2050 County 41 NW, Backus, Minnesota
Ducted heat for buildings and finish work
An indirect fired heater uses a heat exchanger to keep combustion exhaust separate from the air supplied to your workspace. BCI Rentals offers 200K through 1M BTU catalog size classes, including diesel and propane or natural gas units, for temporary building heat across northern Minnesota.
Call with the building dimensions, target temperature, fuel and electrical service. We will help choose a heater and a practical duct layout for the job.
In an indirect heater, the burner heats a metal exchanger while a separate fan moves the working air across it. Exhaust goes through a flue instead of into the supply duct. With the equipment set up correctly, this gives you heated air without adding the burner’s combustion moisture or exhaust to the space.
It is a useful choice for enclosed construction, drywall and painting work, shops and other projects where direct fired exhaust or added water vapor would be a problem. The heater and exhaust are normally positioned outside, away from the air intake and openings. Follow the selected unit's placement, ventilation and clearance requirements.
Indirect heat does not remove existing moisture by itself. Pair the heat with suitable ventilation, air circulation and, where needed, dehumidification to support the material manufacturer's drying conditions.
| Listed size | Fuel | Equipment | Sizing note |
|---|---|---|---|
| 200K BTU | Diesel | Model confirmed when reserving | Smaller indirect heater option; call for unit specifications. |
| 400K BTU | LP / NG | Frost Fighter family; confirm model | Listed airflow: 2,800 CFM. |
| 500K BTU | LP / NG | Frost Fighter IDH500QR | Listed airflow: 4,800 CFM. |
| 500K BTU | Diesel | Frost Fighter IDF500 | Listed useful heat output: up to 420,000 BTU/hr. |
| 600K catalog class | LP / NG | Temporary Climate Solutions HCI-600D | Listed heat rating: 550,000 BTU/hr. Call to confirm output for your project. |
| 1M BTU towable | Diesel | Frost Fighter IDH1300 | Dual heater arrangement; listed airflow: 9,600 CFM total. |
Product names describe catalog size classes. Burner input and useful heat output are different, and specifications can vary by unit. Confirm the actual output, power and ducting requirements before final sizing. Availability changes with reservations.
Floor area alone is not enough. Start with building volume: length × width × height. Then account for the required indoor temperature, outdoor temperature, insulation, air leakage, door use and any exhaust that must be replaced.
For example, a 100-foot by 60-foot space with a 16-foot ceiling contains 96,000 cubic feet. Its heat requirement changes substantially if the walls are uninsulated or a large door stays open, even though the floor area remains 6,000 square feet.
Tell BCI whether you need continuous fresh air or whether a compatible return-air arrangement is appropriate. Recirculation is available on select indirect units, but the building's ventilation needs still apply.
Choose the heater location and duct entry points together. Long runs, tight bends, split ducts and return-air arrangements affect airflow and usable heat at the work area. A heater with a higher BTU rating does not automatically solve a restricted duct route.
BCI's HCI-600D listing allows ducting up to 150 feet, while other units have different limits. That is a unit-specific maximum, not a recommended length for every layout. Confirm the correct duct type, diameter, route and allowable length for the selected heater.
Browse forced air heater accessories and discuss them when you reserve. Schaefer fans can help spread heat after it enters a large space, reducing stagnant corners and temperature differences.
If the project needs a high volume of heated outdoor air to replace exhaust, start with make-up air heater rental. BCI's direct fired make-up air units supply 4,400 to 14,000 CFM in the listed sizes. Their fresh-air supply and planned exhaust can help manage indoor moisture, but combustion still adds water vapor to the supply air.
A portable direct fired heater is another option where the manufacturer's ventilation requirements can be met. Our heater comparison guide explains where direct, indirect, make-up air and hydronic heat fit.
Direct fired heat puts combustion products in the heated airstream. Indirect heat uses a heat exchanger and a separate exhaust path, keeping combustion products out of the supply air when properly installed. That makes indirect heat a useful starting point for enclosed finish work and moisture-sensitive projects.
They do not add combustion moisture to the supply air. They also do not collect moisture already in the building. Ventilation or a dehumidifier may still be needed to remove water released by drywall, paint, wet materials and other work.
Yes. BCI's indirect fleet includes Frost Fighter units such as the IDH500QR, IDF500 and towable IDH1300. Call to confirm the model, fuel, power and availability for your dates.
Some units list 120V power, but circuit capacity and starting load vary. Larger equipment and different configurations can have other requirements. Tell us the voltage and breaker capacity available, and confirm the assigned unit before planning power.
Call (218) 947-3353 with the job location, dates, dimensions and available fuel and power. We serve Backus, the Brainerd Lakes area, Bemidji, Walker, Park Rapids, Grand Rapids and surrounding northern Minnesota communities.
Call (218) 947-3353 for a rate and availability. A few site details help us put together a useful heating plan.