Altos 20ºF vs Celsius Regular 0˚F: Mummy Bag Showdown
By TETON Sports | Published: 2026-10-26
Category: Comparisons
Compare TETON Sports' Altos 20ºF and Celsius Regular 0°F mummy sleeping bags. Learn which offers better warmth, comfort, and value for your camping needs.
Quick answer
Choose the Altos 20ºF if you value a roomier, less claustrophobic mummy fit with down insulation for milder cold. Pick the Celsius Regular 0°F if you need a warmer, budget-friendly bag for deep winter camping.
Warmth vs. room: the core trade-off
The Celsius Regular 0°F uses a survival temperature rating of 0°F, meaning it's designed to keep you alive at that extreme, not necessarily comfortable. The Altos 20ºF has a 20°F survival rating, so it's less suited for deep cold but offers a wider cut and longer length to reduce that trapped feeling. Your choice depends on whether you prioritize warmth or freedom of movement.
Insulation and weight differences
The Altos 20ºF is filled with down, which packs smaller and weighs less for its warmth—great for backpackers. The Celsius Regular 0°F uses synthetic fill; it's heavier and bulkier but retains some insulation when wet. If you camp in damp conditions, synthetic's moisture resistance is a real advantage.
Trade-offs at a glance
- Warmth: Celsius Regular 0°F has a lower survival rating (0°F) vs. Altos 20ºF (20°F). The Celsius is warmer in extreme cold.
- Fit & comfort: Altos 20ºF is oversized—wider shoulders and longer foot box—reducing claustrophobia. Celsius is a standard mummy cut, more snug.
- Insulation type: Altos uses down (lighter, more compressible). Celsius uses synthetic (heavier, better when wet). Down is great for dry cold; synthetic is safer in damp climates.
- Price: Altos 20ºF is USD 131.39 (down from USD 179.99). Celsius Regular 0°F is USD 60.29 (down from USD 89.99). Celsius offers significant savings for comparable warmth.
Product facts at a glance
- Altos 20ºF: Oversized mummy bag with down fill, wider at shoulders and longer at feet, designed to reduce claustrophobia while preserving heat. You get the thermal efficiency of a mummy bag without feeling confined, making it ideal for side sleepers or those who toss and turn.
Altos 20ºF - Celsius Regular 0˚F: Uses a survival temperature rating of 0°F; the bag is built to keep you alive at that temperature but may not guarantee comfort. For actual comfort in sub-freezing weather, you may need extra layers or a warmer bag—plan your sleep system accordingly.
Celsius Regular 0˚F
Which bag fits you?
Best for
- Backpackers who want a lighter, roomier mummy bag for temperatures around 20°F and above (Altos 20ºF).
- Budget-conscious campers who need reliable warmth down to 0°F and don't mind extra weight (Celsius Regular 0°F).
Not for
- Extreme cold below 20°F if you prioritize comfort over survival (Altos 20ºF).
- Ultralight backpacking where every ounce counts (Celsius Regular 0°F).
