homecatalogdealer locator




Winter Use Composting Toilet


Sun-Mar units serve as a reliable year-round facility when prepared for continuous or periodic use during the cold winter months. All units are made of fiberglass and marine grade stainless steel; so even if the compost freezes in the drum, sub-zero temperatures will cause no damage.

Limited Use

For limited use (i.e. only a couple of weekends a month at most) in cold temperatures, the unit can be used simply as a holding tank. For this, sufficient space must be available in the Bio-drum and the drum should not be rotated if it contains frozen compost. Electric units should be plugged in when in use, so that the fan eliminates all odors even though no composting is taking place. If you have an Excel-NE or an AC/DC that you are using primarily in DC mode, you should install a 12 Volt fan to assist airflow during use in the winter months.

This advice is applicable to all planning on using the unit once a month or so in winter. If you are planning on using the unit more frequently during the winter months, please follow the advice in the section below.

Extended Winter Use

For continuous or extended use in winter (i.e. every weekend, or residential use), the composting unit will have to be kept warm (at least 55°-60° F) so the composting activity does not stop.

  • Insulate all piping in unheated areas to avoid ice blockage including vent stacks (on all units), and waste inlet and drain piping where appropriate.
  • While the composting unit is not in use, energy costs can be reduced by installing a speed control on the fan so that very little cold air is being pulled in and the heater is operating less frequently. This speed control is available from our parts department.
  • Keep self-contained electric units plugged in if they are in a cold place. If a self-contained unit is being operated in an unheated space, consider putting a blanket over the unit to keep the unit insulated and further reduce heating costs. Please note that this will not be enough to bring the unit up to a proper composting temperature.
  • If you are planning on installing a unit in a climate with extreme temperatures (ie Alaska or Northern Canada), consider installing a 3" pipe around the insulated 2" pipe to add an extra measure of installation. Many of our customers in these areas also use heat tape or self-regulated heat cable along the length of the vent to keep ice from blocking the vent in the winter months. Contact us for additional advice if planning to install a unit under these circumstances.