Would You Build a Compost Powered Hot Tub?

How would you like to take some lawn waste, use it to heat your hot tub for 18 months†and†be left with a huge pile of rich compost at the end of the project?

It sounds like the last scene from Back to the Future, right?

Well, Tom Bartels of Durango, CO is a very inventive gardener and has figured this out. The best part is that itís a project that anyone can do with enough space and time to assemble it. The materials are all readily available, no flux capacitor necessary.

How It Works

You know how compost gets hot as it decomposes? Most gardeners would be familiar with that effect but few have ever considered harnessing that heat for any real purpose. But it can be done.

Tom uses a large quantity of wood chips (and a few other minor ingredients) to power his off-the-grid hot tub. It ends up being a 6 foot tall compost pile that he insulates with leaves. The hot tub itself is insulated only with straw bales and a foam topper.

He uses an electric pump to circulate the closed-loop system, which costs him a whopping $3.27 per month in electricity. Hook it up to a solar panel and it would be totally off the grid!

Consistently Hot Water in Freezing Weather

The water temperature in the hot tub stays between 104 to 110 degrees Fahrenheit all day, every day. Any time he wants to take a dip, the water is piping hot, without fossil fuels used to heat the 250 gallons of water.

All his data collection for the project was done over 2 months from mid-December to mid-February in Colorado with nighttime temperatures in the†single digits.

Tom estimates that this heat production will continue for 18 months (!) after which the temperature will decline due to the compost maturing.

Pays for Itself in Year One

The cost to set all this up was about $700, mostly for the pump and pipes. But get thisÖthe market value of the organic compost is $700-$1,200!

So it pays for itself (or more) in the first year; every year thereafter is effectively free because the pump and piping are reusable and the wood chips that provide the fuel are waste material that landscaping companies are happy to get rid of.

Use It for Anything

Tom made a hot tub but what he created is just a system that produces heat from yard waste. You could use that heat for any purpose including:

  • Heating a house using a radiant floor
  • Heating a green house
  • Heating aquaponic fish tanks
  • And more; itís limited only by your imagination…

Want More Info?

You can get complete details on how to create this system for free, from†Tomís website. He teaches this method in one of his†free webinars.

Sabrina Wilson is a natural health enthusiast and a staff writer for the Organic Daily Post. Originally from Boston, MA, she is a recovering Lyme disease sufferer who attributes her recovery to naturopathic remedies and an obsessively clean diet. Find similar posts on Twitter @organicdailypst


John B
John B2 years ago

Interesting concept. Thanks for sharing.

Jim Ven
Jim Ven2 years ago

thanks for the article.

Wendi M.
Wendi M2 years ago


Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Quanta Kiran
Quanta Kiran2 years ago


Keith Feisel
Keith Feisel2 years ago

What a great idea! We have rotting grass clippings right now that are just sitting there...rotting. I'm going to watch his webinar, and get on in this hot idea!

Margie FOURIE2 years ago

Good for you. Wish I had the resourses.

Peggy B.
Peggy B2 years ago


Lenore Kudaka
Lenore K2 years ago