Vent hose allows internal fan to exhaust moist, stinky air outside

Small spaces like vans, RVs and boats have special requirements for toilets. They must be small, and use little or no power. Yet they still must be odor free and easy to use.

Many people are looking for a toilet that requires no electricity. It’s a nice idea. Power consumption is a big concern, especially if travelling off grid. And some manufacturers have responded with small, non-electric models of composting and waterless toilets.

Unfortunately there are BIG disadvantages to a non-electric composting toilet.

Inside any waterless composting toilet is moist, stinky air. Normally a fan is used to blow this air outside the vehicle, and help dry out the contents. A non-electric toilet (without a fan and external vent) might not stink when it’s closed, but as soon as you open it the smell will escape. In hot humid weather, this can be very strong! It doesn’t matter if you have coco coir or wood shavings in there. If there is no fan with an external vent, it will stink inside the toilet, and this will escape when you open it for use.

The humidity also builds up inside the unventilated toilet. Condensation can occur, adding to the odor and promoting the growth of mold.

A vent kit for a DIY composting toilet

In short, while a non-electric toilet might look good on paper, you definitely want a toilet that has a good fan and exhaust vent. They use very little electricity – often as little as 2 or 3 watts. But the fan and vent makes all the difference.

Vent going through floor. The wall or roof are also options.

You can reduce power consumption by turning off the fan at night, or whenever you know people will not be using the toilet.

My advice, after 15 years of selling, distributing, designing and building composting toilets is this: Do it right and find a way to provide the tiny amount of power needed for a composting toilet with a fan and external vent. You will be much happier in the end. So will your guests or your partner.

It can get even worse

Incredibly, there are several composting toilets available that not only don’t have fans – they also do not have view screens or trap doors to conceal the waste! This means that as soon as you open the lid to go #1 or #2, the contents are in full view, and odor is escaping. This is simply gross and unacceptable. These toilets are little more than boxes or milk crates with a urine diverting seat and pee bottle. But they have beautiful websites and people are falling for it. Don’t. Sometimes the simplest and cheapest thing is not the best. You need a toilet with a trap door or at least a view screen – in addition to a fan and external vent.

Solid waste is concealed by this trap door which is closed unless going #2.

The best composting toilets are better than flush toilets

Some better toilets don’t even stink when you are using them, because strong fans are blowing all the air outside constantly, and not letting any escape into your building or vehicle. We actually prefer our composting toilet to a flush toilet for this reason. The bathroom never stinks with our compost toilet – not even when we are using it!

Do your research. Be skeptical of marketing claims. Choose the right toilet and you will never regret spending a little extra for it.