How to heat a warehouse: warm air, radiant or destratification?
Updated 23 October 2026 · SEO Dons Editorial
The main decision in a tall warehouse is whether the heater warms the air or warms the people and surfaces. The two approaches behave very differently once the roof is high and the doors open to the outside.
What temperature does a warehouse legally need?
The law sets no fixed figure. The Workplace (Health, Safety and Welfare) Regulations 1992 say that during working hours the temperature in all workplaces inside buildings shall be reasonable. HSE's guidance adds that the approved code of practice suggests a minimum of 16°C, or 13°C if much of the work involves rigorous physical effort, and that there is no maximum temperature for workplaces. The employer decides what is reasonable by assessing the risk; the workplace temperature law guide has more.
HSE also says air temperature alone is not an accurate indicator of comfort. The Carbon Trust's warehousing guide says many warehouses can operate year-round without heating, depending on the products stored and the building fabric, and that operators should separate storage temperature needs from staff comfort. A pallet store that needs only frost protection and an aisle where staff lift all day are different heating briefs.
What are the main ways to heat a warehouse?
Four options are worth comparing. The government-backed Energy Technology List (ETL) describes both warm-air and radiant heaters as widely used for warehouses, retail sheds, factories and similar large spaces.
| Option | How it heats | Watch-point from the sources |
|---|---|---|
| Gas warm-air heater | A burner heats air and a fan distributes it | Cold air entering a building displaces warm air towards the roof (Carbon Trust) |
| Gas radiant tube or plaque heater | A heated tube or plaque radiates infrared downwards | Should sit directly in line with the person or object needing heat (ETL) |
| Electric radiant heater | An electric element radiates to people and surfaces | Part L expects zone control or presence detection; electricity costs more per kWh |
| Heat pump | Moves heat from outside air, ground or water | Needs a good seasonal efficiency to match gas; see commercial heat pumps |
Permanently occupied offices and welfare areas need a permanent heating solution, the Carbon Trust notes, and boiler-fed systems for those areas are compared on the commercial heating systems page.
How do warm air and radiant heat differ in a tall building?
Warm-air equipment raises the air temperature in the space being heated. A CIBSE Journal module on boiler selection cites CIBSE Guide A as saying a heated-air system in a 3 metre office needs up to 5% more heating than radiators, and that the extra loss rises as the space gets taller. It gives no figure for a warehouse roof, but the direction is clear. The ETL adds that typically 35% of the heated air in commercial buildings is lost through ventilation and air infiltration, and that warm-air replacement should be considered alongside fabric improvements and minimising uncontrolled air leakage.
Radiant heat works differently. The ETL says it reduces these losses by heating the occupants directly, not the air. A CIBSE Journal module on radiant heating explains why: a greater radiant contribution allows a lower air temperature for the same comfort, and a room with high ventilation rates can still hold reasonable operative temperatures because the radiant input is unaffected by airflow. That suits fixed zones such as pick faces and loading bays. It does not hold a stock temperature, which is why the Carbon Trust's split between storage needs and staff comfort matters.
Destratification fans work alongside warm air by pushing risen heat back down; the destratification fans guide shows when that pays. Summer air movement is covered in the HVLS fans guide, and electric panels in the infrared heating guide. At dock doors the Carbon Trust suggests interlocks so heating runs only when loading doors are closed; the air curtains guide covers a related option.
How should the efficiency figures be read?
Different rules use different measures, so compare like with like. Ecodesign Regulation 2016/2281 covers air heating products up to 1 MW and, from 1 January 2021, requires fuel-fired warm-air heaters to reach at least 78% seasonal space heating energy efficiency. Regulation 2015/1188 sets at least 74% for tube heaters and 85% for luminous heaters up to 120 kW. Approved Document L judges radiant heaters on thermal efficiency using net calorific value, and says net figures should be converted to gross where boilers are concerned. The ETL lists only products in the top 25% of the market for their class: at least 80% for warm-air equipment, and 80% to 90% for radiant units depending on type.
What does each option cost to run? A worked example
DESNZ's annual report gives average non-domestic prices across all size bands, including the Climate Change Levy: 24.3 pence per kWh for electricity and 5.3 pence for gas in 2025 (provisional). A site's own contract will differ, so the sums below are illustrations.
For example, suppose a 2,000 square metre warehouse needs 100,000 kWh of useful heat a year. The efficiencies are assumptions, not measurements: 85% for gas heaters, 100% for electric radiant heat (the Part L assumption) and a seasonal coefficient of performance (SCOP) of 3.0, 3.5 or 4.0 for a heat pump. The radiant row assumes a design that gives the same comfort in the occupied zones with 20% less useful heat. That figure is a placeholder, not a finding.
| Scenario | Fuel bought a year | Illustrative cost a year |
|---|---|---|
| Gas heater, 100,000 kWh of heat | 117,647 kWh gas | £6,235 |
| Gas radiant, 20% less heat needed | 94,118 kWh gas | £4,988 |
| Electric radiant, 100,000 kWh of heat | 100,000 kWh electricity | £24,300 |
| Heat pump, SCOP 3.0 | 33,333 kWh electricity | £8,100 |
| Heat pump, SCOP 3.5 | 28,571 kWh electricity | £6,943 |
| Heat pump, SCOP 4.0 | 25,000 kWh electricity | £6,075 |
Gas heat costs about 6.2 pence per kWh delivered at 85% efficiency, against 24.3 pence for electric resistance heat, so electric radiant heat costs about four times as much for the same heat. A heat pump matches the gas heater at a SCOP of about 3.9 (24.3 divided by 6.2). The radiant saving appears only if the design truly needs less heat. The ETL says radiant heating can use significantly less fuel than fan convectors or low temperature radiators, but that has to be shown for the building in question. The cost guide covers capital costs by system.
What do gas safety and ventilation rules add?
Regulation 3 of the Gas Safety (Installation and Use) Regulations 1998 bars anyone from working on a gas fitting unless competent. HSE says work on gas fittings in workplaces such as shops, restaurants, schools and hospitals must be done by a Gas Safe registered engineer qualified for it, that factories and some other premises need a competent person, and that checking is the employer's responsibility. For industrial and commercial plant HSE says the gas supply should be interlocked with ventilation of the appliance and there should be enough ventilation to remove combustion products.
The 1992 Regulations add that heating shall not release fumes, gas or vapour likely to be injurious or offensive. That matters most for unflued heaters: the Ecodesign definition says a luminous heater emits the products of combustion in the space where it is situated, while a tube heater sends them out through a flue duct.
Does the 2027 standard change anything?
For existing warehouses, replacement heaters are still judged against existing-building tables. The 2026 edition of Approved Document L takes effect in England on 24 March 2027 and keeps tables for warm-air and radiant heaters in existing buildings. For new non-domestic buildings, the government's March 2026 consultation response says the Future Buildings Standard will require low carbon heating sources to be used regardless of PV coverage; the Future Buildings Standard guide has the detail. Readers weighing a replacement can send an enquiry through the form on this page.
Sources
All pages checked 22 October 2026.
- DESNZ: annual report, performance report (updated 19 August 2026); Energy Technology List, warm air and radiant criteria.
- HSE: temperature law; thermal comfort; gas safety.
- legislation.gov.uk: Workplace Regulations reg 7; Gas Safety Regulations reg 3; Ecodesign 2016/2281, 2015/1188.
- MHCLG: Approved Document L Volume 2 (2026), 2021 edition; consultation response (March 2026).
- Carbon Trust: warehousing guide (February 2019). CIBSE Journal: boiler module (May 2016), radiant module (November 2014).
Common questions
Can a warehouse be left unheated?
Sometimes. The Carbon Trust says many warehouses can operate year-round without heating, depending on the products stored and the building fabric, and that the heating system may well be set back to frost protection only for most of the year.
Do radiant tube heaters need a flue?
As the Ecodesign Regulation defines them, tube heaters send combustion products out through a flue duct, while luminous heaters release them into the space, which makes ventilation a design point. ETL-listed radiant products are designed to be mounted above head height.
Who is allowed to work on gas heaters in a warehouse?
HSE says work on gas fittings in workplaces such as shops, restaurants, schools and hospitals must be done by a Gas Safe registered engineer qualified for the work, and by a competent person in places such as factories. It is the employer's responsibility to check.
Would a heat pump work in a warehouse?
Possibly, but the arithmetic is tight. At DESNZ's 2025 provisional averages the seasonal efficiency needed to match an 85% efficient gas heater is about 3.9. Flow temperature, electrical capacity and air leakage decide whether that is realistic.
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