Insulating outdoor A/C pipes

[Carolina Breeze HVAC]

Rubatex branded insulation, its about $4 a section at Lowes and Home depot, but about 99 cents a section at any legitimate supply center with a valid contractors licence, about $2 a section without. DO NOT use that cheap ass crap, or it will outgas and be gone in a few months. You are not insulating it from the outdoor heat, you are insulating it to keep it from sweating to the unit and creating damage inside the home as most of the time, the heat pickup will be minimal at best.

[Bob Scheurle]

I want to replace the insulation on my 3/4" copper air-conditioning pipes. The length is about 12 feet. There are two types of insulation available, polyethylene and rubber. Which would be best?

The polyethylene has 3/8" thick walls and an R value of 2. The rubber has either 3/8" or 1/2" thick walls, and I have no idea about the R value.

I'm primarily concerned about which one will insulate the pipe from the outdoor heat better, and withstand the sun, rain, insects, etc. Cost is not an issue.

Thanks...

[Edwin Pawlowski]

Does either one say anything about UV inhibitors? Everything being more or less equal, I'd go with the PE

[Bob Scheurle]

Thank you for your reply. Sorry for being a little thick-skulled here, but are you saying I should use the Rubatex or the polyethylene?

[Carolina Breeze HVAC]

You know..I went back and read that, and damn.it looks like I said not to use the Rubatex.. DO use the Rubatex. NOT that cheaper grey looking crap.

[Stretch]

The rubber stuff will outlast the other stuff unless painted with a UV inhibitating paint. However the rubber sometimes usees amonia af a blowing agent to make the rubber foam up. This amonia will react with the copper and make it brittle over time.

If rou the pipe is somewhere where it will be constantly wet, use the plastic foam.

There have been studies done on this. The effect is called "Stress Crack Corrosion" and can cause refrigerant leaks, especially in under ground lines. (Don't run lines underground for many reasons, this is just one of them).

The reason you insulate the lines, besides reducing the chance oc condensation damaging something, is to keep the refrigerant as cold as possible. The refrigerant cools the compressor motor better if it is cold, prolonging motor life. It also keeps the refrigerant hot gas discharge temperature lower, which is better for the refrigerant oil, as hagh temperatures can break the oil down. The compressor is a gas pump. It pumps just so many CFM at any given pressure difference. If the gas is colder, more mass is pumped, increasing efficiency. So insulate those lines and keep that gas cold.

And if the lines are outside, the insulation will last longer if you wse a UV retarding paint to coat the insulation.

All that said, I usually use the rubber as the best insulation for most of my applications.

Stretch

[Bob Scheurle]

Yeah, that's why I was confused! I wasn't sure what "that cheap ass crap" was.

The pipes have a rubber-type insulation on them, but it's 20 years old and not in great shape. I've got the garden cleared-out, so now's the time to replace the insulation, before the new plants and mulch go in.

Thanks... Bob

[Stretch]

20 years ago they probably used rubber. Put rubber insulation on the pipe(just the big one) If you want, you can dig under the pipe with a claw hammer, gently. Or you can lift the pipe, gently and put the insulation around the pipe. It isn't rocket science, Just don't be abusive to the pipe. Reasonable care should sufice nicely. Don't sweat it :-)

Stretch

[Carolina Breeze HVAC]

Now, thats punny.

[Bob Scheurle]

Now you're making me nervous. The pipes are 20 years old, and are just laying on top of the dirt. Maybe I should leave well enough alone instead of moving the pipes around trying to replace the insulation.