PVC pipe is lightweight and very durable, but I was curious about how it holds up in the sun as I heard PEX would fail if you leave it in the sun. I did some research, and here’s what I found.
As a general rule, PVC pipe will last 50 to 80 years in the sun. Interestingly, the sun does not affect PVC negatively in any way. The lifespan of PVC pipes is estimated at 50 to 80 years.
So PVC pipe will last a long time in the sun. However, are there any drawbacks to leaving it outside exposed to the sun or installing it on the house's exterior? All of these critical questions will be answered below.
Does PVC Degrade in Sunlight?
Sunlight is known to be very bad for PEX, and if it’s left in direct sunlight for 30 days, it will break apart. But, does PVC degrade in sunlight?
Overall, PVC does not degrade in sunlight. PVC is made to be resistant to sunlight and therefore is unaffected by sunlight in any way. PVC is OK to use on the exterior and as a main cold water supply. However, PEX is typically much easier to install.
PEX is bendy, unlike PVC, which is relatively rigid. Because PVC is rigid, it makes it slightly more challenging to transport and install. However, PVC is more lightweight than copper and is much less expensive.
PVC, on average, lasts half as long as copper pipes. PEX is likely your best option when doing a renovation because it’s the easiest to maneuver into position.
Especially when there are existing walls and fixtures, however, with new builds, you could go with either PVC, PEX, or copper, depending on your preference.
How Long Will PVC Last Outdoors?
Some pipes need to lead from the exterior of the house to the ground floor. Rainwater on the roof gutters also flows through pipes that are on the exterior of the house. But, can PVC pipes be used for that, and do PVC pipes last outdoors?
Generally, PVC will last 50 to 80 years outdoors, according to the Plastics Industry Association (source). Extreme weather is not accounted for as it is not considered general wear and tear. PVC is water-resistant and unaffected by the sun.
The white color also looks very elegant. But, this color will typically only last a year. And so you’ll want to paint PVC pipe that’s exposed to the sun. I’ll explain more about this point further below.
PVC Pipes Can Use Compression Fittings
The main advantage of PVC is that it is so light and makes it easy to install. You also don’t need to solder the joins, unlike copper, where you need to have an open blowtorch to solder the joins together.
With PVC, you can use compression fittings that are very easy to use. An open flame used to solder adds a range of complications. For example, you need to put up steel barriers on the walls not to burn the walls. And there is a risk of causing a fire. Therefore, overall it’s easier to use PVC or PEX.
Industry experts claim that some 50% of homes in the USA have PEX plumbing. Copper plumbing also was the GO TO method for plumbing and was well regarded as lasting for a very long time. It had the bonus of looking very nice.
As recently as the last 50 years, plastic plumbing has burst onto the scene and has a big advantage over copper in that it is dramatically cheaper. However, copper still holds the prize as the best-looking pipes.
Its surface does get a build-up of black/green oxide known as verdigris. As you may know, the Statue of Liberty has a copper finish that is green from oxidation.
I recently wrote about this in an article about [how to clean copper pipes, link: ‘how to clean copper pipes’]. It explains how to make copper pipes look new, and the interesting thing is it doesn’t require much work.
How Hot Can PVC Pipes Get?
PVC pipes are fine to be left in the sun, but I wondered whether they would melt at a certain temperature, especially since you can fry an egg on a car bonnet on some days! Here’s how hot PVC can get before it starts to change shapes.
PVC pipes can get as hot as 140°F (60°C) and still function. The hottest known day on record in the USA is 134°F (56°C). Therefore, they won’t melt and fail even on the hottest day.
However, PVC pipes should ideally not operate near the end of their temperature range all the time. Therefore, PVC pipes are not recommended to be used for hot water lines.
PEX or copper are better options for hot water lines. But, overall PEX is the easiest to install for hot water lines.
How Do You Protect PVC Pipe From Sunlight?
If PVC pipe is to be used outdoors, it’s generally a good idea to not leave it too long or protect it so that it doesn’t go a funny color. Here’s how to do that…
PVC can be protected from the sunlight by painting it. That will add a barrier between the sun and the surface of the PVC. Light colors are generally preferred because they remain cool when exposed to sunlight, unlike darker colors that get hot. Water-based paints are preferred as they adhere the best.
Paints that are oil-based or solvent-based can cause damage to the PVC pipes. It can also not adhere and begin to flake and split soon after you paint it.
People have observed that PVC pipes left outdoors will tend to begin showing discoloration within about a year. So, a good option could be to install it first and then paint it once it starts to discolor. There are also specially formulated paints designed specifically to be used on PVC.