About Us

Who We Are

Appropriate Designs is a team of engineering professionals dedicated to advancing the science and proper application of modern hydronic(water-based) heating. We are specialists in the application of engineering principles, computer aided design, technical writing, and teaching. We integrate these capabilities as necessary to continually develop new support materials for the hydronics industry.

Specific services discussed in detail on this website include:

  • Development of customized design and analysis software
  • Development of training publications for hydronic heating

If you have a project that requires technical support in the field of hydronic heating, please contact us to discuss how we might assist you.

Company History

Appropriate Designs was formed in 1983 by John Siegenthaler to provide engineering design services specifically focused on low-energy-use buildings. Specialties include solar energy applications, super-insulated construction, and hydronic heating.

In the years that followed, Appropriate Designs developed construction plans and energy systems for dozens of homes and light commercial buildings. Many used advanced energy systems including solar heating, geothermal heat pumps, and off-peak thermal energy storage. Many of these systems where based on the use of hydronic heating technology.

During the 1990s, Appropriate Designs began offering customized training seminars on hydronic heating, specializing in radiant panel heating. Since then, hundreds of seminars and workshops have been presented across the US and Canada.

Today the company focuses solely on state-of-the-art application of hydronic heating. Through extensive research and application of engineering principles, Appropriate Designs has developed advanced modeling methods for simulating the thermal and hydraulic performance of hydronic systems. These models have been used to develop software-based sizing and selection programs for several manufacturers, as well as numerous publications, and training seminars.


Principal: John Siegenthaler, P.E.

John Siegenthaler is a mechanical engineering graduate of Rensellaer Polytechnic Institute and a licensed professional engineer. He has over 36 years of experience in designing modern hydronic heating systems. John is also an Associate Professor Emeritus of engineering technology at Mohawk Valley Community College in Utica, NY. He is the author of the textbooks Modern Hydronic Heating, and Heating With Renewable Energy, and has written numerous other publications dealing with hydronic heating.

Associate: Mario Restive

Mario Restive is an Engineering graduate of Cornell University and has done extensive graduate course work in Computer Science at SUNY IT. He has been an educator for over 32 years in the Engineering and Engineering Technology field and retired as an Assistant Professor in the Mechanical Engineering Technology Department at Mohawk Valley Community College in Utica New York. Mario has also consulted in industry over the past 30 years, specifically in product design, machine design, computer-aided design and computer modeling. Currently Director of Research and Development at The Fountainhead Group where he has received 13 U.S. and 11 international patent. He is Co-developer of the Hydronics Design Toolkit, Heat Load Pro, Hydronics Design Studio software and has developed other engineering related custom designed software packages for national and international firms. His interests are in computer modeling, simulation, and discrete optimization of Engineering systems.