Oxygen Not Included Tips & Tricks — Pro Strategies & Hidden Mechanics

Oxygen Not Included is Klei Entertainment's colony survival sim where you manage a group of Duplicants trapped inside a procedurally generated asteroid. Every breath of oxygen, calorie of food, and degree of temperature must be meticulously managed through complex piping, ventilation, and power systems. The Spaced Out! DLC adds multi-asteroid colonies and interplanetary rocket logistics. With hundreds of hours of depth in thermodynamics, gas physics, and liquid mechanics, ONI rewards systems-thinking players who enjoy solving cascading engineering puzzles.

These tips go beyond the basics. They're the strategies experienced players use to play more efficiently, the hidden mechanics most people miss, and the optimizations that compound over a full playthrough.

Essential Tips

1. Build a SPOM (Self-Powered Oxygen Module) by cycle 30 — one Electrolyzer, two Gas Pumps, a Gas Filter, and a Hydrogen Generator in a sealed room provides oxygen for 8 Dupes with zero external power

Build a SPOM (Self-Powered Oxygen Module) by cycle 30 — one Electrolyzer, two Gas Pumps, a Gas Filter, and a Hydrogen Generator in a sealed room provides oxygen for 8 Dupes with zero external power.

2. Insulate your base perimeter with Insulated Tiles made from Igneous Rock (not Sandstone) to prevent heat bleed from hot biomes — temperature creep is the silent colony killer

Insulate your base perimeter with Insulated Tiles made from Igneous Rock (not Sandstone) to prevent heat bleed from hot biomes — temperature creep is the silent colony killer.

3. Meal Lice into Liceloaf at a Microbe Musher is your safest early food chain: it requires no water, no cooking skill, and provides enough calories until you set up ranching or farming

Meal Lice into Liceloaf at a Microbe Musher is your safest early food chain: it requires no water, no cooking skill, and provides enough calories until you set up ranching or farming.

4. Never dig into Slime Biomes without Atmo Suits — Slimelung in polluted oxygen causes debuffs, and the Slime off-gasses polluted oxygen when exposed to regular atmosphere

Never dig into Slime Biomes without Atmo Suits — Slimelung in polluted oxygen causes debuffs, and the Slime off-gasses polluted oxygen when exposed to regular atmosphere.

5. Wheezeworts cool rooms by 12kDTU/s without power but consume Phosphorite as fertilizer

Wheezeworts cool rooms by 12kDTU/s without power but consume Phosphorite as fertilizer. Place them in your farm or server room for passive cooling before you research Steam Turbines.

6. Set up a permanent Carbon Dioxide scrubbing solution: either a Carbon Skimmer (uses water + power) or let CO2 pool at the bottom of your base and pump it to Slicksters, which convert it into oil

Set up a permanent Carbon Dioxide scrubbing solution: either a Carbon Skimmer (uses water + power) or let CO2 pool at the bottom of your base and pump it to Slicksters, which convert it into oil.

7. Smart Batteries should control every generator — set automation to turn generators on at 20% and off at 80% to prevent wasting fuel and overheating from continuous operation

Smart Batteries should control every generator — set automation to turn generators on at 20% and off at 80% to prevent wasting fuel and overheating from continuous operation.

8. Prioritize Athletics on all Dupes — movement speed affects everything

Prioritize Athletics on all Dupes — movement speed affects everything. A Dupe with 20 Athletics completes tasks nearly twice as fast as one with 5, across all errands.

9. Use Automation wires and sensors extensively: Thermo Sensors, Hydro Sensors, and Atmo Sensors let you build systems that self-regulate without manual intervention

Use Automation wires and sensors extensively: Thermo Sensors, Hydro Sensors, and Atmo Sensors let you build systems that self-regulate without manual intervention.

10. Don't print more than 8 Duplicants until your food and oxygen systems are stable — each new Dupe consumes 100g/s oxygen and 1000 kcal/cycle, and overpopulation spirals fast

Don't print more than 8 Duplicants until your food and oxygen systems are stable — each new Dupe consumes 100g/s oxygen and 1000 kcal/cycle, and overpopulation spirals fast.

Advanced Strategies

Build Optimization

The difference between an average build and an optimized one is massive:

For Researcher (S-Tier):

• Researchers are essential early game and remain valuable throughout. A high-Science Dupe stationed at a Super Computer tears through the tech tree, unlocking critical systems like Insulated Tiles and Smart Batteries before cycle 50. Late game, they operate Telescopes and Virtual Planetariums for space research.
• Core gear: Super Computer, Virtual Planetarium, Data Banks, Telescope
• Stat priority: Science, Learning

For Farmer (A-Tier):

• Farmers handle all food production from Mealwood farms to Bristle Blossom hydroponic setups. High Agriculture skill increases crop tending speed and prevents withering. Late game, they manage Grubfruit and Nosh Bean farms for +8 morale food recipes.
• Core gear: Farm Tiles, Hydroponic Tiles, Fertilizer Synthesizer, Cooking Station
• Stat priority: Agriculture, Creativity

Mechanic Interactions

Understanding how Oxygen Not Included's systems interact is where the real optimization lives:

gas management + pipe systems: Gases in ONI have realistic density — oxygen sinks below hydrogen, carbon dioxide pools at the bottom, and chlorine settles above CO2. Combined with pipe systems, liquid and gas pipes form the circulatory system of your base, carrying water, polluted water, petroleum, and various gases.

duplicant skills + research tree: Each Duplicant has innate attributes (Athletics, Strength, Creativity, Science, etc. When paired with research tree, research progresses through tiers using research stations (tier 1-2), super computers (tier 3), and eventually interplanetary research for space-age tech.

space exploration scaling: Space exploration requires building rockets from modular components — nosecone, fuel tank, engine, cargo bay, and habitat modules. In Spaced Out!, you send rockets to nearby planetoids to establish satellite colonies for rare resources like Isoresin and Fullerene. Rocket automation with scheduling and fuel logistics is one of the game's most complex late-game systems.

Equipment Efficiency

Location Efficiency

Starting Biome (Cycles 1-50): The temperate starting area contains Oxylite for initial oxygen, Mealwood seeds for food, and Algae for early Oxygen Diffusers. Temperature stays around 25-30C, which is comfortable for Dupes. Prioritize securing water access and building basic infrastructure here before expanding.

Caustic Biome (Cycles 30-80): A hot biome (40-50C) filled with Chlorine gas, Bleach Stone, and natural gas geysers. Chlorine kills germs, making it useful for sanitization rooms. The natural gas geysers here provide reliable fuel for Natural Gas Generators. Don't dig in without Atmo Suits.

Frozen Biome (Cycles 40-100): Sub-zero temperatures (-20 to -40C) with Wheezeworts, Ice, and Wolframite. This biome acts as a natural heat sink — smart players route hot pipes through it for free cooling. Wheezeworts provide 12kDTU/s of cooling without power. Rich in Wolframite for high-temperature-tolerant builds.

Oil Biome (Cycles 80-150): The deep, hot biome (70-90C) containing Oil Reservoirs and Leaky Oil Fissures. Oil is refined into Petroleum for generators and Plastic for advanced buildings. This biome also contains Lead for radiation shielding. You need Atmo Suits and heat-resistant infrastructure to work here.

Space Surface (Cycles 150+): The asteroid surface is a vacuum exposed to meteor showers and solar radiation. Build Bunker Tiles and Bunker Doors to protect solar panels and telescopes. Regolith from meteors must be cleared by Robo-Miners. This is where you launch rockets and harvest solar power.

Mistakes Even Veterans Make

1. Printing too many Duplicants early — each Dupe adds 100g/s oxygen demand and 1000 kcal/cycle food demand, and colony death spirals start from overpopulation before infrastructure is ready.
2. Ignoring temperature management until everything overheats — by cycle 100, heat from machines and hot biomes will cook your crops and stress your Dupes if you haven't built cooling loops.
3. Building Electrolyzers without proper gas separation — unfiltered output mixes hydrogen into your oxygen supply, which Dupes can't breathe and which can cause hydrogen buildup in living quarters.
4. Not insulating the base perimeter — hot biomes at 70C will slowly heat your 25C starting area through regular tiles, killing Mealwood farms that die above 30C.
5. Running generators without Smart Battery automation — continuously running generators waste fuel and dump excess heat into your base, creating both resource drain and cooling problems.

Efficiency Quick Reference

Pro Quick Tips

• Build a SPOM (Self-Powered Oxygen Module) by cycle 30 — one Electrolyzer, two Gas Pumps, a Gas Filter, and a Hydrogen Generator in a sealed room provides oxygen for 8 Dupes with zero external power.
• Insulate your base perimeter with Insulated Tiles made from Igneous Rock (not Sandstone) to prevent heat bleed from hot biomes — temperature creep is the silent colony killer.
• Meal Lice into Liceloaf at a Microbe Musher is your safest early food chain: it requires no water, no cooking skill, and provides enough calories until you set up ranching or farming.
• Start with Farmer, switch to Researcher when ready
• Invest in Electrolyzer above everything else
• Clear areas in order: Starting Biome → Caustic Biome → Frozen Biome → Oil Biome → Space Surface
• gas management + pipe systems together are stronger than either alone

For full build details, check builds. For progression path, see the walkthrough.