Keeping a composting toilet warm in winter is essential to maintain the decomposition process and ensure effective waste management. Read our blog for some strategies to keep your composting toilet warm during the colder months.
As the microorganisms, AKA microbes, that do the composting slow down and hibernate in cold temperatures below 12°C, compost chambers can tend to fill up quicker in winter. The microbes most prefer a temperature range between 18°C to 45°C. As temperatures warm up in the spring, microbial activity will resume.
In a self-contained toilet, the air temperature around the compost remains at room temperature since the compost chamber sits inside the pedestal within a bathroom. However, a split-system toilet has its compost chamber outside the building which can be exposed to the elements and can experience slow composting.
If you want to speed things along during winter, follow these tips below to get those microbes munching along happily in your composting toilet.
Insulation
Insulate the Toilet Room
Ensure the room housing the composting toilet is well-insulated. Add insulation to walls, ceilings, and floors to retain heat.
Insulate the External Composting Chamber
Use insulating materials around the composting chamber to help retain the heat generated by the composting process.
Less technical ways of insulating the chamber are by:
-
Placing the chamber in a box with hay bales, with an up-cycled window for the lid
-
Wrapping the chamber in insulating material like a yoga mat, bubble wrap, or reflective foil barriers
-
Placing the chamber in a pop-up greenhouse with the use of glass, perspex or other transparent material on the sun-facing side
Some customers have syphoned air from their roof space and, using the existing ventilation system, pulled the hot air through the chamber.
Insulate the ventilation pipes
Ensure that the ventilation system is not drawing in excessively cold air. Consider using insulated ducts to minimise heat loss while still providing necessary ventilation.
Add Thermal Mass
Incorporate materials with high thermal mass (like bricks or concrete) around the composting chamber to absorb and slowly release heat, helping to stabilise the temperature.
Heating
Use a Space Heater
Install a small, energy-efficient space heater in the toilet room to maintain a consistent temperature. Ensure it is safe for use in the area and follow all safety guidelines.
Use Heat Mats
Place heat mats or heating cables around the composting chamber. These can provide a steady source of warmth to keep the composting process active.
Moisture and Oxygen
A compost pile needs the right amount of oxygen and water (in addition to carbon and nitrogen) to be successful. Water takes longer to evaporate in winter than summer. Too much moisture (i.e. urine) will force air out of the spaces in your compost pile, suffocating our dear aerobic bacteria friends.
Maintain fan
We recommend you leave the ventilation fan on 24 hours a day. Ensure there are no blockages.
Use bulking agent
Use bulking agents such as hemp bedding to absorb the excess moisture. Ensure the bulking agent you are using is between 1-3 cm in length. Bulking agent that is too fine reduces the ability to create air pockets in the pile.
Location
Optimal Placement
Place the composting toilet in a location that naturally retains heat, such as a basement or an interior room. Avoid placing it against exterior walls if possible.
Regular Maintenance
Monitor Temperature
Regularly check the temperature inside the composting chamber using a thermometer (we recommend using a smart sensor with an app). Aim to keep the temperature above 12°C for optimal decomposition.
By implementing these strategies, you can help maintain a warm environment for your composting toilet during the winter months, ensuring efficient and effective composting.
