Winter Is Coming. Japan Should Turn Up the Air-Con

(Bloomberg Opinion) -- For Japanese households, the coming winter may be even more bitter than usual. 

An export ban by South Korea, stemming from disputes over restitution for women forced into prostitution under Japan’s 35-year occupation, could cause shortages and price spikes for kerosene, Bloomberg News has reported. That’s a serious threat because about 61% of Japan’s winter domestic heating is provided by kerosene heaters, which provide instant (if sometimes stinky) heat at the touch of a button.

As with the regular winter gas disputes between Russia and Ukraine, there’s no more potent worry when ice grips the landscape than the promise to cut off a nation’s supply of heat.

Fortunately, there’s a solution at hand for many Japanese households: Switch to air conditioning.

If used properly, air conditioners equipped with warming functions are by far the most efficient way of heating a room. That’s because they’re heat pumps, meaning the energy they consume moving heat around is only a small proportion of the warmth they can provide. A kerosene heater will never be able to provide more heat than is contained in the fuel it burns, but heat pumps can have efficiencies as high as 300% or more.

While the world’s growing demand for cooling from air conditioning is likely a major source of energy consumption in the decades ahead, using the same devices instead of electric or fossil-fired radiators for warmth offers the prospect of significant energy savings. The share of such devices in building heating must triple from the current 3% to hit efficiency targets needed to avert the worst effects of climate change, according to the International Energy Agency.

Air conditioners’ efficiency seems to go against the perception in Japan that kerosene-fueled heaters are the cheapest option, but in truth a lot depends on how you use the device. A liter of kerosene contains about 10 kilowatt-hours of energy and costs 90.9 yen (85 cents), comparable to the 99 yen you’d spend producing the same amount of heat from an air conditioner using Tokyo Electric Power Co.’s highest tariff and 300% efficiency.

That assumes actually reaching peak performance – something that doesn’t happen with an old or badly maintained air conditioner, or one that points to the wrong part of the room, or one left on when the householder goes out. In the depths of winter in the most frigid parts of the country, such as Hokkaido, the performance of heat pumps drops dramatically with the temperature – but for most of the country, they should still be an attractive option.

Anyone who’s spent winter in a Japanese home, their feet tucked under a kotatsu table for warmth, will know that the country is in many ways remarkably frugal when it comes to household comforts. Heating energy consumption per household runs at about a quarter the level that prevails in the U.S. and western Europe, despite terrible standards of insulation and the tendency of kerosene heater-users to crack a window open to help fumes escape. Western households that heat the entire building to t-shirt temperatures in the depths of winter could learn a lot from the Japanese preference to save energy by warming only the rooms you spend time in.

Still, those worried about how they’ll make it through the winter if South Korea pushes up the price of kerosene should take comfort from the fact that air conditioners are already almost universal in Japan. Most modern ones will incorporate a heat-pump function. Learning to use it better this winter might save people from making trips in the cold to fill up their kerosene tank, as well as a few yen. Even with Japan’s coal-heavy current generation mix, the climate may well be the better for it, too.

To contact the editor responsible for this story: Patrick McDowell at pmcdowell10@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

David Fickling is a Bloomberg Opinion columnist covering commodities, as well as industrial and consumer companies. He has been a reporter for Bloomberg News, Dow Jones, the Wall Street Journal, the Financial Times and the Guardian.

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