Direct Gas Fired Make-Up Air Unit

direct gas-fired make-up air unit, r series
Direct gas-fired make-up air heaters efficiently introduce heated air into buildings, providing significant cost savings in both equipment and operating costs.

This method, powered by natural gas or liquid propane, ensures 100% of the generated heat is delivered into the space. While there are limitations due to gas byproducts, safety measures within the equipment protect the building occupants. Recirculation is possible but capped at 85% to comply with ANSI standards (source).

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This efficiency leads to significant cost savings over other methods in both equipment costs and operating costs.

Horizontal Industrial Direct Fired Recirculating Heater

Vertical Industrial Direct Fired Heater

Vertical Industrial Direct Recirculating Fired Heater

Compact low CFM Direct Fire Heater

Modular Direct Fired Heater

Horizontal Industrial Direct Fired Heater

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We are the official distributors of the top make-up air unit manufacturers in the USA. As official representatives, we’ll be happy to help explain the best make-up air unit for your application.

Contact us for a quote or if you have any questions regarding MUA.

Make-up Air Units Help Solve a Distribution Center's Sanitation Conundrum

​​Benefits of Direct Gas-Fired Make-Up Air Units (DGFM):

Energy Efficiency

  • More efficient than traditional HVAC systems.
  • Directly uses natural gas or propane for heating, eliminating the need for a separate heating system.
  • Lowers energy bills by requiring less energy to maintain comfort.

Improved Indoor Air Quality

  • Fresh air is filtered before entering the building.
  • Removes pollutants, enhancing indoor air quality.
  • Crucial in high-occupancy buildings to prevent health issues.

Control Over Humidity

  • Equipped with humidifiers or dehumidifiers.
  • Maintains optimal humidity levels for occupant comfort and prevents moisture-related problems.

Easy Installation

  • Simple and quick installation.
  • Requires minimal ductwork.
  • Ideal for retrofit projects or buildings with limited space.

Zoning Capabilities

  • Allows better control over temperature and air flow in different building areas.
  • Enhances occupant comfort and reduces energy waste.

In summary, DGFM units offer an efficient and effective solution for supplying fresh air, maintaining comfortable indoor temperatures, and controlling humidity levels in buildings. Trust in the advantages provided by DGFM for optimal HVAC performance.

Contact a Pro to help find the best make-up air unit for your application

We are official distributors for the manufacturers listed below. As official representatives, we’ll be happy to help explain the best make-up air unit for your application. Contact us for a quote or any information regarding their products.


Fuel Reliance

  • Rely on natural gas or propane as a fuel source.
  • Potential for higher operational costs and safety concerns if not properly maintained.

Applicability Concerns

  • May not be suitable for all buildings or applications.
  • Especially challenging for those with strict indoor air quality requirements or environmental regulations.

Noise and Vibration

  • May generate higher levels of noise and vibration.
  • Concerning specific settings.

Careful Evaluation

  • It is essential to evaluate the specific needs and constraints of each building.
  • Prioritize carefully before selecting a DGFM unit.

Professional Guidance

Additional Components

  • Various cooling options are available for DGFM units, including:

Authorized Distributor for top USA Manufacturers

We are the official distributors of the USA’s top-rated make-up air unit manufacturers. As official representatives, we’ll be happy to help explain the best make-up air unit for your application. Contact us for a quote or any questions regarding industrial or commercial MUA.

Some manufacturers we work with for make-up air equipment include AbsolutAire and FloAire.


absoluteaire make up air

Setting the standard for leadership in direct-fired "total air management" systems. AbsolutAire is meeting today’s needs for cost-effective make-up air, as well as for efficient heating and ventilating.

Click to learn more about AbsoluteAire.

floaire distributors

Manufacturing quality products to meet the needs of the ventilation industry for 35 years. Continuing to invest in research and testing to improve the efficiency of our makeup air units.

Learn more about FloAire.

Make-Up Air Units Installed
Providing Industrial Equipment to the Following Industries

Providing Direct MUA to the Greater Chicago area & Ship Nationwide

R. Williamson & Associates can provide you with fast quotes on the correct direct gas-fired mua for your application.

We are official representative covering Illinois, Wisconsin, Minnesota, Michigan and Indiana.

We can also send out a trained specialist to assess the area and make certain the proper unit is being used for your specific application. 

We run tests on-site to see how cost effective each model will be to assure maximum efficiency.

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