Alternative Heating Methods: Coffee Can Heater

One of the most requested topics from our “What’s Coming Up Next” post was to discuss some alternative methods of cooling and heating your home. We have recommended in the “Car Kit” portion of our Emergency Preparedness Plan that you place a Coffee Can Heater in your car. These heaters could also be useful in a home if you had no other options available and needed to thaw yourself out a little bit.

A while back, we gave a little tutorial for how to make a coffee can heater, but we had a reader (David H. from Washington) who has refined and perfected this method and makes it so that the outside of the can doesn’t get too hot to the touch. This is a tutorial and pictures put together by him and posted here with his permission. This is the best part about our blog, we learn from our readers every day. You guys are the best!

How to Make a Coffee Can Heater

Items Needed:
1 – Empty tuna can (not shown)
2 – 1 lb cans: 1 empty, 1 unopened
1 – # 10 can empty with plastic lid
1 – Roll toilet paper
1 – Can spray foam insulation
1 – Book or small box of matches
1 – Bottle isopropyl alcohol

Optional Items:
1 – Empty popcorn tin (Three flavor type)
2 – Additional rolls toilet paper

Instructions
Step 1: Clean and dry the empty cans and remove labels if desired. Step 2: Remove cardboard tube from a roll of toilet paper.
Step 3: Place toilet paper into 1 lb can by squeezing bottom of roll to get it started then pushing it in with a twisting motion. Step 4: Place the tuna can into the bottom of the # 10 can.
Step 5: Spray a small amount of foam insulation around the tuna can. Step 6: Place the 1 lb can with the toilet paper into the # 10 can on the tuna can. Step 7: Spray insulation between the sides of the two cans. Fill the foam about halfway up the side of the 1 lb can.
Step 8: Place an unopened 1 lb can on top of the can with the toilet paper roll. This directs the insulation upward as it expands and prevents it from expanding over the top of the toilet paper can. Let it sit for an hour or more so you can determine the amount of expansion. Step 9: Spray in a second layer of insulation, allowing for enough expansion to bring it to the top of the # 10 can. Set this aside for eight hours to allow the insulation to fully expand and set up.
Step 10: Remove the unopened can and use a long-bladed utility knife or a sharp kitchen knife to trim the excess insulation. Slice the insulation from the rim of the # 10 can to the rim of the 1 lb can. If the insulation is still wet inside, it will get on the blade of the knife and is difficult to wipe off. Scraping with a straight edged (not serrated) is the best way to get it off.
Step 11: Pour some alcohol onto the toilet paper and light it with a match. The insulation may burn briefly and char, especially if it hasn’t set up completely. Do this outdoors or with adequate ventilation to avoid smoke buildup in the house. After using the heater for 30 minutes, the # 10 can was cool enough to hold at the top. The rim gets hot enough to melt the plastic lid if placed on it right after using the heater.
Step 12 (optional): If you choose to use the popcorn tin option, the heater, two extra rolls of toilet paper, and a bottle of alcohol will all fit in the popcorn tin with room for a flashlight, some tools, or other similar items. The popcorn can lid is an easy way to put out the fire in the coffee can heater and it won’t melt. Just set it on top and the flames go out.

Some observations from David. Originally, I hoped to make a self-contained heater with room for a small bottle of alcohol and some matches. This can be done by not using the tuna can, however, the 1 lb can with the toilet paper sits too low in the # 10 can and the flames may die from poor air circulation. Drilling a series of holes a couple of inches below the rim of the # 10 can through the insulation will help with the air flow. Use a hammer and nail to make starter holes so the drill won’t skate. Metal burrs may be found around the holes and the metal is sharp, so a file should be used to remove the burrs.

With four attempts at making the heater, I used about 1.5 cans of spray insulation. I estimate that one can could produce 3-4 heaters.

Note from Jodi and Julie: We hope this has been helpful for you. If you make one of these heaters using this method feel free to share about it in the comments or post a picture in our facebook fanpage. Thanks again to David for submitting this!