you’re thinking of getting a wall air conditioner. In a nutshell, inverter air-conditioners run on a variable speed compressor, whereas non-inverter varieties operate at a full load whenever the compressor is switched on.

Still sound like quantum physics? Basically, the compressor of inverter air-conditioners reduce their running speed once the desired temperature is achieved. This differs from non-invertor air-conditioners, which have fixed speed compressors that only either run on full or minimum capacity. The bottom-line is homeowners usually prefer invertor air-conditioners as they help to save energy and costs in the long run.

System 2/3/4/5

The figure represents a ratio between the number of indoor units to one outdoor unit. For example, a System 3 air-conditioner unit will comprise of 3 indoor units to 1 outdoor unit. Which system combination you ultimately choose depends on the number of rooms you wish to have air-conditioners in. So, if you want all three rooms plus the living room in your 4-room BTO to have air-conditioners, you’ll most likely get a system 4.


2. The size of your rooms matter more than you think

Bigger doesn’t necessarily mean better when it comes to air-conditioners. Smaller rooms won’t need powerful air-conditioners to cool (or in this case, make it resemble a freezer compartment) nor would you want to install an air-conditioner that cannot cool the entire room’s area.

Thankfully, there is a simple way to determine an air-conditioner’s ability to cool a room. All air conditioners come with a standard British Thermal Unit (BTU) rating, which measures their cooling capacity. How much BTUs you’ll need for a particular room is calculated by multiplying the square foot of said room by 35.

There are several other factors that will affect the overall BTU of a room. If the room faces the afternoon sun, you’ll need to add another 10% to the total figure. Conversely, you can subtract 10% if the room does not receive much sunlight.

How the room will be used also influences the recommended BTUs. Kitchens tend to be warmer by virtue of the heavy cooking done, so you should add 4,000 BTUs if installing an air-conditioner. Living rooms have the largest floor area in a property and usually accommodate more than two people at any point in time, so it is necessary to add between 600 – 800 BTUs per person (depending on your household size).

Only by finding out the BTUs per room can you deduce how many air conditioner units you’ll require as well as the total price you have to pay per unit purchased.

Area in Sq. Ft BTUs Needed
100-150 5,000
150-250 6,000
250-300 7,000
300-350 8,000
350-400 9,000
400-450 10,000
450-550 12,000
550-700 14,000
700-1,000 18,000
1,000-1,400 24,000

3. Turning on the air-conditioner all day and night is expensive business

As we all know, using air-conditioners in our climate is inevitable, and it does come at a high price. Air conditioners account for the bulk of our energy bills – so if you’re planning to use it 24/7, be prepared to pay an amount equivalent to a developing nation’s GDP.

Just how much energy does an air-conditioner use? Typically, an average unit uses anywhere from 1000W upwards, as compared to 50-100W for a standing fan. That means if you’re going to use one air-conditioner for 8 hours per night, it would amount to at least $58 – $150 per month.

One way to save on costs is to look out for an air-conditioner’s Energy Efficiency Ratio (EER) when purchasing one. A higher number indicates a more efficient unit – those with an EER of 9.7 – 10.7 are recommended. Air conditioners with a high EER can save you roughly 10% on your energy bill, so it is worthwhile to consider one for the long run.

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4. Additional services may seem like gimmicks, but they can actually help save on maintenance costs

Most homeowners in Singapore either consult with their contractors or head down to electronic stores such as Courts, Harvey Norman or Gain City to get their air-conditioners. If you decide on the latter, the sales person may try to convince you to buy upgrades, at usually another few hundreds more on top of the listing price. These usually comprise of servicing packages, piping upgrades and extended warranties.

While it may seem like hard-selling, it may be prudent to give them some thought. This is because air-conditioners have an average shelf life of 2-3 years, after which they will require regular maintenance. A leaking air-conditioner or a damaged compressor can run up costs quickly, so it is best to fork out a little more at the start, rather than suffer inconveniences later on.

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