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Missing insulation on AC refrigerant lines

0 votes
Mark says:
August 19, 2011 at 4:30 pm

Hello, I recently had my central air unit cleaned/serviced. During the servicing I pointed out the two coolant lines came out of the eave of the house, dropped down to the ground and ran over to the outside unit. They apparently were never attached to the wall in any manner when first installed.

I also noted that the insulation was rotting away and part of one of the copper lines was visible, the other line was cover in what looked like to me electrical conduit. I arranged for the ac guys to come back and properly attach the lines so they’d run along the underside of the eave around the corner and down the wall to the unit.

They came today and did that while I was at work. The job looks good except only one of the lines has any insulation on it, presumably the suction line, the other line has none. Is this normal or recommended?

Aside from any possible hit on my ac’s cooling power (seems to be working fine) I’m not that keen to have any exposed copper lines outside given all the stories of people stealing copper. Thanks in advance for your answer.
asked in Cooling System by darekrudy (21,730 points)
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1 Answer

0 votes
Hi Mark,

The thicker copper pipe, as you correctly named it: suction line, is the only one that requires insulation because it carries low temperature, low pressure gas from the coil inside the house to the compressor on the exterior.

Lack of insulation would cause a lot a condensation and significant energy loss. The thinner line transfers high temperature, high pressure liquid gas from the compressor to the coil located inside the air handler.

Since it operates in already high ambient temperature, there’s no loss of energy (insignificant if any), and insulating is not necessary. An exeption would be if they travel through some areas where the surrounding air temperature is higher than 110°F - that's their approximate temperature (like attic), in which case insulation installation is recommended.

To “hide” your ac lines from… those people, you can use specially designed for such purpose “line set cover” (read my answer below). Let me know if there’s anything else I can help you with.
answered by darekrudy (21,730 points)
Mark says:
Thanks DR, I appreciate the quick, thorough answer!
You are welcome Mark. Whenever you have any questions concerning your home’s functioning, just ask