My shop is in the garage of my home, and effectively has no climate control in it. As many other woodworkers do, I use a kerosene heater to warm the garage during the winter months. Using some common sense, this is a safe and effective way to heat a space. First, as with anything thing that burns there is a risk of carbon monoxide. It wouldn’t be a bad idea to have a detector in your shop space to alert you if the levels are getting too high. I had a friend who had one of theses heaters started having flames go outside the heater. What saved this from being a tragedy is he kept at least the minimum 3′ clearance around the heater. That is not optional. Fortunately for him, nothing was damaged. However, this brings me to my next point, this was completely preventable. What he found after taking apart the heater was what ignited wasn’t creosote or any build up on the walls of the heater, but rather that collection of sawdust and shavings that had worked its way inside of the heater. At LEAST once a year, take the heater apart and clean it out! The spring after his heater ignited, I cleaned mine out, after many years of use. I will say I am fortunate as well that I didn’t have the same thing happen! I found I had next no build up of creosote or any other crud on the walls of the heater, but I had a good thick layer of sawdust just under the heating element. Keeping the heater clean, and keeping debris away from it is paramount!
Something to note for your tools, a byproduct of burning kerosene, or any other fossil fuels, is water, and will put water in the air. For most dry winter days, this won’t be an issue. If it happens to be a little more humid outside due to snow melt off, it can really raise the humidity in the shop. You will also get a situation where the air gets warmer then the tools, which on smooth cast iron will create condensation. I was not happy when I found a layer of orange on my brand new jointer bed! (Fortunately it was a very light layer, and cleaned up well) The lesson from this is, keep up with tool maintenance, make sure your cast iron surfaces are protected. When the heater is lit, don’t leave it unattended! When you extinguish the flame, make sure it cools completely before leaving it. Also, make sure it is completely turned off. As the heaters age the turn off tends to catch so it is always wise to make sure that the dial is all the way in the off position.
Most gas stations that sell kerosene only charge sales tax on it, so it is not street legal. Being that kerosene is chemically similar to diesel, the stations will only allow you to dispense into a blue container. Note, there are two types of kerosene available. Once is clear, the other has a pink dye in it. Use the clear stuff as it burns more efficiently. In fact most heaters state that clear kerosene is required.