Portable heaters for professional use
The world's most affordable way to heat any hall space. The new Airrex AH-500i and AH-900i burn diesel with a blue flame — cleaner and hotter than any Airrex before. No exhaust pipe — and a 2+3 year warranty that extends to 5 years when you register online.
*Example: a 500 m³ hall, 0 °C outside, +15 °C inside — approximately 2.5 litres of diesel per day.
Core range
Airrex Blue Flame heaters
The biggest renewal in Airrex history: everything inside the unit is new — the burner, the fuel pump, the fan motor and the controls. Two sizes, both with selectable output.
No products yet.
Blue Flame Burner — diesel burns with a blue flame
In a conventional diesel burner the fuel and air mix only as they burn, and the flame is yellow. In the new Airrex burner the diesel is vaporised and mixed with air before ignition — the fuel burns like gas, with a blue flame, just like on a gas stove. The result: the cleanest possible combustion, a higher flame temperature and more heat from the same fuel.
The blue flame ignites in the lowest tube and the hot flow circulates through the entire heat exchanger — illustration from the 2026 brochure.A new burner head, dome and ultra-tuned diffuser mix the fuel with air before ignition — it is not liquid that ignites, but a gas-like mixture.
A ceramic igniter lights the premixed charge. It burns evenly and completely — like a gas flame — without the hot spots where NOx emissions form.
A blue flame is hotter than a yellow one, so the heat-exchanger tubes heat up more effectively — the same amount of fuel delivers more radiant heat into the space.
The new burner assembly, component by component
- —New burner head and dome — the core of premixing
- —Ceramic igniter
- —Ultra-tuned diffuser
- —Brushless BLDC fan motor — controllable speed
- —Two-stage fuel pump — enables Dual Power
- —New control software — MiCOM WiFi controller
- —Thermostat-controlled preheating — for arctic conditions
Adjust the temperature, switch power levels and monitor fuel from anywhere. The app also holds the unit's documentation and service requests. Built-in WiFi, optional 4G — and the heater works fully without a network connection.
What's new compared to the AH-200i, AH-300i and AH-800i?
The AH-500i and AH-900i replace the previous three models. The frames are familiar — the AH-500i is in the AH-300i's size class and the AH-900i in the AH-800i's — but everything inside the unit is new: the burner, the fuel pump, the fan motor and the software.
| New: AH-500i & AH-900i | Previous: AH-200i · AH-300i · AH-800i | |
|---|---|---|
| Burner | Blue Flame burner — premixed, blue flame | Conventional burner — yellow flame |
| Emissions | Very low NOx emissions | Low-emission |
| Heating output | Selectable Dual Power: 11/15 kW and 19/24 kW | Fixed: 13 kW · 15 kW · 22 kW |
| Total output range | 11–24 kW with two models | 13–22 kW with three models |
| Fuel pump | Two-stage | Single-stage |
| Fan motor | Brushless BLDC, controllable speed | AC motor |
| Igniter | Ceramic | Conventional |
| Cold start | Thermostat-controlled preheating (down to −20 °C) | — |
| Electricity consumption | 50–60 W | 80 W |
| Control | MiCOM WiFi · Rex Nordic app · Bluetooth | WiFi · Airrex app |
| Warranty with registration | 2+3 years = 5 years | 2+1 years = 3 years |
Familiar frames also mean that switching is easy: the units fit the same spots and go through the same doors as their predecessors. Spare parts and service for the previous models continue as normal — 100% spare-parts availability covers them too.
Why should I upgrade my old heater to a new one?
If an AH-200i, AH-300i or AH-800i is serving your hall, it will keep serving — spare parts and service continue as normal. But there are good reasons to upgrade:
The hotter blue flame heats the heat exchangers more effectively. And when full output is not needed, Dual Power's low setting burns less: the AH-500i runs at 1.05 l/h and the AH-900i at 1.81 l/h.
Premixed combustion produces very low NOx emissions — no smell, no visible smoke. You can feel the difference in a space where people work all day.
On the new models the warranty extends to 5 years with registration, compared with 3 before. Two extra years protect the investment.
In the old heater the output was fixed. Dual Power gives full output for fast heat-up and a low setting for economical maintenance heating — with the same machine.
Thermostat-controlled preheating keeps the nozzle assembly at the right temperature during ignition — reliable starting down to −20 °C.
The new model is in the same size class as your old one — it fits in the same place. The old unit can stay as a backup: its spare parts and service continue.
Choose by the size of the space
| Airrex AH-500i | Airrex AH-900i | |
|---|---|---|
| Heating output (Dual Power) | 11 / 15 kW | 19 / 24 kW |
| Space size | up to 1,500 m³ | up to 2,500 m³ |
| Fuel consumption | 1.05 / 1.42 l/h | 1.81 / 2.3 l/h |
| Fuel tank | 45 l | 70 l |
| Electricity consumption | 50 W | 60 W |
| Running noise (low / high) | 47 / 50 dB | 48 / 51 dB |
| Control | MiCOM WiFi controller · Rex Nordic app · thermostat 0–40 °C | |
| Dimensions (W × D × H) | 95 × 30.5 × 108 cm | 130 × 35 × 140 cm |
| Weight | 47 kg | 81 kg |
| Meets EU emission requirements | ✓ | ✓ |
Sizing rule: choose the model by the volume of the space (m³) — and one size up if the hall is poorly insulated or doors are opened often.
Fuel: renewable diesel HVO100 (EN 15940) or diesel (EN 590) · 230 V / 50 Hz · operation down to −20 °C · 2+3-year warranty with registration.
Full technical data on every product page.
Where this works
Electric heaters for smaller spaces
When the site has enough electrical power and the space is smaller, an electric heater is the simplest solution: no fuel, no service needs, emission-free at the point of use. The HEAT series now covers outputs from 2 to 9 kW.
A compact PTC fan heater for small spaces and spot heating.
A more powerful PTC fan heater for workshops and storage spaces.
A three-phase PTC fan heater — a powerful fan spreads the heat far.
The most powerful HEAT model for work sites and halls with three-phase power.
A quiet, emission-free infrared heater for indoor spaces and terraces — remote control and timer.
Why PTC? A PTC element is self-regulating: its resistance rises as it heats up, so output and temperature limit themselves automatically. Lower overheating risk, optimised electricity use and a longer service life than conventional resistance heaters. HEAT fan heaters carry a 3-year warranty — and the new Blue Flame heaters have their own service kits ready, like every Airrex model.
Why Rex Nordic
Europe's largest
Portable professional heating and cooling is our whole business.
Heaters sold
Over 100,000 Airrex heaters sold across Europe and North America.
Spare parts in stock
Warranty work at your premises, not in a queue.
Frequently asked questions
16 answers in three groups — choosing the right technology, Blue Flame diesel heaters, and electric heaters.
Ask our sales teamChoosing the right technology
Should I choose a diesel infrared heater or an electric heater?
Choose a Blue Flame diesel heater when you heat a large space (a hall, work site or warehouse) or when electrical power is limited — the unit needs only 50–60 W. Choose an electric heater when the space is smaller and the site has enough electrical power: the 2–3 kW models run from a wall socket, the 5–9 kW models from three-phase power.
How do I choose the right size of model?
Size by volume: the AH-500i covers up to 1,500 m³ and the AH-900i up to 2,500 m³. Choose one size up if the space is poorly insulated or doors are opened often. Thanks to Dual Power you can always turn the output down.
Is an infrared heater suitable for dusty or humid spaces?
Extremely well suited. Infrared heat goes directly into surfaces and structures and needs no fan to distribute the heat — air and dust do not circulate. That is why it suits agricultural production buildings, wash halls and construction drying, among others.
Blue Flame diesel heaters
What is the Blue Flame burner and what does it do for me?
In a conventional diesel burner, fuel and air mix during combustion (a yellow flame). In the Blue Flame burner the diesel is vaporised and mixed with air before ignition, so it burns like gas — with a blue, hotter and cleaner flame. The benefits: more heat from the same amount of fuel, very low NOx emissions, and no smell or visible smoke.
Does the heater need an exhaust pipe?
In ordinary work spaces — halls, workshops, warehouses, tents and terraces — no separate exhaust pipe is needed. Please note: Airrex heaters must never be used in premises where people sleep.
How much fuel does the heater use?
The AH-500i uses 1.05–1.42 l/h and the AH-900i 1.81–2.3 l/h depending on the power level. The thermostat brings real-world consumption below this. A maintenance-heating example: keeping an insulated 500 m³ industrial hall at +15 °C in freezing weather uses about 2.5 litres per day.
What fuel can I use?
Renewable diesel (HVO100, EN 15940) or regular diesel (EN 590). In temperatures below +10 °C, use winter-grade fuel.
Does the heater work in severe frost?
Yes. Thermostat-controlled preheating keeps the nozzle assembly at the right temperature during ignition even in arctic conditions. The manufacturer's recommendation is operation down to −20 °C.
How loud is the unit?
At low output the AH-500i runs at 47 dB and the AH-900i at 48 dB; at full output 50–51 dB — the level of normal conversation. The redesigned burner, brushless motor and new sound damping make it the world's quietest blue flame burner.
Can I control the heater remotely?
Yes. Built-in WiFi and the Rex Nordic app (Android/iOS) let you adjust and monitor the temperature from anywhere — the app also holds the documentation and service requests. Optional 4G connection, and the unit works fully without a network.
What happens in a power cut?
The unit restarts automatically with the same settings when power returns — no need to go and restart the hall.
How does the 5-year warranty work?
The unit has a 2-year standard warranty. When you register the unit online within four weeks of purchase, the warranty extends to 5 years free of charge. Annual maintenance is a condition of the warranty — service kits and original parts are always in our stock.
What about service and spare parts?
Warranty service is carried out on site, so the unit never needs to be shipped anywhere. We keep all original spare parts in our own warehouses — including parts for previous Airrex models. Technical support is available by phone.
Electric heaters
What is a PTC fan heater and why is it safe?
A PTC element's electrical resistance rises as the temperature rises, so the unit limits its own temperature and output. This reduces the risk of overheating and fire, optimises electricity use and extends service life.
Is a wall socket enough or do I need three-phase power?
The HEAT2000 (2 kW) and HEAT3000 (3 kW) run from an ordinary wall socket. The HEAT5000 (5 kW) and HEAT9000 (9 kW) need a 16 A three-phase connection — both have a 3-metre cold-resistant H07RN-F cable.
What warranty do the electric heaters have?
HEAT-series PTC fan heaters carry a 3-year warranty.
