Essentially, a tube heater is a torch into a steel tube, which heats it to a temperature high enough to radiate. Because the operating temperature is not high enough to make the tubes glow, itís called low-intensity infrared. Some systems blow, and some suck. No, really. Some brands opt for blowing the hot gases through the tube, which is commonly called a forced-draft or positive-pressure system. Others use an inducer fan to suck the gases through: they are called vacuum-vented, induced-draft or negative-pressure systems. Although we prefer and recommend vacuum-vented, we stock both types from Space-Ray.
Whichever type you install, itís important to keep in mind that the output from a tube heater is lopsided. Where the flame enters the tube, temperatures will reach their peak at up to a thousand degrees, so the radiant output is far greater near the burner than at the vent end. Bear this in mind when youíre planning a layout. Put the burner where heat load is greatest, such as near an overhead door. If the mounting height is sufficient, diffusion will spread the heat evenly. At lower heights, youíll get uneven heating from a straight tube: too much near the burner, not enough near the vent. Thatís why, more often than not, we end up recommending U-tube models. Their counterflow (up-and-back) design ensures even coverage. Different mounting heights require different input ranges: weíll help you with that and all aspects of design.
How much will it save on operating costs? That depends on the buildingís height and infiltration (air changes). The higher the building, the more you save due to elimination of heat stratification. With unit heaters, heat collects at the roof due to hot air rising (thatís why hot-air balloons work!). Radiant heat doesnít fight the buoyancy of hot air, but delivers its heat the same way as light, releasing its energy as itís absorbed into the floor and objects in the space. Thatís also why opening overhead doors doesnít lose all the heat: itís sunk into the floor (heat sink).
Bottom line: commercial and industrial spaces save at least 30% and often 50% compared to forced-air heating, while providing warm surfaces, reduced noise and dust, and better comfort.