Gas Unit Heaters

Gas Unit Heaters – Natural Gas or LPG Gas

vertical gas fired unit heater, centrifugal fan gas unit heater for ducted heating

Output Range – 13 kW to 73 kW

Gas Unit Heaters from Flexiheat UK provide a cost effective and efficient warm air heating solution for industrial and commercial buildings. They have been designed in conjunction with installers, consultants and end users in mind, to provide the perfect solution to your warm air heating needs. The “FHATX”  unit heater series are suitable for indoor installation  and thanks to the closed combustion chamber and atmospheric burner, the “FHATX” gas fired unit heaters achieve up to 95% efficiency, and fully comply with the ERP regulations for air heaters that came into force on the 1st January 2021 – known as ErP Lot 21 – 2021, which now requires warm air heaters that provide warmth and comfort for personnel to have a seasonal efficiency of 78% as a minimum, as well as reduced NOx emission levels for gas at 70mg/kWh, to help minimise the impact of global warming .

A gas unit heater is a perfect solution for  Gas Warm Air Heating for warehouse heating, factory heating, or a workshop heater for example. They can be wall mounted , or suspended from the ceiling in high ceilings buildings, saving valuable floor space, that can be put to better use.

Gas Unit Heaters – The Range

This gas unit heater range have efficiency ratings that fulfil the UK Part L Building Regulations’ minimum heater efficiency requirements, as well as being ErP 2021 approved.

The combustion chamber and heat exchanger combination are designed and manufactured to combine thermal efficiency with long service life.

We can offer the following –

The FHATX-H Range – which comprises of 5 models with Axial fan for horizontal blowing. These models offer outputs ranging from 13 kW to 73 kW

The FHATX-C Range – which comprises of 5 models with Centrifugal fan for ducted applications. These models offer outputs ranging from 13 kW to 73 kW. Ducted applications allow you to place the gas unit heater wherever you require, with the centrifugal fan pushing the heated air to the desired location via a duct system.

The FHATX-V Range – which comprises of 5 models with high efficiency and are suitable for vertical mounting applications -i.e. blowing warm air downwards. These models offer outputs ranging from 13kw to 73 kW

All units can be used in a room sealed configuration, with the air for combustion being taken from the exterior of the building being heated.

This range of gas fired heaters are easy to maintain, as the heater function controls, gas valve, and burner assembly are all accessible through a full-width door on these warm air unit heater range


Gas Unit Heater Options – free blowing or ducted; unit heaters gas fired;

Industrial Gas Unit Heaters Applications

  • Warehouse Heating
  • Car Garage Heating , both the Workshop and the Showroom areas
  • Factory Heating
  • Retail Heating
  • Agricultural Heating
  • Sport Hall Heating
  • Workshop Heating
  • Garden Centre Heating
  • Greenhouse Heating
  • Aircraft Hanger Heating
  • Distribution Centre Heating
  • Horticultural Heating
  • Rail Shed Heating
  • Industrial Manufacturing Heating
  • Showroom Heating

Performances and Dimensions of the “FHATX” Suspended Gas Heaters – ERP Rated as per EU ErP Lot 21 – 2021 

gas fired unit heaters; gas unit heaters; gas unit heaters for sale; natural gas unit heaters garage;





Gas Unit Heaters; dimensions of gas fired unit heaters

Dimensions of the FHATX series heater range from Flexiheat UK



Download the Gas unit heaters brochure – FHATX series

Download Flexiheat Manual for FHATX Gas Unit Heaters

Gas Unit Heater – Product Advantages

  • Atmospheric burner, with 2 stages – Hi / Low for the best efficiency, and to keep your fuel costs minimal
  • 2 mm thick heat exchanger with seamless pipe
  • 4 – route heat exchanger
  • Compact device
  • Automatic security system
  • Horizontal heat exchanger
  • Pilot wired card
  • Regulation of several gas fired unit heaters with only one thermostat


YouTube video


Gas Unit Heaters – Customer Benefits

  • Thermal efficiency of 92% on high fire or 95 % on low fire
  • Efficient heat exchanger, long life service
  • Maximum use of combustion energy
  • Rapid and easy installation
  • Efficient air distribution
  • Safe use
  • Low height of the suspended gas device, useful for buildings with low ceilings

The standard range are an axial fan ,with two stage burners in mains gas or LPG .

We also do a gas fired condensing unit heater range, which has higher efficiencies of up to 106%, as a condensing unit heater recovers some of the latent heat from the combustion gases thus a stainless steel heat exchanger along with a stainless steel combustion chamber are used.

This means that condensate produced when a condensing unit heater is in operation, which has to be drained away from the unit and go into a drain which adds to the installation time and cost of a condensing unit heater.

We have a dedicated webpage on these high efficiency gas fired unit heater range here – condensing unit heater


Mounting Options

This range of gas heaters have three mounting options:

Swivelling console

For mounting on walls, consisting of 2 plates and 2 lateral supports. The heater can be placed on top of the console or suspended from it. The device can be swivelled horizontally through 180° for placement in corners of the building . This bracket is available for all models except the 75 & 95 models


Wall console bracket

Wall Mounting Brackets 

For wall mounting, consisting of two steel brackets. The heater can be placed on top of both supports and can also be suspended from them. Suitable for all heater models.


Wall Bracket Set
Threaded tapping’s

For suspension from the ceiling. On top of each gas unit heater are M8 fastening points in which threaded rod , or threaded eyelets can be inserted. Thus you can suspend the units from chain or rod depending on your preference.

Room Sealed Unit Heaters – Versatile Flue Installations

The balanced flue terminal provides both the combustion air inlet and flue outlet from a single building penetration. The terminals are ordered separately from the heaters to suit either a wall outlet or roof outlet. Additional flue and combustion air pipes may be added, up to a maximum of six metres of flue pipe, plus six metres of combustion air pipe. (This reduces by one metre for every 90° bend fitted).
To comply with CE approvals, balanced flue appliances must be used with the manufacturer’s balanced flue system.
The units are also certified for fan assisted flue installations, where the air for combustion is to be drawn from within the heated space; an alternative wall or roof terminal is required for this application.

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Gas Fired Unit Heaters Flue Configurations – FHATX Range from Flexiheat UK


Gas Unit Heater – Installation Notes

A single phase electrical supply is required to each unit. This supply should not be switched off except for maintenance. A unit heater must not be installed in atmospheres containing flammable or explosive vapours, combustible dust, halogenated hydrocarbons or chlorinated vapours. They are also unsuitable for areas where contaminants may affect electrical motors or connections.
You may call these warm air heaters – gas unit heater, factory heaters , propane workshop heaters , propane warehouse heaters ,commercial unit heaters, ceiling mounted space heaters, unit heaters natural gas , ceiling mounted space heater- whatever you call them , we have the solution for your requirements with our gas unit heaters. Call us now to discuss your requirements, or drop us an email via our contact form.