Sun Mar Composting Toilet Reviews: Top Tiny House Models - Tiny House Blog

Best Sun Mar Composting Toilets for Tiny Homes

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In the world of composting toilets, Sun Mar sets a standard of excellence that few other brands are able to match.  (Though if you want something without the bells and whistles, and for a whole lot less money, check this out.)

The Tiny House Blog has combed through the various models they have to offer, and we think these are the best two options:

Sun Mar Mobile Electric Composting Toilet

Designed for use in a mobile marine environment, this model is perfect for those who want to have an indoor composting toilet with NO odor and a minimum of maintenance, as well as those who are living out their tiny house dreams on the open road.

It’s comparable in price to similar competitive models, but has a three-chamber system to reduce the number of times the unit has to be emptied – everything goes in the same reservoir, so there will never be a need to empty urine and wash a separate tank for liquids. A special gasket, intended to prevent leakage on the high seas, means that this model is particularly odor-free.

A 4” ventilation duct is necessary to evacuate gasses resulting from microbial decomposition, assisted with a small electric fan and heater, making this model less accessible to folks living off-grid. Sun Mar offers a filter for boat owners to filter the exhaust of their toilet at deck level – this will be useful to tiny-house-on-wheels owners who want to stay well within road-worthy legal requirements.

Price: $1,775.00

– Carbon Zeolite filter available to help tiny-house-on-wheels owners vent their toilet effectively while staying within road-worthy legal requirements
– Rated for 1 full-time user, or three part-time users
– Requires a steady supply of electricity to function smoothly
– Fan and heater operate continuously, creating a constant draw of electricity
– Overflow drain and holding tank required

Sun Mar Excel Non-Electric Compost Toilet

This model, unlike the one above, is specifically designed for use in an off-grid environment. It does not require the aid of electric fan or heater to vent gasses created by microbial decomposition. Instead, it relies on a 4” vertical ventilation shaft that extends two or three feet above the roof line to create a natural air convection current. This could prove a challenge for mobile home owners, because the ventilation pipe could alter the overall height of your vehicle, relative to road-worthy height requirements.

Price: $1,789.00

– High usage capacity of 2 full timers, a couple with one child, or as many as five part-time users
– No electricity required to use
– Ventilation relies on installation of a shaft that will stand 2-3 feet above your roof line
– Overflow drain and holding tank required

If you’re interested in learning how Sun Mar stacks up against some of its competitors, check out this article comparing Sun Mar with Airhead.

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Click Here to Leave a Comment Below

Margy - March 11, 2016 Reply

I’ve used a Sun-Mar non-electric (NE) for five years now. It’s a great product and has made our off-the-grid home much easier. We do use a small electric fan run by solar power to vent gasses and we feel this is one of reason ours works so well. I use diatomaceous earth to help reduce gnat issues in spring and fall. The cold of winter and heat of summer don’t foster hatching. – Margy

Mildred Sargent - March 14, 2016 Reply

This article is spot on in every way. After spending some quality time with my EcoJohn i’ll never go back to the water wasting splash toilets. I purchased mine from Thank you for this article!

Ted Knight - March 22, 2016 Reply

You might want to update it with our amazing Sanitizer Evaporative Toilet (Patent No. 9301659). It is far superior to current sanitation solutions, especially for mobile tiny homes with the following attributes:

• waterless and odorless
• no discharge into the environment
• no infrastructure requirements such as piping, treatment systems,
tanks or leach or drain fields
• no chemicals – no pumping or dumping
• kills harmful bacteria
• large capacity
• minimal maintenance
• solar or generator power versatility
• simple to install
• compact and light weight
• functional in freezing climates
• environmentally friendly
• American invented, manufactured and distributed
• affordable and customer friendly.

The Sanitizer™ Toilet is unlike any other toilet on the market. It evaporates liquids and dries solids rendering them harmless for sanitary disposal in the household trash.

Please feel free to contact me with any questions you may have.


Ted Knight
Vice President
Clean Up America, Inc.
P. O. Box 5169, Arlington, VA 22205
“Join the revolution in human sanitation!”
703 532 2210

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