Ductwork installed properly? Check.

HVAC system sized properly? Check.

Tested and balanced? Check and check. 

But there is another step that some contractors may be forgetting: protecting the refrigerant line sets that connect the air-conditioning compressor to the HVAC system and allow refrigerant to flow to it. 

It’s an important action that is now required by many building and construction codes. That’s what officials with Carlisle HVAC Products are reminding contractors as the company promotes two products designed to boost energy efficiency and keep air conditioners working well. 

At the recent AHR Expo in Orlando, Florida, Carlisle showcased the products, Hardcast TPO-2265, which stands for “thermoplastic polyolefin,” and Hardcast Seal-Tack White. Designed to go over line sets as either an external wrap or brushed-on coating, either can help HVAC contractors meet code requirements while keeping customers’ compressors running efficiently — and ensure comfortable indoor environments. 

According to Tim Eorgan, Carlisle HVAC’s specified products manager, ultraviolet rays from the sun causes unnecessary heat gains to unprotected line sets. In much of the country, air-conditioning condensers are outside in areas with little to no shade much of the day. The line sets, usually made of copper, quickly heat up when the sun hits them and insulation wraps, unprotected, can quickly deteriorate as well.


That makes the air-conditioning compressor’s job difficult when it has to work longer to cool a structure with the refigerant that’s flowing through the line set tubes, which typically range from 2 to 6 feet in length, Eorgan said. 

“It puts more strain on that condenser to get rid of that hot refrigerant,” he said. 

Stressed coils are bad for the environment and HVAC equipment. 

That’s where Carlisle HVAC’s new products come in. They offer contractors flexibility in meeting code requirements in a variety of conditions, officials say. 

“It’s a good procedure to have that copper pipe protected,” Eorgan said. “And if you’re going to protect it, you might as well protect it with insulation to get needed R value.”

In Florida, where the sun shines strongly year round, HVAC units are especially prone to line set wear. That’s why the state’s building code requires they stand up to the weather. The code states: “Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas or plastic cover. Cellular-foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation that can cause degradation of the material.”

And weather isn’t the only reason that line sets should be shielded, Eorgan pointed out.

“Insulation is needed on those line sets to increase the efficiency of those HVAC units,” he said, adding that it also keeps lines from sweating and getting overheated.

Code compliant

Hardcast’s coating and covering products can meet all of Florida’s criteria and states with similar rules, officials say. 

The company’s covering, Hardcast TPO-2265, uses a material — thermoplastic polyolefin — that Eorgan said was originally developed as a protective single-ply membrane for the roofing industry. The 6-mil-thick covering is laminated with a rubber-backed adhesive to give a total protective thickness of 26 mils.
Before insulation goes on a line set, the covering is rolled longitudinally onto the insulation. 

“This gives you added protection against mechanical damage,” he said. “And that mechanical damage could be windblown debris or it can even be lawn equipment, like a Weed Eater.” 

The other option Hardcast is offering HVAC construction contractors is a coating, Seal-Tack White, designed for situations when technicians prefer to brush-on a protectant rather than wrapping the line set. Eorgan said line sets with a lot of angle changes make a brushed coating a particularly good choice. 

Seal-Tack White is “a great UV-resistant coating,” Eorgan said. “It’s water-based, so there’s no odor. And it has a fast dry time.” 

After the insulation is in place, simply use a 2-inch-wide “chip” brush and apply the coating to the insulation. Strong and weather resistant, it can provide years of protection. It fights mold growth and offers a seamless, no-splice appearance.

Despite more construction codes requiring protective substances like Hardcast HVAC’s Seal Tack White and TPO-2665, Eorgan said it’s still common to see uncovered line sets or unprotected insulation that is hard, brittle and flaking away. It’s up to HVAC contractors to make building owners and homeowners aware of the problem and provide the solution. 

An HVAC condenser is not a cheap piece of equipment, he added.

“It’s an investment that you want to protect and make work as efficiently as possible,” Eorgan said.