Sun-Mar Excel
#2 in CompostingFull review
For cabins and homes on grid power that need a certified toilet for a full time household; its power draw rules out vans and small solar systems.
Sun-Mar $2,040$2,040
The Sun-Mar Excel and the BioLet 55 are evenly matched, rated 3.1 and 3.1. The Sun-Mar Excel leads on value. The Sun-Mar Excel costs $215 less ($2,040 vs $2,255).
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
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 Excel for value ($2,040 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 | Sun-Mar Excel | BioLet 55 |
|---|---|---|
| Overall rating | 3.1/5 | 3.1/5 |
| Value 30% | 42 $2,040 | 31 $2,255 |
| Capacity 25% | 40 rated for 3 people full-time | 50 household rating not published (neutral score used) |
| Power 15% | 1 35 W fan, 250 W heater | 50 power draw not published (neutral score used) |
| Certification 15% | 100 certified to NSF/ANSI 41 | 50 NSF/ANSI 41 certification not stated (neutral score used) |
| Warranty 15% | 50 3-year warranty | 50 3-year warranty |
Specifications
| Sun-Mar Excel | BioLet 55 | |
|---|---|---|
| Capacity | ||
| Type | Composting drum or chamber | Composting drum or chamber |
| Full-time residents | 3 people | - |
| Urine drain option | No | No |
| Agitator | Yes | Yes |
| Power and venting | ||
| Power | 120V | 120V |
| Fan | 35 W | - |
| Heater | 250 W | - |
| Vent size | 2 in | 2.2 in |
| Build | ||
| NSF/ANSI 41 | Yes | - |
| Dimensions | 22.5 x 33 x 33.25 in | 22 x 28 x 26 in |
| Weight | 60 lb | 60 lb |
| Material | - | High-density composite |
| Warranty | 3 years | 3 years |