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EXCEL AC/DC Self-Contained High Capacity Combination Electric/Non-Electric Unit
Excel AC/DC self contained high capacity composting toilet by Sun-Mar

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Product Code: EXCEL_ACDC
Our Price: $2,150.00

Availability: Usually Ships in 1 to 2 Weeks

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Sun-Mar Excel AC/DC

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How to Operate the Sun-Mar Excel AC/DC
Product Features
Technical Specs
Return Policy
Customer Reviews For This Product

The Sun-Mar EXCEL AC/DC is our "hybrid" self-contained composting toilet. With its ability to operate either electrically or non-electrically, it offers you the best of both worlds. The EXCEL AC/DC is the preferred unit for those who are running on generators, experience frequent power outages, or do not have electricity now, but expect to in the future.

The Sun-Mar EXCEL AC/DC is equipped with all the standard electrical features of the EXCEL, including a thermostatically controlled heater located in the base of the unit and a fan assembly in the rear top of the unit. In the event that the electricity is out, the EXCEL AC/DC is also equipped with the features of the EXCEL NE, which include a 4" vent stack running straight up from the unit and a 1" safety drain connected in the back of the unit.

Depending on whether or not electricity is present, either the fan assembly or the 4" vent stack will maintain a partial vacuum in the unit to ensure odorless operation. The EXCEL AC/DC is a waterless unit, which means an easy installation because there is no plumbing to worry about. When there is no electricity, however, the evaporating capacity of the EXCEL AC/DC is variable. This means that it is important to hook up the 1" safety drain when you install your unit.

A 12 Volt fan is included with the EXCEL AC/DC. If the unit is going to be used residentially or heavily, or if it's in a location that may be subject to downdraft, this fan should be installed in the vent stack. This fan draws 1.4 watts and can be powered by a solar panel and/or 12 Volt battery, neither of which is included. The Composting Toilet Store does sell separately a 10 watt Solar Panel that can be used to power the 12 Volt fan that comes with your EXCEL AC/DC unit. Please see the Solar Panel page for more details.


Sun-Mar's EXCEL family of self-contained composting toilets are the world's only self-contained units to be NSF certified to operate odorlessly and producing a clean, dry compost. When you purchase an EXCEL, you are literally purchasing the unit that sets the standard for self-contained composting toilets!

Operation steps of the EXCEL AC/DC:
  • For initial start up, add some Compost Sure (peat bulking material) into the Bio-Drum™ together with some Microbe Mix.
  • You may use your favorite toilet papaer, the composting toilet will compost it without a problem.
  • For day to day operation, add Compost Sure as specified in the product instruction manual. Every 2-3 days (while unit is in use), rotate the drum 5 or 6 full revolutions. For weekend use, just rotate before you leave at the end of the weekend.
  • When the Bio-Drum™ is half to 2/3 full, some of the compost should be moved to the finishing drawer. This is accomplished by releasing the drum lock and rotating the drum backwards. Finished compost drops automatically into the finishing drawer. This process takes less than a minute, and most importantly, you never come into contact with fresh material.
  • The compost is left there for at least 4 weeks so it can finish and sanitize. In the finishing drawer, it will be isolated from contamination by fresh material in the toilet. Once 4 weeks have passed, you can remove the finished compost from the finishing drawer at any time, no tools are needed to open the drawer.
  • Add the finished product to your flower garden! The final compost is clean, dry, non-offensive, and sanitary. It will look and smell just like any other regular compost that might come out of a garden composter.

Composting Toilet

  • Self-contained waterless unit
  • Please note, the Excel AC/DC is comprised of the Excel standard electric unit plus an AC/DC Conversion Kit. See Instruction Manuals below for more information.
  • Designed for use in areas with or without electricity, particularly for those who operate on a generator, experience frequent power outages, or who do not currently have electricity, but expect to in the future
  • Features large, patented Bio-Drum™ for high capacity use
  • NSF tested and certified for a continuous 6 months at maximum rated capacity (click here to view NSF certification)
  • When operating electrically, a thermostatically controlled heater warms liquid in the evaporating chamber for fast evaporation, and a fan in the top rear of the unit ensures odorless operation. When electricity is not present, the 4" Vent at top rear of the unit maintains a partial vacuum, also preventing any odor.
  • A 12 Volt DC fan drawing 1.4 watts is included with the unit, and should be installed in the vent stack if the unit is going to be used residentially or heavily, or if it's in a location that may be subject to downdraft. (Please note, power source for the fan is not included.)
  • Unit also features a 1" emergency drain that should be hooked up at the time of installation, because evaporating capacity can vary when the unit is operating non-electrically
  • Available in two colors, Bone or White
  • All Sun-Mar units feature 3-chamber technology:
    • The patented Bio-Drum™ - compost is mixed and aerated
    • The Evaporating Chamber - excess liquid is evaporated
    • The Finishing Drawer - finished compost is kept separate from unfinished material

Composting Toilet

Technical Specs:
  • View Dimensional Line Drawing
  • View Excel Instruction Manual
  • View AC/DC Conversion Kit Instruction Manual
  • Composting Capacity When Operating Electrically:
    • Residential & Continuous Use: 3 Adults or a Family of 5
    • Weekend & Vacation Use: 6 Adults or a Family of 8
    • Please note, family numbers above include both adults and small children
  • Composting Capacity When Operating Non-Electrically:
    • Residential & Continuous Use: 2 Adults or a Family of 3
    • Weekend & Vacation Use: 5 Adults or a Family of 7
    • Please note, family numbers above include both adults and small children
  • Electrical:
    • Max Amps (with heater on): 2.4
    • Fan Watts: 35 (when operating electrically) or 1.4 (12 Volt) fan that comes with the unit, for use when operating non-electrically (power source for the fan is not included)
    • Heater watts (when thermostat switches it on): 260
    • Average Power Use in Watts (heater on 1/2 time): 150
  • Vent & Drains:
    • Vent Pipe: 4" Sewer pipe and 2" Cent. Vac. tubing
    • Drain: 1" O.D. (Note: drain hookup is required, because the evaporating capacity can vary)
  • Dimensions:
    • Unit Dimensions: 22-1/2" W x 33" D x 33-1/4" H
    • Shipping Carton Dimensions: 35-1/2" L x 28" W x 36" H
    • Height of Footrest (when in use): 10-1/2"
    • Height (footrest to seat): 18"
  • Rough-in Measurements:
    • Depth required to remove finishing drawer: 46"
    • Vent outlet center distance from left side (looking at back of unit): 11-1/4" (to 4" vent) and 8-1/2" (to 2" vent)
    • Height to center of 2" vent: 28-3/8"
    • Height to top of 4" vent outlet assembly: 36"
    • Depth with footrest: 41-1/4"
  • Unit shell is constructed of durable fiberglass and ABS plastic
  • Product Weight: 60 lbs.
  • Shipping Weight: 110 lbs.
  • This product ships via common carrier truck line from Tonawanda, New York
  • Limited Manufacturer's Warranty:

Return Policy:
Please note, there is a 20% restocking fee on all returns of this item. For complete details, please see our store Return Policy page.

NOTE: Free Ground shipping for contiguous United States (lower 48 states) only. Sorry, we do not ship outside the contiguous United States (lower 48 states).

Model: Excel AC/DC
Birch Pond Lodge Eco Resort Lodge, Willow, AK
Reviewed By:
Bill Royce


Birch Pond Lodge uses your products and has figured out how to keep a composting toilet working year round in an off the grid cabin which sees winter temps to -40 F. We also have been pleased to have been selected one of the top 10 eco-lodges in the world by Outside Magazine, March 2003 and one of 25 great eco-lodges in an article in Travel & Leisure, July 2003. I thought I would pass along this good news to your firm.

We are located 70 miles north of Anchorage, Alaska and our cabins overlook pristine lakes and ponds. Using Sun-Mar composting toilets has solved the problem of disturbing the ground for a septic tank and drain field and eliminated the possibility of contamination of our lakes and ponds. Our concern was finding a way to keep the composter working in winter in a stand alone cabin which is not always occupied and thus not always heated. We solved this by building a well insulated bathroom within the cabin which is heated when necessary using a direct vent propane heater. In future cabins we will experiment by designing in some solar heat gain where siting allows to minimize the propane use.

We chose to purchase your product (Excel AC/DC) knowing we would have some problems to solve. Happily we can report these problems solved. We rarely use the AC or DC as the unit functions well so long as the bathroom stays above 50 and our cabin design has the venting exiting at the roof peak and this creates sufficient draft in most

You are welcome to share the content of this letter as you wish.

Thanks for supplying a good product.
Best regards,
Bill Royce

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