How Indoor Automatic Composting Systems Work

To understand how indoor automatic composting systems came to be, it's important to first get a sense of some outdoor home composting system basics. There are several large-scale approaches to outdoor composting, such as field, sheet and trench methods, but these are typically used in local communities or on a county or state level as an alternative to landfills.

When composting at home, you should begin by selecting a dry spot outdoors, ideally near a source of water. The size of the spot depends on how large of a pile you want to create or how big of a bin you want to use. Regardless, once the location is determined, the basic ingredients needed are the same:

[source: EPA: Compost]

One method is to mix the brown and green materials simultaneously while making sure to moisten anything that's dry, then covering it up with a tarp once complete. Another approach is to layer the ingredients starting with a 6-inch heap of the brown materials, followed by 3-inch layers of green then brown, and mix the pile around about once a week.

It can be anywhere from a month or to as long as a year or two before the compost is ready to be used. The time depends on a few factors, including:

Once you have the basics of manual home composting down, it may be easy to understand why the automated method was created. Read on to find out what's involved in these systems.

Getting a traditional outdoor composting system to run efficiently at home can be a tricky process. You have to consider the initial construction of a compost, figure out how to keep the ingredients balanced, make sure piles are correctly cultivated and be aware of climate conditions, just to name a few. That's why automatic indoor composting systems were developed.

First things first: Let's take a look at the pieces involved a standard automatic indoor composting system and how they work together. Most automatic indoor composters are made up of the following key components:

To operate a unit, you should first deposit the wastes into the machine, which usually involves just lifting a hinged lid at the top. Depending on what type of unit you use, you also might need to add regular soil and sawdust pellets, along with a small amount of baking soda, which is often recommended to help balance acidity levels.

Wastes are then dropped into a preliminary internal chamber that takes care of heating, mixing, and aeration. The fertilizer that results is then deposited through a second chamber into a cure tray that can easily slide out. Most automated models also feature a control panel on the front that allows users to adjust the settings.

The cycle generally takes 10-14 days to complete. This is significantly faster than most outdoor home methods, which can take months or even years to complete. But the overall output from indoor systems is smaller than those outdoors (cure trays will hold up to about 5 pounds of waste before needing to be cleared).

Now that you understand the basic parts involved in an automatic indoor composter, read on for some pros and cons to decide whether a system might be right for you.

Many automated indoor composters can accommodate up to 120 pounds (55 kilograms) of waste per month [source: Nature Mill]. However, along with the benefits of these units also come a few drawbacks. There are the usual maintenance issues, such as strong odors, additional energy usage and costs, and loud noises during operation. Plus, you need a compact way to house all the necessary parts, in addition to an accessible yet out-of-the-way place to store it.

Most automatic indoor composting systems are encased in some sort of stainless steel and aluminum combination, though many also feature plastic elements (often made from recycled materials). Newer models are quite sleek in their overall design, resembling a large, modern coffee pot, espresso machine, or slow cooker. Units tend to weigh between 10 to 20 pounds (4.5 to before composting. They generally take up about as much space as a kitchen garbage can (or about 20 inches in height and depth and 12 inches wide), though some models can actually be installed in cabinets, similar to trash compactors that slide in and out to blend in with your cabinetry.

Automated composters are primarily intended for indoor placement within a kitchen, laundry or utility room, or garage, but if you don't have room for one, many can actually be used outdoors if you choose. If you do plan on using one indoors, you might consider one that offers thermal insulation along with airtight sealing to prevent one of the main drawbacks: foul odors escaping into your home.

Wherever you use your composting system, combating and controlling the smell they produce can be tricky. If an overpowering odor is present, it's usually a sign that the system needs more turning and aeration. The automated system should maintain aeration on an ongoing basis, but you may need to check the unit to be sure it is working properly. You might also consider using carbon filters within indoor units to keep the smell in check.

Another potential drawback to consider is the noise the systems make during operation. Whirring and snapping sounds at the onset of the composting cycle are typical, along with humming from the air pumps. Most units produce minimal noise once materials have been heated and the actual process is underway. Before you buy one, you might want to read product reviews to see what other people have to say about the noise particular units make.

Lastly, as with any other home appliance you own, you also should be mindful of general upkeep and maintenance. Many machines start out with a minimum one to three year manufacturer's warranty, though there are options for extending or additional coverage. You'll also need to know how often to change the air filters and carbon filters, as well as when to empty and clean the system.

If you think an automatic composter might be something you'd like to add to your home, read on to find out what it could cost you.

Is an automated indoor composting system worth the investment? To get started, a potential user can expect an initial investment of $300 to $400 for a base unit. This is slightly less than the cost of some other household appliances, such as a lower-end dishwasher, but it's still a bit steeper than what you'd spend on a blender or toaster oven.

In addition to the initial cost and setup, you also need to consider the energy costs. You can expect to add about 5 kwh (kilowatt hours) per month to your energy bill. Depending on your local rates, this should only set you back about 50 cents [source: Nature Mill].

It's also important to point out that there are indeed cheaper indoor alternatives. One involves anaerobic composting, which involves a fermentation process aided by the use of a wheat bran-based powder. These types of units are also about the size of a wastebasket and run around $60-$80. The trade off is you lose the automation process, and therefore the maintenance requirements and odor potential are much higher [source: Foley].

Another indoor method centers on vermicomposting, which uses worms to break down the materials -- and that revelation alone might be enough to ward a person off. If worms don't make you squeamish (and keep in mind, we're talking about hundreds to thousands of them in one unit), this system costs about half of what an automated unit might cost, but offers little to no odor protection. You also face the risk of worms escaping from the unit [source: Foley].

So, if you want to take a step into the composting world, can afford the initial costs, and are prepared to put up with a few of the drawbacks, then adding an automatic indoor unit to your household might be the way to go. With more easy-to-use models now on the market, along with the technological advances developed to help keep odors and noises to a minimum, these machines offer an efficient way to help protect and improve the environment.

Learn even more about composting at home and elsewhere by visiting the links on the next page.