The paradox of air conditioning

Warming the planet to keep myself cool?

I have a love-hate relationship with air conditioning.  Love, because it’s cool comfort on a hot day; but hate because of the trade-off it represents.  Air conditioners consume a ton of energy in buildings and vehicles, resulting in an enormous amount of emissions.  In other words, air conditioning is short-term cooling that contributes to long-term warming.

So what to do?  In vehicles (where AC can increase fuel consumption by up to 20%):

  • Use fresh air instead of AC whenever possible.  For city driving, open windows or sunroofs and enjoy the breeze.  For highway driving (where open windows are noisy and actually cause more wind resistance for your vehicle’s engine to overcome), use your vehicle’s fan to blow fresh air (and maybe open a back window a crack).
  • Resolve to use AC only when you really need it, on the hottest days.  Even then, use as sparingly as you can.  Select economy mode if your vehicle has one, and set the thermostat to comfortable, not cold.
  • When using AC, set the system to ‘recirculate’ so it cools the air already in your vehicle instead of having to cool warm outside air.
  • Park in the shade or use window shades whenever possible so your vehicle won’t be as hot in the first place.  Open the windows to get rid of that first, hottest air for free before turning on your AC.
  • Be sure all your windows are closed when the AC is on, so the air you’ve paid to cool isn’t escaping.
  • Have your vehicle’s AC system serviced regularly to ensure it is operating at maximum efficiency

In homes and buildings:

  • As with vehicles, set the thermostat to comfortable not cold.  If your building has cool spots, ask your maintenance team to investigate and fix.
  • Choose the most efficient air conditioner possible.  Look for the ENERGY STAR label, or a high SEER rating.
  • In commercial buildings, install a Building Automation System with automated settings and setbacks for huge potential savings.  In homes, install a programmable thermostat (or use the programming function of already on your AC’s thermostat)
  • Make sure all windows are closed when the AC is on so cool air doesn’t escape.  When appropriate, open windows at night to take advantage of natural cooling
  • Use window shades to block intense sunlight and prevent a lot of heat from coming in in the first place
  • Cool only the spaces where people live or work, for the time they are there.  Close off sunporches and other exposed rooms to prevent them from overheating your entire home
  • Dress lightly to reduce the need for AC
  • Turn off everything you can that produces heat, such as photocopiers and coffee makers, because that heat makes your AC work harder

Keep your AC equipment serviced for maximum operating efficiency

Until the energy that runs them is entirely from renewable sources, air conditioners contribute to climate change.  So let’s strive to use them as little and efficiently as possible.

Serendipity: this news story, issued after this edition of Green Ideas was prepared, offers a nice summary of the issues of air conditioning, with additional suggestions for sustainable action.  

In the news:

With high temperature weather records seemingly being broken everywhere, it shouldn’t be too surprising: June was the hottest month on record.

The biggest player-led climate action in soccer history: 44 Women’s World Cup players are donating money to offset the impact of their flying to the tournament.
A creative solution: in Australia, people struggling to pay their energy bills are being given a free block of solar power; good for them and good for the power grid!


“Financial self-interest drives every aspect of the institutional response to the climate emergency, its influence so central and decisive that officials rarely name it out loud.”

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