We’re celebrating John Siegenthaler’s 25th anniversary as a Plumbing & Mechanical columnist. Siggy, a well-respected hydronics expert, is a consulting engineer and principal of Appropriate Designs in Holland Patent, New York. His Hydronics Workshop column is the most-read column on This eBook features Siggy’s most-read content from both Plumbing & Mechanical and PM Engineer, covering topics ranging from piping to thermal storage tanks to the dos and don’ts of hydronic system design.

John Siegenthaler’s Top 25 most-read articles

Shower head with water coming out
Liquid, Water, Azure, Purple, Fluid, Violet

Sensible plumbing

Common sense is the best guarantee of a well-performing, safe plumbing system.

Tail pipes and back alley shops

Lessons learned from those that came before.

Why 120° F is not a safe water temperature for potable water storage vessels

Preventing Legionella while protecting against scalding at points-of-use.

Dead wrong

It never hurts to perform your own inspections.

Feeling flushed

The lost art of repairing flush ells.

Inverter air-to-water heat pumps

Tips and tricks for adopting this increasingly popular technology.

Twinning water heaters

The best method for piping two water heaters.

The battle of the joints

The pace of change in the plumbing industry seems to be a bit faster than it was prior to 1954.

Watts up, Doc?

Troubleshooting an electric water heater.

Batting cleanup

Fixing others’ installation and servicing mistakes.

Waxing eloquent

Wax Toilet-Bowl Gaskets: Do you like them plain or with a horn?

Orphaned water heaters

The importance of proper venting.

Interior design, Product, Toilet, Flooring, Bathroom, Floor, Comfort