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Composting Toilet Guide 2017: Top 5 Toilets

Find the best composting toilet for your tiny home today with our reviews and buyer’s guide. We’ve got everything you need to know in one place.

best-composting-toilet-reviews-of-the-yearComposting toilets are a great alternative to traditional flush toilets. They don’t require any plumbing or water, and are much more environmentally friendly.

If you have a tiny house, holiday cabin, or just care about your impact on the environment, then a composting toilet could be a great choice.

We’ve reviewed 5 of the best composting toilets below. See how they compare in the comparison table, before checking out the reviews that follow.

We’ve even compiled a handy buyer’s guide that has everything you need to know before you buy a composting toilet.

The Top Rated Composting Toilets

The comparison table can be sorted in each column, so you can focus on the points that matter. There are more detailed reviews of each model following the table.

PictureModelPriceRatingPositivesNegatives
natures-head-self-contained-composting-toiletNature's Head Self Contained Composting Toilet$4.6- No odor
- Easily emptied
- Water-free
- Robust
- Compact
- Spider handle is not as user friendly as crank
separett-villa-9210-dcac-smallerSeparett Villa 9210 AC/DC$$N/A- Accepts 12V battery or solar power
- Odor free
- Easy change container
- Designed to look like a regular toilet
- Requires power
Sun-Mar Excel Non-Electric Self-Contained Composting ToiletSun Mar Excel Non-Electric Composting Toilet$$$3.7- Non-electric
- Suits medium to high capacity use
- NSF/ANSI Certified
- Water-free
- Expensive
natures-head-dry-composting-toilet-crank-handleNature's Head Dry Composting Toilet$4.3- Fast composting
- Waterless operation
- Lightweight
- Odorless
- Robust
- Crank handle adds extra width to unit
sun-mar-compact-self-contained-composting-toiletSun-Mar Compact Self-Contained Composting Toilet$$$3.5- Low profile
- Water-free
- Easy composting
- Compact design
- NSF/ANSI Certified
- Uses electricity

Composting Toilet Reviews

Here are the top 5 compost toilets reviewed in more detail. We recommend the Nature’s Head toilets, as they are durable and easy to use, but remain competitively priced. Read on to find out more.

natures-head-self-contained-composting-toiletNature’s Head Self Contained Composting Toilet (Spider Handle) – OUR TOP PICK 

This model from Nature’s Head packs an impressive Amazon rating, and is also one of the less expensive composting toilets available. It has an innovative design which makes life in a small space that much easier.

It was originally designed for marine use and packs all of the features that are needed for making a success of a small space. Since it doesn’t require a water supply or sewage connection, the installation is really easy. It is just a matter of connecting the hose to the outside to ventilate the unit, and connecting an electricity supply to power the fan. This isn’t a complicated task and the unit ships with everything included that you will need (except the outside vent).natures-head-big-picture

Removing and emptying the waste containers is really simple. There are a couple of clips at either side of the liquids tank that need unhooked, and then you can lift it out by its handle. The solids waste container (composting bin) is started with peat moss, which helps with the decomposition of the waste. This is said to last for about 90 uses before it needs emptied, but it can last much longer. The solids bin has an agitator handle at the side (spider handle) which is well designed for use in tight spaces. This handle is used to mix the compost mixture. A cool feature of this model is that the handle can be mounted on either side of the unit. The ventilation hose can be mounted on either side too. This gives you extra options with the installation, which can make the whole process a lot easier.

This Nature’s head model uses a simple system, but it is effective and trouble-free. It’s environmentally friendly, energy efficient, and perfect for tiny spaces. It’s also cheaper than the rival brands. This is our top choice and in our opinion the best composting toilet for a tiny house. You can read our more detailed review here.

 

Key Features

  • A seat that is easy to clean and never needs replaced
  • Separate liquid and solids containers
    • High capacity
    • Easy to empty
    • Odor-free
  • Robust polyethylene construction
    • Originally designed for marine use
    • Compact design
    • Stainless steel fittings
  • Easy to disassemble for composting
  • Space saving spider handle
    • Can be mounted either side of the unit
  • Full 5-year warranty
  • Vent hose and fan included
    • Can be mounted either side
  • Excellent customer service support
  • Dimensions:
    • Height: 21.5 inches
    • Width: 18 inches
    • Length: 17.75 inches
    • Weight: 28 lbs.

Sun-Mar Excel Non-Electric Self-Contained Composting ToiletSun-Mar Excel Non-Electric Self-Contained Composting Toilet

This model from Sun-Mar is another that requires no water to operate and is odor-free too. Sun-Mar have been around a long time and are very experienced manufacturers of compost toilets. This system requires no electricity and is perfect for life off the grid.

It uses two separate bins (solid & liquid). The solids bin will require emptying after around a month if being used by 2-3 people on a daily basis. It will easily decompose toilet paper too.sun-mar-excel-big

This model has a minimalist design and is very compact. It was made with small spaces in mind and the handle is used at the front of the unit instead of the side. This means it can easily squeeze into a very narrow space.

The Excel is an NSF certified composting toilet. To receive its award it was tested at maximum capacity continuously for 6 months. It produced no odor over this time, and produced safe, clean compost too. This model can handle quite heavy use and is designed for 2-3 residential use and 5-7 people for weekend and vacation use.

The installation and maintenance of this unit are both very easy. Installation is just a matter of hooking up the ventilation vent. There is an optional electric fan that can be used if you need to install the vent with any bends in it. Before using the unit for the first time a peat and microbe mix (supplied with the unit) is added to the compost bin. This helps with the decomposition process. Maintenance-wise, you must add some peat mix periodically and stir the compost mixture with the handle. When the time comes to empty the solids bin, it is easily removed in a sliding tray.

Key Features

  • Electricity-free
  • Lightweight fiberglass tank
  • Separate liquid and solids bins
  • NSF/ANSI certified components
  • Medium to high capacity
  • Venting kit included
  • Detachable foot rest
  • Compact design
  • Front operated agitator handle is ideal for narrow spaces
  • 3 year parts warranty + 5 year tank warranty
  • Dimensions:
    • Height: 32 inches
    • Width: 22.5 inches
    • Length: 33 inches (including foot stool)
    • Weight: 50 lbs.

natures-head-dry-composting-toilet-crank-handleNature’s Head Dry Composting Toilet (Standard Handle)natures-head-big-toilet-picture

This is the other offering from Nature’s head. It retails at around the same cost and has many of the same features. The main difference here is the agitator handle. This model has a standard handle which adds almost 2 inches to the width of the unit. The alternative model uses a special spider handle, which conveniently saves space while remaining functional. In my opinion, the handle of this model is slightly easier and quicker to use, but there is the trade-off for space.

This model has the option of using an electric fan. This would be useful if the ventilation shaft has any bends or is longer than 5 feet in length. This fan draws little power, but if you are using 110V power then you will need to use an adapter.

Key Features

  • Separate liquid and solids containers
    • High capacity
    • Easy to empty
    • Odor-free
  • Robust polyethylene construction
    • Compact design
    • Stainless steel fittings
  • Easy to disassemble for composting
  • Full 5-year warranty
  • Vent hose and fan included
  • Excellent U.S. based customer service support
  •  Dimensions:
    • Height: 21.5 inches
    • Width: 20.75 inches
    • Length: 17.75 inches
    • Weight: 28 lbs.

sun-mar-compact-self-contained-composting-toiletSun-Mar Compact Self-Contained Composting Toilet

The Sun-Mar Compact is smaller than the Excel model and is more suited to small households of up to 2 people. It’s smaller than the Excel model, but it is definitely more attractive.

It has an elegant, low-profile design and will squeeze into most small spaces. It is made smaller by using Sun-Mar’s patented Bio-drum. This is smaller at the front and bigger in diameter at the rear. A single agitator handle is used to stir the drum. It extends from the front of the unit. The fact that it recesses into the body of the unit is a nice space saving feature that the Nature’s Head models lack. Having a front operated handle makes this model ideal for narrow spaces, but not quite so good for bathrooms that are short in length.

Key Featuressun-mar-compact-big-pic

  • Compact design
  • Elegant
  • Odor-free
  • Front operated recessed handle
  • Patented Bio-drum
  • 100% non-polluting
  • Uses no water
  • Uses standard household current
  • Dimensions:
    • Height: 28 inches
    • Width: 22 inches
    • Length: 33 inches
    • Weight: 50 lbs.

separett-villa-9210-dcac-smallerSeparett Villa 9210 DC/AC – PERFECT FOR A TINY HOUSE 

The Separett Villa is highly regarded by the off-grid community as a top quality composting toilet. The electric fan can be easily powered by the DC supply that a battery pack, solar panels, or wind turbines provide. Likewise, it is can also receive AC power if need be.separett-villa-9210-big-pic

The Separett Villa has a unique pressure sensitive seat. Once it senses that someone is sitting down, it will open the otherwise
covered solid waste bin. At the same time it even rotates the waste so that the contents are mixed. This helps with the waste decomposition process. The fact that it doesn’t have a handle for mixing the contents means that is is very compact, and measures only 18 inches in width. This makes it ideal for use in a small bathroom.

The 9210 is well designed and has convenience in mind. Emptying the waste bin is the drawback of composting toilets like these, but this toilet makes that process really easy. Simply remove the toilet seat layer and then place the lid on the waste container to seal the bin. It then slides out quite easily for you to add the waste to your garden compost. It also looks pretty good, and doesn’t look quite as odd as some composting toilets can.

The 9210 has separate containers for the solid and liquid waste. By keeping them separate there is no unpleasant odor from the toilet. The toilet has a large capacity and Separett state that normal use by a family of four will require the solids waste bin to be emptied about every 3-6 weeks.

For those that wish to run the toilet using a DC power system, the requirements will vary according to location and installation. In general terms, a battery of 60-75 amps and cell size of about 25 watts would be sufficient. The unit will use 12 V. 2.5 W, 210 mA or 0.06 kWh every 24 hours. This low power consumption makes it perfect for tiny house living.

Key Features

  • Pressure sensitive seat
  • Automatic waste bin mixing
  • Easy to empty operation
  • Looks like a traditional toilet
  • Highly regarded by tiny house community
  • No odor
  • Can run off-grid
  • Low power consumption
  • 5-year guarantee
  • 2 speed fan
  • Compact size
  • Dimensions:
    • Height: 21.3 inches
    • Width: 17.95 inches
    • Length: 26.4 inches (including foot stool)
    • Weight: 47 lbs.

What’s a Composting Toilet?

A composting toilet is a more environmentally friendly alternative to the traditional flush toilet. They use no water and instead create compost when the human solid waste is mixed with peat moss and microbes.

Most systems separate the liquid and solid human waste into two containers. The solid bin contains the compost mixture and can be left for months at a time with no unpleasant odor. The liquid container needs emptied more frequently. The container usually unclips and slides out, and can be easily carried using a handle. By separating the two types of waste, the compost can form more easily. It also prevents unwanted odors.

These systems are ideal for those that are conscious about the environment, and also those who don’t have access to a septic tank. By not using the sewage system they are less of a drain on the energy and water resources of the world. If you are a keen gardener then composting like this is an awesome way to help your crops too.

Why Get a Compost Toilet?

Here are 5 great reasons why everyone should own a composting toilet.

Reason Number 1

According to The Guardian, “the water-flush toilet devours 30% of the UK’s water supply”. That’s a quite staggering statistic, and you can only imagine the amount of water that is wasted in this way world-wide.

We are much too used to our home comforts, and it is only now that we are starting to question our ways. A composter toilet is a good place to start making a change, and it will dramatically reduce the amount of water you waste.

Reason Number 2

Despite what most of us think, the waste that gets dumped in the toilet isn’t actually useless. The bin of a composting toilet provides a rich fertilizer which will do amazing things to your garden. The fertilizer is 100% natural and free of charge.

Reason Number 3

It will reduce your water bills. By reducing your water usage by 30% you can expect to significantly save on your water bills too. Composting toilets are initially expensive, but you can expect to save money in the long term.

Reason Number 4

It’s much better for the environment. Besides, saving water there are other great reasons why these toilets are much better for the world. Firstly, they reduce the amount of blackwater in the system that needs treated. Blackwater must be separated from grey water and then treated. These tasks require energy and resources.

These toilets also reduce the amount of sewage that is pumped into our oceans and rivers. By recycling, our waste is put to good use in the form of fertilizer.

Reason Number 5

It gives you independence from the sewage system. Since, you don’t require a drainage, septic, or sewage system, you are free to roam wherever you like. This makes these kinds of toilets perfect for tiny house enthusiasts.


Pros and Cons

Pros

  • Great for the environment
  • Save on water bills
  • Space saving design
  • Easy to install (no plumbing involved)
  • Produces compost for the garden
  • Odor-free operation
  • Can be electricity free

Cons

  • Can be an expensive initial cost
  • Has to be manually emptied
  • Not very elegant

Installation and Maintenance

Installation

Composting toilets need no plumbing to install. You must make sure there is adequate room to remove the waste bins and to turn the agitator handle though.

Most models will attach to the floor using brackets. You will also need to run a ventilation hose to the outside. If the ventilation shaft is overly long or has bends in it, then you should install an electrical fan to help the ventilation process. These usually run on 12 volt power. Everything you need for installation is included with the unit except the outside vent (as these will vary depending on installations). The basic installation kit for the Nature’s Head models contains:

  • 5 feet of hose with ends inside vent flange
  • 4 mounting bolts
  • 2 mounting brackets and knobs
  • 18” single pin cable for 12 volt fan
  • Allen wrench (to install handle)
  • fuse holder and fuse
  • Spray bottle

Before using a compost toilet it is necessary to fill it with peat moss mixture. Around two gallons of sphagnum peat moss or coconut fiber should be about right for most systems. It’s important that the moss is not wet, only damp and it should be crumbly too. If it is totally dry then you should add a little water to moisten it.

Maintenance

The maintenance of these toilets involves just a few simple things. The first one is that you need to turn the handle every time you add solids to the bin. This helps the composting process. The other maintenance tasks are obvious and that is just monitoring the liquid and solids bins, and making sure they are emptied routinely. The liquid bin will usually hold around two gallons of urine, while the solids bin can last for six months. It really depends on how well the toilet is used. Once the solids bin is emptied you must add the peat moss mixture again before you use it.

Tips About Using a Composting Toilet

If you use a compost toilet correctly, you should never have any issues with odor or flies. Here are some top tips to get the most out of your composting toilet.

  • The lid should always remained closed when not in use. This prevents insect from entering and allows proper ventilation through the vent system.
  • The sphagnum peat moss (recommended type) is easily available from Lowe’s and Home Depot. A $10 bag should last a year.
  • It is is really important that the solids and liquids remain separate. If liquids get into the compost bin then the compost will be inhibited from forming and there will be an odor.
  • Toilet paper can be added to the compost bin too. It will decompose a bit slower but will get there in the end.
  • After adding to the solids bin you should always turn the agitator handle a few times. This helps the composting process.
  • Seated usage is recommended. It is less likely that there will be crossover of solids and liquids this way.
  • Add some white vinegar to the urine tank if there is a strong odor.

For more top tips, check out this awesome video.


FAQs

How much electricity does the fan use?

The fan draws less than 2 amps over 24 hours. The figure is likely to be closer to 1.5 amps.

Does the toilet smell bad?

No, because the solids and liquids are separated. The toilet will have a slightly earthy kind of smell.

How do I install it?

Installation requires no plumbing, but you will need to hook up the ventilation fan. Check out the ‘Installation and Maintenance’ section above for a video of the installation of a Nature’s Head model.

Where do I get the peat moss?

Peat moss is available at garden stores and also at Home Depot and Lowe’s. It is relatively inexpensive.

Do they take toilet paper too?

Yes, toilet paper can be disposed of in the toilet. It will take a bit longer to decompose than the other waster though.

Where should I empty the waste?

The organic waste is great food for plants. Otherwise, it can be buried or stored away.


Before You Buy: Checklist

Check out the dimensions and configuration – If you are planning on installing a composting toilet in a tiny house then space is probably going to be tight. These toilets have handles that extend from the front or side (depends on manufacturer) that are used to mix the compost. Make sure you have enough space in your bathroom for the handle to be turned easily.

Plan for ventilation – A narrow ventilation shaft will run from the toilet to the outside of your home. For efficient ventilation this shaft should be a short as possible with no bends in it. You do have the option of running a fan to increase the effectiveness of the ventilation, but it would be nice not to have to use one all the time.

Plan for the size of your household – These systems aren’t designed for prolonged heavy use. If you have a big family then one of these toilets might not be a good fit. They are capable of heavy use over short periods (holidays) however.


Well that’s a wrap for our guide and composting toilet reviews. If you have any questions then we’d be happy to help. Drop us a message at the bottom of the page or on the contact page.

Check out our latest post on solar panels to find out other ways you can reduce your impact on the environment.

Keep an eye on us as we’ll be posting again soon about the must have accessories and appliances for tiny house living. Until next time!

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