If Mr. J’s pump system is set at 20/40, he’s toast. Even if it’s set up to operate at 30/50, there’s going to be trouble brewing the instant a lower floor or lower-resistance-to-flow fixture is used. If you were water, which way would you go? Here’s your sign.

Well water systems contain higher levels of organic material than most municipal systems, which means greater odds for biofilm in the tubing and, therefore, more amplifiers for bacterial growth. Low flow in long horizontal lengths of tubing, no matter the materials used, promotes sedimentation and biofilm layers. Here’s your sign.

Free air conditioning? OK, let’s introduce that 55°F well water into the 1,000 ft. of in-floor PEX tubing for the 15-minute duration of Mr. J’s shower. Will this chill the room appreciably? Will the tubing sweat if it’s installed in a staple-up underfloor application and sees humid basement air? Will Mr. J need to lay flat on the floor to appreciate the benefits?

If Mr. J is on a municipal system, he won’t be getting chilled water and will likely be receiving water at or above his room’s air temperature during those peak air conditioning load days. Do the “benefits” outweigh the pressure, flow and health-related issues? Here’s your sign.

What about the claim that such a system increases the capacity of your water heater by up to 50%? That assumes the floor is heated to its upper limit, the circulator is running and the water heater has just finished recovering to full temperature. You know what they say about the word “assume”! Here’s your sign.

Dave Yates owns F.W. Behler, a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at .