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Air Duct Cleaning: How to Handle Air Handlers

Posted by Peter Haugen on Fri, Sep 05, 2014 @ 03:29 PM

residential furnance rooftop air handlerair handler in mechanical room

large rooftop packaged system

Air Handlers are the heart of any HVAC system. They move the air (with a fan) and may also clean (filter) the air and condition (heat, cool, humidify) the air. Air Handlers come in all shapes and sizes from the furnace in your home to a 40’ long commercial rooftop unit to a simple exhaust fan to the 5-15 ton packaged rooftop units you see on the roofs of most strip malls and office parks. Attached to the air handler is ductwork (supply and return, fresh air intake, etc). When cleaning an HVAC systems you should clean everything in the air stream (per the NADCA Cleaning Standard, ACR 2013) but this article will take a close look at how to clean the heart of the HVAC system, the air handler.

Cleaning Options:

An air handler can contain some or all of the following components: fan, motor, coils (heating or cooling or both), condensate/drain pan, filters, fresh air intakes, and mixing boxes. You can’t clean all of these components the same way so let’s look at your cleaning options:

  • Contact vacuuming is probably the most popular air handler cleaning tool. You can contact vacuum all of the internal surfaces (sheet metal and insulation if it’s in good shape), fans, motors, walls, ceiling/floor, coils, drain pans etc.
  • Air washing with high pressure air can be used if you have the air handler under negative pressure (to control and collect the dirt/debris) from your vacuum collection system.
  • Pressure washer can be used on large air handlers without internal insulation where you can control the water flow. You must protect the motor and other electrical components however.
  • Coil cleaning can be done via the dry method (contact vacuuming, air washing) or via the wet method (applying coil cleaner and then rinsing off with water). You must be able to control the water when wet cleaning a coil.
  • In many cases you will use several of these cleaning methods on one air handler. The desired end result however, it so remove the accumulated dirt and debris from all the air stream surfaces.

coated air handler sectionair handler with closed cell insulation  

Dealing with Fiberglass Insulation

Many air handlers have internal fiberglass insulation. You need to take a good look at the insulation to determine if the insulation is in good enough condition to withstand the rigor of cleaning. If the insulation is not in a cleanable condition then it must be removed. Depending on the condition of the insulation you have the following options:

If the insulation is in good condition (cleanable)

  • You can contact vacuum it.
  • You can contact vacuum it and then apply an insulation repair coating. This is an economical way to improve the insulation surface and extend the life of the air handler. The coating locks down any remaining loose fibers, gives you a more durable air stream surface that is more resistant to air erosion and water, locks in and isolates any particulate remaining after cleaning, and is easier to clean in the future.

If the insulation is damaged, deteriorated (not cleanable)

  • Remove the insulation and clean the air handler. You lose the acoustical and thermal benefits of the insulation plus it’s very hard to get all the fiberglass fibers out of the glue used to hold the insulation in place.
  • Remove the insulation and apply a coating over the cleaned surface to lock down any remaining fibers.
  • Remove the insulation and replace it with new insulation. Over time the new insulation will degrade just like the insulation you just removed unless a coating has been applied.
  • Remove insulation and replace with close cell liner. Closed cell liner is a good long lasting solution.


Air handlers come in all shapes and sizes and you need to be able to clean and refurbish them as needed. You have several cleaning methods to choose from and several options to deal with internal insulation.

If you have any questions about this blog article, contact Peter Haugen, ASCS, CVI at 855-Vac-Systems, 952-808-1619 or phaugen@vacsysint.com. Click on the following links for additional information on Coating HVAC Systems and Closed Cell Insulation.



Tags: air duct cleaning, coating, air handler, close cell insulation