Heating a large, uninsulated warehouse is one of the toughest challenges in climate control. These buildings aren’t designed to retain heat. They often have high ceilings, large open volumes, metal walls, draughty roller shutters and constant air movement from loading bays. In winter, temperatures inside can drop close to outdoor levels, making the environment uncomfortable for staff, inefficient for machinery and even damaging for stored goods. The traditional heating approaches used in offices or homes simply do not work in these harsh, industrial conditions. Instead, warehouses require specialised, high-output heating strategies engineered for cold, draught-filled spaces.
To understand why heating a cold warehouse is so difficult, it helps to consider how quickly heat is lost in a large, uninsulated volume. Warm air naturally rises, collecting at the roof level while the occupied working zone remains cold. Any open shutter pulls warm air out immediately, and metal cladding absorbs heat instead of reflecting it back into the space. This is why a small or moderately sized heater will never keep up. The heat output must be powerful enough to replace lost heat continuously while delivering airflow that pushes warm air down into the areas where people are actually working. Without this approach, the building will feel cold regardless of how long the heater runs.
The starting point for choosing the correct heater is calculating the volume. For example, a warehouse measuring 20 m × 20 m with a 7 m roof height has a total internal volume of 2,800 m³. Once the volume is known, the next step is matching it to an appropriate heating requirement. In poorly insulated or draught-prone buildings, this typically ranges from 50–60 W per cubic metre. For a 2,800 m³ warehouse, this results in 140–168 kW of heat output. It becomes clear that domestic or small commercial heaters simply aren’t capable of producing this level of sustained heating. Industrial warehouse heaters are designed specifically for these high-demand situations.
A useful reference guide is shown below:
Estimated Heat Requirements for Uninsulated Warehouses:
| Warehouse Size (m³) | Insulation Level | Required kW | Suitable Heater Type |
|---|---|---|---|
| 500 m³ | Poor | 25–30 kW | Electric or Oil-Fired |
| 1,000 m³ | Very Poor | 50–60 kW | Diesel or Oil-Fired |
| 5,000 m³ | Very Poor | 200–300 kW | Diesel / Indirect |
| 10,000 m³ | Very Poor | 300–450 kW | Multiple Industrial Diesel Units |
| 20,000+ m³ | Extremely Poor | 500–800 kW | Industrial Heating Plant |
For businesses unsure where to begin, Orion Air Sales provides a simple heating calculator that makes the process easier by estimating the correct heater size based on your space volume and insulation level.
You can try it for free here:
👉 https://www.orionairsales.co.uk/which-space-heater-15-w.asp
Once sizing is understood, the next step is choosing the correct heater type. This is where industrial heaters differ dramatically in performance and application. High-airflow diesel heaters offer some of the largest heating capacities available, making them ideal for huge, draught-heavy warehouses. They deliver strong warm air movement, allowing them to push heat into high-bay spaces where stratification is normally a problem. Oil-fired heaters provide similar output but are often favoured for continuous operation due to their robust build quality and stable fuel burn characteristics. These systems are commonly used in logistics centres and production environments where heat must be maintained for long periods.
Infrared heaters provide a completely different approach. Instead of heating the air, they heat people, surfaces and work zones directly. This makes them extremely effective in environments where heating the whole building is either unnecessary or impossible, such as open loading bays, cold packing areas, or doorways that are frequently opened. Infrared heat remains unaffected by draughts, which makes it particularly efficient in problem zones that traditional air heaters cannot warm. For concentrated workstations, they can provide significant comfort without the cost of running a high-output space heater.
Electric industrial fan heaters are ideal when clean, fume-free heat is essential or where ventilation is limited. These are commonly used in enclosed workshops, fabrication rooms, modular warehouse offices and small distribution rooms. While they cannot match the output of oil or diesel systems for large spaces, they offer excellent performance for smaller volumes and deliver heat instantly with zero combustion fumes.
Running cost is another important factor. Electricity typically has the highest cost per kWh, but its simplicity and cleanliness make it suitable for certain scenarios. Oil-fired and diesel systems are generally more cost-effective for heating large volumes and can maintain output at a lower operational cost. Infrared heating is the most efficient when only specific zones require heating, as it avoids wasting fuel warming air that does not need to be heated.
In real-world scenarios, these principles translate into clear choices. A small 200 m³ workshop with average insulation would require around 10 kW of heat, making an electric fan heater a perfect solution. A medium-sized draughty warehouse of 1,000 m³ may need up to 60 kW, meaning a diesel space heater is more appropriate. A 5,000 m³ cold-storage facility with high ceilings may require 200–300 kW, usually achieved through multiple oil or diesel heaters working together. Construction environments needing to dry materials, such as plaster or concrete, often rely on oil-fired heaters due to their powerful heat output and stable performance.
Orion Air Sales supplies a comprehensive range of industrial heating solutions engineered specifically for these demanding environments. Our JetHeat electric fan heaters provide clean, efficient heating for workshops and enclosed areas, with sizes up to 30 kW. For larger industrial or warehouse spaces, we offer diesel heaters up to 200 kW, capable of delivering the airflow and heat volume needed for high-bay applications. Oil-fired heaters up to 150 kW provide robust, steady heating for continuous operations and are widely used across logistics, manufacturing and construction sectors. These systems are built to perform in tough UK winters and deliver reliable heat where conventional systems fail.
Heating an uninsulated warehouse requires more than simply placing a heater inside the building. It demands the right power, the right heating strategy and the right technology matched carefully to the space. With effective planning, correct sizing and the right industrial heater, even the coldest warehouse can be transformed into a safe, productive and comfortable working environment.
