The Japanese Way: No insulation, no central heating


Kotatsu Kitty says hello. (Photo by Matthew McVickar / Published under Flickr Creative Commons License CC BY-NC-SA 2.0)

Editor’s Note: Today’s column debuts a recurring feature called The Japanese Way. In this monthly column, Courtney Coppernoll will attempt to shed light on how and why certain aspects of Japanese culture differ from our own.

By Courtney Coppernoll

So, you’re a foreigner living in Japan. You’re not exactly sure how you ended up here – one minute you have no idea what you’re going to do after graduation and the next you’re telling three strangers in suits about your lifelong dream to be an English teacher – but here you are nonetheless. You now find yourself in a strange, strange land and you’ve got questions that need answering.

For instance, why are ATMs closed after 5 p.m.? Why is there mayonnaise on your pizza? And why on earth is that vending machine over there filled with lacy underwear? On second thought, you don’t mind that last one so much. Whatever your quandary may be my fine, foreign friend, there is no need to fret. I’m here to put an end to your Japan-induced befuddlement once and for all.*

*Note: If you remain in your befuddled state after reading my articles it is almost certainly due to some failure of communication between yourself and I, not because the article failed to answer your query.

Each month I’ll address some aspect of Japanese living that has a tendency to confuse and/or frustrate… well, anyone who’s not Japanese.

Let me make it clear, though, that the purpose of these articles is not to discuss what is and is not “correct” about the Japanese way of life. Instead, it is my hope that, even if I fail to solve a problem you may have (refer to above notation), that you will at least have a better understanding of why the Japanese do things the way they do after reading my column. At best, I hope you’ll develop a sense of humor about something you previously found frustrating. So, with that in mind, let’s get started!

With colder weather settling in, I thought it’d be appropriate to kick off my column with an age-old complaint made by many foreigners living in Japan: the lack of insulation and central heating in Japanese homes and schools. After all, in many other first world nations, housing regulations make insulation a mandatory part of building construction and trying to sell a house without central heating or air conditioning would be like trying to sell water to a fish (i.e. he might buy it if he were suffocating).

Yet, the Japanese continue to build homes and schools with single-pane glass (which allows the free flow of air between indoors and outdoors) and no insulation. Instead, they make do with localized heating devices such as the kotatsu and kerosene heaters. To be fair, some housing in northern parts of Japan (such as Hokkaido) is required to have central heating, and most department stores and office buildings have it as well, but the majority of Japanese people continue to heat only one or two rooms of their homes during winter.

So, why is it that Japan – a nation touted for its technological advances – lacks what many other countries consider a basic element of building design? Well, after polling many of my (extremely confused, but helpful) Japanese co-workers, I have not just one, but several possible reasons why the Japanese do not insulate or centrally heat their homes and schools.

• The Cost Factor:

Almost every person I talked to mentioned the high cost of central heating as the main reason for not having it in homes and schools. Expense is a factor in other countries as well (my parents’ electric bill goes up more than 50 percent during the winter months), but it seems to be an expense most Japanese can live without. One of my friends even suggested that central heating wastes money because you may be paying to heat an entire house where you’re only actually using one or two rooms. Some websites also claim that the lack of insulation is a way for Japanese construction companies to save money by building houses more cheaply, but so far no one has offered any evidence to support this.

• Short Winters:

Many of the people I asked also said that since Japanese winters are short, houses are built to be comfortable during the hot, humid summer months, rather than the chilly winter ones. Due to a warm water current flowing past the southwestern side of Japan (the Kuroshio Current in case you’re interested) the southern half of Japan at least does tend to have milder, shorter winters. So, according to my co-workers, small space heaters like the kotatsu are sufficient to last through a few short cold months.

• Water Damage:

One friend’s explanation had to do with the traditional building materials for Japanese homes: wood and paper. Due to the extreme humidity Japan experiences in the summer months, homes were traditionally built of thin materials (i.e. materials that allowed air to flow freely between indoors and out) in order to prevent homes from literally rotting away due to all the extra moisture in the air.

• Enjoyment:

Another Japanese friend couldn’t stop talking about how much she loooves her kotatsu. For her, sitting under a kotatsu and having that one, comfortable warm spot when the rest of the room is freezing is a wonderful feeling, and she’d genuinely miss that if her home had central heating.

• Sense of Community:

The reason given by one obaachan I asked is the one that I think may be at the heart of why the Japanese don’t use central heating. She recalled fond memories from her childhood when her whole family would huddle around a single, small kotatsu to have dinner, watch TV, and eat mikan together. For her, a cold house without insulation wasn’t an inconvenience, but an excuse for her family to spend time together and keep each other warm.

I realize that for some of you these explanations may leave you feeling a little less-than-satisfied. After all, preventing water damage is hardly a major concern for those of us who live in impenetrable cement blocks. Likewise, single JETs may take little comfort from the fact that Japanese families bond over their shared hypothermia.

Keep in mind what I said at the beginning, though. This column is meant to give some insight into how the Japanese view their own way of life, however unusual and foreign we may find it to be. So, when you find yourself grumbling and shivering under 20 layers of clothing and blankets next January, hopefully you’ll remember that the Japanese have their own reasons for making houses the way they do. It won’t keep you warm, but it might help ease the suffering…at least a little bit.

Do you have questions you’d like Courtney to explore in The Japanese Way? Email them to wideislandview (atto) gmail (dotto) com.


  • HS

    I also just stumbled upon this old post as I was just sitting in my one room apartment in Kansai thinking to myself “it sure is cold right now…”

    What surprises me is nobody that the OP talked to mentioned earthquakes. I totally thought they would have brought that up as one of the first reasons.

    Other than that, I agree on most of the points in the comments. If the walls are not insulated, then heat can penetrate easily, but so can cold, making the comment by the Japanese colleagues completely false.

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  • William Timms

    “single JETs may take little comfort…”

    What about the rest of the foreigners that live in Japan? Are we allowed to take comfort too?!

  • Benchi


    I am not a native english speaker, thus please ecuse my bad writing.

    I lived in Japan for 1 year (2014-15) and visited many places, slept in many hotels, visited many friends in winter and summer. Japanese houses are extremely poor insulated.
    Even my garden shed has better insulation than some houses I stayed in Japan. In germany I lived in an house built in 2000. Although one wall was one big windows I never had to use central heating in 2 of the rooms, just because of the perfect insulation. The heat from neighbouring rooms was more than efficient to keep 18-20°C on normal winter days.

    In Japan it looks different:
    One example is the newly build house of my japanese professor, which wasn’t insulated. Once we had a home party in his new house. We entered in early evening and the temperature was the same as outside (5°C) !!!. I was even able to feel airflow close at the window.

    Sometimes I asked people why the houses are so poorly insulated and I only got strange answers:
    – “that’s how we build houses
    – summers are so hot, thus insulation would be bad (I think the japanese just don’t know what “insulation” means)
    – winter are short
    –> no one mentioned earthquakes !

  • Bridget

    I really liked the obaachan’s reason to why there is no need for central heating in Japan.
    I live in the suburban areas in North Borneo, and once in a while we’d get electricity blackout, usually for several hours.
    Though most might disagree, I enjoy not having electricity especially in the evening as my family members would sit around a table, and talk with each other, have a laugh, have meals together and so on. It’s as if there was no need to rush, even though there were deadlines to meet, work to be done etc.
    Being the youngest among 5 siblings and currently studying overseas, with most of the other siblings always on the road for work, times like this is very precious to me 🙂

  • James

    Thank you very much for contributions and the nice comments,
    My experience in Japan was really pretty, in many homes there was a central heating system, and in the ancient or traditional ones i founded very confortable to stay around a table with friends by drinking a tee or a hot sake.