Heating a workshop, outbuilding, chalet or garden room efficiently is no straightforward task. Large volumes, often minimal insulation and intermittent use all place clear demands on any heating system. This is precisely where warm air heaters and space heaters come into their own. They are now among the most effective solutions for bringing a space up to temperature quickly and reliably.
In this FUXTEC Garden Guide, we explain the systems available, how they work and which solution suits your situation — from an industrial warehouse to a small timber cabin.
Why warm air heaters are so effective for large spaces
Warm air heaters work on a straightforward principle: air is drawn in, heated via a heat exchanger and then blown back into the space by a fan. This produces rapid and even warming throughout the room.
The key advantage is response time. Even large areas of several hundred square metres can be noticeably warmed within 15 to 30 minutes. Conventional heating systems such as radiators or underfloor heating are considerably slower to respond.
Another benefit is installation simplicity. No water-carrying pipework or complex plumbing is required. This saves significant time and cost, particularly in existing buildings.
At FUXTEC, our experience shows that warm air systems are especially worthwhile when spaces are only used periodically and need to be heated up quickly.
Heating systems for large spaces: what are the options?
Choosing the right system depends heavily on the size of the space, how it is used and what infrastructure is already in place.
Gas-fired space heaters
Gas-fired space heaters are among the most widely used solutions. They run on natural gas or LPG and deliver high outputs of around 20 kW up to over 100 kW.
They can be permanently installed or used as mobile units. Mobile heaters are particularly useful when only certain areas need temporary heating.
Natural gas operation is generally cheaper to run. LPG offers greater flexibility, as no fixed gas supply is needed.
Diesel heaters
Diesel-powered heaters are commonly used on construction sites or in temporary structures. They are robust and deliver high output, but running costs are higher than gas-powered equivalents.
They are best suited to situations where no gas supply is available.
Electric heaters
Electric heaters are the simplest and cleanest solution where a mains electricity supply is available. They require no flue or exhaust routing and are ready to use immediately. They are particularly practical in smaller workshops, garages or garden rooms. Output is more limited, but they excel in terms of low maintenance and high safety. FUXTEC recommends them for flexible, short-term use.
Infrared heating systems
Infrared heaters work differently. Rather than warming the air, they heat surfaces and people directly. This makes them especially efficient in very high-ceilinged spaces, where warm air would otherwise rise rapidly to the roof.
The warmth is felt immediately, though placement must be carefully planned to ensure effective coverage.
Heating a garden room: which solution is right for you?
A garden room or small timber cabin has different requirements from an industrial unit. Here the priority is less about maximum output and more about efficiency, comfort and safety.
For smaller spaces between 10 and 40 m², several options are worth considering. A wood-burning stove provides pleasant radiant heat but requires a flue and good ventilation. A mobile LPG space heater is quick to set up and flexible, though less suited to continuous use. A heat pump works very efficiently where a mains electricity supply is available. Infrared heating panels are straightforward to install and deliver warmth rapidly for shorter periods of use.
The decision comes down to how often you use your garden room. For regular use, a permanent solution is worthwhile. For occasional use, a mobile unit will suffice. You can find more detailed advice on preparing your garden room for winter in our FUXTEC Garden Guide "Winterising your greenhouse: how to get the most from your greenhouse in winter".
Heating a chalet: particular considerations
A chalet is typically situated in a cold region and is often well insulated. At the same time, outdoor temperatures can be significantly lower.
You need a system that works reliably and delivers sufficient output. For medium-sized chalets, warm air units of around 30 to 50 kW are appropriate, often combined with air distribution throughout the building.
Ventilation is an important consideration. Modern systems with heat recovery ensure fresh air is supplied without unnecessary heat loss.
FUXTEC recommends always looking at the overall energy efficiency of such projects. Insulation, glazing and air circulation all play a crucial role.
Installing a warm air heater: what matters most
Correct installation is the deciding factor for both efficiency and safety.
The first step is calculating the heat requirement. This takes into account the volume of the space, insulation levels and the desired temperature, from which the required output in kW is derived.
Next, the optimum position is selected. In larger spaces, air distribution is critical to avoid cold spots.
For gas-fired units, the connection must be carried out by a Gas Safe registered engineer. The same applies to the flue, which must safely vent to the outside.
After installation, fine-tuning follows. Thermostats and controls ensure the temperature remains constant and energy is used efficiently.
Wood-burning stoves as an alternative: when do they make sense?
A wood-burning stove is a particularly attractive option in smaller buildings. It is independent of both mains electricity and gas, whilst providing a very pleasant warmth.
Modern appliances achieve efficiencies of over 80%. For a garden room, an output of as little as 5 to 8 kW is often sufficient.
Adequate ventilation is essential. Without a fresh air supply, there is a risk of carbon monoxide build-up.
Heating systems compared
| System |
Typical output |
Installation cost |
Annual running cost |
Response time |
| Warm air heater (gas) |
20–120 kW |
£1,300–£4,300 |
£700–£2,600 |
15–30 minutes |
| Diesel heater |
15–100 kW |
£260–£1,300 |
£1,050–£3,900 |
5–15 minutes |
| Infrared heater |
0.5–6 kW |
£175–£700 |
£350–£1,300 |
3–5 minutes |
| Wood-burning stove |
5–30 kW |
£870–£3,500 |
£175–£520 |
30–60 minutes |
| Heat pump |
3–20 kW |
£2,600–£7,000 |
£260–£780 |
10–20 minutes |
Safety and legal requirements
With all heating systems, safety must come first.
Gas and diesel-powered appliances must be installed by qualified professionals. This includes approved connections, safe flue routing and adequate ventilation.
Carbon monoxide detectors are required by law in enclosed spaces with combustion-based heating systems in the UK. Regular servicing is equally important.
FUXTEC strongly recommends that installations are always carried out by qualified, Gas Safe registered engineers.
Planning for larger spaces: key considerations
In spaces of around 1,000 m² or more, a single unit is rarely sufficient. A strategic distribution of multiple heating points is required.
Units are positioned so that airflows complement one another, producing an even temperature distribution throughout the entire space.
Air circulation also plays a role. A minimum level of air exchange helps maintain a healthy indoor environment and can be integrated into the heating system.
Smart controls can also deliver energy savings of up to 40%.
Maintenance and service life
A well-maintained warm air heater can reliably operate for 15 to 20 years.
Regular maintenance includes cleaning filters, checking the burner and inspecting all safety-critical components.
These measures ensure a longer service life and consistently high efficiency.
Properly planned and installed, a warm air heating system is a reliable and cost-effective solution — whether for a large industrial space, a chalet or your garden room.
FUXTEC heaters and their features
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Gas Heater FX-GH10 With an output of 10 kW, this model is the ideal choice for smaller greenhouses or garden rooms. Its compact design makes it easy to transport and flexible in use. Running on propane/butane, the FX-GH10 delivers rapid and even heating even without a mains electricity supply. It is particularly handy for hobby gardeners wanting to keep individual container plants or small growing areas frost-free.
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Gas Heater FX-GH33
The FX-GH33 at 33 kW is suited to medium to large greenhouses. It impresses with its robust build quality, high heating output and built-in safety features such as overheat protection. Its power allows it to maintain consistent conditions in a winter shelter even at very low outdoor temperatures. Ideal when multiple tender plants need protection simultaneously or the greenhouse covers a larger area.
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Gas Heater FX-GH51
This professional-grade unit is the most powerful model in the range. With 51 kW of heating output, the FX-GH51 is designed for very large greenhouses, industrial spaces or extensive plant collections. It delivers enormous heating power, maintaining stable temperatures even during prolonged periods of frost. Its size makes it particularly suited to growers with professional requirements or very large installations where reliability and endurance are paramount.
