How to size your cold room: volume, capacity and insulation

1. 01Usable volume

   Product storage + 30-40% circulation

2. 02Power kW

   Transmission + doors + product load

3. 03Insulation

   PIR 100 to 180 mm depending on cold regime

4. 04Refrigerant mode

   R290 pre-charged or on-site charging

Sizing is the most important stage of any cold room project. Get it wrong by 30% and you pay for 15 years of over-consumption, or you saturate at peak times. Here is the method used by our design office.

1. Calculate the usable volume

Usable volume = product volume + 30-40% for shelving and circulation.

For shelved storage (carcasses, pallets, vegetables in crates):

• Density of fresh products (meat, cheese): 250-350 kg/m³ usable
• Density of compact products (pressed cheese, tinned goods): 400-500 kg/m³ usable
• Density of bulky products (flowers, delicate fruit): 80-150 kg/m³ usable

Example: a butcher stores 800 kg of meat on shelving -> 800 / 300 = 2.7 m³ of product, i.e. ~4 m³ usable with circulation. A 10 m³ room is a good fit (with margin for peaks).

For pallet storage: 1 Euro pallet (1.2 × 0.8 m × 1.5 m loaded height) = 1.4 m³. A 20 m³ container holds 8-10 pallets on the floor.

For hanging game: 1 adult wild boar = 1.5 m of rail × 0.2 m³ = 0.3 m³ usable per animal, plus clearance. A 20 m³ room with 2 hanging rails holds 14-16 boar.

2. Calculate the refrigeration capacity

The required capacity depends on four loads:

Transmission load (heat loss through the walls):

P1 = (ext. temp - int. temp) × wall area × U-value

With U = 0.22 W/m²·K for 100 mm PIR panels. A 20 m³ room has ~30 m² of external walls. At 30 °C outside and +2 °C inside: P1 ≈ 200 W continuous.

Air-change load (door openings):

• Lightly used room (3-5 openings/day): ~10% of the transmission load
• Moderately used room (15-20 openings/day): ~20% of transmission
• Intensively used room (50+ openings/day): ~40% of transmission, plan for an air-lock

Product load (pulling down the temperature of incoming products):

• Already-cold product (entering at +8 °C, brought to +4 °C): low, < 5% of total
• Warm incoming product (warm meat at +20 °C to be brought to +2 °C): very significant, can double the required capacity for the first few hours

Internal load (lighting, people):

• 24 W LED: negligible (≤ 2% of total)
• One person inside for 30 min: ~100 W equivalent - negligible

Typical total for a 20 m³ chiller: 1.5 to 2.5 kW of refrigeration. Our standard unit delivers 3 kW (30-40% margin). Our high-capacity unit delivers 4 kW for intensive use.

3. Choose the insulation

Configuration	Wall insulation	Floor insulation	Ceiling insulation
Chiller ≤ 20 m³	PIR 100 mm	PIR 80 mm	PIR 100 mm
Chiller ≥ 30 m³	PIR 120 mm	PIR 100 mm	PIR 120 mm
Freezer ≤ 20 m³	PIR 120 mm	PIR 120 mm	PIR 150 mm
Freezer ≥ 30 m³	PIR 150 mm	PIR 150 mm	PIR 180 mm
Laboratory +2/+8 strict	PIR 120 mm	PIR 100 mm	PIR 150 mm

Insulation is the investment that pays back fastest (3-5 years). Do not under-insulate to save EUR 800 at purchase - it costs you 10 years of over-consumption.

Worked examples

Case 1: shooting syndicate taking 30 boar/year, peak of 8 animals/weekend

• Usable volume: 8 × 0.3 + 4 m³ circulation = ~7 m³
• Format: 10 m³ positive, R290 pre-charged
• Capacity: 2 kW refrigeration (standard unit is enough)
• Insulation: PIR 100 mm walls, 80 mm floor
• Indicative price: ~EUR 6,500 ex VAT

Case 2: craft butcher, 200 kg/day production

• Usable volume: 800 kg average storage + 14-day ageing = 1,200 kg / 300 = 4 m³ of product, i.e. ~12 m³ usable
• Format: 20 m³ positive, R290 pre-charged
• Capacity: 3 kW refrigeration
• Options: 4-tier stainless steel shelving, air-lock
• Indicative price: ~EUR 10,500 ex VAT

Case 3: 100-cover restaurant, mixed service

• Positive volume: ~10 m³ (daily fresh)
• Negative volume: ~5 m³ (buffer frozen goods)
• Format: 20 m³ dual-zone (14+6)
• Capacity: 2.5 kW chiller + 2 kW freezer
• Indicative price: ~EUR 17,800 ex VAT

Case 4: diversified market gardener, 2 ha, 30 t harvest/year

• Usable volume: 30,000 kg / 350 kg/m³ × 0.8 (turnover) = ~70 m³ usable, but spread across the season
• Format: 30 m³ positive with dual set-point zones (leafy vegetables + long-storage fruit)
• Capacity: 4 kW refrigeration
• Options: humidifier, HACCP log, pre-filled rural-development grant file
• Indicative price: ~EUR 22,500 ex VAT (before any EU rural-development grant of 20-40%)

For each of these cases, we refine according to the seasons, activity peaks, site constraints and the desired headroom for growth. That is exactly what we include in our quote within 48 working hours.