Warm Air Heating Guide


Safety, Ventilation and Return air

Poorly installed or badly maintained open flued warm air units can cause dangerous carbon monoxide fumes to be distibuted around the home via the fan unit.

Warm Air and Safety

Properly installed modern day warm air units are efficient, quiet and extremely safe. They provide immediate, controlled heat when you need it.

However, as with all gas appliances it is very important that your unit has been installed correctly and has been maintained in a proper fashion. It is for this reason that ourselves and Johnson & Starley are encouraging the public to use proper warm air experts to install and maintain their warm air units. If you have a Company or a friend who maintains your warm air unit, our advice would be to check their Gas Safe registration (you can do this online)  to ensure that they have the specific Warm Air Qualification. This guarantees that they have been assessed as competent to work in this specialist area. Remember that a boiler engineer is not automatically qualified to work on warm air!

Because warm air units blow air around a property, if there is an issue with a flue or ventilation, then in the worst case scenario, products of combustion (carbon monoxide) may be blown in to all of the rooms in the house.

So what are the main items of safety that must be considered when installing and maintaining warm air?

  • Return Air / Relief Air - All open flued units require a full and unobstructed independent return air duct, connecting the main return air gille with the air heater return air spigot. This is usually supplied by using a purpose made return air kit. Relief air should be provided in all heated rooms (except kitchens, bathrooms and toilets) in which there is no return air grille. Openings can be in doors or walls and must not be subject to accidental blockage
  • Combustion ventilation / compartment ventilation - As with all open flued appliances it is vitally important that there is sufficient combustion air supplied to the appliance for proper combustion to occur. If you need more information on proper sizing of compartment or combuistion air grilles for your appliance please contact us
  • Flueing - It is extremely important that the flue from your warm air is correctly installed, terminates properly and is in good condition.

  Are you sure that your warm air unit is safe to use?

We have been installing and maintaining warm air for decades. Do not leave the safety of you and your family to chance. A simple and inexpensive service from our expert engineers can put your mind at ease.


If you are looking to find out more about warm air heating unit, our team can advise you further. Please contact us

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