Composting Toilet Performance in Various Climates

Did you know that the your local climate can have an impact on the performance of a composting toilet?  It's true.  Whether your climate experiences especially cold and long winters or very humid summers, the weather does play a role in how you will use and maintain your system.  If you're thinking about adding a composting toilet to your home, climactic conditions are definitely something you should consider before you select and purchase a unit.

First and foremost, it's important to understand that the primary function of any composting toilet is evaporation.  Because our waste is approximately 90% water, the composting toilet has to have a good capacity to evaporate all that excess liquid.  Electric units usually feature a heating element in the base and a fan assembly in the back to assist and speed up the evaporation process.  However, if you live in an extremely humid climate, and the toilet is to be located in a building without air conditioning, you can expect that evaporation will occur at a much slower pace.

Most composting toilets come equipped with an emergency overflow drain, and in many cases, the manufacturer advises that hooking the drain up is not necessary.  This is because under normal operating circumstances, no liquid will ever get high enough in the unit to reach the drain valve.  However, in a humid climate, it is imperative to hook up the emergency overflow drain, because the humidity will affect the unit's evaporation capacity so significantly.  The issue of humidity may also affect your decision about whether to buy a waterless or low-flush system.  Remember that low flush systems may face more problems with evaporation capacity than waterless units, simply because of the added water going into the compost with every flush of the toilet.

The second critical job of a composting toilet is to break down the remaining 10% of the waste, which is basically a composite of various nutrients.  This decomposition process is performed by aerobic bacteria, or tiny microbes present in the compost that break the waste down with the assistance of oxygen.  Aerobic bacteria are highly efficient, performing their job quickly, without creating any sulfate or methane gasses as a byproduct of the breakdown process.  However, these bacteria are only active at temperatures of 55 degrees Fahrenheit and above.  If you live in a very cold climate, it will be important that your composting toilet is located indoors in a heated area during the winter months if you expect to use it on a continuous basis year-round.

Some composting toilets called central systems are designed so that the toilet in the bathroom is connected by plumbing pipe down to a central composting unit in a basement, cellar, or even outdoors.  If you own such as system, remember that the central unit where the compost is held is the critical place to keep heated.  If this central unit isn't heated, then you won't be able to use the toilet on an ongoing basis during the winter.  Composting toilet drums that are allowed to freeze can usually still be used on an occasional basis as a holding tank, assuming there is enough room in the drum to hold the waste.

No matter what type of climate you live in, it is possible to have a composting toilet, provided you do your research first.  If you're unsure how your climate might affect the performance of the system, contact the manufacturer prior to making your selection and ask some questions.  They will be happy to steer you in the direction of a system that's right for you.