Sandustry Heat and the Thermal Buffer
Three buildings name the Thermal Buffer as their heat source. Which ones, what each costs, and how water, snow and steam convert into each other.
GamePrimer EditorialUpdated Verified
The Thermal Buffer stores and distributes heat to nearby machines, and three buildings name it as their heat source: the Burner Belt, the Pyro Dispenser and the Smelter. Only the Smelter is given a second option — Lava. Unlock the Buffer at 1,000 Gold in tier 2.
Fire in this game comes from the Flamethrower and from Lava. The Thermal Buffer does not make heat — its description says it stores and distributes it — but it is the shared hub three machines point at when they describe their own fuel, so that is where this page starts.
The Thermal Buffer is the hub
The Thermal Buffer “stores and distributes heat for nearby machines”. That is the game’s own description, and it is what gives this system a shape: three other buildings describe their own fuel by pointing at it.
Three of them name it explicitly:
- The Burner Belt ignites flammable materials Officialwhen fuelled by heat through a Thermal Buffer
- The Pyro Dispenser fires a flame burst every 3 seconds Officialwhen fuelled by an adjacent Thermal Buffer — adjacent is the tightest placement word the research tree uses here; the Buffer itself only says “nearby”
- The Smelter smelts what is placed on top of it, Officialfuelled by heat from a Thermal Buffer or Lava
The Burner Belt and the Pyro Dispenser are described with the Buffer as their fuel and no other source named, so build it first. The Smelter is the one given a documented alternative — Lava — and the research tree gives it no prerequisites at all.
What each piece costs
| Unlock | Tier | Cost | What the research tree says |
|---|---|---|---|
| Burner Belt | 2 | 500 Gold | The Burner Belt, which ignites flammable materials when fuelled by heat through a Thermal Buffer. |
| Thermal Buffer | 2 | 1,000 Gold | The Thermal Buffer, which stores and distributes heat for nearby machines. |
| Pyro Dispenser | 3 | 2,000 Gold | The Pyro Dispenser, which fires flame bursts every 3 seconds when fuelled by an adjacent Thermal Buffer. |
| Drying & Condensing | 4 | 2,500 Gold | The Steam Dryer, to dry materials using Steam, and the Condenser, to convert gasses into liquids using snow. |
| Smelter | 5 | 3,000 Gold | The Smelter, to smelt elements placed on top, fuelled by heat from a Thermal Buffer or Lava. |
The last column reports the research tree's own description of each unlock. Cost is the unlock's own price, before prerequisites.
The Buffer and the Burner Belt together are 1,500 Gold, both in tier 2 — automated ignition lands early and cheap next to tier 5’s Energy unlocks, which take 11,500 Gold to unlock as a set. The Pyro Dispenser is a tier-3, 2,000 Gold alternative that fires on a timer rather than igniting on contact.
Heat without the Buffer: trapped Lava
There is a heat source that needs no Thermal Buffer, and for burning Residue it is the one worth building first. It costs the Filter (250 Gold) and the Flamethrower (400 Gold) — the Flamethrower because only its direct flame melts Cinder back into Lava.
Put a solid Block directly under a Filter and anything that enters has no way out. Set the Filter to allow Cinder only, fill it, and ignite: the Cinders melt back into Lava and the Lava stays where you put it. Run Residue along the belt above and it ignites on contact.
Lava is also one of the two fuels the Smelter accepts.
Getting Cinders is a round trip through the cold side of this page: freeze Lava with Snow to make Scoria, break the Scoria with any weapon to get Cinders, carry them wherever you want. Cinder needs the Flamethrower’s direct flame to melt back — passive heat will not do it.
The slag processing page has the full auto-burner build.
The cold side, and why it is the same system
Every one of these is a documented conversion, and together they close a loop:
| Start with | Apply | You get |
|---|---|---|
| Water | Fire | Steam, which rises and becomes rain |
| Ice | Fire | Water |
| Water | Snow | Ice |
| Lava | Snow | Scoria |
| Steam | Snow, via the Condenser | Liquid again |
| Water | Snowmaker, using Energy | Snow |
Two tools drive most of it. The Flamethrower (tier 2, 400 Gold) burns residue, melts ice, and vaporises Water into Steam. The Cryoblaster (tier 2, 1,000 Gold) produces infinite Snow, which freezes water, solidifies Lava, or can be steamed into rain.
“Infinite” is the game’s own word for the Cryoblaster’s output, and it is the important one: your snow supply is not a resource you have to mine.
| Unlock | Tier | Cost | What the research tree says |
|---|---|---|---|
| Flamethrower | 2 | 400 Gold | The Flamethrower, to burn residue, melt ice and vaporise Water into Steam that rises and becomes rain. |
| Cryoblaster | 2 | 1,000 Gold | The Cryoblaster, which produces infinite Snow that can freeze water, solidify Lava, or be steamed into rain. |
| Snowmaker | 5 | 2,500 Gold | The Snowmaker, a powered structure that converts Water into Snow using Energy. |
The last column reports the research tree's own description of each unlock. Cost is the unlock's own price, before prerequisites.
Drying & Condensing (tier 4, 2,500 Gold) unlocks two buildings at once — the Steam Dryer, which dries materials using Steam, and the Condenser, which turns gases back into liquids using snow. Steam already returns on its own, since the game says it rises and becomes rain; the Condenser is what lets you decide where that happens instead of waiting for weather.
What this page does not tell you
The research tree names each building and what it does. It does not describe how far a Thermal Buffer’s heat reaches, how many machines one Buffer can supply, or how the buildings should be arranged relative to each other — beyond the Pyro Dispenser’s stated adjacency.
Nothing official covers that, so nothing here does either.
Related
- Sandustry Slag and Residue Processing — the auto-burner in full
- Sandustry Energy Unlocks — the other supply system, and what runs on it
- Sandustry Research Planner — costing tier 2 against everything else
