Warehouse Temperature and Humidity: Storage Ranges, Sensor Placement and Why Display Size Matters

Most stock damage in storage doesn’t come from accidents. It comes from heat and humidity, slowly: labels peeling, cartons softening, powders caking, metal parts rusting, pharma stock drifting out of its label conditions. This guide covers what conditions different goods need, where to measure, how condensation forms, and why being able to see the reading matters more than people expect.

What Temperature and Humidity Do Different Goods Need?

There’s no single right number. These are typical working ranges; always check the product label or supplier specification first.

Stored goods	Typical temperature	Typical RH	What goes wrong outside range
General dry goods, FMCG	Below 30 °C	40–60%	Cartons soften, labels lift, mould
Pharmaceuticals (room temp.)	As per label, often below 25 °C or 30 °C	Below 60–65%	Loss of potency, regulatory non-compliance
Pharmaceuticals (cold chain)	2–8 °C	—	Vaccines and biologicals degrade
Electronics, PCBs, components	15–30 °C	30–60%	Moisture absorption, corrosion; static if too dry
Paper, packaging, labels	18–25 °C	40–55%	Curling, warping, printing problems
Food grains, spices	Cool, ventilated	Below 65%	Mould, insects, aflatoxin
Cement, fertiliser, chemicals	Ambient	As low as practical	Lumping, caking, reduced quality

Where Should Gauges Be Placed in a Warehouse?

A single gauge near the office door tells you about the office door. Conditions inside a large shed can vary by several degrees and 15–20% RH from one corner to another. Place sensors at the worst points:

• Under the roof sheets. Upper racks under a metal roof can be 8–10 °C hotter than floor level on a summer afternoon.
• Near loading doors, where outside air enters every time a truck docks.
• Along sun-facing walls, usually south and west.
• At more than one rack height: bottom, middle and top.
• Away from direct sunlight, fans and lights shining on the sensor.

For regulated storage like pharma, a temperature mapping study (logging many points over a few days in summer and in the monsoon) is the standard way to find these hot and humid spots before deciding where permanent sensors go.

Why Does Condensation Form Inside a Warehouse?

When warm, humid air touches a surface colder than its dew point, water condenses on it. In practice this shows up as:

• Water dripping from metal roof sheets on cool monsoon nights
• Damp floors after a hot, humid day followed by a cool night
• Wet cartons near cold-room doors, where cold air meets humid warehouse air

The fix is rarely more cooling. It’s usually ventilation, dehumidification or insulation, and keeping an eye on humidity, not just temperature.

Why Does Display Size Matter?

A reading nobody looks at doesn’t protect anything. If staff have to walk up to a small gauge, it gets checked once a shift at best. A large display that can be read from across the floor gets glanced at many times a day, and problems get noticed while they’re still small.

A common rule of thumb is about 10–12 metres of comfortable reading distance per inch of character height:

Digit height	Comfortable reading distance	Good for
0.56 inch	5–7 m	Panels, small rooms
1 inch	10–12 m	Labs, small stores
2.3 inch	25–30 m	Production floors
4 inch	40–45 m	Large warehouses, halls

Common Storage Monitoring Mistakes

1. Only measuring temperature. Humidity causes most slow damage.
2. One gauge for the whole building.
3. Gauge placed in the coolest spot, usually near the office or an AC.
4. Never checking the gauge against a reference. Cheap hygrometers drift by 5–10% RH within a year.
5. Readings noted only in the morning, when it’s coolest. The problem is at 3 pm.
6. No action written down when a reading is out of range.

Quick Checklist for Your Store or Warehouse

• Storage conditions for each product category written down
• Sensors at the hottest and most humid points, not just the door
• Readings visible from the working area
• Checked at least twice a day, including the afternoon peak
• Gauges compared against a reference at least once a year
• A clear action plan when limits are crossed