Add-A-Cool is a retrofit sub-cooling coil designed to increase efficiency of residential and commercial air-conditioning condensing units. The coil is shown in the initial mounted position; a complete piped installation takes less than two hours.

Amos Snow III, the president and chief executive officer of Bois D’Arc International, took the company in a new direction about eight years ago, after purchasing the company from his father. Bois D’Arc has grown from just 85 customers to more than 850 customers in that time, as it transitioned from a sales company to a sales and manufacturing organization.

How did business get to be so good in Longview, Texas?

Snow says that he has been putting his name on the line with every coil that goes out the door, many of them custom-designed for customers, and he isn’t going to build any product that doesn’t meet a customer’s requirements.

He isn’t going to let any grass grow under his feet either. Snow thinks of himself as a “coil man” and challenged himself to be innovative in order to come up with a new product that could help everyone save energy. Ergo, the Add-A-Cool came into being while Snow was convalescing from back surgery in 2007. Just as its name implies, the patent pending invention is literally added to the side of a condensing coil. Add-A-Cool is a retrofit sub-cooling coil designed to increase efficiency of residential and commercial air-conditioning condensing units. There is nothing new in the theory behind his invention, said Snow; however he is quick to note that many people still aren’t sold on the idea.

“There has been a lot of snake oil in this business. People have heard so many energy efficiency savings claims that they are very gun shy of unfulfilled promises. That’s why I haven’t bought into the testing procedures that we are allowed to use. There are too many variables that enter into the equation, which would actually result in phenomenal energy savings claims. I could say I had ETL test the coil and it resulted in an 18 percent efficiency gain, but that would not necessarily be accurate under a given field condition. The field is always different than what takes place in a lab,” said Snow.

“If people see these flawed test results, they expect the same results everywhere in the country, and they would end up being disappointed. I’m not going to let that happen.”

If this is such a great invention, why hasn’t someone else already come up with it?

Snow said that years ago coils were actually made with a higher propensity for sub-cooling, as much as 20 to 25 percent. In fact, commercial units over 100 tons often have a separate sub-cooling circuit, something almost never seen in designs under 100 tons. In addition, over the years, coil surface has been shrunken down, to where now the dedicated sub-cooling often only represents 5 percent of the coil design.

According to Snow, sub-cooling the liquid refrigerant leaving the condensing unit results in a greater heat enthalpy factor as well as a greater density. The cycle times and frequency of the evaporation cycle are reduced, which results in greater efficiency.

“What I did was add the coil instead of adding condensing coil surface, which is what most designs have attempted to do. The problem with those designs is there is not enough sub-cooling to positively affect cooling efficiency,” said Snow.

According to the Texas coil man, the concept is very simple. More sub-cooling results in greater efficiency.
How much is the average energy savings?

The Bois D’Arc Website only touts about 6 percent additional savings, and probably won’t ever promise much more than that. “Our initial calculations were only based upon lab conditions because that is always the starting point. We didn’t take advantage of all the variables that allow us to play with the numbers.”

Snow said that the actual operations in the field are pointing to better results. “We found that the higher the ambient conditions, the better the Add-A-Cool actually performs. We are actually reporting the high teens and low twenties for energy savings.”

What about air restriction or warranty issues with OEM coils?

“We design these so as not to have a negative effect on the condensing unit air flow. The restriction is under .2 inch mercury, and no OEM has ever invalidated a warranty for one of their products that also used an Add-A-Cool,” said Snow.

Visit for more information on Add-A-Cool retrofit sub-cooling coils.

Sidebar: Quick Facts

WHAT:Add-A-Cool, a new product being manufactured and marketed by Longview’s Bois D’Arc International Inc.

WHY:Inventor Amos Snow III said the product boosts the efficiency of air-conditioning systems and saves consumers money.

WHERE:Longview, Texas

PRODUCT FEATURES:Wide space, smooth surface, high-pitched corrugated fins, thick copper. Installs in less than two hours.

SIZES:Residential: 3–5 tons. Commercial: custom designs beginning at 7.5 tons.

Publication date:01/11/2010