BioLet 55
#3 in CompostingFull review
For grid-powered cabins and cottages that want a hands-off composting toilet: automatic mixing and evaporation with no urine bottle, at a high price.
BioLet $2,255$2,255
The BioLet 55 is the better toilet overall, rated 3.1 to 2.8. The Sun-Mar Spacesaver wins on value. The Sun-Mar Spacesaver costs $320 less ($1,935 vs $2,255).
Sun-Mar Spacesaver
#4 in CompostingFull review
For a small cabin bathroom on grid power with one full time user or occasional guests, where a certified toilet is required.
Sun-Mar $1,935$1,935
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Sun-Mar Spacesaver for value ($1,935 vs $2,255).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every composting toilet; a clear win is highlighted. How we rank explains each one.
| Factor weight | BioLet 55 | Sun-Mar Spacesaver |
|---|---|---|
| Overall rating | 3.1/5 | 2.8/5 |
| Value 30% | 31 $2,255 | 48 $1,935 |
| Capacity 25% | 50 household rating not published (neutral score used) | 0 rated for 1 person full-time |
| Power 15% | 50 power draw not published (neutral score used) | 8 35 W fan, 160 W heater |
| Certification 15% | 50 NSF/ANSI 41 certification not stated (neutral score used) | 100 certified to NSF/ANSI 41 |
| Warranty 15% | 50 3-year warranty | 50 3-year warranty |
Specifications
| BioLet 55 | Sun-Mar Spacesaver | |
|---|---|---|
| Capacity | ||
| Type | Composting drum or chamber | Composting drum or chamber |
| Full-time residents | - | 1 people |
| Urine drain option | No | No |
| Agitator | Yes | - |
| Power and venting | ||
| Power | 120V | 120V |
| Fan | - | 35 W |
| Heater | - | 160 W |
| Vent size | 2.2 in | 2 in |
| Build | ||
| NSF/ANSI 41 | - | Yes |
| Dimensions | 22 x 28 x 26 in | 19.5 x 23 x 30 in |
| Weight | 60 lb | 43 lb |
| Material | High-density composite | - |
| Warranty | 3 years | 3 years |