Summer Again

It’s summer (but it’s not me in the photo): the magnetic needle inside my old-fashioned max-min mercury thermometer shows the temperature on my veranda reached 47°C recently. Close Comfort, an old PC8 model made in 2015 improved with the latest compact focus enhancer. It sits at the end of my bed each night and my Igloo tent is in the wardrobe should I need it. I move it to my study if I’m working from home.

As the inventor, it’s nice to be able to tell you that I use it practically all the time I need cooling.

It’s not just that I invented it.  Or the knowledge that even one small tree absorbs more CO2 than is created at the power station by the electricity that it uses. Even less CO2 with solar electricity.

I have even noticed that I adapt to the heat more easily when using Close Comfort, so I don’t have use it all the time. There is evidence emerging from physiological studies that might support this perception. It’s good because my wife uses it too in her study: the kitchen where she just has to reach across to make herself cups of tea.

The new normal

It looks like COVID-19 is going to be with us for a while yet. In any case, working from home, at least for part of the week, may be the new normal for many of us. 

It’s tougher than many people thought to keep your spirits up while handling challenges of working from home. Managing kids, chores, partner, and staying in touch with your family have to be juggled around work commitments. 

Air conditioning is a major contributor[JT1]  to power bills in hot climates. This makes air conditioners not only the most popular household appliance but also one of the most power-hungry appliances. The situation is exacerbated during hot summer days when you just can’t work without your aircon. In cities, with hot walls, roofs, roads, cars and air conditioners all heating the air, your air conditioner has to work even harder. In Australia, while global warming has raised temperatures by about 1°C in the last few decades, summer temperatures are rising even faster. Recently, investigating temperature records kept by the Australian Bureau of Meteorology, I was surprised when I found that inner city temperatures have risen by up 8°C in the same period!

Before the pandemic, you might have been at the office on weekdays and in the malls at the weekend, so keeping cool was paid from someone else’s budget. Working from home has transferred that cost onto your own household budget: a shock for many.

Besides, using your home aircon more also means more maintenance and repair work, raising the overall cost. Those aspiring to the flexibility of working from home may find the dream of a productive home-office more expensive than they expected.

Close Comfort dramatically shrinks the cost, as attested by thousands of our customers. 

Simplified air conditioning physics and economics

Let’s dive a little deeper into the physics and economics of air-conditioning to understand why traditional air conditioning costs so much.  

A three way multi-split, popular for a modest 2-room Singapore apartment, sets you back by an average of $3,500 for purchase and installation. It will use an average of 900 – 1200 W for every room to be cooled. Now, let’s assume that you run ACs for 10 hours during the day when you are pounding your keyboard. You’re not going to switch if off during breaks and while attending to kids and in-laws. That’s 9 – 12 KWh. That’s more than $60 a month extra on top of the normal $80 – $100 cost for cooling through the evening and night. For the first year, with 9 months use like that, this would mean your total air-conditioning cost, including the purchase price of the unit, is around $5,000. Studies have shown that the usage of air-conditioning in Singapore has shown links to seasonal factors such as humidity and temperature, which means you can expect a figure north of $5,000 if you plan to run the ACs for a few more hours during summer. (I am using Australian dollars which are almost the same as Singapore dollars just now. Electricity cost is assumed to be $0.25 per kWh unit.)

If you think that’s expensive, spare a moment for families in Pakistan. The summer temperature in a typical city swings from about 28°C to 46°C. The indoor temperature without air conditioning hovers around 40°C continuously. Our customers tell us that the cost of cooling a bedroom with a split aircon, only at night, comes to around $150 – $300 monthly, including the generator fuel and maintenance for the inevitable power outages. 

They also tell us that Close Comfort reduces their bill to about $20 a month!

The second law of thermodynamics tells us how much energy we need to move heat “uphill”, from your cooler room to the hotter air outside. No matter how efficient your split aircon, this law still applies. 

Shrinking the bill

There are only three ways to reduce the energy cost. Using a brand new, clean and highly efficient air conditioner can reduce the cost … maybe by 30% or so. However, to really reduce the cost, there are only two options. Either reduce the indoor-outdoor temperature difference or avoid cooling the whole room.

Knowledge of human physiology tells us that heat-adapted people feel fine at 27 – 28°C. A fan makes us feel 2°C cooler, so you can safely set your split aircon to 29°C and turn on your ceiling fan to provide the comfort you need for working or sleeping. With an outdoor temperature at 33 – 35°C, you will have reduced the indoor-outdoor temperature by almost two thirds compared with a thermostat setting of 22°C, and that will save you much of the electricity cost.

Personal air conditioners focus the cooling on you: they avoid the need to cool the whole room so they can shrink the bill even more. 

Let’s take the Close Comfort personal air conditioner for example. The unit cost of a Close Comfort unit is $649 in Singapore, $699 in Australia. $800 should cover most of the purchase and running cost for the first year. 

Now here comes the best part, a personal air conditioner is easily moved. Like me you can simply carry it from your home-office to your bedroom or even to the living room when you’re enjoying a relaxed evening. It will throw a blanket of cool air over your bed at night, even with a mosquito net in place. In Pakistan, many customers take it up to the roof to sleep under the stars at night. Running Close Comfort for even 18 hours a day for will only cost you about $1.35, at the most $350 for an entire 9 month summer season. 

Personal air conditioners are not only cost-effective but also offer comfort and convenience – ideal to improve your productivity when working from home. For example, Close Comfort personal air-con units are not only ready to use straight out of the box. Unlike traditional “portables”, the ones with the large, inconvenient and ugly exhaust pipes, Close Comfort does not make enough noise to distract you from your work calls and meetings. 

Personally I hate being boxed in behind closed windows and doors with a traditional air conditioner recirculating stale air. I like to live in healthy fresh air. I feel better. Ask anyone who has had to spend two weeks in quarantine, boxed up in a hotel room with windows that cannot open.

Now you understand why I just like Close Comfort?

The Net Zero by 2050 Challenge

Joe Biden’s election win in the USA is likely to change climate politics fundamentally. Reducing air conditioning emissions to net zero by 2050 will be a challenge for countries like Singapore, Pakistan, Indonesia and especially Australia. In coming weeks I will write about this challenge and some of the solutions… and you guessed it … Close Comfort is one of them.


How important is STEM education?

Recent reports have highlighted Australia’s declining results in PISA testing of maths, science and reading capabilities of children. Some in particular have drawn attention to Australia’s relatively weak performance compared with China and Singapore. I am unsure what this means. Should we invest more in maths and science education?

The Singaporean government is making it harder for foreigners to work there. International company people I meet in Singapore complain that young Singaporeans cannot perform as well as foreigners and demand too much pay, and the government is trying to force companies to employ more locals.

Read more: I argue that STEM is not the most important priority

Pakistan Launch: Islamabad

“The Making of an Expert Engineer” was officially launched in Islamabad at the Serena Hotel on January 7th before a gathering of 120 engineers, engineering faculty, aspiring engineers, and friends.  The Hon. Ms. Marvi Memon, Minister Chair of Benezir Bhutto Income Support Fund spoke about the potential impact of the research on the poorest 5.8 million people in Pakistan served by the fund. Lieutenant General (R) Syed Shujaat Hussein, former rector of National University of Science and Technology presided at the launch.Close-Comfort-FB-Logo-151207

The event was sponsored by Close Comfort Air Conditioning


James Trevelyan speaking about the book – transcript of speech appears below.

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Opportunities for Pakistan Engineers

In my last piece I pointed out some of the challenges for engineers in Pakistan.  Yet each of those challenges is an opportunity for any engineer who is prepared to take advantage of them.  Yes, water and power are far too expensive. However, reliably supplying water and power at a lower cost represents a huge commercial opportunity because ordinary people will happily pay for a high quality service that provides real economic value over the alternatives.  Given that water is the equivalent of US$50-$150 per tonne today, supplying safe drinking water at $10 per tonne is a huge improvement.

Here’s an example, my own personal invention, mentioned in the book (Ch13). Air conditioning is unaffordable for the vast majority of Pakistan people because most Pakistan buildings are not insulated. Conventional air conditioning consumes large amounts of electricity. Too many people are using conventional air conditioners, leading to electricity load shedding. Continuous air conditioning requires a generator and the electricity cost (with fuel) for a typical room air conditioner is about 20,000 Rs or US$190 for one month.

Take a look at

This technology can provide similar comfort, running continuously through load shedding on a UPS, for about 1,200 Rs or US$12 monthly electricity cost which is much more affordable. The first production units will be on sale in Islamabad and Lahore in a couple of months time.

Challenges like climate change also represent a huge opportunity for engineers.  Engineers can do more than almost any other occupational group, and can earn high rewards from grateful people at the same time.

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Back from Pakistan, UAE, Iran and New Zealand

Some of you may have wondered why there has been a little gap in my blog posts.  I have been pre-occupied with visits to several countries.

My other major project, Close Comfort has developed very quickly with keen anticipation particularly in Pakistan where electricity supplies are subject to frequent interruptions due to load shedding.  Pakistan’s electricity grid is struggling to keep up with demand for air conditioning, and I hope to be able to offer a sustainable solution, as explained in Chapter 13 of the book. Continue reading