High Electricity Costs With An Old Air-con System : What Did I Do?

By now, Singaporeans are no strangers to rising electricity prices in recent years due to the perfect storm of global factors such as the pandemic and the Ukraine war.

Without a doubt, the use of air-conditioning is the main reason why my utilities bill has stubbornly refused to budge despite my best efforts to reduce the use of electricity.

In earlier and crazier days, the highest we have clocked is 700 kWh in a month which is mind-boggling for just the two of us.

These days, we’re aiming for around 400 kWh which is a tad higher the national average (oops) if I’m not wrong.

Coupled with the fact that my Mitsubishi Electric Inverter air-conditioning system is fast approaching twelve years of age, it is now far from being the most efficient machine that it used to be when it was brand new.

I have a Mitsubishi System 4 aircon installed with one larger BTU (forgot the exact number) for the living room and three 9000 BTU fan coil units for each of the bedroom.

Usage is quite different for each of the fan coil units at home.

Living and dining room – 0 to 2 hrs / dayStudy – 2 to 4 hrs / dayBedroom – 7 hrs / daySpare – usually less than 1 hr / day

Due to our usage patterns, the conditions of the fan coil units vary quite significantly.

What happens if the condition of the fan coil units has degraded with time, either with high usage or poor maintenance?

This was what happened to my master bedroom as I have been using the air-conditioning daily for close to 12 years.

We find ourselves having to adjust the temperature with the remote control to lower temperatures of 20 to 23 degrees celsius to feel like what we originally had at around 25 to 26 degrees celsius.

Basically, the air-conditioner is working harder and using more electricity but producing less results.

In order to solve my problems of :

Air-con “not cold”Air-con using “too much” electricity

I could choose from one of the below three options.

I would do my best to avoid this option due to the high cost involved and the fact that my air conditioners in other rooms are working well; they actually feel quite cold when in use.

Gonna hurt my pocket quite a bit so I’m not doing this.

This option is possible if the BTU / dimensions compatibility allows for it to be done.

For example, 9000 BTU and 12000 BTU (for bedrooms) dimensions are usually the same but a 24000 BTU unit for the living room would be longer.

In my case, all my 3 bedrooms have units with 9000 BTU so they are identical units that can be swapped with one another.

Air-con technicians can perform a one-to-one swap e.g. from my spare room (little to no usage) to my master bedroom (extremely high usage) and they will charge a fee for doing so.

This is because of the labour costs involved – they will need to remove the mounted fan coil units from the walls, along with re-connecting the attached piping (ensure no leaks) and patching up the insulation.

If I recall correctly, I was quoted $180 if I wished to proceed with this job.

Pros and cons to this approach.

Pros – I know exactly what you’re getting, which is an extremely good air-conditioner unit.Cons – The problem is merely shifted to another room. If I wanted to use it for another purpose in future? Yikes.

By the way, this also means that if you have a regular air-con servicing technician or company, you could possibly swap spare parts between your air-conditioners for free e.g. blower wheel, air vanes etc if one set is damaged, if little to no extra work is involved.

In my case, my master bedroom’s air-conditioner blower had a broken fin (affects air flow) which I asked my helpful technician to switch with the one in my spare bedroom, when both sets were cleaned during regular servicing.

This option is possible if your favourite air-con technician has the resources or connections (they usually do) to source for decent quality second-hand fan coil units.

Now, the question is, where do these second-hand fan coil units come from?

Well, they come from people like .. you and me!

Let’s say I’m selling my HDB apartment today, alright?

The new occupants would probably rip out my existing air-conditioning system that has been in use for 12 years and install a new one.

When dismantling my air-conditioning system, their technicians would realise that my fan coil units in my living room, master bedroom and study room have probably seen better days and wouldn’t be worth much to anyone.

On the other hand, the fan coil unit in my spare room would probably be somewhat in the category of mint condition due to its extremely low usage – which they would probably salvage and sell it for about $100-$200.

Before installation, I was able to check the condition of the fan coil unit prior to any works being done, so that was great.

Depending on the BTU requirements, I was quoted $280 for the 9000 BTU unit and $320 for the $12000 BTU unit.

Long story short, I ended up taking this option and replacing my master bedroom air-con fan coil (which includes the evaporator coil, motor, blower wheel, air filter etc).

Turns out my outer plastic casing looked better (haha) so I retained my old one – the outside looks the same but the interior is entirely changed.

Key thing to note is that when the fan coil unit is replaced, the techs would take time to check for leaks (signs of bubbling when hand soap is applied on the pipes).

For the replacement unit, it comes with a warranty of 1-month. Considering that I use it every night, I figured any obvious problems would surface rather quickly.

Anyway, I have been with my air-con techs for a while. If there are any issues or spare parts required in future, I can always ask them to help.

Pro-tip : when choosing and installing an air-conditioning system, it might be a good idea to go for a system that is extremely common and popular. That’s where the spare parts are going to come from.

To be fair, I’m not entirely sure if this helps with my utilities bill (still monitoring) but my master bedroom is now a chilly haven when the need arises.

Of course, we know that reducing usage is still the best solution so we have been cutting down usage of air-conditioning where possible.

Especially when the weather has been rather kind to us lately, so that helped.

But far too often, the hot and sunny weather can be a little too much for us.

Don’t forget to perform regular basic cleaning such as:

Air-con filters (simply vacuum or wash with water)Clear drainage pipe (use a wet vacuum cleaner to suck out the “jelly” or remove clogs)Use a wet vacuum cleaner by PowerPac etc which costs a little as $70 and not your regular vacuum cleaner, since it might either kaboom in worst case scenarios or cause soggy/moldy dirt to accumulate which is disgusting and a health risk

I’m also considering installing a ceiling fan in my study (concrete ceiling) so that we’d be using that instead of the air-conditioner where possible.

Do you have a ceiling fan at home? And has it worked well for you? Anything to look out for if I’m considering to install one?

Disclaimer for this blog post : I’m just a regular home-owner and nowhere near an expert when it comes to air-conditioning needs. Just sharing from what I learnt during chats with my air-con techs.

Hope you’re enjoyed this blog post and it has given you some ideas if you’re experiencing the same issues as we did.