IEA (2018), 10 tips to stay cool in today’s heat, IEA, Paris https://www.iea.org/commentaries/10-tips-to-stay-cool-in-todays-heat
Across the world, extreme weather and prolonged heat waves are setting records. In Europe, the historical heat record – set in Athens 41 years ago – may be broken today if parts of Spain and Portugal creep above 48°C. In Japan, temperatures are still in the mid-30s after Tokyo saw its highest ever recorded temperature of 41°C in late July. And in South Korea as many as 29 people died from heatstroke this week, after temperatures in Seoul hit a 111 year high. Beijing also broke a 50-year record in June.
Understandably, this has driven a demand for cooling. Recent reports in France, which is presently suffering its second heat wave this summer, show that sales of household fans in July increased 125% over last year, while air conditioner (AC) sales jumped nearly 200% compared to 2017. In Montreal, stores ran out of ACs during the prolonged heat wave in July. And in India, AC producers expect that sales this year will reach double-digit growth as rising household incomes – paired with recent high temperatures – lead to greater demand for cooling services.
This growing demand is part of a major global emerging trend: rising need for cooling comfort – and in particular air conditioners. Cooling is now the fastest growing use of energy in buildings, and ACs and electric fans already account for about 10% of all global electricity consumption. This is one of the most critical blind spots in the energy world today – by 2050, cooling demand could more than triple. Our recent report on the Future of Cooling highlights why this is such a dilemma: while greater access to much needed cooling services is a good thing, it could place a major strain on energy systems if we don’t do something about how efficiently we keep cool.
Fortunately, there are many solutions – many of which we can all take today. Here’s a list of ten things we can all do to be cool, efficiently:
- Shut your shades and close the blinds. As much as 80% or more of the heat from the sun can be transmitted through your windows. This solar heat gain is a significant factor in the need for cooling in buildings. In the short term, keeping the curtains drawn or the shades shut can make a big difference in how much of the sun’s heat comes indoors. If you’re thinking of replacing your windows, ask for a low-emissivity coating to let the light in but keep the solar heat out.
- Use fans and ventilation. The power consumption of a fan is typically between 25 and 150 Watts, compared to a small AC unit that is often between 1 000 and 1 500 Watts. So before turning on that AC, think about using a fan. And when you can, letting a little air in can make a world of difference, especially when cooler nights set in or when there is a good breeze.
- Take a second look at your thermostat. Raising the temperature set point on your AC by 1°C can reduce its energy consumption by as much as 10%. Most ACs use a vapour compression cycle, moving heat from the inside to the outside by using energy. Just like us, the more work they do, the more energy they burn. So the next time you go to touch that dial, think about turning it up a notch.
- Take a second look at what you’re wearing. Experiences with programmes like Japan’s Cool Biz (which encourages employees to ditch the ties and formal wear in summertime) show that appropriate summer attire can let people stay comfortable at higher indoor temperatures. The next time you think about throwing on a sweater in summer, consider raising the thermostat first.
- Maintain your AC. Something as simple as a clogged filter can lower AC performance by 5% to 15%. Neglecting regular maintenance of AC filters, coils and fins (all the pieces that help exchange the heat from the inside to the outside) can lead to poor energy performance. Making sure your AC passes a good bill of health (preferably through a trained technician) can improve its performance and cut down on your energy bill.
- Keep an eye out for energy labels. If you’re buying an AC or replacing an existing model, be sure to take a look at the AC energy label (or if you can’t find one, try looking for product information online). Our Future of Cooling report finds that people often buy ACs that are significantly less efficient than what is available on shelves – even when the more efficient ACs are similarly priced. Be cool and take a look at the energy performance label to buy the most efficient choice.
- Get a programmable or smart thermostat. A smart thermostat can cut AC energy use by as much as 15% or more. Programmable thermostats can also cut back on energy demand by setting fixed hours for AC operations. Smart thermostats take this a step further by monitoring, predicting and adjusting cooling needs to cut back on energy use when and where it is needed. So keep cool and let your thermostat do the thinking for you.
- Part-time, part-space is part of the solution. Research by the IEA Technology Collaboration Programme on Energy in Buildings and Communities found that household electricity use for cooling can be as much as 10 times lower when ACs are only used as and where needed. This can be as simple as turning off the AC when you leave a room. Try turning on your AC to get comfortable before going to bed and then turning it off when you go to sleep. Or get a smart thermostat to monitor and control when your AC goes on.
- Watch out for those pesky plug loads. On really hot days, think twice before using your stove, running the washing machine or turning on the dishwasher. Electrical plug loads – ranging from large appliances to computers and hair-dryers – all generate heat when operating. Avoid heat build-up in your home by turning those devices off for the day and reduce your electricity consumption at the same time.
- Build it right. The building envelope – the parts of a building that form the primary thermal barrier between interior and exterior – plays a key role in how much energy is required to heat and cool a building. Cool roofs, awnings and insulation can all help cut down on the need for mechanical cooling. Let in the light but keep out the heat with double-glazed, low-e windows. And don’t forget to seal those cracks with proper air sealing. So when renovating or building, make sure to build it right and keep cool for years to come.
10 tips to stay cool in today’s heat
John Dulac, Energy Technology Policy Analyst Commentary — 06 August 2018