Thinking about wood heat for your tiny house? Great! Wood stoves can provide affordable, clean and renewable heat all winter long. The first step is determining how many BTU’s you need to heat your space.
What is a BTU?
A BTU is a British Thermal Unit, a unit of measure which is the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit. Heaters are typically rated in either BTU/hr or kW (kilowatts). 1 kW is about 3,412 BTU/hr.
How many BTU’s do I need?
Figuring out how many BTUs you need for your tiny space and translating that to the right stove can be tricky. Traditional BTU calculators and rules of thumb (like 15 x Volume of Space = Requred BTUs) tend to overestimate the amount of heat you need for your space by quite a bit, which results than a stove that is much larger than needed.
Having a larger heater than necessary makes sense with a traditional thermostatically controlled gas or electric heating system. You never really want to max out the capacity of an electric heat pump, for instance.
But wood stoves can only be controlled within a limited range. If you try to slow down the fire too much, your low smoldering fire will fill your chimney with creosote, which can cause a chimney fire. If your stove is too large for your space, you won't be able to burn the stove cleanly (or at all) without making your living space uncomfortably hot.
The most common complaint we hear from owners of wood stoves, both in tiny spaces and traditional homes, is that they can't build a fire in their stove without making their home uncomfortably hot! A wood stove can be a wonderfully useful and enjoyable appliance, but if you can't use it, you can't enjoy it.
The solution, of course, is to use a wood stove that isn't too big or too small. A stove perfectly matched to your space will be a fixture of your home from brisk Fall mornings and cool Spring evenings, and for all the cold Winter days between.
BTU Calculator for Tiny Spaces
After several years of working with folks in the tiny living community to add wood stoves to their small spaces, we've developed our own BTU calculator specifically for small stoves in tiny spaces. If you want to use a wood stove to heat your tiny home, bus, RV, yurt, shed, van, or other tiny structure, our BTU calculator is the best place to start. Click here to run your project through our calculator, and find out how many BTUs you need to heat your tiny space with a wood stove.
Which stoves will work for my space?
So now you know how many BTUs you need, but you aren't done yet! Wood stove BTU ratings, especially for smaller stoves, can be frustratingly inconsistent! Some stove manufacturers report an engineered rating based on the firebox volume, some report a BTU rating based on the EPA test procedure, and some report a theoretical maximum based on how much high BTU wood they think you could possibly burn in an hour. The EPA ratings and engineered ratings tend to be fairly close, but the theoretical maximum is sometimes an absurdly high number that you could never reach without damaging the stove.
In order to provide an "apples to apples" comparison, we've grouped stoves by which ones will work best in each BTU range, based on our own BTU calculator's results. If you'd like to see a comparison of popular small stoves that will fit your heating needs, run your space through our BTU Calculator, and click on "Compare Stoves in this Size."
As always, if you need some guidance with your project, drop us a line at firstname.lastname@example.org and we'll be happy to help!