In this chapter in our series on how to live in a Japanese apartment, we discuss different options for heating your home and how they compare in terms of energy efficiency.
Air Conditioner (Aircon)
Many rental apartments in Japan come equipped with pre-installed wall-mounted air conditioner units (called “aircon”). You will want to use the 暖房 (danbou) setting to use the heating function. For a detailed explanation of how to use your air conditioner remote control, please see this article (Using air conditioner and heater remote control in a Japanese apartment, which also has tips for efficiently using your aircon).
Wall-mounted air conditioners do a good job of heating a room, but there are few drawbacks. One is that, since hot air rises, a lot of the heat will tend to collect near your ceiling, rather than the closer to the floor where you need it. To prevent this, point the vents downward during the winter).
Air conditioners can also be energy hogs, if they aren’t used efficiently (for example, if you constantly turn it off and on; if you don’t use the eco-setting; if you don’t supplemental it with a circulating floor fan that moves the hot air around the room; and if you don’t clean the filters regularly).
According to one study, the hourly cost of using an air con on the danbou function can vary between 105W and 1,980W, or between ¥2.8 and ¥53.5. The upper end of this range would make an aircon the most energy inefficient way of heating your home, but the lower end compares well with other heating options described below.
Halogen Heater (ハロゲンヒーター)
A halogen heater is device that produces heat by using halogens, when plugged into an electric current. Unlike other electrical devices that produce heat through coils and heat conductors, these heaters use halogen elements enclosed in lamps or bulbs to provide a direct source of radiant heat or energy (Source: naturalinsulation.co.uk). You can buy a halogen heater for as little as ¥3,000 to ¥4,000.
Below is a breakdown of the hourly cost of using a halogen heater on various watt settings.
Average hourly cost of using a halogen heater on the following settings: 400W (¥10.8), 800W(¥21.6), 1,000W (¥27), 1,200W (¥32.4).
Fan Heater （ファンヒーター)
A fan heater is a heater that works by using a fan to pass air over a heat source. This heats up the air, which then leaves the heater, warming up the surrounding room. They can heat an enclosed space such as a room faster than a heater without fan. A downside to a fan heater is the sound created by the rotating blades. A big upside is that it pushes heat throughout the room.
A 1,200W fan heater costs about ¥32.4 a hour to run. The cost for a fan heater varies widely depending on the size the type of heating element (heated coils, halogen, etc.)
Ceramic Heater （セラミックヒーター）
A ceramic heater generates heat by using a central heating element surrounded or encased by ceramic plates. The element heats the surrounding ceramic plates, and internal fans thrust the heat from the ceramic plates out into the room.
They are different than fan heaters because fan heaters utilize a series of coils to generate heat. An external fan on the front of the unit quickly spins and throws the heat generated from the heating coils into the room.
Ceramic heaters have the advantage of ceramic plates that produce heat quickly and cool quickly when the unit is turned off, which reduces the risk of burns.
Carbon (fiber) heaters are thin and have a large surface area which heats at a lower temperature. The advantages of using a carbon heater are low surface temperature, even heat and infrared wave distribution, and a large heating surface area.
Kerosine Heater 石油ヒーター
Kerosine heaters are commonly used throughout Japan, especially in rural areas. Kerosine heaters (or “stoves) are said to lower your electricity bill, though you do have to buy the kerosine. In this study, it was found that if you run a kerosine heater on a high setting (1,200W), the cost per hour is about ¥32.4, which is about the same as for a halogen heater at that setting. The lower the setting, the less expensive: at a medium setting (700W), the hourly cost is about ¥18.9 and at a low setting (500W), the cost is about ¥13.5).
If you choose to use a kerosine heaters, be sure to ventilate your home! This means you should leave a window open to allow air circulation, because the fumes are toxic.
An electric blanket will not heat a whole room, of course, but it will very efficiently heat the space that it covers.
Electric carpets are very energy efficient compared to the heating options discussed above. A two-tatami-mat-sized electric carpet costs about ¥9 an hour to run on a high setting and about ¥6.2 an hour on a medium-setting. Prices for electric carpets vary widely, but you can buy a one or two-mat-sized one for as little as ¥3,000 to ¥4,000.
A kotatsu (火燵) is a low, wooden table frame covered by a heavy blanket, underneath which is a heat source. It is the way that many families in Japan stay warm in the winter.
A kotatsu heats up your whole body with a minimum of heat loss because most of the heat is trapped under the blanket. The downside of a kotatsu, of course, is that once you comfortably settle yourself in, you may not ever want to get up.
Kotatsu are super energy efficient. Of the different heating options covered in this study, they came in number one for energy savings. A kotatsu costs about ¥4.6 an hour to run on a 510W setting and about ¥2.2 on a low setting.
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