# Hot air - Stage 2 (technology)

internal name `hot-air-mk02` · tier 2 (Logistic science pack, [tier 2](https://factorio.kalzumeus.com/tier/2.md))
HTML page: https://factorio.kalzumeus.com/tech/hot-air-mk02/

## Cost

175 units of (1 × [Logistic science pack](https://factorio.kalzumeus.com/item/logistic-science-pack.md), 2 × [pY science pack 1](https://factorio.kalzumeus.com/item/py-science-pack-1.md), 3 × [Automation science pack](https://factorio.kalzumeus.com/item/automation-science-pack.md)), 60 s each.

## Requires (2)

- [Biomass Power - Stage 1](https://factorio.kalzumeus.com/tech/biomassplant-mk01.md)
- [Mining machines - Stage 2](https://factorio.kalzumeus.com/tech/machines-mk02.md)

## Leads to (1)

- [Hot air - Stage 3](https://factorio.kalzumeus.com/tech/hot-air-mk03.md)

## Unlocks (4 recipes)

### Soot (`cog-void-soot`)

- 2 s · tier 2 · productivity modules allowed
- Ingredients: 30 × [Coke oven gas](https://factorio.kalzumeus.com/fluid/coke-oven-gas.md), 10 × [Water](https://factorio.kalzumeus.com/fluid/water.md)
- Results: 1 × [Soot](https://factorio.kalzumeus.com/item/soot.md)
- Made in: Wet scrubber MK 01, Wet scrubber MK 02, Wet scrubber MK 03, Wet scrubber MK 04
- Unlocked by: [Hot air - Stage 2](https://factorio.kalzumeus.com/tech/hot-air-mk02.md)

### Coke oven gas (`reheat-coke-gas`)

- 4 s · tier 2
- Ingredients: 100 × [Coke oven gas](https://factorio.kalzumeus.com/fluid/coke-oven-gas.md) (≤100°C), 50 × [Hot Molten Salt](https://factorio.kalzumeus.com/fluid/hot-molten-salt.md) (≥950°C)
- Results: 95 × [Coke oven gas](https://factorio.kalzumeus.com/fluid/coke-oven-gas.md) (500°C), 50 × [Molten Salt](https://factorio.kalzumeus.com/fluid/molten-salt.md)
- Made in: Heat exchanger MK01, Heat exchanger MK02, Heat exchanger MK03, Heat exchanger MK04
- Unlocked by: [Hot air - Stage 2](https://factorio.kalzumeus.com/tech/hot-air-mk02.md)

### Hot air (`warmer-air-2`)

- 2 s · tier 2
- Ingredients: 20 × [Warmer stone brick](https://factorio.kalzumeus.com/item/warmer-stone-brick.md), 150 × [Pressurized air](https://factorio.kalzumeus.com/fluid/pressured-air.md)
- Results: 300 × [Hot air](https://factorio.kalzumeus.com/fluid/hot-air.md), 20 × [Stone brick](https://factorio.kalzumeus.com/item/stone-brick.md)
- Made in: Regenerative heat exchanger
- Unlocked by: [Hot air - Stage 2](https://factorio.kalzumeus.com/tech/hot-air-mk02.md)

### Warmer stone brick (`warmer-stone-brick-1`)

- 5 s · tier 2
- Ingredients: 5 × [Warm stone brick](https://factorio.kalzumeus.com/item/warm-stone-brick.md), 100 × [Coke oven gas](https://factorio.kalzumeus.com/fluid/coke-oven-gas.md) (≥500°C)
- Results: 5 × [Warmer stone brick](https://factorio.kalzumeus.com/item/warmer-stone-brick.md), 100 × [Coke oven gas](https://factorio.kalzumeus.com/fluid/coke-oven-gas.md) (250°C)
- Made in: Regenerative heat exchanger
- Unlocked by: [Hot air - Stage 2](https://factorio.kalzumeus.com/tech/hot-air-mk02.md)