Tips & Tricks: Heat, Geysers, Coolants Guide

Intro: Practical tips help you avoid common pitfalls, improve efficiency, and make better long‑term decisions in Oxygen Not Included. The following condensed advice covers recurring gameplay systems (morale & schedules, heat management, reservoirs & storage, geyser/volcano handling, ranching/critters, rockets, and numerical/engineering caveats) so you can apply proven practices across many colonies.

Morale, schedules, and recreation

• Morale directly affects stress gain and recovery. Track required morale for trained duplicants: higher-skilled duplicants need higher baseline morale to avoid stress.
• Short, frequent morale buffs (Washroom, Mess Hall, Park) are great for keeping morale steady; long‑duration recreation (Beach Chair, Hot Tub) must be managed so duplicants don't repeatedly use them and lock themselves into long interactions. Provide faster, shorter rec options nearby so duplicants choose quick buffs during downtime rather than constantly reusing long‑duration buildings.
• Downtime scheduling: the schedule system uses 24 blocks (25 seconds each). Bathtime, Work, Downtime and Bedtime blocks strongly affect priorities. Bathtime forces bathroom use; Downtime makes duplicants eat and seek recreation. Use schedule design (e.g., 2–3 downtime then bedtime) to smooth peaks for toilets and mess halls.
• Many morale sources are instantaneous buffs listed in the morale table (e.g., Mess Hall +3, Great Hall +4, Banquet Hall +6, Washroom +2). Place the highest‑value facilities accessible and distribute lower‑value fast options to prevent long building lockups.

Heat management and thermal engineering

• Heat exchange follows discrete rules: transfer depends on temperature difference (ΔT), material thermal conductivity, tile/building thermal mass and simulation tick length. Use materials with low thermal conductivity (e.g., insulated tiles, abyssalite) to block heat flow and metals/fluids with high heat capacity to buffer heat spikes.
• Floating point limits can prevent heat exchange when temperature deltas are too small relative to 32‑bit float precision; extremely large or highly insulated objects may not exchange heat with adjacent tiles unless ΔT exceeds the engine's minimum threshold. Keep designs with reasonable size/ΔT to avoid math limits.
• For high, bursty heat sources (metal volcanoes, geyser ejection phases, rocket exhaust) design a three‑part strategy:
  • Buffer: a thermal mass (high mass, high specific heat reservoir or liquid tank) to absorb heat during ejection.
  • Active cooldown: move heat away during idle periods with pumps, radiators, or Thermo‑Aquatuners so the buffer is ready for the next eruption.
  • Containment: never rely solely on dormant phases to cool systems — idle phases are the planned cooldown windows.
• Insulated Doors and Insulated Tiles use the game's heat equations to limit conduction; for critical high‑temperature plumbing/piping, route lines through thermally isolated channels.

Geysers, volcanoes, and vents

• Geysers and volcanoes are random within defined parameter ranges; they pick active yields, periods, and active percentages independently. Plan systems for peak ejection phases, not just average outputs.
• Cool Steam Vents: cannot directly run a Steam Turbine unless steam reaches the turbine's temperature trigger. They can be integrated into Aquatuner/Steam Turbine loops with careful balancing and, optionally, Super Coolant. Tie a Geotuner to a vent to raise its output reliability where available.
• Metal Volcanoes eject molten metal and large amounts of heat during Ejection Phases. Each eruption dumps metal + heat rapidly; use large buffers and active cooldown during Idle phases to avoid equipment overheating. Niobium volcano behavior is special—treat it separately when planning.

Reservoirs and storage

• Gas Reservoirs: avoid exposing reservoirs to extreme environments; when a reservoir is fully damaged it releases its entire contents as gas which spreads rapidly. Contents exchange heat only with the tile containing the reservoir's output port and the tile below it — you can thermally isolate reservoir contents by placing those two tiles in vacuum or controlled environments.
• Liquid Reservoirs: storing liquids in reservoirs is pump‑efficient and often space‑efficient. Note that a full surface tile of water is 1000 kg: a single reservoir (6 tiles footprint) can hold large mass via tile‑filling behavior, but this can make access by duplicants difficult. Submerge reservoirs in Chlorine to quickly kill germs on contents when decontamination is required.
• Using reservoirs reduces pump cycling and automation load; design with staged reservoirs and timed airlocks for bulk processing and contamination control.

Ranching and critters

• Ranching errands require duplicants with Critter Ranching skill. Stable sizes: most critters require 12 tiles, Pufts require 16. Maximize stable efficiency by matching species to appropriate stable sizes and grooming/feeding cadence.
• Critters reproduce and produce resources; for species with special diets:
  • Sweetles + Grubgrubs loop: keep Sweetles in dedicated ranches (no plants) to maximize eggs and stable sucrose output. Sweetles need ~12 tiles each; Grubgrubs ~16. For Mud production, feed Grubgrubs Sucrose (100% mass → Mud) and maintain a ~3:1 Sweetle:Grubgrub ratio to optimize conversion from Sulfur to calories.
• Hatches for meat: hatches produce substantial calories if optimized—account for lifecycle egg production and planned replacement to keep population productive. Overcrowding or cramped stables reduce production; clear eggs promptly to avoid cramped debuff.

Rockets and exhaust handling

• Rocket engines produce extreme heat and/or steam on launch and landing. Hydrogen Engines release several tonnes of very hot steam and huge heat spikes that can melt most metals and boil nearby liquids. Rocket parts/platforms are immune to direct fluid heat exchange, but adjacent infrastructure (pipes, ports, wires, tiles) can be damaged.
• To capture rocket exhaust you must provide large heat sinks and capture systems; otherwise, let exhaust vent into void-free space to avoid collateral damage. If recovering exhaust, surround launch/landing areas with tolerant materials, buffered fluid reservoirs, or dedicated heat exchangers sized for the ~burst output.
• Rocket preconditions: Command Capsule requires fuel, an assigned pilot, an Atmo Suit in the capsule, empty Cargo Bays, and a selected destination within range. The capsule outputs a green automation signal when ready; send green to start launch. Avoid blocking the flight path with tiles or doors.

Pressure, liquids, and tile safety

• Liquid depth and mass cause pressure damage to tiles. Deep or high‑mass liquid stacks can crack and eventually break tiles; thicker walls (3+ tiles) without pipes can be immune. Some tiles/buildings are pressure‑immune (airflow tiles, manual/ mechanized airlocks, bunker doors, solar panels).
• Depth stacking and storage design: calculate potential tile mass and ensure walls and tanking are rated or reinforced. Use pressure‑resistant tiles or increase wall thickness for large liquid storage.

Automation, sensors, and control tricks

• Use Atmo/Temp/Cycle sensors with Gas Pumps, Liquid Pumps, Deodorizers, and Airflow management to automate harvesting and protection of fragile systems (e.g., Morbs need minimum pressure, or Atmo Sensors to avoid vacuum penalties).
• Cycle sensors combined with mechanized airlocks and logical gates (NOT, AND) create timed batch transfer systems for liquids/gases (useful for staged decontamination or rotating reservoirs).
• Place sensors on extraction/harvest machines to prevent them from running into dangerous states (overheating, empty resources, or pumping into full tanks).

Numerical and practical caveats

• Game uses 32‑bit floats for temperatures; very small deltas may not register and will stop heat transfer. Avoid absurdly large or tiny isolated thermal systems where precision limits prevent intended transfer.
• Trait generation: duplicant traits are balanced by "trait rarity." High‑rarity positive traits often come with offsetting negatives. When recruiting, expect trait balancing and select duplicants by whole‑package suitability (skills + traits).
• Initiative/achievement planning: many achievements and Initiatives depend on long‑term design choices (population targets, monuments, rockets). Plan early for required morale and infrastructure when aiming for late‑game objectives.

Summary: design conservatively for peak events (geyser/volcano ejections, rocket exhaust), use reservoirs and buffers to smooth flows, schedule and place recreation to control morale, and avoid edge‑case numerical pitfalls by keeping systems within reasonable thermal/pressure ranges. These practices will make your colony robust, productive, and easier to expand into late game.