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How to save on heating bill AND stay warm!

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It’s about this time of the year that all the personal finance magazines and blogs come out with articles on how to save money on heating.  This time, I will join the fray and reveal my secret.  The usual advice to save money on the heating bill is to turn down the thermostat and bundle up.  This is good for the wallet, but the Mrs. really hates being cold.

how to build a kotatsu table

I love my kotatsu table!

My secret is the kotatsu table. This might not work for everyone though, especially taller folks that can’t sit comfortably on the floor.  A kotatsu table is basically a coffee table with two top surfaces, a heating element, and a big blanket to keep the heat in.  Every household in Japan has one and it is the best place to take an afternoon nap.

You can purchase an authentic kotatsu table, but it is expensive because they have to be imported.  Instead, I will show you how to make one.


lack ikea kotatsu table

  • $40 Coffee table – You need to find a coffee table with two top surface.  A LACK Coffee table from IKEA is what we have. You can also search Craigslist for a used LACK coffee table.  If you have long killer legs like Angelina Jolie, you probably want to get a taller coffee table.

 kotatsu table heater

  • $55 to $100 heating  element – There are some “kotatsu heater unit” for sale on EBAY for $70, but the shipping cost is another $30.  An alternative is the “cozy legs” radiant heater.  I found one on Amazon for about $55 or you can try the local Ace Hardware for $60.  The cozy legs works okay, but it takes a long time to warm up, about 10-15 minutes. I would go with the real kotatsu heater if you want instant warmth. *2011 update. The real kotatsu heating element heats up much faster than the cozy legs. It’s 100 times better so I recommend that. It’s not worth cheaping out on this one, trust me.
  • $0 old king size blanket – We like the king size, but a queen would probably work too.  A comforter is better in colder climate.
  • $? pillows to sit on.  You can pick up some big pillows from IKEA while you’re there.

Instructions – Put the coffee table together and leave the lower panel out for now.  Mount the heater element to the bottom of the coffee table (you’ll have to figure it out yourself.) :)  Throw the blanket on top of the coffee table and center it.  Put the bottom panel on top of the blanket and TA DA! you’ve got a kotatsu table.  Don’t forget to put the pillows under your bums.

If you can sit on the floor comfortably, a kotatsu table will be the best thing that ever happens to you. We rarely turn on our force air heater these days.  Our climate is temperate and the concrete condo retains the heat well so our indoor temperature hovers around 64 degrees Fahrenheit.  We spend a lot of time under the kotatsu table every winter and save tons of money on heating bills.  Our November electric bill went up $10 from our summer bill. Enjoy!

Let me know if you have any questions. I can send you more pictures in an email.

mount kotatsu heater

how to mount kotatsu heater unit

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{ 36 comments… add one }

  • Jack Fuller November 7, 2011, 2:07 am

    Wow. A unique way of staying warm this winter.

    • retirebyforty November 8, 2011, 7:37 pm

      Heh heh, thanks. I was getting tired of the usual advice to turn down the thermostat.

  • Little House November 7, 2011, 6:54 am

    Those tables sound really great on a cold day. However, on the DIY version, how do you make sure the heater doesn’t catch the table on fire? I’m a stickler about fire safety (my step-dad was a fireman).

    • retirebyforty November 7, 2011, 10:04 am

      I try my best to not leave it on when I’m not using it. If your legs are next to the heater, you’d know when it gets too hot. From what I understand, the ceramic heater element is not supposed to catch fire, but the risk is always there with any electronic heater.

      • joedartjr September 22, 2013, 8:03 pm

        An authentic kotatsu heater does not heat up like a space heater, it wont light the wood on fire. But it is possible if the blanket isn’t flame retardant that if someone was to physically put it into the heater and hold it there it could catch on fire, but you would have to purposefully do it.

  • PKamp3 November 7, 2011, 7:41 am

    We have a sun-room (other areas of the country might call them three-season rooms) and it’s gotten pretty cold at night the last month or so. We were looking at a cheap way to heat it since if we leave the door open the thin walls will radiate all of our heat away, haha.

    How hot does a kotatsu get? Is it so hot I have to be careful what type of wood I purchase on the table? Think it would be good in a 14×15 sun-room with tile floors… or is it the space heater for us?

    • retirebyforty November 7, 2011, 10:07 am

      My heater element is pretty hot, but I don’t think it can reach wood’s combustion point. The LACK table is made of particle boards and I haven’t had any problem yet. I don’t know about sitting on tile floors. It doesn’t sound comfortable…

  • MoneyCone November 7, 2011, 8:11 am

    I remember reading that post last year! The Kotatsu table sounds fantastic!

  • Miss T @ Prairie Eco-Thrifter November 7, 2011, 8:29 am

    This looks really neat. Not only on a functional level but they look really nice in a room too. Plus I love the name. It just sounds warm and cozy. I might just have to look into one of these.

    • retirebyforty November 7, 2011, 10:08 am

      It’s quite expensive to import one from Japan. If you live in LA, there are some stores that sell a ready made one starting at $150 or so.

      • Miss T @ Prairie Eco-Thrifter November 8, 2011, 6:22 am

        Good to know. Thanks. Looks like I will need to import either way if I want one since I live in Canada.

      • Jarrod May 31, 2012, 6:14 pm

        I live in LA and would love to buy on for my fiance who lived in Japan for two years. Where can I buy them in LA for the $150?

        • retirebyforty May 31, 2012, 8:52 pm

          We got one from Murakai market. Not sure how much it cost now.

  • Jeff @ Sustainable life blog November 7, 2011, 12:46 pm

    That’s a really creative idea and I love DIY projects, but I may be too tall for this one!

  • Roshawn @ Watson Inc November 7, 2011, 5:42 pm

    It does look really nice. I intially had the same question as Little House though.

    I think it is always good to rethink conventional wisdom, and since your November heating bill was only $10 more than the summer, that’s speaks volumes.

  • Aloysa November 7, 2011, 6:34 pm

    I remember this article! It was great then, it is great now! I also remember thinking wow! Never even heard about this table. :)

  • SB @ One Cent At A Time November 7, 2011, 7:08 pm

    This is great. But nothing beats a thermostat and a one click heating :) Unless you are counting pennies

  • Kellen November 8, 2011, 6:44 am

    Sometimes it’s cozier to have a warm spot like this than to heat the whole house – like how nice it is to snuggle under blankets when it’s cold. If the whole house is heated, then most of that warm air is not being used, PLUS can make all the air in the house even drier than winter air usually is.

    Thanks for the tips on making your own!

    • retirebyforty November 8, 2011, 11:06 am

      In our old house, we warmed the bedroom at night with a space heater and use the kotatsu table in the living room. The room temp was around low 60s and it worked quite well.

  • Tushar@EverythingFinance November 8, 2011, 6:46 am

    This is a neat little tip. We all like to cozy up next to the fireplace. Now we can also cozy up to a coffee table :)

    • retirebyforty November 8, 2011, 11:06 am

      A coffee table is much nicer to cozy up to than a fireplace. There is a spot to put your coffee, magazines, and laptop. 😉

  • Melissa November 8, 2011, 7:35 pm

    I love these! My husband’s parents still live in Japan, and their house gets very cold. These were wonderful; the whole family sits around it!

  • 101 Centavos November 8, 2011, 7:56 pm

    I’m not much of a floor sitter, but I think for warm legs on a cold night, I could adapt.

    • retirebyforty November 9, 2011, 10:26 am

      I was already sitting on the floor playing video games and such so it was an easy adjustment for me. :)

  • Paula @ AffordAnything.org November 8, 2011, 9:27 pm

    That’s fantastic! It’s great to read an actual unique tip like this — not just the same ol’, same ‘ol. And I marvel at the Japanese; they have great design and efficiency.

    • retirebyforty November 9, 2011, 10:25 am

      We love our Kotatsu table. It’s the best spot to gather in the winter.

  • catawba county nc real estate November 10, 2011, 7:22 am

    Great idea! This is a great solution to staying warm in the winter without paying an expensive power bill. Thanks for sharing!

    • retirebyforty November 10, 2011, 12:58 pm

      It’s really great, we love it.

  • Hank November 10, 2011, 9:40 am

    This is a very interesting idea. I had never even heard of a kotatsu table before.

    • retirebyforty November 10, 2011, 12:59 pm

      It works very well and saved us a lot of money on the power bill.

  • Steve January 25, 2012, 2:30 pm

    How do you use the table? When you “spend a lot of time under the kotatsu table” are you literally under the table, like it’s a kid’s fort? Or do you just stick your legs under there? Does it provide warmth if you’re just sitting next to it, or if you’re sitting on a couch and maybe just putting your feet underneath?

    • retirebyforty January 25, 2012, 2:52 pm

      It’s best to sit on the floor and stick your legs under the table then pull the blanket over your waist. It works great and warm your whole lower body!
      You can sit on the couch and stick your feet underneath too, but it is not as warm then. Sitting next to it is no good.

  • Gerard June 21, 2013, 10:18 am

    I wonder if you could get the heat from a dog bed heater instead of the heater you show in the picture. They’re cheaper and they look like they don’t use much power, or overheat.

  • Mary March 25, 2014, 6:43 pm

    I think an electric heating blanket might work here too.

  • Suzanne December 10, 2014, 9:50 pm

    We don’t have a kotatsu but we do use yutampo (Japanese hot water bottle) to warm our beds here in Japan. Yutampo is far better for one’s health — than an electric blanket, for example. One winter we went skiing in the Japanese alps at Nagano and the Inn had kotatsu for each room but no heating. So we were forced to sleep under the kotatsu — a bit dangerous in my opinion due to fire potential and health reasons, however, it was preferable to freezing to death those nights!

    Our homes here have electric flooring but it is too expensive to use often and I object to it for health reasons, as with the electric blanket or electric heating pad for pets. Electric ‘hot carpets’ are also popular here, but again, I do not think it is wise to expose one’s body to electrical current all winter long.

    • retirebyforty December 11, 2014, 10:09 am

      The Yutampo is a great idea. I will keep a look out for it. Mrs. RB40 uses a heat pack thing she warms up in the microwave. That works pretty well too, but it doesn’t last long.

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