Copper or PEX radiant heat baseboard supply in crawl space

BradHotNCold

House located in MidCoast Maine. Crawl space insulated on perimeter walls with blue-board. No insulation in floor joists.
Just had a freeze leak (location not yet determined, but suspect it is in crawl space). Radiant hot water baseboard heat fed by copper piping. As we look for leak, does it make sense to consider replacing copper with PEX. This is a second home, and ADT heat detector system apparently failed as we received no call about the loss of heat. Fortunately, I had turned off the well pump, so we did not lose our water supply! Not sure about costs, yet, and have not asked plumber for quote on my idea. All suggestions welcomed.

And Happiest of Holidays to Dan and all the DeadHeads who turn out in the snowy winters to keep their customers warm!

Jamie Hall

Tough call. With PEX, you're kind of pushing the temperature limits with baseboard heat, but if you can keep the highest temperature down below 160 -- certainly below 180 -- it survives pretty well. And it doesn't burst as often when it freezes. Use Oxygen barrier, if you do go PEX, and I'd support it in troughs -- otherwise it sags and becomes almost impossible to drain if you ever need to.

Copper is a much better solution, quality wise, in my opinion -- but when it freezes, it bursts, every time.

Either one is more reliable than a heat detector alarm, unless the latter is locally monitored by someone coming by.!

hot_rod

Remember that the id is smaller and on long loops it will make a difference.

Consider Pex al Pex and also buy straight 20' lengths, it works easier in crawls compared to coiled 3/4" regular pex.

I like Viega Fosta pex, it does require a special tool to remove extra outer jacket for crimping.

flat_twin

What happened that allowed it to freeze? Power outage? For a 2nd home that's unoccupied at times during the winter maybe a glycol mix should be considered?

BradHotNCold

Thanks to all. Forgot to mention that much of the copper is uninsulated. Perhaps fiberglass pipe insulation and glycol solution are best ways to go.

Ironman

Also: if the system is zoned, make sure all of the thermostats are calling for heat and that one zone isn't heating the other one. That can cause the pipes to freeze in the one that's not heating.

BradHotNCold

Good point, as there are three zones.

motoguy128

I’m northern climates, I think at least 20% glycol is a smart move with a crawl space or low temp radiant floor systems or low mass systems. Seen too many frozen systems.

The slight loss of performance is worth the piece of mind if there’s a longer power outage.

hot_rod

> @motoguy128 said:
> I’m northern climates, I think at least 20% glycol is a smart move with a crawl space or low temp radiant floor systems or low mass systems. Seen too many frozen systems.
>
> The slight loss of performance is worth the piece of mind if there’s a longer power outage.

Maybe boost the inhibitors at 20% blend %. I think Dow suggest 30% minimum blend

Gordy

You can up size to 1” pex to gain the reduced diameter of 3/4” pex if runs are long.

The temp ratings can be misinterpreted.

Pex is good up to 200 degrees at 80psi. Far above the usual 12 psi in most hydronic systems.

motoguy128

Good point. PG should be above 25% to prevent microbial growth. Although it’s already pretty well inhibited. Seen industrial system with food grade PG in chilled water system at 20-25% or Lower without any noticeable issues.

Ironman

Use type A PEX with cold expansion fittings which are much less restrictive than crimp fittings.