Friday, March 12, 2010

Shipping Container / Earthship'esk Heating Report

On February 24th the temps in Montello were in the high 30's during the day and low 20's at night. I filled the small wood burning stove before retiring to bed around 11 p.m. The stove took five small pieces of wood before it was maxed out and dampered down for a long slow over night burn. I woke up twice in the night literally sweating. Admittedly, I was sprawled on a negative 20 degree sleeping bag and a thermarest pad, but I was sleeping "ON" it, not inside it. By morning the wood had expired and a few coals remained. The inside container temperature was very comfortable, so I didn't add anymore wood to the stove.

We left for a days driving around the valley at about 7:30 or 8:00 a.m. and didn't return until 3:00 p.m. The heavy steel container doors were open all day allowing the sun to shine through the sliding glass door for maximum solar gain. I was excited to return and feel the comfort level inside the container, but was expecting a chill due to the mostly overcast day. Much to my surprise, the container felt just as comfortable at 3:00 p.m. as when we left seven hours earlier.

I attribute this to the insulation board and earth berming on the exterior. I believe the overheating is due to a lack of thermal mass on the interior side of the insulation board. My research indicates that traditional earthships require many weeks to heat up the thermal mass to the point of providing a well regulated interior environment. The next shipping container placed in Montello will include similar construction with insulation board and bermed walls, but much earth will be placed between the exterior wall of the container and the insulation board to deliver increased thermal mass.

I really like the idea of having both types of construction (nearly none and mucho thermal mass). Our current setup works well for our present visitation schedule in the winter. The lack of thermal mass and abundance of insulation allows us to arrive in Montello after a month of being away and quickly bring the room temperature to a pleasant level with very little fuel. Adding the second container with more thermal mass will accomodate a longer term stay and hopefully provide a steady year round temperature with little to no external heat source required (besides the sun).

All of this is still very much an experiment. An experiment that I'm loving! With experience and a good neighbor with a backhoe, I can easily adjust the thermal mass factor over time with minimal effort. It's an amazing feeling to live in an extremely frigid winter zone and know I require very little resources to stay warm. I currently spend $160 a MONTH to heat my city home in the winter. That's about the same price as a cord of wood, which I'd guess to last two winters in Montello! The container is currently so efficient that I am seriously considering a propane heater setup for ease of use and temperature control. I'll keep the wood burning stove and a couple cords of wood on standby!

less fuel = less cost = less labor for $ = more leisure time = TIME FREEDOM!

This is a pic of the propane heater I'll likely use in the container. It manufactured by "Mr. Heater" and is recommend for areas up to 200 square feet. I'll likely install two units at opposite ends of the structure for quick heating and redundancy. One of these units on the low setting (4,000 btu) will operate off of a 100 pound propane tank for 22.5 days without interruption. Preliminary experience (no real science) suggests one 100 pound tank should get me through a long winter with much help from the sun! Winter heating costs ~ $50.


  1. I just finished the initial assembly of 2 global buckets, courtesy of one of your previous posts!!

    Having read this, I'm wondering whether totally burying a container would offer additional benefits to temperature control... Just thinking about the Walapini idea...

  2. Oh Wow! If want to send me some pics of the buckets I'll post them.

    Good point on totally burying a container. I'm hoping this summer will prove cool and comfortable in the container as it sits, but if not I'll definitely be thinking about tapping into the cooler temps deeper down and the possibility of a basement.

    I really need more winter exposure to comment on going deeper for winter temperature control...meaning, I need to spend a week out there without a fire and varying weather patterns to see how well the sun warms the unit by itself.

  3. Hi! Please contact me at We have one container in place and need some more - and are in south west colorado and at the beginning of building an earthship. Can you email me re pricing and transport of more containers? THANKS! Jessica

  4. Will do! Gotta get the soil mix figured and we should be good to go. My kids have really gotten into them. Dad! When can we finish the Global Buckets... Dad, when can we finish the Global Buckets...

  5. I'm interested in knowing how the Mr. Buddy heater works out. Since the elevation is well over 4K feet I'm assuming you may have issues with the propane canisters and tanks and gas flow.

  6. Hey Richard, the Mr. Heater Buddy works very well at elevation. I live at 4500 elevation (similar to Montello) and use it all the time in my garage. I also frequently use it camping in the mountains at 8,000 - 9,000 feet without flaw. When it's really cold out a one pound propane canister will tend to freeze, but I've never had any issue with it connected to a 20lb tank. That said, I too am eager to see how well it heats the space!