Part 1 of this 4-Part Series Covers:
- How to test your Air Conditioner’s cooling performance.
- Air conditioner low on refrigerant.
- A/C outside unit is very dirty, reducing air-flow through the unit, and reducing it’s ability to get rid of the amount of heat it’s designed to.
- Cooling losses due to under-insulated or uninsulated ductwork.
- Adding insulation to existing ductwork.
- Properly installed flexible ductwork — what it looks like.
- Improperly installed flexible ductwork — what it looks like.
- Air-leakage from ductwork.
Any or all of these problems can cause an air conditioner to be under-performing, and running longer & harder than it needs to.
If your air conditioner is not producing the cooling described above (14-20 degrees) there is an operational issue. If it’s producing output-air that’s more than 20 degrees cooler, there is also an operational issue (likely too little air-flow through the system).
The two most common reasons the a/c is not cooling properly are:
- Air conditioner is low on refrigerant
- Outside unit is very dirty and cannot perform as designed
The first evidence that refrigerant is low is the cooling temperature-spread is not present. Also, an a/c low on refrigerant may form visible frost or ice. If you see frost anywhere on your a/c (inside or outside) it’s likely low on refrigerant.
- 3 Outside (condenser) units showing frost.
- An Indoor cooling-coil (evaporator coil) showing frost. Note: The cooling coil is behind a panel (that must be removed) in order to see if it’s frosted.
The outside unit is far too dirty. This restricts air-flow through it, and reduces its ability to get rid of as much heat as it’s designed to. The condenser unit needs to be cleaned at the beginning of each cooling season to ensure it’s able to perform at its maximum ability.
If you are handy around the house, you may be able to do this. If not, call Al’s for a Spring A/C Tune-UP. The Technician will advise you if the condenser coil needs to be cleaned, and if other operational problems exist and need to be corrected. With any needed maintenance or repairs completed, your A/C is able to cool at its maximum ability, resulting in lower cooling costs and increased comfort inside the home. Your A/C will also last longer and require fewer repairs if it’s able to perform as it was designed to.
These photos show flexible ductwork installation that is not supported correctly. Flex-Duct is to be installed using hangers, not components of the home’s construction to support it. The photo on right shows a bend in the ductwork that is way too tight.
The photo on the left shows two pieces of Flex-Duct that have come apart. The diagram on the right shows how a metal collar must be used to connect 2 pieces of Flex-Duct (so the pieces can be properly attached to the collar).
The photo below is flex-duct that has torn because it’s worn out. Flexible ductwork has a lifespan of around 15 years.
In an older home, it’s not uncommon to find metal ductwork that is not insulated or sealed for air leakage. If it is insulated, there may be very little. If it was sealed, it’s likely duct tape was used. Duct tape fails very fast in the high temperature settings (like DFW attics).
The photo below shows where someone added some insulation on top of uninsulated ductwork. You will also see that only the main / trunk-line has insulated added, the branch lines (round ductwork) have no insulation.
This ductwork was a good candidate for adding Closed-Cell Spray Foam Insulation. There will be the benefits of both added insulation + air-leakage sealing.
“After Photo” with Spray Foam Insulation Added.
Today’s Metal Ductwork
Today’s new Metal ductwork can be purchased: Uninsulated, Insulated on the inside, or Insulated on the outside
2. Air Leakage From Ductwork
The U.S. Department of Energy (DOE) states research found that 30–40% of the air traveling through ductwork leaks out.
Read the entire article here: Article About Leaking Ductwork — #1 Energy Waster
Flexible ductwork does not last as long as metal. Even if the ductwork installation was perfect, flexible ductwork degrades with age. According to Certified Home Inspections in Oregon, Flexible Plastic and Fiberglass ducting has a lifespan of 14-16 years (which is longer than the air conditioner and furnace are expected to last). You can see more details with this link: Flexible Ducting Lifespan.
In DFW attics during summer, ductwork is subjected to temperatures of up to 160 degrees. Replacing the HVAC Components, but reusing flexible ductwork (installed when the previous system was installed) is a bad idea. Flexible ductwork needs to be replaced each time the HVAC Components wear out and are replaced.
As the plastic liner in flexible ductwork ages, it’s more likely to split, especially where there are bends in it. Also, some flexible ductwork moves each time the furnace blower turns on and off, creating movement year round. Additional benefits of new flexible ductwork: it’s new and clean & clear of: dust, pet hair & dander, mold spores, and other built up contaminates.
Worn out flexible ductwork with tears and holes
1/3 Or More Of The Money Spent Cooling & Heating Your House May Be Ending Up In Your Attic Due To Leaking Ductwork!
The one energy-saving effort of having ductwork inspected and repaired or replaced could reduce your cooling and heating costs by up to 40%. Additionally, if your older home has uninsulated ductwork, your savings are further increased by adding insulation. It’s not difficult to realize you may reduce cooling and heating bills by 1/2 or more if you correct both uninsulated + leaking ductwork.
Actual Photos Of Existing Ductwork
Older Homes’s HVAC Metal Ductwork:
- Was installed back when little or no attention was paid to ensure it did not leak air
- Even well installed ductwork can come loose, or be bumped by a worker in the attic.
- Duct Tape was a common method of sealing (if any). Duct tape fails within a year.
Duct Tape Fails Quickly In Very Hot Environments Like DFW Attics, And Has Been Has Been Replaced With Mastic
Newer Ductwork Installation With Mastic Sealing Every Connection
Benefits of Sealing Ductwork With Mastic Sealer
- Seals areas of air leakage
- Goes on soft and pliable
- Does not harden or crack over time
- Because mastic is applied on the outside of ductwork, it won’t be affected by future ductwork cleanings
Photo Showing Spinning-Brush Used For Ductwork Cleaning
Most Ductwork Cleaning includes a spinning-brush to break away any soil that is stuck. Ductwork sealing products (installed inside the ductwork) may be subject to damage or degradation due to the spinning brush.
3. Insufficient Or Blocked Air-Flow Due To Ductwork
We have discussed how poorly installed flexible ductwork can restrict or block air flow. While blocked air flow is less likely with metal ductwork, restricted air flow can easily be a problem due to ductwork being too small. This problem can be further compounded by installing a new HVAC System that produces a larger amount of air-flow than the existing ductwork was designed for. Existing ductwork can often be modified by increasing the size of some ductwork, or adding additional ductwork lines.
A 1996 Study For The Arizona Public Service Co revealed: *
- 14% of newly constructed homes had an air-flow of 90% of normal air-flow requirements (400 CFM)
- 39% tested at 80%
- 14% tested at 70%
- 7% tested at 60%
Many ductwork problems began when the home was built. Years later, if a larger replacement HVAC System (with a larger air-flow capacity than the original) was installed — air-flow problems are increased. It’s safe to say that while most homes built today have better ductwork systems, some may still not have the ductwork system needed.
* Source: Troubleshooting Ductwork Is Easier Than You Think — See link below to the complete article. We have provided this article which goes into more detail than our blog post: Ductwork Troubleshooting