When the time comes to choose the best fire heater for a specific job, one big dilemma comes upfront. Should you purchase a direct or an indirect one? There are several differences between direct and indirect fired heaters. We present you with the essential information about each type.
Direct Vs Indirect Technology
Both types of equipment use propane or natural gas to produce heat. However, there is a structural difference between the two. On one hand, the direct fire heater technology forces the air directly through the flame, and it heats the air. You could see it as the equivalent of a gas barbecue grill, or a gas stove. The flame is entirely exposed in the space where you intend to use it.
On the other hand, the indirect fire heater technology contains the flame in a burn chamber, which then heats a so-called heat exchanger. The stream of cool air in the environment circulates above and all around this heat exchanger raising its temperature. In this case, you could say that the indirect equipment resembles a furnace with a chimney. Its great advantage is that you can easily use it indoors, even in smaller rooms of your home. There is no direct exposure to the flame.
Benefits Vs. Drawbacks
Indirect fire heaters’ benefits.
- The air in the room or space you heat is 100% clean and dry. This happens because the air in your space never gets in direct contact with the heating flame.
- Thermostats are almost always built-in. This means you can easily control and maintain a constant temperature where the heater is running.
- It doesn’t generate carbon dioxide. So the indirect fire heater is the safest variant of the two. You can use it in small, sealed rooms without any worries.
Direct fire heaters’ benefits.
- They have good efficiency and the heat power is high. The direct unit transfers 100% of the fuel into heat, thus reducing costs.
- No need for electricity, for some models.
- All costs are smaller in the case of direct fire heaters. Unlike the indirect fire heater, you will pay less to purchase, rent, and even for the maintenance operations.
- There is a thermostat that controls the temperature level, in the large majority of models.
- It doesn’t need much supervision while running. Due to its big number of in-built safety features, you don’t need to always keep your eye on the direct fire heater.
Cons for the Indirect Fire Heater
- The price is higher than with the direct unit. Renting it costs times more.
- The efficiency is only 80% of the fuel.
- Some models require an electrical source.
- It needs exhaust ventilation.
Cons for Direct Fire Heater
- It brings monoxide into the space that is heated. Thus it can become dangerous for health if you don’t have a good ventilation system.
- Some heat will be lost. You cannot use the unit in small spaces, and windows or doors must be open from time to time.
- The direct fire heater also lets the air quite moist and more difficult to breathe.
Practical Use
Here you will also find some differences between the direct and indirect equipment.
Indirect Unit Applications
- Homes, offices, school units
- All types of healthcare buildings
- Construction sites
- Chemical production units
Direct Unit Applications
- Warehouses
- All types of industrial spaces (construction, food, mining, petrochemical, etc.)
