INSIGHTS & GUIDES
Infrared Heating vs Unit Heaters: Which Is Better for Warehouses & Workshops?
Infrared heaters and unit heaters are both widely used in warehouses, workshops, garages, factories and other large commercial buildings — but they deliver heat in fundamentally different ways.
A typical unit heater warms air and uses a fan to distribute it through the building. Infrared heating uses radiant energy directed towards people and surrounding surfaces.
That distinction becomes particularly important in large buildings with high ceilings, frequently opened doors or work areas that are occupied at different times.
Rather than asking which technology is universally “more efficient”, the more useful question is which heating method best matches the building, occupancy pattern and areas that actually require heat.
Quick Answer
Infrared Heating or Unit Heaters?
Unit heaters can make sense when the objective is to heat and circulate air throughout a building. Infrared can be particularly useful when warmth needs to be directed towards occupied areas without relying on the complete air volume being heated first.
In warehouses, workshops and other large spaces, factors such as ceiling height, open doors, working zones, insulation, operating hours and heater positioning can therefore be just as important as the rated efficiency of the heating appliance itself.
Infrared Heating vs Unit Heaters at a Glance
| Factor | Infrared Heating | Unit Heater |
|---|---|---|
| Heating method | Radiant heat directed towards people and surfaces | Typically heats and circulates air |
| Energy source | Electricity for the IHS systems discussed here | Can be gas-fired or electric depending on the unit |
| Heat distribution | Based on heater position, orientation and radiant coverage | Warm air distributed by a fan |
| High ceilings | Does not depend on warm air remaining at occupant level to deliver radiant heat | Warm-air distribution and stratification need to be considered |
| Zoned heating | Can be designed around individual occupied areas | Depends on the number, layout and controls of the units |
| Moving parts at heater | RADI8 electric infrared bar heaters do not require a fan | Fan-assisted units contain moving components |
| Combustion | No combustion at an electric infrared heater | Gas-fired units use combustion; electric units do not |
| Typical application | Targeted, zoned and high-level radiant heating | Whole-space or broad warm-air heating |
What Is a Unit Heater?
A unit heater is a self-contained heating appliance commonly installed at high level in commercial and industrial buildings.
Depending on the design, the unit may be gas-fired or electrically heated. A fan then moves warmed air away from the heater and into the surrounding space.
Unit heaters are widely used because they can provide substantial heating output and distribute warm air across large areas.
In a tall building, however, the behaviour of that heated air needs to form part of the system design. Warm air can rise and temperature differences can develop between higher and lower areas of the building.
Conditions can also change when large doors are opened, ventilation operates or outside air enters the space.
How Infrared Heating Works Differently
Infrared heating takes a different approach.
Instead of relying primarily on a volume of warmed air being circulated through the building, the heater emits radiant energy towards people and solid surfaces within its effective coverage.
Depending on the installation, those surfaces can include:
- Floors
- Walls
- Work areas
- Machinery and surrounding objects
- People within the heater's effective radiant area
Because heat delivery is not dependent on a fan moving warm air from the heater to the occupied area, infrared can be particularly useful where the objective is to heat specific working zones within a much larger building.
High Ceilings & Open Doors
Why the Building Matters as Much as the Heater
Warehouses and workshops are very different heating environments from small domestic rooms.
A large industrial building may have a substantial internal air volume, high roof level, loading bays, roller doors and areas that are occupied only intermittently.
With a warm-air system, the designer needs to consider where heated air travels and how temperature is distributed throughout that volume.
Infrared does not make heat loss disappear. The building can still lose energy through its walls, roof, floor, ventilation and open doors.
The difference is that radiant heat can be directed towards occupied areas without relying solely on maintaining the temperature of the complete air volume first.
That distinction can make infrared worth considering in tall or intermittently occupied commercial spaces.
Infrared vs Unit Heater Running Costs
There is no responsible way to say that one system will always cost less to run.
A gas-fired unit heater and an electric infrared heater use different energy sources, so simply comparing appliance wattage or fuel prices does not provide a complete answer.
The overall comparison should consider:
01
Total Heating Requirement
How much heat does the building actually require based on its size, construction and heat loss?
02
Area Being Heated
Does the complete building need heating, or only particular production lines, workstations or occupied zones?
03
Operating Hours
A system used continuously throughout a working day has a different energy profile from one serving intermittent shifts or occasional work areas.
04
Controls and Zoning
Heating areas independently can avoid operating heaters where heat is not currently required, provided the system and controls are designed accordingly.
05
Energy Price
The electricity or gas tariff forms part of the operating-cost calculation and can change over time.
For a closer look at calculating electric infrared consumption, see how much infrared heating costs to run in the UK.
Heating a Whole Warehouse vs Heating Work Areas
This is often one of the most important considerations in a commercial project.
Imagine a large warehouse where staff spend most of their time around packing benches at one end of the building.
If the objective is to maintain a relatively consistent air temperature throughout the entire warehouse, a whole-space heating strategy may be appropriate.
If the priority is instead to provide heating around occupied working areas, a zoned radiant system can be considered.
Infrared heaters can be positioned according to the required heating areas and divided into appropriately controlled zones.
Important: zoning does not automatically mean lower energy consumption. The potential benefit comes from matching heater output and operating time more closely to the parts of the building that actually require heating.
How Do the Two Systems Feel in a Large Space?
Infrared
Radiant Comfort
- Radiant energy is directed towards the heating area
- Does not require a fan to deliver heat
- Can focus heating around occupied zones
- Suitable positioning is important for effective coverage
Unit Heater
Warm-Air Comfort
- Raises and distributes air temperature
- Fan helps move heat through the building
- Can provide broad whole-space heating
- Air distribution and stratification need consideration in tall spaces
Neither approach is automatically more comfortable in every building. Heater output, positioning, ceiling height, occupancy and the required indoor conditions all affect the result.
Installation and Building Disruption
Installation requirements vary considerably according to the type of unit heater being compared.
Gas-fired unit heaters can require a suitable gas supply, combustion arrangements, flue system, electrical supply and professional installation and commissioning.
Electric unit heaters do not require a gas supply or combustion flue, but they still require an appropriately designed electrical installation.
Electric infrared heaters require suitable mounting positions and an electrical supply appropriate to the heater and controls.
Infrared installations can also be designed around individual zones, which can make phased upgrades possible where the building and electrical infrastructure allow.
Maintenance and Long-Term Ownership
Maintenance requirements are another difference worth considering over the lifetime of a commercial heating system.
Fan-assisted unit heaters contain moving components. Gas-fired models also contain combustion-related components and require appropriate servicing and safety checks.
Electric infrared bar heaters do not require combustion and do not rely on a fan to distribute heat.
That can reduce the number of mechanical and combustion-related components associated with the heater itself, although the installation, controls and electrical system should still be inspected and maintained as appropriate.
When Might a Unit Heater Make More Sense?
A unit heater may be appropriate where:
- The objective is to raise the air temperature throughout a large space
- A suitable existing gas or electric unit-heater system is already installed
- The building is occupied consistently across most of its floor area
- Warm-air circulation suits the required heating strategy
- The cost of replacing an existing functioning system would outweigh the expected benefits
When Might Infrared Heating Make More Sense?
Infrared is particularly worth considering where:
- The building has high ceilings
- Large doors are opened regularly
- Only particular work areas require heating
- Different zones operate at different times
- A radiant rather than warm-air heating strategy is preferred
- An all-electric heating solution is required
The suitability of infrared still depends on correct output, mounting position, heater orientation and the characteristics of the building.
You can also explore how infrared compares with other systems in our infrared heating vs traditional heating guide.
Calculate the Correct Heating Output
Correct sizing is essential whichever system is selected.
An undersized infrared installation may not provide the required comfort, while simply installing excessive wattage can increase electrical demand and operating cost unnecessarily.
The heating requirement should therefore consider the building dimensions, construction and intended use rather than relying on a generic watts-per-square-metre figure.
You can estimate the required output using our room-based Wattage Calculator.
Infrared Heating vs Unit Heater FAQs
What is the main difference between infrared and unit heaters?
Infrared heaters use radiant energy directed towards people and surfaces, while typical unit heaters warm air and use a fan to distribute it through the building.
Is infrared heating better for high ceilings?
Infrared can be particularly useful in high-ceilinged buildings because radiant heat delivery does not depend solely on maintaining warm air at occupant level. Correct heater output, mounting height, positioning and radiant coverage still need to be considered.
Is infrared cheaper to run than a gas unit heater?
Not automatically. Gas and electricity have different costs, and the two systems may also heat the building differently. The comparison should include the area being heated, operating hours, total system output, controls, energy tariff and building heat requirement.
Can infrared heating work in a warehouse with roller doors?
Infrared can be considered in buildings where doors open frequently because radiant heating does not depend solely on maintaining a volume of warmed air. Open doors still increase the building's overall heat loss, so they must be considered when designing the system.
Can infrared heat individual warehouse work areas?
Yes. An infrared system can be designed around specific occupied areas or zones, provided the heater output, positioning and controls are appropriate for each area.
Do infrared heaters require maintenance?
Electric infrared heaters avoid the combustion components of gas-fired unit heaters and do not require a fan to distribute heat. The wider electrical installation, controls and heaters should still be inspected and maintained as appropriate.
Infrared or Unit Heaters: Which Should You Choose?
The right choice depends on what you are actually trying to heat.
Unit heaters can provide an effective way to warm and circulate air throughout a commercial or industrial building. Infrared takes a different approach, directing radiant heat towards people, surfaces and occupied areas.
That difference becomes particularly relevant in high-ceilinged warehouses, workshops with frequently opened doors and buildings where only certain areas are occupied at any one time.
Rather than choosing a system from headline efficiency figures alone, compare the building's actual heating requirement, operating hours, zoning opportunities, installation requirements and energy costs.
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