Nature's Head vs. Separett vs. Sun-Mar: Full Brand Comparison

If you're going to live with a composting toilet every single day — not just on weekend trips, but as your actual, full-time bathroom — the brand you choose matters a lot more than it would for occasional use. Capacity, maintenance rhythm, and long-term durability stop being nice-to-know details and start being things you deal with weekly, sometimes daily.

Nature's Head, Separett, and Sun-Mar are three of the most established names in composting sanitation, and PowerGen Store carries all three. Each takes a genuinely different approach to the same core problem — how to safely process waste without water or a sewer line — and that difference shows up most clearly when you're using one full-time rather than a few nights a month.

This guide focuses specifically on the full-time-living case: which brand handles daily, sustained household use best, what the maintenance workload actually looks like over months and years, and how to think about the decision if you're outfitting a permanent residence rather than a weekend cabin or occasional-use rig.

What "Full-Time Living" Changes About the Decision

A composting toilet used a few weekends a month has a lot of forgiveness built in — there's time between uses for things to dry out and for you to stay ahead of maintenance. Full-time use removes that buffer. The chamber fills faster, the fan (if the model has one) runs more, and any weak point in a design — a seal that needs more frequent attention, a chamber that's a little small for your household size — gets found quickly.

That means the questions worth asking shift: not "does this fit in my bathroom" but "can this keep up with two or three people using it every day, and how much of my time does that cost me each week."

Nature's Head — Best for Consistent, Low-Fuss Daily Use

Nature's Head built its reputation in the RV, marine, and van-life world, but the same urine-diverting design that makes it reliable on the road makes it a strong full-time performer in a permanent home. Separating liquids from solids at the source is the single biggest factor in keeping a composting chamber dry, and a dry chamber is a low-odor, low-hassle chamber — which matters enormously when you're not just visiting, you're living there.

For full-time residential use, the Structure Kit is the version built specifically for permanent installs rather than vehicles, and the standard Spider Handle model is the one most full-time off-gridders already trust. The trade-off: Nature's Head is a self-contained, single-unit design, so for a household of three or more using it daily, you'll be emptying the solids side more frequently than you would with a higher-capacity remote system.

• Best fit: 1–2 person households, or anyone who wants one proven, well-supported design rather than a system with separate remote components
• Maintenance rhythm: Frequent, small actions (agitator crank after each solid use, liquids container emptied often) rather than infrequent big ones
• Watch for: Solids chamber capacity is the limiting factor for larger households in full-time use

Shop Nature's Head composting toilets

Sun-Mar — Best for Larger Households and Higher-Capacity Full-Time Use

Sun-Mar is the brand built with year-round residential use in mind from the start, and it shows in the product line. Alongside self-contained models like the Compact and SpaceSaver, Sun-Mar's Centrex remote systems separate the toilet fixture from the composting chamber entirely — the chamber lives elsewhere in the building, sized specifically for the household using it.

That matters most for full-time living because capacity scales with the model, not just with how often you empty it — and it's worth knowing that Sun-Mar sells each Centrex size in both a standard electric version and a non-electric (NE) version built for off-grid setups without continuous power. The Centrex 1000 NE is Sun-Mar's own entry point and is rated by the manufacturer for light seasonal or vacation use rather than year-round daily demand, so a full-time household should size up. The Centrex 2000 NE steps up to medium-to-heavy seasonal or light residential use, and the Centrex 3000 NE is a continuous-flow system built for heavy cottage use or medium residential demand — the closest of the three to genuine full-time household use.

• Best fit: Permanent, foundation-built homes with 2–4+ full-time residents, or anyone who wants a more conventional-looking toilet fixture with the composting mess handled out of sight
• Maintenance rhythm: Less frequent hands-on attention per use since the chamber is larger and remote, but periodic bio-drum maintenance is still required
• Watch for: The NE models are non-electric by design — great for off-grid power budgets, but match the specific model's residential/seasonal rating to your household size rather than assuming any Centrex handles full-time use equally. Remote/Centrex systems also need dedicated space (a utility closet, basement, or crawl space) below or near the fixture — plan the install before you commit to a model.

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Separett — Best for a Conventional Look With Full-Time Reliability

Separett's Swedish "urine-diverting dry toilet" design sits between the other two: self-contained like Nature's Head, but styled to look and sit like a standard household toilet rather than a purpose-built off-grid fixture. For full-time living, that's a real advantage if the bathroom needs to feel like a normal bathroom — for resale value, for guests, or just for your own day-to-day comfort.

The full-size Separett Villa 1255 is the model built for sustained residential use, while the Weekend Prime is explicitly a lower-cost, part-time option — worth knowing if you're comparing listings, since not every Separett model is designed for daily full-time demand.

• Best fit: Full-time residents who want a composting toilet that doesn't look or feel like one
• Maintenance rhythm: Similar cadence to Nature's Head — urine diversion keeps things dry, but it's still a self-contained chamber that needs regular attention
• Watch for: Confirm you're looking at the Villa (full-time rated) rather than the Weekend Prime (part-time rated) if daily use is the plan

Shop Separett composting toilets

Side-by-Side: Full-Time Living Comparison

Specs and household-size guidance above reflect the manufacturers' own product positioning as offered through PowerGen Store's catalog. Always confirm current capacity ratings on the individual product page before purchasing.

Keeping Any of These Running Long-Term

Whichever brand you land on, full-time use means maintenance becomes routine rather than occasional. We've put together a full breakdown of what that routine should look like — daily, weekly, and monthly — in our Composting Toilet Maintenance Schedule. And if something's already gone sideways — odor, flies, or excess moisture — our troubleshooting guide walks through the most common causes and fixes across all three of these brands.

Before you buy, it's also worth confirming your composting toilet plans are compliant with your local codes — regulations vary significantly by state. Our state-by-state guide to composting toilet codes and permits walks through NSF/ANSI 41 certification, health department approval, and what New York specifically requires.

If you're weighing a composting toilet against an incinerating one for your full-time setup, we've compared the two approaches directly, including EcoJohn's incinerating lineup as an alternative.

And if space — not brand — is your main constraint, our guide to the best composting toilet for tiny homes goes deeper on footprint and small-bathroom fit specifically.

The Bottom Line

For full-time living, the decision usually comes down to household size and how much you value a conventional-looking fixture. A solo resident or couple who wants a proven, well-supported design will likely be happiest with Nature's Head. A larger household in a permanent, foundation-built home gains the most from Sun-Mar's higher-capacity Centrex systems. And anyone who wants their bathroom to look and feel like a normal bathroom — without sacrificing full-time reliability — should take a close look at the Separett Villa.

All three are proven, NSF-category composting designs sold and supported by PowerGen Store as an authorized dealer, so you're not choosing between a good option and a bad one — you're matching the right design to how your household actually lives.