Ask anyone in cold chain construction which core material to use, and the answer comes back fast: PU or PIR. EPS has a reputation problem - it's seen as the cheap option for warehouses and temporary structures, not something you'd specify for a cold room. That reputation isn't wrong, exactly. But it isn't the whole picture either.
The thermal gap is real. EPS has a conductivity of roughly 0.033–0.038 W/m·K, while PU sits at 0.022–0.026. That difference matters - but how much it matters depends entirely on what temperature you're holding.
Where EPS stops working
For a frozen storage room running at −18°C or below, the gap is decisive. You'd need significantly thicker EPS to hit the same U-value, and the added thickness eats into usable space, adds weight to the structure, and eventually erases the cost advantage. For those rooms, PU or PIR is the right call. Blast freezers, ice cream storage, frozen meat and seafood - this is PU territory, and EPS doesn't belong there.
Where it still makes sense
But not every cold room runs at −18°C. A large share of cold storage in practice operates in the 0°C to +10°C range: fruit and vegetable pre-cooling, dairy holding, fresh produce distribution, floral storage, beverage chilling. At those temperatures, the thermal difference between EPS and PU narrows considerably. A 100mm EPS panel performs close to a 60mm PU panel in this range. If you have the space for the thicker panel, EPS works - and the cost saving is substantial.
There's another factor that rarely makes it into the spec sheet: repairability. PU panels, once damaged, are difficult to fix on site. The foam is rigid, bonded to the facings, and a puncture or impact damage often means replacing the entire panel. EPS is different. It can be cut, patched, and replaced locally. In a working cold room where forklifts operate and doors take a beating, that repairability has real operational value. It's not a performance metric, but it's a cost metric - and for many operators, it matters more than a few points of thermal conductivity.
Seasonal agricultural cold storage is where EPS makes the strongest case. Apple, potato, garlic, and onion storage facilities often operate for only part of the year, at temperatures between 0°C and 4°C. The building is often a simple steel frame with insulated panels, and the budget is tight. EPS panels meet the thermal requirement, cost less, and are easier to source and install in rural areas. Specifying PU for a seasonal apple store is over-engineering, and the extra cost buys nothing the operation actually needs.
Temporary and demountable cold rooms follow similar logic. Exhibition cold storage, event catering, emergency cold chain response - these need to go up fast, come down clean, and be reused. EPS panels are lighter, easier to handle, and more tolerant of repeated assembly and disassembly. PU panels are heavier and more brittle at the edges, and the higher cost makes damage during handling more painful.
One thing EPS does demand more of is sealing. The foam surface is less dense than PU, and the panel edges are more vulnerable to moisture ingress if the joint isn't properly sealed. In a cold room, that means paying closer attention to gaskets, sealant selection, and the vapour barrier. Get the sealing right and EPS performs reliably. Cut corners there and you'll have condensation, ice build-up, and eventual core degradation - the failure mode that gave EPS its bad reputation in the first place.
None of this argues that EPS should replace PU in cold storage. It shouldn't. For frozen goods, blast freezers, and any room running below −18°C, PU and PIR remain the correct choice. The point is narrower: EPS has a legitimate place in the cold chain, and the projects where it fits are more common than the industry conversation suggests. The material isn't wrong. It's just been specified for the wrong rooms - and judged on jobs it was never suited for.
Match the panel to the temperature, the budget, and the repair reality. Not to the default answer.
