Sun-Mar Composting Toilet: Model- Compact

A lot of features packed into one. This is what best defines the Excel self-contained composting toilet from Sun-Mar Corp. It can help serve you if you want to live off the grid, consumes no water, and is totally nonpolluting. It is ideal for campers and hikers due to its low maintenance in relation to water and electricity consumption.



Sun-Mar might just be the most well-known brand when it comes as far as composting toilets are concerned. The Excel composting toilet, in particular, is a fairly huge model and a tall one to boot compared to other self-contained portable toilets in the market. In fact, it’s so tall that it even features a stepping stool.

While its huge size affects its overall portability, it does make up for it with its high capacity. As such, it’s an ideal model for larger families who can use this toilet in their RV.

Here are the features that the Excel composting toilet comes with:


The toilet system requires electricity for it to operate effectively.

 High Waste Holding Capacity

The Excel has been designed to be used in a normal household setting serving up to five people. It is also ideal for camps and even for other gatherings. The storage composting chamber is large enough to ensure waste is not always full to compel its regular removal.

 Odor-Free Operation

The Excel comes with a venting kit to help get rid of excess waste odors, thereby helping maintain the environment in the long run.

 Water-less Operation

It features a waterless operation as it uses the waste’s water content to convert waste to compost. As such, it requires no water and no plumbing in general, which in turn, helps save water and plumbing costs.

 Small Profile

The small profile helps the toilet fit into the most household as it does not require a wide space for installation. In spite of that, it’s still technically larger than other products but smaller than the conventional toilet.

 Easy to Clean

The toilet’s shiny finish makes it easier to clean without exerting a lot of effort. Aside from that, it’s also easier to detect dirt.

 Detachable Foot Rest

The Excel features a detachable footrest to make sure that you can experience some relative comfort while seated on the toilet.



  • Environmental-friendly as it turns human waste into compost which is later converted into safe fertilizing soil
  • Requires no water for its operation, thus allowing you to save on plumbing and water costs. It also means you don’t need any water; unlike flushing toilets
  • Comes with a venting kit for an odorless operation
  • Easy to install and move around
  • Requires no sewer system as it is self-composting



  • Comes with a large maintenance need to make it suitable for human use. Poor maintenance and wrong handling can prove to be such a hard task
  • The drum handles are not robust and can break easily


Frequently Asked Questions

Q: How does it work?

A: The mechanism behind the Excel, like any other composting toilets, is actually very simple. Waste is decomposed in the same way that a garden composter decomposes garden waste. However, the difference lies in the material.

A composting toilet will need three different things to work efficiently. First, a vent system is required to evaporate water from the waste and remove any odors. Second, the environment should be suitable for decomposition to hasten the process. Lastly, the final product should be safe and easy to handle. Modern composting toilets are specifically designed to handle these elements without a lot of effort required.

Q: Can you use a heated toilet seat with this?

A: Yes. As long as you ensure that the heat is not too high to melt the plastic component of the seat.

Q: Why is there urine leaking from under the slideout drawer?

A: This might be due to the heater not turned on. Also, you might want to consider a urine overflow setup as the Excel isn’t that efficient when it comes to urine. You can choose to place a bucket or container to catch the excess urine, although it might not be that much help if the overflow tubes are not capable of diverting the liquid.

Technically, the Excel has a poor design due to urine overflow which happens almost every time.

Q: When do I need to clean the compost storage chamber?

A: With proper maintenance, you will only need to clean it once in every two months.


Final Verdict

If you want something that is good for the environment and at the same time helps in saving of resources such as water and money in the long run, then the Sun-Mar composting toilet might be the one you need. Its versatility ensures that it can be used in various situations or settings. Additionally, it comes with a number of features designed for convenience.

Ethan has been working on the 'Home Renovation' niche for the last decade. He always admires the minimalist design and architectural efficiency. A father of two and an awesome writer.

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