Choosing PIR panel thickness
The temperature bands
- 80 mm — chiller rooms down to about −5 °C; the standard for +2…+8 °C fresh-produce and dairy rooms.
- 100 mm — freezer rooms down to −18 °C; the default for mixed-use stores that may be re-purposed later.
- 120 mm — freezer rooms to −25 °C and high-ambient sites; the extra 20 mm pays back in one summer.
- 150 mm — blast freezers and −30 °C and below, or any room standing outdoors in southern European summers.
The energy trade-off
Each step of 20 mm cuts transmission losses by roughly 15–18 %. On a 20 m³ freezer running 8 700 hours a year, the difference between 100 mm and 120 mm is a few hundred kWh per year — the panel upgrade pays for itself in two to four seasons, and it is the only time you can buy insulation at panel prices instead of renovation prices.
Cost per m² and what we recommend
Panel cost rises roughly linearly with thickness, installation cost does not. If the room may be re-purposed from chiller to freezer later, choose 100 mm now — the second-hand value of a re-usable panel box is real money.