Human beings love avoiding the “ick” factor when it comes to dealing with pee and poop. Out of sight, out of mind is often our motto. Luckily, a composting toilet does keep waste hidden away and smell free.
A composting toilet can be a great solution for people who live off-the-grid or on the go.
Maybe you’re an RVer who’s sick of dealing with a nasty blackwater tank and finding places to dump your poo.
Maybe you live in a camper van, and you’re looking for a simple, odorless option for a small space.
Or maybe you’re building a tiny home and don’t want the hassle of connecting to the sewer system or dealing with a septic tank.
A good composting toilet might be just the ticket to solve all your dumping needs.
What is a composting toilet?
For eons, people have been trying to figure out just how to deal with their #1 and #2. The waterless toilet system started in ancient China, where rumor has it they stored human waste in ceramic containers to destroy any parasites. They’d then dump that waste on their soil, as fertilizer. Hence the very first composting toilet.
Our more modern edition of the composting toilet was commercialized by the Clivus Multrum company in Sweden in the 1960s. Then, in the 1970s, another Swedish company called Biolet started manufacturing composting toilets on a larger scale.
The composting toilet is special because it uses natural elements to compost human waste; no water is necessary.
Bacteria and bulking agents are mixed with human waste to create compost over time, which is called humus. If the toilet is maintained properly, the toilet will compact waste to 10-30% its original volume. Then, you can use that humus as fertilizer, bury it, or throw it away depending on your state or city’s regulations.
Read on to learn the specifics of how a composting toilet works.
How does a composting toilet work?
A composting toilet needs three main elements to properly digest your waste: moisture, warmth and oxygen.
After you use the composting toilet, you add a scoopful of bulking agent to the bowl, which is anything from peat mix, to coconut fibers, to straw or sawdust. You turn a handle to mix it all together, or some toilets do this themselves.
Once everything is mixed together, anaerobic bacteria use oxygen to break down the waste. It works a lot like your backyard compost pile.
The toilet needs to evaporate excess moisture to work, so many toilets have separate containers for #1 and #2. If that’s the case, you dump the urine separately, then wait for the #2 to become compost.
It’s important that the bacteria have enough oxygen and moisture to work correctly, and the toilet also has to be at the proper temperature, somewhere above 55 degrees. If the temperature gets below 55 degrees, the toilet will just pause in its composting and resume when it heats back up again.
According to Let’s Go Green: “The correct balance between oxygen, moisture, heat and organic material is needed to ensure a rich environment for the aerobic bacteria that transform the waste into fertilizing soil. This ensures odor-free operation and complete decomposition of waste.”
When your waste is done composting, the toilet has a finishing chamber or drawer, so you can easier slide the compost out and dump it according to your state’s regulations.
Why you need a composting toilet
Composting toilets solve a lot of problems for people, and the environment. Take a moment to think about how much water a traditional toilet needs for flushing. Some of the older models use 7 gallons every flush. That is insane! Luckily, the newer toilets use far less – a little over one gallon – but that’s still a ton of water.
According to Conserve H20, more than 47% of water use in the average American home occurs in the bathroom, with nearly 24% being used by toilets.
But when it comes to composting toilets, the environmental impacts are actually positive. In fact, one person using a composting toilet for one year creates 80 pounds of compost and saves 6,600 gallons of water per year. Holy crap!
Besides the environmental impacts, using a composting toilet also has a positive impact on your pocketbook. Your water bills will go way down, and if you’re building a tiny home, you won’t have to pay to get hooked up to the city water and sewer system.
Van lifers, RVers and sailors also love composting toilets due to their ease of use and lack of odor. It’s awesome not having to head to a pump out station, or deal with chemicals.
The negatives of a composting toilet
Yes, even though there are many positives about using a composting toilet in your van, RV, sailboat or tiny home, there are also negatives to be aware of before you buy. Composting toilets are expensive, so it’s good to have all the information and weigh your options to find the solution that best fits your needs.
Here are some of the key negatives to be aware of, according to the Environmental Protection Agency:
- If you don’t handle your compost correctly, it could make you sick. You have to wait the correct amount of time to move the compost to make sure the pathogens from your poo are no longer there
- Composting toilets require more maintenance than traditional toilets
- The toilets could stink if not properly maintained
- Most composting systems require a power source
- If you don’t properly set up the ventilation system for your composting toilet, bugs and insects could get in there (ew!)
- They are much more expensive than other toilet systems
- They are not meant to be moved around
Good food for thought if you’re thinking of a composting toilet.
Do composting toilets stink?
A lot of people wonder if composting toilets stink, and the answer is this: no. That is, if they’re installed, maintained, and properly ventilated they do not stink.
A composting toilet that’s functioning properly should have absolutely no odor, and here is why:
- Aerobic bacteria break down your waste, which produces odorless carbon and water vapor. Another type of bacteria, called anaerobic bacteria smell really bad because they excrete methane, ammonia and hydrogen sulfide
- Composting toilets also seal off the moment after you use them, which keeps the waste and any potential odors safely tucked away. Also, a ventilation system keeps moving the odor out of the container where all the magic happens. If the vents are properly routed outdoors, no nasty fumes will enter your living space.
The different types of composting toilets
There are two main types of composting toilets: self-contained and central systems.
Self-contained composting toilets are the type you’d see used in a van or an RV. There’s the toilet, the bowl, and right under is the container where the composting happens.
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With a central composting system, your toilet is in one room, and the composting chamber is located in another room. This is often done in a house, as it looks most like a regular toilet and the composting is kept far away from the bathroom.
For this review, we’re going to stick with self-contained composting toilets as they’re the most common for campervans, RVs, sailboats and tiny homes.
Factors to think about when picking a composting toilet
Sizing: You’ll need to make sure you have enough room in your van, RV or sailboat to install a composting toilet. Some take up more space than others, and it’s important to measure the handle and see how much room it needs to function correctly.
Installation: The composting toilet needs a way for its exhaust vent to reach the outside, so you may have to cut a hole in your rig. They are designed to bolt right to your floor, so aren’t really moveable. You’ll also need some sort of 12-volt fan to ventilate the compost, and a battery system to power that fan. In reading various RV and van life forums, installation tends to be fairly easy.
How it diverts urine: As you’ll read below, the toilets recommended divert urine into another container, so the #2 can turn into compost faster. Some of those containers are located near the main composting bowl, which you have to open briefly to grab the urine tank. The AirHead toilet keeps the urine container on the outside of the toilet, so you don’t have to disturb the main container, which might smell a little when opened.
The best composting toilets of 2018
There are so many toilets on the market right now, but there are several that stand tall above the rest. Composting toilets are designed for different needs. Some are better in vans, RVs and sailboats, and some work really well in a tiny home. In this review, we’ll walk you through the main features of each toilet, and their positives and negatives.
1. Nature’s Head Composting Toilet
Nature’s Head composting toilets are by far the most affordable ones on the market, and are very popular amongst van lifers, RVers and sailors. They were invented by two sailors who wanted a robust, odorless toilet for the ocean, without the need for a holding tank. These toilets, which use stainless steel hardware, can take the jostling and vibration of life on the road. They’re also small enough to fit in the tiniest space. For the price, we think this is the best choice on the market if you want a composting toilet.
This toilet is self-contained and has separate containers for pee and poop. Plus, there’s a trap door design that opens when you sit on the toilet, which eliminates the need to buy separate liners for the bowl.
There are two types of Nature’s Head Composting Toilets. The real difference between the two is the type of handle used for stirring the compost. One has a space-saving spider handle, and one has a standard crank handle.
- Nature’s Head Composting Toilet with Spider Handle
- Nature’s Head Composting Toilet with Standard Crank Handle
The positives of Nature’s Head composting toilets:
- Cheapest on the market
- Separate containers for pee and poop
- Small enough to fit in a van, RV or sailboat
- Hardy design and stainless steel parts
- Connects to a 12-volt system for mobile use
- All installation parts (Mounting brackets, fuse, fuse holder, agitator, handle, inside vent flange, and 5 feet of venting hose with attached ends) are included with your order
- Fan only pulls 1.7 amps in 24 hours, which is about 4 cents per month in electricity
- Quick and easy installation
- 5-year warranty
The negatives about Nature’s Head composting toilets:
- They need additional hardware to connect to a 110-volt system
- Some reviewers say the urine tank doesn’t work well
- There are complaints that the fan isn’t quite strong enough
- You have to open the main tank to empty the urine container
Check out this video by Gone with the Wynn’s about why they love their Nature’s Head Composting Toilet:
2. Separett Composting Toilets
Separett is a company from Sweden getting a foothold in the U.S. market when it comes to composting toilets. They’ve been popular toilets in Europe for over a decade. Separett’s toilets are sleek and minimalistic, and most-closely mimic a normal toilet. According to Separett’s website, their toilets “overcome the ‘visual acceptance’ hurdle of changing toilet systems.”
A huge difference between Separett and the other options listed here is that the composting doesn’t happen inside the toilet. Instead, you remove the biodegradable bag and put it somewhere else, like in the ground or a separate composting pile so it can continue composting.
Another huge difference between this toilet and others is the urine is piped somewhere else, so if you’re in an RV, you’ll need to divert it to your greywater tank. In a tiny house, the urine can be diverted outside.
Separett manufactures three toilets: The Villa 1920 AC, The Villa 1920 AC/DC and the Weekender.
The positives of Separett composting toilets:
- Urine-diverting toilet, which either runs to a greywater tank or a collection container
- Includes a biodegradable bag so you can easily lift out compost and bury it
- Sleek design; looks a lot like a regular toilet
- Ships with all the parts you need to connect the toilet
- Weight-activated trap door that prevents the user from seeing the contents of the toilet
- Can be connected to both 12v DC or 110v AC power
The negatives of Separett composting toilets:
- A little more expensive than Nature’s Head
- The urine is diverted to a tank, container, or outside, which could make it a little more difficult for van life
- We browsed many sites and forums and couldn’t find complaints on Separett toilets
To learn more about the Separett Villa DC toilet, check out this video:
3. Sun Mar Composing Toilets
Sun-Mar composting toilets ring in at twice the cost of Nature’s Head, and use a patented Bio-drum technology to compost waste. The Bio-drum is engineered with three separate compartments, each which handle a different part of the composting process. The drum keeps the moisture level constant and maintains the correct temperature. In the electric unit, a fan draws air in, and a vent chimney does the work in a non-electric unit. Those ventilation systems evaporate liquid and pull in fresh air. Sun-Mar electric toilets also have a thermostatically-controlled heater, which helps with the evaporation step.
Sun-Mar is one of the original composting toilet companies; it claims its founder invented self-contained composting toilets in the early 1970s.
There are a lot of toilets to choose from if you’re interested in Sun Mar – the company makes 22 models. There are electric toilets, non-electric toilets, solar toilets, a compact toilet and a mobile toilet for the traveling lifestyle.
The National Sanitation Foundation certified Sun-Mar’s best-selling composting toilet, the Excel.
The positives of Sun-Mar composting toilets:
- Uses a Bio-Drum patented technology for waste so you don’t have to deal with dumping a separate urine container
- Some raving fans claim their Sun-Mar toilets last decades
- Higher capacity than other composting toilets
- Has a space-saving recessed handle for mixing the compost
- The National Sanitation Foundation tested this toilet and found it did not have odors after six months
The negatives of Sun-Mar composting toilets:
- Some models can’t be used in a van, RV or sailboat
- Very expensive
- Complaints some models draw way too much power
- Some models come only with AC power
- Bigger than other composting toilets
To check out Sun-Mar toilets, click the link below:
4. Air Head Composting Toilets
The Air Head Composting Toilet claims its the smallest composting toilet on the market, close to the size you have at your home. The toilets have a regular toilet seat and lid, and look a lot like a regular plumbed toilet. This can ease people’s fears of using a new toilet system. According to its website, Air Head says it’s the only diversion system that allows emptying of the urine bottle without opening the solids tank. Designed for marine use, the Air Head can fit in very small spaces. The toilet’s 5-gallon capacity means a liveaboard couple can expect 60 uses in a month before emptying the solids tank.
The positives of Air Head Composting toilets:
- Smaller than other composting toilets on the market
- You don’t have to open the solids tank to remove the urine container for dumping
- No nasty streaks on the bowl; the Air Head uses a paper bowl liner that carries solid waste down to the tank
- Looks the most like a regular toilet; easier for guests to use
The negatives of Air Head Composting toilets:
- Pricier than Nature’s Head
- It has to be emptied more frequently as its smaller than other models
- We didn’t find many negatives for this product
Check out the below video to see why one sailor loves the Air Head composting toilet:
Composting toilet best practices
There are several things to keep in mind if you’re just starting out using a composting toilet:
- Single ply toilet paper works best as it breaks down faster
- Don’t spread your compost on edible plants just in case there are still pathogens in the poo
- Check your state or local regulations before dumping your compost – they vary
- Check out the Humanure Handbook: A guide to Composting Humane Manure if you want to learn even more about turning poop into compost
- Put a little vinegar in the urine tank if that pee smell is too strong
- Remember to prepare your bulking agent by getting it damp and breaking it apart
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