Known for their robust design and sustainable waste management, these toilets ditch water and chemicals in favor of a natural composting process that’s perfect for Kiwi off-gridders who care about the planet and practicality. In this review, we’ll unpack everything you need to know: the standout features, how they perform, their eco-credentials, and how they stack up against options like the EcoLet™ Separera Mini. Whether you’re a solo adventurer or hosting a full house, let’s see if Sun-Mar™ is your off-grid match!
Key Features: What Sets Sun-Mar™ Apart
Sun-Mar™ toilets come loaded with features that make them a top contender for off-grid sanitation. Here’s the full rundown:
Bio-Drum™ Technology: This is the star of the show—a patented rotating drum inside the toilet that you turn by hand. It mixes waste with oxygen and compost starters (like wood shavings), speeding up decomposition and keeping everything odor-free. Unlike simpler systems that just let waste sit, the Bio-Drum™ actively works to break it down faster.
Waterless (or Nearly So): The Excel™ and Centrex™ AirFlow models use zero water, saving you thousands of litres annually—an absolute win if you’re relying on rainwater tanks. For those who like a flush, the Centrex™ MicroFlush uses just 0.2 liters per flush (compare that to 4–9 liters for a standard toilet), making it a water-saving champ.
Odor Control That Works: A small electric fan (30 watts for standard models, 1–2 watts for non-electric) pulls air through a vent stack, whisking away smells before they can linger. Users consistently report fresh bathrooms, even with heavy use—it’s almost hard to believe it’s a composting toilet!
Big Capacity for Real Life: The Excel™ handles 3–4 full-time users (or 6–7 part-time, like weekenders), while the Centrex™ bumps it up to 6–7 full-time users. That’s ideal for families, group retreats, or even small eco-communities—no one’s left waiting.
Power Options for Flexibility: Electric models (Excel™ 240 and Centrex™ 240) run on 240 volts for faster drying, perfect if you’ve got reliable power. Off-grid? The non-electric versions (Excel™ NE and Centrex™ NE) use passive venting or a 12-volt fan powered by solar—great for remote setups.
Composting Done Right: Waste breaks down in the Bio-Drum™, then moves to a finishing drawer (Excel™) or tray (Centrex™) for the final stage. The result? Safe, usable compost you can pull out without a mess—ready to enrich your garden after some curing.
Certified for NZ: Both models meet AS/NZS 1546.2:2008 and NSF/ANSI-41 standards, proving they’re tough enough for New Zealand’s conditions and built to handle consistent use without faltering.
Design: Durable, Practical, and Surprisingly Sleek
Sun-Mar™ toilets are built to last and look good doing it. Here’s what you’re working with:
Excel™: This is a self-contained unit that sits on your bathroom floor—no plumbing needed. It’s got a glossy white pedestal that looks like a modern toilet, so it blends into any space without screaming “composting system.” Inside, the Bio-Drum™ spins with a handle, and there’s a slide-out drawer for finished compost. It’s compact but sturdy, made from fibreglass and stainless steel to handle years of use.
Centrex™: This split-system design is a bit different—the composting tank lives below the floor (say, in a basement or crawlspace), and only a sleek pedestal sits upstairs. It’s ideal for larger homes where you want big capacity without cluttering the bathroom. Like the Excel™, it uses the Bio-Drum™ and has a tray for compost removal.
Build Quality: Both models are tough as nails, with corrosion-resistant materials that stand up to humid Kiwi climates. The design is user-friendly—spin the drum, vent the air, and empty when ready. They’re not just functional; they’ve got a polished vibe that fits modern off-grid homes.
Performance: Odor-Free and Ready for a Crowd
When it comes to how these toilets hold up, Sun-Mar™ delivers the goods:
No Smells, No Worries: The Bio-Drum™ keeps waste aerated, and the fan pulls odors out through the vent. Whether it’s the Excel™ with 3–4 full-time users or the Centrex™ with up to 7, the system stays fresh. Users say you’d never guess there’s a composting toilet in the mix—it’s that effective.
High Capacity: The Excel™ can go months between empties for a small household (once or twice a year for part-time use), while the Centrex™ often needs just one annual empty for holiday homes with bigger crews. That’s a huge relief if you hate frequent maintenance.
Flush Option: The Centrex™ MicroFlush adds a familiar flush feel with almost no water, and it still composts like a pro. It’s a nice middle ground if you’re easing into waterless living.
Real-World Proof: Certified for odorless operation at max capacity, these toilets handle busy scenarios without breaking a sweat. Think family gatherings or eco-lodge guests—Sun-Mar™ keeps up, no problem.
Environmental Benefits: Green Living, Kiwi Style
For anyone passionate about sustainability (and New Zealanders tend to be), Sun-Mar™ checks all the boxes:
Water Savings: Waterless models eliminate usage entirely, while the MicroFlush cuts it down to a fraction of standard toilets. In a country where water conservation matters, this is a big deal.
Nutrient Recycling: The compost you get is chemical-free and garden-ready after curing—perfect for growing veges or natives. It’s a closed-loop system that turns waste into a resource.
Low Energy: Non-electric models use 1–2 watts with a solar fan, and even electric ones sip just 3 kWh/day—barely a blip on your off-grid power setup.
No Pollution: No blackwater, no chemicals—just a clean process that aligns with NZ’s eco-conscious values. It’s off-grid sanitation you can feel proud of.
Maintenance: Simple and Straightforward
Keeping a Sun-Mar™ running is low-effort and fuss-free. Here’s the full scoop:
Daily: Add a scoop of wood shavings or peat mix per person (it helps the composting), spin the Bio-Drum™ a few times to mix, and you’re done. Toilet paper goes in—no need to separate it.
Weekly/Monthly: Check the liquid evaporator (a tray that dries excess moisture) and wipe it if needed—usually only for heavy use.
Periodic: Empty the compost drawer (Excel™) every few months for full-time use, or once a year for part-timers. The Centrex™ tray might only need it annually, even with bigger groups. It’s dry, odorless, and easy to handle.
Installation: The Excel™ needs floor space and a vent pipe (0.6–1 meter above the roof, per NZ regs). The Centrex™ goes underfloor with a small drain for excess liquid if you’re in a wet climate. No chemicals or complex servicing—just set it up and let it work.
Use Cases: Where Sun-Mar™ Thrives in NZ
Tiny Homes & Cabins: The Excel™ fits tight spaces with no plumbing, while the Centrex™ suits homes with a bit more room below. Both save water and manage waste effortlessly.
Holiday Homes: The Centrex™ shines for groups (up to 7 full-time users), and the Excel™ is great for smaller crews or couples who want low upkeep.
Vanlife: The Excel™ NE could work in a big mobile cabin with solar, but Sun-Mar™’s GTG™ model is better for true vanlife (a story for another day!).
Eco-Communities & Lodges: The Centrex™ handles shared setups or eco-tourism with its high capacity and compost output—perfect for sustainable living hubs.
Sun-Mar™ vs. EcoLet™: A Fair Comparison
How does Sun-Mar™ stack up against the EcoLet™ Separera Mini? Let’s break it down:
EcoLet™ Strengths: It’s lightweight, portable, and ideal for 1–2 people—think solo vanlifers or couples. You empty it weekly, and it’s super simple with separate liquid and solid waste.
Sun-Mar™ Strengths: Bigger capacity (3–7 users), less frequent emptying (1–2 times a year), and the Bio-Drum™ for faster, odor-free composting. It’s built for fixed setups like cabins or holiday homes.
The Trade-Off: EcoLet™ wins for mobility and small spaces; Sun-Mar™ takes the crown for larger, permanent installations. Both are eco-friendly and odorless, but Sun-Mar™ scales up better.
Vs. Alternatives: Compared to cassette toilets (chemicals, frequent dumping) or bucket systems (smelly, manual), Sun-Mar™ offers a cleaner, more sustainable option with less hassle.
The Verdict: Is Sun-Mar™ Right for You?
The Sun-Mar™ Excel™ and Centrex™ composting toilets are powerhouse solutions for off-grid Kiwis who need capacity, reliability, and a green edge. They cost more upfront than the EcoLet™, but you get less maintenance, bigger loads, and years of dependable performance in return. If you’re in a tiny home or van, the EcoLet™ might edge out for simplicity, but for cabins, families, or eco-communities, Sun-Mar™ is tough to top. It’s sustainable sanitation that feels right at home in New Zealand—whether you’re off the grid by choice or necessity. Ready to make the leap? This could be your ticket to hassle-free, eco-friendly living!
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