Category: Technically Speaking

When is a good time to clean coils?

Over the years our company has been asked about best practices for cleaning coils.

  • When should coils be cleaned?
  • How to tell if the coils were properly cleaned?

This is the first in a short series of blogs that addresses these issues.

A primary variable that determines ones coil needs to be cleaned is the pressure drop across the coil itself. Usually, higher pressure drops are indicative of a coil that is fouled with dirt and/or organic growth.

IPK Photo Application
Dirty Cooling Coil 

Sometimes the coils appear visibly dirty, this in itself might be reason to go through a coil cleaning. Another factor is that the AC unit doesn’t cool as it should.

For example, a brand new through-the-wall AC unit, such as found in many hotels, might take 3/4 hour to drop the room temperature 8 degrees. The same unit with a dirty coil might take several hours to cool the same room. One major drawback is the unit is running several times longer to do the same work. Occupants can be dissatisfied with the slow cooling. In my own experience, I actually left my hotel room because it took several hours for the temperature to go down.

As mentioned, the unit works strenuously when it is dirty. This increased usage of power raises the electrical costs monthly. All this unnecessary work & money out of your pocket, when you have a solution as simple as cleaning the coil.

Over the past decades, we all have intuitively known that dirty coils drive energy costs up, but few know how much or if it was of any true financial consequence. Since up to 50% of a buildings electrical usage is consumed by the HVAC system, it would be good to know from actual studies how dirty coils affect your bottom line. Is it substantial or not?

Fortunately, the ASHRAE society did a complete engineering study specifically on this matter & published it in their journal.

While the results are not surprising, the affect on your bottom line is. If you do not have the article, feel free to contact us.

Drop us a line with comments, questions, suggestions, feedback on what you do with your coil. Any experiences you can comment with?

Lynn Burkhart – President of Controlled Release Technologies 


Contact us: – 800-766-9057 –



Water in Ductwork, NOT TODAY!

Have you heard the following things listed OVER & OVER again in regards to your HVAC unit?

“No one wants any sort of strain on their HVAC unit. Strain that could cause many problems that are an extra cost to you. Such as:

-Higher energy bill
-Frequent maintenance on your HVAC unit
-HVAC replacement

There are many ways to keep your HVAC unit stress free. Below are just a few basic steps you can take to keep your HVAC system stress free. Very easy stuff, and they each only take a few moments of your time.

-Keep vents clear
-Keep those coils clean
-Change out the air filters regularly”

BUT, one thing that goes unmentioned quite often is the ductwork. Of course it would. Out of sight, out of mind, right?

Did you know, ductwork carries the warmth in the winter and holds the cool air in the summer. Without proper ductwork insulation, the temperature of the air being carried could be lost while transferring from the HVAC unit to the vents in your home. Ductwork can also play a major role in your energy bill. Even the Department of Energy claims so.

So, you see how important ductwork is. What if just a little bit of water entered your ductwork from the HVAC system? It’s just a little water. No biggie, right? Actually, YES! Even the smallest water droplet is a huge deal! To name a few, it can cause the following:

-Rust out metal ductwork
-Breeding ground for mold, mildew, and bacteria
-Decrease Indoor Air Quality greatly
-Water damage
-Degradation & De-lamination

Although, water in the ductwork can cause many problems. Your health alone should be enough reason to want to get your ductwork checked out. Exposure to mold can lead to allergies, infections, rashes, even alzheimer’s. The list just goes on and on.

When water gets in the insulation in your ductwork, those water droplets fly through your airstream. These water droplets create a breeding ground for mold & mildew. Water droplets will wreak havoc on the insulation in the ductwork causing degradation & de-lamination. Not only would this be tearing your insulation apart to later be replaced (more bucks from your pocket) but that delaminated insulation would be freely roaming the air in your home (remember you & your family are breathing this).

Why worry about water in your ductwork causing this step ladder of issues when there is a solution?

For the new home-owner, why not be preventative & go ahead and protect yourself?

Ductile is a coating that protects the HVAC ductwork from degradation and insulation de-lamination. Ductile locks down fiberglass particles that would enter the air stream. Hallelujah!
No stress of your insulation breaking down & no worries about your health. Did you hear that, NO STRESS!


Contact us for more information on Ductile. Shandi or Candice will be more than happy to give you some information. 800-766-9057 or if you’re like me and prefer email reach out to or

“A Clean Coil is a Happy Coil”: How to Clean A/C Coils

“A clean coil is a happy coil!” according to the ACHR news, which published this very informative article on how to clean A/C coils. Clean coils also extend the life of the HVAC unit AND make it more efficient. Check it out!

One important thing the ACHR says: you shouldn’t use high-pressure washers, because they can bend the coil fins. We hear a lot of people in the industry do clean coils with pressure washers. Do you?

What are your best tips for cleaning coils? What problems do you run into on the job?

We’ll be doing an article soon on the benefits of coil cleaning and the best ways to clean a coil, and we want to hear your input! 

Click in that box below and comment! Or send us a quick email at We’re also on Twitter: @cleanac. Thank you!

A/C Coil Cleaning – an Art or a Science?

As a busy service technician, what’s often the last thing on your to-do list? For some, it’s cleaning the coils on HVAC units.

Why? It’s messy work, can take up your time, and often feels unnecessary. For those reasons, coil cleaning isn’t usually the first thing that comes up in HVAC conversations.

Over the years, we’ve seen several magazine articles on how to clean coils. More than a dozen contractors have done full-scale tests on coil cleaning. Some have even pulled the entire coil out of the unit and immersed it in cleaning solutions. It’s easy to say that coil cleaning is simple and of little consequence. But nothing could be farther from the truth.

In next month’s newsletter and here on the blog, we’ll share with you the best and easiest ways to clean coils, the benefits for you and for the owner, and all kinds of other important factors.

Do you have questions about coil cleaning? How do you clean coils? 

All questions and comments are welcome! 

Drop us a line at or comment on this post! We’ll answer your questions in our upcoming newsletter and blog posts.

Technical Corner: “Did You Know – HVAC Corrosion”

Corrosion is found everywhere. Structures such as bridges, buildings, radio towers, and marine vessels all experience it. Corrosion results in billions of dollars per year worth of damage, and potential hazards to human life.

Studies on corrosion over the past centuries have been numerous. The National Association of Corrosion Engineers have for decades been deeply involved in how corrosion occurs and under what circumstances.

One major area of corrosion many are too familiar with occurs in the HVAC field. In this area corrosion can take many forms and affect many areas. For example, a critical area of concern is often what a person doesn’t see.

Chilled water systems often corrode, causing metal deterioration and pitting on the inside of water piping, and inside condenser tubes in the chiller unit itself. Costs for retubing a chilled water condenser is expensive and time consuming. For this reason, one would be foolish not to monitor the corrosion in this closed system.
Another area frequently attacked by corrosion are evaporator coils and outside condenser coils. Typically, corrosion of these coil types results in aluminum corrosion or whitish aluminum oxide deposits being seen.

Costs each year are huge. One major manufacturer of PTAC (packaged terminal air conditioners) lost over 8 million dollars in just one year due to warrantee replacements due to corrosion. Although the vast majority of corrosion related issues are located in coastal regions, corrosion also affect inland units as well. It is not uncommon for AC units in Illinois or other midwestern states to experience other types of corrosion.

Suffice it to say, in no cases I have run into over the past few decades were owners pleased with the prospect of replacing their units. Even the smaller PTAC units have replacement costs exceeding $1,200 or more each.

Not much for big business to handle when looked at as a single unit, but when one considers that many hotels have upwards of 300 – 400 units, you can see over $500,000 being spent. Not too many firms can withstand this type of expenditure every few years.
There are many ways to handle and prevent corrosion. The easiest way is to prevent it from happening in the first place.

In part 2 of this blog, we will address solutions to a few of these corrosion types.

lynnLynn Burkhart is the founder and president of Controlled Release Technologies, Inc. located in Shelby, North Carolina. More information about the company, and its products, can be found at and by calling (800) 766-9057.