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Sun-Mar Composting Toilets
Sun-Mar Composting Toilets for Off-Grid Living, Cabins, RVs & More
If you're looking for a Sun-Mar composting toilet, you're in the right place. We carry the full line of Sun-Mar toilets — from compact, self-contained models like the GTG, to high-capacity systems like the Excel and Centrex. Whether you're off-grid full-time, living tiny, or just want a more sustainable setup, there's a Sun-Mar model that fits your life.
Why Sun-Mar
Sun-Mar has been a leader in composting toilet systems for decades. Their toilets are designed to manage waste safely, naturally, and without the need for plumbing or septic systems. Best part? No bad smells.
Sun-Mar’s patented Bio-Drum™ technology kickstarts the composting process right inside the unit. It’s clean, simple, and surprisingly low-maintenance.
It's also North America's #1 selling Composting Toilet!!
Sun-Mar Model Comparison
| Model | Sun-Mar Excel | Sun-Mar Excel NE | Sun-Mar GTG | Sun-Mar Compact | Sun-Mar Spacesaver |
| Dimensions | 33.25" x 22.5" x 33" | 31.5" x 22.5" x 33" | 19.8″ × 15.75″ × 24″ | 28.5" x 21.5" x 33" | 30"x19.5"x23" |
| Users | Family of 5 Full Time or 8 people seasonally | Family of 5 Full Time or 8 people seasonally | “Unlimited” in that it uses removable canisters – no internal compost drum limits. | 1 - 2 adults Full time or 3 adults seasonally | 1 adult full time, or 3 adults seasonally |
| Electrical Req. | Max Amps (Heater On): 2.4 Fan Watts: 35 Heater Watts: 250 Avg. Power Use: 150W Requires constant AC power. |
Non-electric OPTIONAL 12V 1.4W/1.9W fan available |
12V DC fan 0.6W Includes 110V/240V AC adapter |
Max Amps (Heater On): 2.0 Fan Watts: 35 Heater Watts: 200 Avg. Power Use: 125W Requires constant AC power. |
Max Amps (Heater On): 2.0 Fan Watts: 35 Heater Watts: 160 Avg. Power Use: 110W Requires constant AC power. |
| Vent Size | 2″ Thin-wall PVC | 4″ Thin-wall PVC | None | 2″ Thin-wall PVC | 2″ Thin-wall PVC |
| Best For | Heavy Residential (3 adults/5-person family) Extensive Seasonal (6 adults/8-person family) |
Off-grid living Remote cabins No continuous 110V power |
Tiny homes RVs, Boats Small spaces requiring unlimited capacity |
Smaller Residential (1 adult/2-person family) Light/Medium Seasonal (3 adults/4-person family) |
Extremely limited spaces Closets, small corners 1 adult residential / 3 adults or 4-person family seasonal |
| Model Highlights | High capacity Patented Bio-drum for fast decomposition Robust for heavy usage |
Completely non-electric Odor control via natural draft with 4" vent Ideal for sustainable living |
Ultra-compact & lightweight Urine-diverting for efficient waste separation Low power fan Quick, easy install |
Compact yet effective Patented Bio-drum Suitable for light residential/medium cottage use |
Smallest footprint Designed for tight installations Electric operation for efficient evaporation |
Sun-Mar Centrex Central Composting System - Model Comparison
| Model | Centrex 1000 | Centrex 1000 NE | Centrex 2000 | Centrex 2000 NE | Centrex 3000 | Centrex 3000 NE |
| Weight | 50 lbs | 45 lbs | 97 lbs | 87 lbs | 102 lbs | 102 lbs |
| Dimensions (H × D) | 28″ × 32.5″ | 28″ × 32.5″ | 28″ × 27″ | 26.5″ × 26.5″ | 30.25″ × 27.5″ | 29.25″ × 27.5″ |
| Width & Handle Clearance | 22.5″ × 24.5″ | 22.5″ × 24.5″ | 45.5″ × 49″ | 45.5″ × 49″ | (Width 71″; clearance 27″) | (Width 71″; clearance 27″) |
| Vent Pipe & Diffusor | 2″ ABS ×6 4″ diffusor |
2″ ABS ×6 4″ diffusor |
2″ ABS ×6 4″ diffusor |
4″ ABS ×5 6″ diffusor |
2″ ABS ×6 4″ diffusor |
4″ ABS ×5 6″ diffusor |
| Compost Sure Blue Bags | 1 | 1 | 2 | 2 | 2 | 2 |
| Drawer Removal Depth | 46.25″ | 46.25″ | 45″ | 45″ | 45.5″ | 45.5″ |
| Electrical Specs | Max 2.5 A Fan 35 W Heater 260 W Avg 150 W |
— (no electricity) | Max 3.6 A Fan 35 W Heater 370 W Avg 200 W |
— (no electricity) | Max 3.6 A Fan 35 W Heater 370 W Avg 215 W |
— (no electricity) |
Note: All models require a 3″ plumbing pipe and associated fittings (not included) to connect a 1‑pint flush toilet.
Our Top Picks
Sun-Mar GTG
Great for vans, tiny homes, or cabins with limited space.
Sun-Mar Excel
Perfect for full-time use in cabins, cottages, or off-grid homes.
Sun-Mar Centrex
Designed for larger groups and families or setups with multiple bathrooms.
Why order your Sun-Mar from Wild Oak Trail?
We’re not just another online store. We’re a family-run business that’s been helping people live off the grid since 2017. We know these toilets inside and out, and we’re here if you ever need advice, tech support, or just someone to talk through your setup.
When you order from us, you get:
✅ Free shipping in the lower 48
✅ Expert support from real humans
✅ Fast, friendly service from a small team that actually cares
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