Best-selling, highest-rated composting toilet for medium to high-capacity use
Sun-Mar makes several models of self-contained composting toilets. The Excel model is the best-selling unit in North America, and for good reason. It's a high-capacity Bio-drum toilet that's very simple to operate, features well-proven technology and is extremely reliable. The Excel was the first ever self-contained composting toilet to be certified by the National Sanitation Foundation (NSF). It's the toilet that sets the standard.
The Excel has enough capacity that it can be used just about anywhere including in residences, cottages and even light commercial applications.
Sun-Mar also makes mobile, compact (low profile) and space-saver self-contained composting toilets; see below for descriptions.
Composting toilets use the natural process of decomposition to break down waste into usable nutrient-rich top soil. To begin the process, add microbes to the drum. As waste continues to enter the toilet, the drum must be turned at least every two to three days.
Solid waste must always be followed by a scoop of bulking material. When the toilet is half-full, the finishing process begins. Thirty days later, there's usable odor-free compost.
Electric (E) - Standard Model: For those with continuous 120v power, an electric unit is suggested. Electric units feature a 370w 120v thermostatically-controlled heater in a sealed compartment beneath the unit. Odor-free operation is maintained by a standard 30w turbo fan directing air up a 2" vent stack.
Non-Electric (NE): If you have no electricity, then a non-electric (NE) unit is the right selection. A 12v fan is supplied with Centrex 2000 and Centrex 3000 series for battery/solar hook-up, non-electric units, but are not normally needed for cottage applications unless the system is used heavily or is particularly subject to downdraft.
AC/DC units: are dual vented units with both a 2" and 4" vent for those who expect to have 110v power in the future, or are running a generator for 12 or more hours per day.
Listed capacities refer to the number of people, on average, using the unit per day. It's important not pick a unit that is below your capacity.
Seasonal/Vacation Batch unit - (Adults/Families) six adults or families of eight: Batch composting means that the catchment receptacle is filled, removed, and allowed to decompose and cure without the addition of more excrement. Thus, a toilet using a batch composting process typically requires more than one catchment chamber (i.e. composting reactor).
Residential/Continuous unit - (Adults/Families) three adults or families of five: Continuous composting means that the catchment receptacle is constantly receiving new waste materials, while at the same time producing finished product. A toilet using a continuous composting process usually requires only one catchment chamber.
Self-contained unit sizes
The selection should be based on both whether the unit is used seasonally or residentially, and the number of people that will be using the unit.
Excel E (Electric) — high-capacity suitable for light to medium cottage use
Excel AC/DC (Electric) — operating in standard electric mode suitable for very heavy cottage use, or medium residential use
Excel NE (Non-Electric) — MOST POPULAR MODEL; regular-capacity suitable for medium to heavy cottage use or light residential use
Compact (Electric) — low profile; medium-capacity suitable for very heavy cottage use or medium residential use
Space Saver (Electric) — smallest self-contained unit; medium-capacity; suitable for very heavy cottage use or medium residential use
Mobile (Electric) — for RVs, boats and trailers in motion (no pump outs!); includes a special drum lock to ensure the composting drum stays upright in all conditions; suitable for medium-capacity use; low-maintenance and offers a pollution-free alternative to sewers, septic systems and chemical toilets; includes a fold-away foot rest for tight spaces; vent stack includes a continuous 12v fan; runs on its own circuit
This item description was written by Joel