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The short answer
- Trelino Evo L: much lighter, slimmer, unpowered by default, normal seat height, bag-based solids. Great for vans where weight and simplicity matter.
- Nature's Head: heavier and bulkier, but ventilated with a 12 V fan and an agitator, and quoted for far more solid uses between emptying. Designed with full-timers in mind.
| Spec | Trelino Evo L | Nature's Head |
|---|---|---|
| Dimensions (W×H×D) | 33 × 43 × 39 cm | — |
| Weight | 4.9 kg | 23 lb |
| Urine container | 10 L (18–22 uses) | — |
| Solids | 10 L (11–20 uses) | approx. 60–80 uses (manufacturer) |
| Seat height | Normal (per manufacturer) | — |
| Dimensions (H×W×D) | — | 21 × 20 × 19 in |
| Liquid bottle | — | 2.2 gal |
| Ventilation | — | 12 V fan, fuse included |
| Mixing | — | Spider-handle agitator |
| Best for | Light, compact separating toilet with standard seat height, no wiring needed. | Full-time living with an agitator and a vent fan. |
Source: manufacturers' product pages (linked on each product card), checked 2026-11-14. “—” = not published on the page.
Weight and footprint
The Trelino Evo L is 33 × 43 × 39 cm and 4.9 kg. The Nature's Head is 21 × 20 × 19 in (about 53 × 51 × 48 cm) and 23 lb. In a small van bathroom or under a bench, that difference in width and depth can decide the layout.
Emptying routine
Liquids are the frequent job with any separating toilet. The Trelino Evo L's 10 L container is quoted for 18–22 uses; the Nature's Head bottle is 2.2 gal. For solids, Nature's Head quotes approx. 60–80 uses, versus 11–20 for the Trelino Evo L, which uses compostable bags that you remove and replace.
Odour and ventilation
The Nature's Head includes a 12 V fan, which pulls air from the solids chamber to outside – the most effective odour control, at the cost of a vent hole and a power feed. Trelino relies on separation and cover material, with ventilation available as an add-on.
Trelino Evo L
Best for: Light, compact separating toilet with standard seat height, no wiring needed.
- Dimensions (W×H×D)
- 33 × 43 × 39 cm
- Weight
- 4.9 kg
- Urine container
- 10 L (18–22 uses)
- Solids
- 10 L (11–20 uses)
- Seat height
- Normal (per manufacturer)
- No fan as standard – ventilation kit sold separately
- Uses compostable bags; budget for consumables
Specs: manufacturer page, checked 2026-11-14. Based on manufacturer specs and public reviews – not a hands-on test.
Nature's Head
Best for: Full-time living with an agitator and a vent fan.
- Dimensions (H×W×D)
- 21 × 20 × 19 in
- Weight
- 23 lb
- Liquid bottle
- 2.2 gal
- Solids
- approx. 60–80 uses (manufacturer)
- Ventilation
- 12 V fan, fuse included
- Mixing
- Spider-handle agitator
- Needs a 12 V feed and a vent hose to outside
- Bulky for small vans – check the footprint
Specs: manufacturer page, checked 2026-11-14. Based on manufacturer specs and public reviews – not a hands-on test.
Verdict
Living in your van full-time and happy to cut a vent? Nature's Head. Weekend or part-time user, or tight on space and weight? Trelino Evo L. For other options including the OGO, see the full composting toilet guide.
Frequently asked questions
Which is lighter, Trelino or Nature's Head?
By manufacturer figures, the Trelino Evo L weighs 4.9 kg (about 10.8 lb) and the Nature's Head 23 lb (about 10.4 kg).
Does the Trelino have a fan?
Not as standard on every model; ventilation can be added. The Nature's Head comes with a 12 V fan and fuse.
Which lasts longer between emptying?
On solids, Nature's Head quotes approx. 60–80 uses versus 11–20 for the Trelino Evo L (manufacturer figures). On liquids, the Trelino Evo L's 10 L container is larger than the Nature's Head 2.2 gal (about 8.3 L) bottle.
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