Sustainable approach to air-conditioning

Submitted by: Jonathan Ramayia, Friday, June 1, 2012

The two main environmental issues regarding air-conditioning is that they require refrigerants to operate which are harmful to the environment and that they consume large amounts of electricity which increases the carbon footprint of your home or organisation. This article explains what you should consider with regards to air-conditioning.


1.       Avoid air-conditioning

The first place to start is to establish whether you need an air-conditioner. The Urban Earth office which is located in Durban, a sub-tropical humid location, was faced with a test earlier this year in summer. A decision was made by members of the office to minimise the use of air-conditioning given its high energy consumption and use of refrigerants.  On some sweltering days the air-conditioner was turned on, but since a commitment was made to not use the air-conditioner we thought of other ways to keep cool.

One way was to use natural ventilation. The Urban Earth office opens onto a narrow corridor which has a wind tunnel effect. By simply opening the door some of the air flowing down the passage air channels into the Urban Earth office and escapes through the open window providing an effective draft and reducing the need for air-conditioning. Beware though, there are other problems associated with keeping an office door open, including noise, security risks and being the resident information desk in your office block.

In addition to this, we have relaxed dress codes to cope with the heat and humidity. If that fails, you could always install a ceiling fan, which circulates the air in your room and uses much less electricity.

In summary:

  • Channel a natural draft
  • Dress down if it’s acceptable in your office environment. If it isn’t, perhaps make a case to your management as to why you should wear slops to work!
  • Use a ceiling fan

2.       Using your current air-conditioner sensibly

If your building manager or superiors are not having any of your talk of slops and ceiling fans and you have to use the air-conditioner then make sure you consider the following.

  • Ensure that your office is ‘air-tight’

If your office isn’t insulated properly, humid air will be forced into your office or home. You should do a check that your windows and doors close properly before purchasing an air-conditioning unit.

  • Regular Maintenance

Regular maintenance of your air-conditioning system will improve its efficiency. You might want to ensure that the supplier you are buying the air conditioner from has a maintenance contract included in the deal. It is recommended that maintenance takes place once a year.

  • Set your thermostat and timer to use less electricity

Remember that you can adjust the temperature of your air-conditioner, generally the colder you set the temperature the more energy you are using. You can also switch to a fan or eco-setting which uses less electricity. Importantly, make sure that if you have an automatic timer you switch the air-con off after hours.

3.       Buying a new air-conditioner

You’ve gone through a few steps, first deciding that you can’t channel natural ventilation and secondly that your old air-conditioning is not good enough. Here’s what you should bear in mind when installing a new air-conditioner:

  • Install the correct size

If your air-conditioner is too small for the office, it might be forced to do harder work to keep the room at the temperature you’ve selected. This wastes electricity, adds to your carbon footprint and increases your monthly running costs.

  • Two-stage compressors are better

Compressors typically use most of the energy of an air-conditioning unit. Compressors, which are located on the outside of your air-conditioning unit are important in the functioning of an air-conditioner as they expel humid air thereby keeping the refrigerant cool. Two-stage compressors are more energy efficient because they automatically compress less on cool days and more when it’s hot, saving energy.

  • Look at the label

Most energy efficient air conditioners have an energy star seal. This might be worth looking at when purchasing an air-conditioner.

  • Refrigerants

Does the air-conditioner have the capability to use unbanned refrigerants? If it’s primary refrigerant is R-22 or similarly banned refrigerants then you should consider buying an air-conditioner that uses more environmentally acceptable refrigerants.

  • Programmable Thermostats

Try to go for an air-conditioner that has a programmable thermostat so that you can programme your air-conditioner to turn off automatically after hours and to turn back on during work hours. In general, the higher you set your thermostat, the less energy is being used, so do a test to determine what the ‘comfort level’ in the office is.

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Jonathan Ramayia