An unvented infra-red heater can be installed in ________ application:

An unvented infra-red heater is designed to provide direct heating to space without requiring a venting system to the outside. This capability allows it to be utilized in various applications, including warehouses, commercial buildings, and industrial settings.

In a warehouse, the heater can effectively warm larger areas quickly by radiating heat directly onto objects and people. Such systems can be beneficial in maintaining comfort in large, open spaces where heat retention can often be a challenge.

In commercial buildings, unvented infra-red heaters can provide efficient heating solutions in spaces such as retail shops, workshops, or offices, delivering immediate warmth to areas where there is a high demand for comfort while minimizing energy costs.

Similarly, in industrial buildings, these heaters can be used effectively in spaces that require targeted heating, like assembly lines or workstations, where workers need to stay warm while performing tasks without the complexities of ductwork or ventilation.

Therefore, the flexibility and versatility of unvented infra-red heaters make them suitable for all these applications, which are represented in the answer option that includes all of the above.