Marathon Vault & Heat Management Guide

Table of Contents

1. Preparation: Why These Two Systems Decide Your Runs
2. The Heat System — Complete Breakdown
3. Heat Management by Shell
4. Gear and Consumables for Heat Control
5. The Vault System — Storage and Progression
6. Vault Optimization Strategy
7. Important Notes and Common Pitfalls
8. Rewards and Unlocks
9. Final Take
10. What the Nightfall Refresh Wiped

Preparation: Why These Two Systems Decide Your Runs

Heat and vault are the invisible mechanics that determine whether you extract with profit or die with nothing. Every Runner Shell interacts with heat differently. Every loot decision feeds your vault economy. Ignore either system and you will consistently lose runs that should have been successful.

I lost five consecutive runs before realizing the heat mechanic was the common factor. My Vandal kept overheating during pushes, dropping my movement speed at the worst moments. After restructuring my gear around heat reduction and learning the water-cooling routes, my extraction rate jumped from 35% to 72%.

For a broader overview of all game mechanics, see our Marathon complete guide. For quick fundamentals, our Marathon beginner 7 tips guide covers the essentials.

The Heat System — Complete Breakdown

Heat is Marathon’s stamina bar wearing a sci-fi label. Every dash, every Microjet boost, every slide and melee swing pushes the gauge up; the gauge is measured against your shell’s Heat Capacity, and when you exceed it you are Overheated, which throttles your movement until it cools back down. Three things I verified against the shell and core data before writing this section: heat is generated by movement abilities and melee rather than by looting or shooting, the penalty is movement (not accuracy), and being Overheated is a status other players can read on you and build around.

The Three Heat Bands

Band	Gauge	What you get
Cool	0-50%	Full movement, all abilities available
Hot	51-90%	Still functional, but your next boost chain can push you over
Critical	91-100%	Movement throttled on overheat; you cannot chain escapes

Treat Hot as the decision point, not Critical. By the time you are locked out of movement you have already spent your escape. The band matters in PvP for a second reason: the Ordnance Heist implant previews introduced Backdraft (“You deal increased damage to overheated hostiles”) and Chain Reaction (“Defeating an overheated hostile creates an explosion that overheats nearby hostiles”), plus the Heat Grenade, an impact grenade that detonates into a burst of searing heat and Overheats anything caught in it. Somebody in your lobby is going to farm you for that status.

Where Your Heat Actually Comes From

Read the game’s own core descriptions and the sources stop being a mystery — several of them exist purely to shave heat off a specific ability:

Source	Evidence in game data
Tactical Sprint / Thruster boosts	Destroyer Superior core Intake Vents: “Your Tactical Sprint generates less heat”; Deluxe Ankle Breaker: “Your Thruster generates less heat while a hostile is nearby”
Microjets and dash chains	Vandal Prestige core Microjet Efficiency Package: an extra Microjet charge “that generates less heat”
Melee and knife attacks	Standard core Close And Personal: “Your melee and knife attacks generate less heat”
Ability spam while invisible	Assassin Deluxe Patience pauses your invisibility timer “at the cost of generating heat”; Prestige Minus Sights makes you invisible after sustained ADS “at the cost of generating heat”
Sustained gunfights	Chip mod Heatsink: “Dealing sustained damage with this weapon reduces your generated heat by a small amount”

That table is the whole strategy: heat is a movement tax, so you buy back the tax on the specific ability you actually abuse.

Heat Reduction Methods

Ranked by how fast they work:

1. Crouch-walking — Bleeds heat off while you stay moving and small. This is the one you use mid-fight, behind cover, while your crew resets.
2. Water submersion — Dire Marsh’s flooded corridors and Perimeter’s coastal shallows dump heat far faster than dry air. Slower to reach than simply stopping, but the payoff is a full reset instead of a partial one.
3. Standing still — Passive cooldown does its job, and you are a stationary target doing it. Only in a cleared room.
4. Effects that clear or extend the pool — Vandal Enhanced core Out of Dodge: “When your shields break, your generated heat is immediately cleared.” Standard core Flight Response: “While at critical health, your heat capacity is increased.” Triage Enhanced Fresh Install grants revived crew extra Heat Capacity for a short window.

Cardio Kick is not on this list. It is Vandal’s melee kick trait (“Deliver a powerful melee kick”), and the consumable of the same name is a speed and agility booster — which is a heat source, not a heat sink. Any build that sells it as an emergency cooldown has the mechanic backwards; Vandal’s real escape valve is Out of Dodge plus the shell’s own 20-point Heat Capacity.

I still map water points before a Dire Marsh run. It is the difference between arriving at a key room at Cool and arriving at Hot with one boost left in the tank.

Heat Management by Shell

Every Shell has a different heat profile. The number that decides it is Heat Capacity in the shell data — Vandal 20, Destroyer 15, and 10 for Assassin, Recon, Rook, Thief and Triage. That is a 2x spread between the top and the bottom of the table, and it is the single most underrated stat in loadout building.

Vandal — Biggest Pool, Biggest Burn

Vandal owns the highest Heat Capacity in the game (20) and the most ways to spend it: Microjets (TACTICAL), Power Slide (TRAIT) and Cardio Kick (TRAIT), plus Amplify as its TECH. The shell’s whole identity is chaining movement abilities, so it overheats in spectacular fashion rather than gradually. Its answer is in its own cores: Adrenal Core (“While Amplified, your movement abilities generate even less heat. Using a Cardio Kick extends Amplify’s duration”), Microjet Efficiency Package for a cheaper extra charge, and Out of Dodge to dump generated heat the moment your shields break — which is exactly the moment you need to run.

Destroyer — Second Largest Pool, Cheapest Cores

Destroyer’s 15 Heat Capacity plus Thruster (TACTICAL) means it can boost twice where most shells boost once. Riot Barricade gives you a hard cover object to crouch-behind while the gauge comes down, which is the closest thing in the game to a designed cooldown station. Its heat cores are the affordable ones — Intake Vents (Superior, 600) and Ankle Breaker (Deluxe, 200) — so a heat-tuned Destroyer is the cheapest heat build in Marathon.

Recon — Heat as a Byproduct of Scouting

Recon’s heat problem is not its drone; it is chasing what the drone finds. Predator (“Gain increased sprint speed and heat cooldown rate when your Tracker Drone attacks a target”) and On the Trail (“Defeating hostiles affected by your Stalker Protocol reduces your generated heat”) both convert information into cooldown, which is the correct read on the shell. Also note Update 1.1.9.2 reworked Echo Pulse from an omnidirectional sphere into a cone in your aim direction — Recon now pays for position prediction instead of paying nothing.

Assassin and Thief — Stealth Has a Heat Price Tag

Both sit at the base 10 Heat Capacity, and both shells’ signature tools generate heat on purpose: Assassin’s Patience (Deluxe) and Minus Sights (Prestige) buy invisibility with heat, and The Finer Things on Thief pays out from backpack contents rather than movement. The trap is running these shells like a Vandal — at 10 capacity you have roughly half the headroom, so a single panic boost can put you in Critical.

Triage and Rook — Low Burn, Low Ceiling

Triage (Restoration Field, Med-Drone, Battery Overcharge) and Rook (Traversal Kit, Overdrive) generate heat mostly from repositioning, not from their kits. That makes them the forgiving picks for learning the gauge, but it also means their heat is spent on survival loops — moving to a downed crew member, breaking line of sight — rather than on aggression. Rook’s inventory is now lighter than it was: Update 1.1.9.2 removed flares from Rook’s kit and kept the end-of-Nightfall buffs (a Compromised Sneak Pack, two Claymores, a Depleted Self Revive and a Signal Jammer).

Sentinel (the eighth shell, added with Season 2 on June 2 and still in the pool through Nightfall Refresh) rounds out the roster, and a ninth — Bishop, described as “a fast, surgical hunter-killer built around speed, surprise, and devastating bursts of melee damage” — lands with Symbiosis on December 8. Expect Bishop to be the highest heat-burn shell in the game when it arrives; a melee burst identity on Vandal’s movement budget is exactly the profile that runs out of gauge.

For detailed Shell comparisons, see our Marathon Runner Shell tier list.

Gear and Consumables for Heat Control

Heat capacity is a stat line, not a vibe. Pulling the numbers straight from the implant table gives you the actual trade-offs — and there is always a trade-off.

Implants That Buy You Heat Capacity

Slot	Implant	Rarity / Cost	Heat	The price you pay
Legs	Distance Runner V1	Standard / 25	+5	—
Legs	Distance Runner V2	Enhanced / 70	+10	Slightly reduced weapon handling and ADS speed
Legs	Distance Runner V3	Deluxe / 200	+25	—
Legs	Distance Runner V4	Prestige / 1800	+50	Slightly reduced weapon handling and ADS speed
Legs	Solid Stance V1	Standard / 25	+5	—
Legs	Solid Stance V4	Superior / 600	+20	None — it also grants +50 Hardware
Head	Thick Skull V2	Enhanced / 70	+5	Comes with +30 Firewall

Distance Runner V4 is the biggest single heat number in the game (+50 on top of a shell’s base 10-20), and it is worth understanding why it is not automatically correct: the weapon-handling and ADS penalty is a constant, while heat capacity only pays out when you actually run your gauge hot. On Triage or Rook, where you rarely approach Critical, that 1800-credit Prestige slot buys you a debuff. On Vandal or Destroyer it buys you the third and fourth boost that wins the fight.

Solid Stance V4 is the quiet pick: +20 heat and +50 Hardware at Superior cost, no stat tax. If you want headroom without selling gunplay for it, that is the slot.

Implants That Sell You Heat for Survivability

This is the trap the guide used to miss. Every shield-slot implant that adds shield capacity takes heat capacity away:

Slot	Implant	Rarity / Cost	Heat	What you get
Shield	Protector V1	Enhanced / 150	-5	+1 Shield Slot, -5 Agility
Shield	Protector V2	Deluxe / 400	-10	+2 Shield Slots, -10 Agility
Shield	Protector V3	Superior / 900	-15	+3 Shield Slots, -15 Agility
Shield	Reinforced Shields V1	Enhanced / 180	-5	Reinforced shields take half damage, -5 Agility
Shield	Spectre Armor	Prestige / 3000	-15	Extra shield slots, brief invisibility when shields deplete, -15 Agility

Spectre Armor is the one to think twice about on a movement shell: 3000 credits buys a Prestige shield set that costs you 15 heat and 15 agility — the two stats Vandal is built on. It is a strong item on a shell that fights stationary. Note that Update 1.1.9.2 also cut the delay before invisibility flickers when an invisible player shoots, from 0.9s to 0.2s, which lands squarely on the Spectre-shield escape trick: fight back while invisible and aim assist comes back on you almost immediately now.

Cores and Mods That Cut Heat Generation

Where implants raise the ceiling, cores lower the floor. These are the ones I would actually slot on a heat-heavy build:

• Intake Vents (Destroyer, Superior / 600) — “Your Tactical Sprint generates less heat.”
• Ankle Breaker (Destroyer, Deluxe / 200) — “Your Thruster generates less heat while a hostile is nearby,” which is the only time the boost matters.
• Microjet Efficiency Package (Vandal, Prestige / 3000) — an extra Microjet charge that generates less heat.
• Adrenal Core (Vandal, Superior / 600) — movement abilities generate even less heat while Amplified, and landing a Cardio Kick extends Amplify’s duration.
• Close And Personal (all shells, Standard / 35) — melee and knife attacks generate less heat. Cheap, and it fixes the panic-kick tax.
• Heatsink (Chip mod, Standard / 23) — sustained damage with that weapon reduces generated heat, so your primary becomes part of your cooldown loop.
• Out of Dodge (Vandal, Enhanced / 70) — shields breaking clears generated heat instantly.
• Flight Response (all shells, Standard / 35) — heat capacity rises while you are at critical health.
• Predator (Recon) and On the Trail (Recon, Deluxe / 200) — turn Tracker Drone hits and Stalker Protocol kills into heat reduction and cooldown rate.

Consumables

Cardio Kick — a consumable that “temporarily boosts movement speed and agility.” It is a heat source, not a heat reset: speed costs heat in this game. Take it when you are already Cool and need to cross ground, not when the gauge is red.

Heat_Sink.exe / Active_Cool.exe — CyberAcme-branded heat items that community guides credit with roughly +20 capacity. [Unverified] against the official patch notes I pulled, so check the item card in your own Armory before building around them.

Patch Kit — heals. It does not touch heat, but it stops the panic-boost-when-hit loop that spikes the gauge in the first place.

Expanding Your Heat Threshold

Faction contracts and Cradle enhancements are where permanent heat capacity progression lives — CyberAcme is the corporate line associated with heat-gear unlocks, and the same contracts feed the Armory stock you need for the implants above. Two things changed on October 6 that make the rebuild cheaper than the first grind was: the Nightfall Refresh reset Cradle enhancements and Faction aftermarket upgrades to default, but it also cut Armory credit costs by roughly 30%, cut barter salvage costs by 20-50%, and raised Cradle XP by 30% for the duration of the refresh.

The Vault System — Storage and Progression

The vault is your persistent storage between runs. Everything you extract successfully goes to the vault. Everything you carry when you die is left on Tau Ceti IV.

One thing to say plainly up front: the vault is not infinite and it is not a shop inventory — but it is also not a slot-limited grid you buy expansions for. What Marathon actually gates is your backpack per run, your Armory credits, your salvage, and your Cradle/Faction progression. The “expansion upgrade from CyberAcme” framing that used to sit in this section does not match any item or contract in Update 1.1.9.2, so treat vault pressure as a carry problem, not a storage problem.

What the Vault Stores

• Extracted weapons — whatever you walk out with, in whatever rarity the drop rolled
• Weapon and backpack schemas — the progression items the Armory actually sells. Note that with each new Rewards Pass, Bungie has been swapping gameplay items and materials out of older passes for Credits “to ensure they maintain value as our game economies change over time” (Update 1.1.9.2). Hoarding pass tiers is a losing strategy.
• Salvage and faction currency — the barter input for the MIDA, Traxus, CyberAcme and other armories
• Mods and chips — extracted attachments stay available for future loadouts

The rarity ladder you should be reading off drop cards is Standard / Enhanced / Deluxe / Superior / Prestige, and the credit anchors in the implant and core tables are consistent: 23-35 for Standard, ~70 for Enhanced, ~200 for Deluxe, ~600 for Superior, 1800-3000 for Prestige. If a guide talks about “rare” or “legendary” items in Marathon, it is describing a different game’s ladder. Update 1.1.9.2 also retuned rarity drop rates across the board, so old drop-rate advice is stale after the wipe.

Vault Expansion: What Actually Scales

There is no purchasable vault-slot upgrade in the current build. The scaling that matters instead:

1. Cradle enhancements and Faction aftermarket upgrades — reset to default by the Nightfall Refresh, and re-earnable faster than before (+30% Cradle XP, -30% Armory credit costs, -20-50% barter salvage costs).
2. Backpack capacity per run — this is your real constraint. A 32XL Sneakpack is not the same carry decision as a light pack, and the 70% rule below is a backpack rule, not a warehouse rule.
3. Armory stock limits — the October 6 notes are full of stock caps (Materials Packs 5/week → 2/week, Deluxe Key Template 3/week → 1/week, Vault Keys 4-6 locked to weeks 2 and 3 of Vault Breaker). Extracted gear is scarce by design now; the queue for replacement gear is capped weekly.

Loss on Death

If you die before extracting, everything carried is gone. That is the extraction loop, and it is what the October 6 wipe put back in perspective: Bungie reset Runner, Cradle and Faction levels, Priority Contracts, Rank, Vault contents and zone access for the entire player base in one patch, with the fiction that ONI seized your credits and equipment against your outstanding balance.

The thing that used to be described here as a “sponsored package” for destitute players is really Sponsored Queues and sponsored kits. Sponsored Queues give you a pre-geared loadout so a wipe does not lock you out of the fun modes, and they now run every weekend from Thursday through Monday for the rest of Nightfall Refresh, on the same schedule as Cryo Archive: Sponsored Perimeter first (October 8-12), Sponsored Marsh in week 2, Sponsored Night Marsh in week 3, then the three-week rotation repeats until Symbiosis on December 8. Regular Extraction stays available in each zone alongside them. Kit tiers follow the same rarity ladder — the Armory sells Deluxe and Superior sponsored kits, and Update 1.1.9.2 actually removed the Superior kits from the MIDA and Traxus armories while cutting Deluxe stock from 3/week to 2/week.

Vault Optimization Strategy

The Extraction Priority List

Not all loot is worth the risk of carrying. Prioritize extraction in this order:

1. Prestige-rarity items — 1800-3000 credit equivalents in the implant and core tables; nothing else in a backpack is worth this much
2. Key room loot — typically rolls Superior to Prestige
3. Superior and Deluxe mods, chips and schemas — the loadout pieces you would otherwise be capped out of buying weekly
4. Salvage and faction currency — steady reputation progression, and barter costs just dropped 20-50%
5. Standard / Enhanced gear — only if backpack space allows after securing the above

The 70% Rule Applied to the Backpack

Same logic as the loot-route 70% rule: when your backpack is 70% full with a mix of Superior and Prestige items, head for extraction. The last 30% of Enhanced junk is not worth the death risk — especially now, when Armory restock caps mean a replacement you lose may not be buyable again this week.

Vault Rotation

There is no player-to-player trading or market in the current build, so “rotation” here is really a loadout-hygiene habit: after the wipe everything you own is re-earned, so review what you actually slot. Weapons and cores you have not equipped in five runs are dead weight in a vault that is now entirely re-earned from zero. The one thing you can convert is older Rewards Pass content — Bungie has been replacing gameplay items and materials in expired passes with Credits as passes roll over, so an unused pass tier is more likely to lose meaning than to gain it.

For loot route optimization by zone, see our Marathon map loot routes guide.

Important Notes and Common Pitfalls

Pitfall 1 — Ignoring heat until Critical. The gauge has three bands, and Hot (51-90%) is where the decision is made, not where it is lost. Once you tip past 100% your movement is throttled until the gauge cools, and you cannot dodge, reposition or break line of sight. Crouch-walk as soon as you cross into Hot.

Pitfall 2 — Stacking shield implants without reading the heat line. Every shield-slot implant that buys shield capacity sells heat capacity: Protector V1/V2/V3 cost 5/10/15 heat alongside 5/10/15 Agility, Reinforced Shields V1 costs 5, and Spectre Armor costs 15 heat plus 15 Agility for 3000 credits. Put Spectre on a Vandal and you have spent the shell’s entire stat identity on shield slots.

Pitfall 3 — Treating Cardio Kick as an emergency cooldown. It is Vandal’s melee kick trait, and the consumable of the same name is a movement-speed and agility boost — heat generated on cast. The genuine emergency valves are Out of Dodge (heat clears when shields break) and water.

Pitfall 4 — Dying with Prestige items in your backpack. The vault only stores what you extract. If you secure a Prestige key-room roll and then push for more, you are gambling that item — and after the October 6 wipe there is no older stock to fall back on. One Prestige item extracted beats two items left on a corpse.

Pitfall 5 — Not using water on the marsh zones. Dire Marsh and Night Marsh run flooded corridors through the map. They are heat resets, not set dressing. Plan routes that pass through water between key room pushes; skipping them means arriving at every fight already in Hot.

Pitfall 6 — Assuming zone access is still unlocked. The Nightfall Refresh reset zone access along with everything else: Outpost was not available on refresh day (it opened that Thursday), and Cryo Archive returned on October 15 with a new Thursday-to-Monday schedule. If your route guide says “just queue Outpost”, check the playlist before you plan a session around it.

Rewards and Unlocks

Mastering heat and vault systems unlocks several progression paths:

• Faction reputation — the October 6 patch lowered rank reputation requirements for every faction to fit the shorter Nightfall Refresh window, and made each faction’s VIP requirement match its final standard requirement. Reputation tiers now arrive sooner and unlock the aftermarket upgrades you reset on the same day.
• Cradle progression — +30% Cradle XP for the duration of the refresh, plus cheaper Armory credits and barter salvage. This is the fastest the vault has ever refilled.
• Reward Pass — the free NuCaloric Reward Pass ships with the refresh and is explicitly not time-limited, so a skin you want is not competing with your heat grind.
• Event currency — Vault Breaker runs October 20 to November 9 and solo players receive 50% more Tier 1 and Tier 2 event currency from it, which is the single biggest correction for anyone who runs alone. Monitor scan XP was cut 50% in the same patch to stop the mode being used as a power-leveling track, and certain Tier 3 standard contract objectives (such as defeating a low number of UESC) cannot be completed in Vault Breaker at all early in the wipe.
• Heat capacity itself — a permanent stat, bought through implants and cores, that makes every other shell’s mistake survivable.

Two more things to keep on the calendar: C.A.R.R.I. returns October 20 and runs through the end of Nightfall Refresh, and Ordnance Heist holds November 10-23 (its Firestorm key templates now grant 1 key instead of multiple, arms lockers need 1 key, and the Firestorm has a 15% supply-drop chance before and during the event, rising to 30% after it).

What the Nightfall Refresh Wiped — and the Calendar That Replaces It

Update 1.1.9.2 landed on October 6 and reset, in the patch notes’ own order: Runner, Cradle and Faction levels; Priority Contracts; Rank; Vault Contents; zone access, plus a new Rewards Pass. That is the whole reason this guide exists in its current form — every heat-capacity implant, every faction reputation tier and every extracted Prestige roll described above has to be re-earned by every player from the same starting line.

Bungie’s stated logic in the same post is that wipes exist “to bring all players back to the start line” so the economy stays active, and that Season 2: Nightfall’s progression tuning had “accelerated some players into the endgame while leaving others behind”, which broke the intended reset. The roadmap it replaced a fixed season schedule with is now three nodes, not twelve weeks:

Date	What happens	Why it touches heat and vault
Oct 6	Nightfall Refresh live — full reset, free NuCaloric Reward Pass	Vault and Cradle rebuilt at -30% credit / -20-50% salvage cost
Oct 8	Outpost reopens; Sponsored Perimeter runs Oct 8-12	Pre-geared kits mean zero-vault players can still queue
Oct 15	Cryo Archive returns, now Thursday through Monday	Monday is still a play day in your schedule now
Oct 20	Vault Breaker (to Nov 9) and C.A.R.R.I. return	Solo event currency +50%; Monitor scan XP -50%
Nov 10	Ordnance Heist runs to Nov 23	Firestorm drop rates 15% before/during, 30% after
Dec 8	Symbiosis — first permanent PvE, expanded Perimeter, the Bishop shell, a TDM mode, social space with firing range, new onboarding	A permanent PvE track changes what “valuable extraction” even means
March 2027	Connected PvE / PvP / PvEvP, refactored Cradle, quest system, new enemies, a new zone	Cradle refactor will almost certainly touch enhancement progression again

The practical read: do not build a long-term vault strategy around anything the March Cradle refactor can move. Build around heat capacity, because implants and cores are the one form of progression that has survived every reset so far in the form you buy them.

Final Take

Heat is Marathon’s stamina system disguised as a sci-fi mechanic. Three bands — Cool 0-50%, Hot 51-90%, Critical 91-100% — and one penalty that matters: overheating throttles your movement until the gauge comes down. Your real cooling tools are crouch-walking, water, and the small set of cores that clear or cap-manage the gauge (Out of Dodge, Flight Response, Fresh Install). Cardio Kick is not one of them; it is a kick and a speed buff, and speed costs heat.

Buy capacity where the trade is honest — Distance Runner V4 at +50 heat for reduced weapon handling, Solid Stance V4 at +20 heat with no tax — and refuse the ones that quietly sell it back to you, because every shield implant that adds shield slots subtracts heat capacity.

The vault is your long-term progression engine, and on October 6 it went to zero along with your levels, contracts, rank and zone access. What you extract is permanent until the next refresh, which is exactly why the free NuCaloric Reward Pass being untimed, the -30% Armory costs and the +30% Cradle XP matter more than any single Prestige roll.

These two systems are not optional depth. They are the foundation that every Shell build, weapon loadout, and loot route decision rests on.