TL;DR
A reflector fire is any fire with a solid reflective surface behind it. The fire radiates heat in all directions; the reflector captures the heat going backward and bounces it forward toward you. Double the warmth from the same fire. A natural rock face, a built log wall, or a rock stack — any solid surface behind the fire acts as a reflector.
The Physics
A campfire radiates heat as infrared radiation in all directions — roughly equally in a sphere around the fire. When you sit in front of a fire without a reflector, you receive approximately half the radiant output (the forward half). The other half radiates away behind the fire.
A reflective surface behind the fire redirects the rearward radiation forward. You now receive significantly more total heat from the same fire.
Additionally, a solid reflector wall behind the fire acts as a wind block, preventing the wind from pushing heat away from you.
Using Natural Reflectors
The best situation: a fire built in front of a large flat rock face, cliff, or large boulder. The stone absorbs heat, stores it, and radiates it back. Stone that has been heated by a fire for an hour continues radiating heat for hours after the fire dies.
Find rocks first. Let the terrain suggest your camp location.
Building a Log Reflector
When no natural rock face is available, build a reflector from green logs.
Construction:
- Drive two stakes into the ground about 3-4 feet apart and 3-4 feet behind where the fire will be.
- Lean large green logs against the stakes horizontally, stacking them from the ground up to 3-4 feet height.
- The wall should lean slightly away from the fire at the top (angled to direct heat forward and downward toward the user).
Green vs. dry logs: Green logs are preferred for the reflector because they don't burn readily. Dry logs may ignite and become fuel rather than remaining a reflector. A reflector wall of green logs maintains its structure through a long night.
Alternative: Drive 4-6 upright stakes in a row and weave horizontal branches behind them. Less solid but faster to build.
The Camp Layout with a Reflector Fire
Optimal arrangement for maximum warmth:
[USER/SHELTER]
↑
3-5 ft
↑
[FIRE]
↑
2-3 ft
↑
[REFLECTOR]
The user is 3-5 feet from the fire (comfortable radiant distance). The reflector is 2-3 feet behind the fire.
For a sleeping fire: the sleeping position is parallel to the fire (see the long fire article), with the reflector behind the fire and opposite the sleeping position.
Reflector Oven for Baking
A reflector can also be used for baking in front of a fire.
Construction:
- Build a steep-angled reflector behind the fire — nearly vertical at the bottom, angling back at the top.
- Place a grate or shelf in front of the fire, between the fire and the user position.
- Food placed on the shelf receives direct heat from the fire on one side and reflected heat from the reflector on the other.
Traditional reflector ovens were thin metal sheets shaped into a V when viewed from above, angling heat toward a center shelf. Commercial versions exist; improvised versions from any flat sheet metal work for baking biscuits, bread, and fish.
Maintenance
A reflector fire benefits from being maintained brighter and higher-flame than other fires since the goal is maximum radiant heat output (not coal production for cooking). Dry wood, fed consistently, produces the brightest flame. Hardwoods burn cleaner; softwoods burn bright but spark more.
Add wood from the side, not the front — reaching over the fire to add wood from the reflector side is awkward and exposes you to heat.
Sources
- Canterbury, Dave - Bushcraft 101
- Mears, Ray - Bushcraft Survival
- US Army Field Manual FM 21-76 - Survival
Frequently Asked Questions
How much difference does a fire reflector make?
A properly placed fire reflector can effectively double perceived warmth by directing radiation toward the user that would otherwise radiate away in the opposite direction. A fire radiates heat in all directions equally. Without a reflector, you benefit from roughly half the fire's radiant output (the half facing you). A reflective back wall redirects the opposite half toward you, capturing approximately 80-90% of total radiant output.
What materials make the best fire reflector?
A large flat rock face (pre-existing) is the best reflector — it absorbs, stores, and radiates heat. A built wall of green logs leaned against stakes works well. A dry stone wall is excellent. Metal sheets or foil reflect more efficiently but are rarely available in wilderness settings. Wet wood or fresh-cut logs in a horizontal stack work reasonably well. The key is a solid, relatively flat surface at least 3-4 feet tall positioned behind the fire.
How do you position yourself relative to a reflector fire?
The fire should be between you and the reflector. You sit or sleep on the side of the fire opposite the reflector. The reflector bounces heat from the fire back toward you. If you place yourself between the fire and the reflector, the reflector radiates away from you — wrong. Fire in middle, you on one side, reflector behind the fire on the other side.