Turning sunlight into hot showers: best kits or hacks?

I hear you on the copper prices - last time I checked, it was almost double what I paid a few years back. I did a similar thing with my solar setup: started with CPVC near the collector, then switched to PEX for the runs inside. Like you said,

“CPVC...handles heat decently and is a lot easier to cut and glue than sweating copper joints.”

Funny you mention transition fittings - that’s where I always get a bit twitchy. Had a buddy who thought he could save a few bucks with off-brand adapters, and it turned into a slow drip nightmare behind his drywall. Ended up costing him more in repairs than if he’d just gone with the good stuff from the start. Have you noticed any difference in how the PEX holds up over time compared to CPVC? I’ve seen some folks claim PEX gets brittle after a few years in direct sun, but I haven’t run into that myself... yet.

Transition fittings are always the wild card, aren’t they? I’ve seen way too many “budget” installs go sideways because someone tried to save a couple bucks on connectors. The off-brand stuff just doesn’t hold up, especially if you’re mixing materials. I get why folks try it - those name-brand fittings can be stupid expensive - but it’s not worth the headache when you’re tearing out drywall six months later.

On the PEX vs CPVC thing, I’ve worked with both over the years. PEX is great for flexibility and speed, but yeah, direct sunlight is its kryptonite. I’ve actually seen some lines get chalky and brittle after a few years in crawlspaces with sun exposure. Not super common, but it happens. Most of the time, if you keep it shielded or run it through conduit where it’s exposed, it’ll last ages. CPVC doesn’t care about sunlight as much, but it’s way less forgiving if you need to snake around tight corners or do any kind of retrofitting.

One thing I’ve noticed - PEX can sometimes get a little “memory” if it’s been coiled up too long, so you end up fighting with it to lay flat. Not a dealbreaker, just annoying. CPVC is more rigid, but that also means if you bump it wrong during install, you risk cracking it. I’ve had more than one apprentice snap a length just trying to muscle it into place.

If you’re thinking solar hot water setups, I’d lean PEX for anything inside or protected. For outside runs or spots that see a lot of UV, either use UV-rated PEX (it exists, but costs more) or stick with CPVC and just deal with the extra elbows and glue. Either way, don’t cheap out on the fittings - learned that lesson the hard way more than once.

Funny how plumbing always comes down to “pay now or pay later,” huh?

That “pay now or pay later” line really sums it up. I’ve had my share of headaches from tenants calling about leaks, and nine times out of ten, it’s a cheap fitting or someone trying to mix brands. I get the temptation to save a few bucks, but when you’re the one footing the bill for repairs and water damage, it just isn’t worth it.

On the PEX vs CPVC debate, I lean PEX for most retrofits inside rentals - just easier to snake through old framing, and less mess overall. But you’re right about sunlight. Had a run on the south wall of one property that got brittle after a couple summers. Ended up replacing it with UV-rated stuff and wrapping it in insulation for good measure. CPVC is fine if you’re doing straight runs or new installs, but I’ve seen more than one rookie snap a pipe trying to force it around a corner.

For solar hot water, I’d echo the advice - keep PEX shielded or use CPVC outside, but don’t skimp on connectors. The upfront cost stings less than dealing with a flooded ceiling down the line.

Gotta admit, I’m not totally sold on CPVC for outdoor solar lines. Maybe it’s just my luck, but I’ve seen it get brittle and crack after a couple winters - especially if it’s not painted or protected. PEX with a UV sleeve or conduit seems to hold up better for me, even if it’s a bit more work up front. Plus, those push-fit connectors are a lifesaver when you’re crawling under a deck and drop your wrench for the third time...