central air - Simply Additions https://www.simplyadditions.com/Blog/latest/PAGE-1.html Sun, 26 Sep 2021 23:43:53 -0400 en-gb There's a 90% Chance Your Central AC System Is Installed Wrong, Sad But True https://www.simplyadditions.com/Blog/Homeowner-Tips/Theres-a-90-Chance-Your-Central-AC-System-Is-Installed-Wrong-Sad-But-True.html https://www.simplyadditions.com/Blog/Homeowner-Tips/Theres-a-90-Chance-Your-Central-AC-System-Is-Installed-Wrong-Sad-But-True.html b2ap3_thumbnail_bad-central-air-conditioning-installation.jpgDid you know that about 50% of all the money we spend on heating and cooling is due to inefficiencies in the way these systems are installed?





The good news is that there are several things that any homeowner can do to begin the auditing process of their HVAC system. Just keep in mind that for some of these steps, you are better off printing out the article and discussing it with a licensed heating and air conditioning contractor. You can find a HVAC contractor using the form below, or using trusted sources like the Better Business Bureau. 


Have a licensed professional check your HVAC system for energy efficiency by verifying the original installation. John Proctor has found that items like the compressor, coil, and capacitor will last much longer when compared to exactly the same HVAC systems that were installed by a lazy or incompetent HVAC contractors.


Did you know that about 50% of the money you spend on cooling your home is being wasted because of a improper installation?

Standard Installation - Not Good Enough

  • setting the outside unit
  • bringing the set of lines out
  • brazing it together
  • opening the valves
  • turning it on
  • and testing for cold air operation
  • this doesn't cut it

Proper A/C Installation

  1. Match outside unit and inside coil
  2. Braise the lines using nitrogen. So when you flow nitrogen through it you won't get little carbon pieces of carbon; they will end up clogging the unit and making it not work right.
  3. Evacuate inside coil & line before refrigerant. You need to use a vacuum pump, a micron gauge, you have to pull all the moisture and air out of those lines and the inside coil before you put the refrigerant in.
  4. Release the refrigerant into the inside coil & the lines, and then you have to check and make sure you have the right amount. Because it comes with a certain amount but it is not the right amount necessarily for your inside coil and the length of lines you actually have. You usually have to add enough refrigerant to get it up to the right amount of refrigerant in order to have the unit run at its top efficiency.
  5. When you don't evacuate the system, because what you end up with is air and moisture in the system. Decreases durability because the excess moisture will turn into acid and corrode the system.
  6. When you don't have the right amount of refrigerant in the system. You will have too much super heat which means the compressor will overheat and burnout. If you have too much refrigerant it's going to slug liquid back to the compressor and ruin the compressor that way.
  7. When you have low airflow accross the inside coil.

Duct Work

Having leaky duct work system with a seer 14 AC unit will easily drop it down to a seer 10 efficiency. Then if you add the wrong amount of refrigerant in, the efficiency will drop to a seer 8. And lastly if you get the wrong amount of airflow, you're going to drop it down to a seer 7.

Air Flow

The amount of air flow across the inside coil.

4 ton air handler on a tiny duct system equals not enough air flow.

You really need to test it.

Test Method 1: Temperature Split Method

Title 24 Airflow Test in California has a temperature split method which is a common method that is easy to do. What you do is measure the wet bulb and dry bulb temperatures which tells you what the humidity is as well as the temperature on the return side. And also what the temperature is on the supply side. So you see how much the temperatures drop between the return and the supply. Based on the temperature drop you can tell whether or not you got too little air flow or not.

You can compare your results with a table you get from the CDC website www.energyu.ca.gov. It's good for all the states, east coast, Saudi Arabia. If your temperature split is too high, you got too little airflow.

Test Method 2: Using a Flow Grid

This is the best way to measure the airflow. Its a device that you put in where the filter would normally be and you take a few pressure readings, and from that you can get real accurate measurements of how much airflow is flowing through the inside coil.

How do you know if you have the proper amount of airflow. Manufacturers give different specs for different regions to get air flow numbers. 450 cfm per ton across the coil in  California.  Georgia where it's hot and humid needs 350 cfm across the coil per ton.

What About The Size Of The Line Set Itself

As the line set gets longer you have to change the diameter of the line set. It's something that the manufacturers specify but it's most often ignored. Most often mistakes found coming from the back of the unit they will actually use a smaller line set which the machine was designed for. People actually take clamps and squeeze down the unit not put a fitting in there and braze the gap. The efficiency drops significantly using that method because there's a good pressure drop there andnothing is working right at that point.

Top Efficiency Hits

The Durability of a system depends on doing it right. If you don't do it right the first time, it's going to keep coming back and bite you.

Checking Contractors

  1. Make sure they know what the specifications are. Then you need someway to have that information verified by a third-party. The CDC has a way The CheckMe System. www.proctoreng.com
  2. While the technician is still on the site they gather the information and pickup the cell phone and call a toll free number, the numbers are read over the phone. It goes into a computer program that checks everything and makes sure its a good test. And since the technician is on the site, they verify that the airflow is right and that the charge is right. Also if there is a problem, the technician can address it right away. This system helps everybody.

This helps out the builder, state, and HVAC contractor. Good trade schools and manufacturers have training. 


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voitek@simplyadditions.com (Voitek Klimczyk) Homeowner Tips Wed, 18 Jun 2014 12:57:09 -0400