Solar-Aware Building Design

A well-designed building will harvest the winter sun, reject the summer sun and collect daylight all year. The HPD Model 126 Heliodon makes it easy for anyone to learn the principles required for achieving solar access and shading. Within only minutes of use, the Heliodon evokes an "aha" response from both children and adults. The HPD Model 126 Heliodon can be used as a demonstration device, as an interactive hands-on teaching tool, and as an architectural design tool for testing and comparing alternative designs.


The Model 126 Heliodon is used as an:

  • Interactive hands-on teaching tool
  • Architectural design tool for testing and comparing alternative designs
  • Presentation tool to explain the virtues of a specific design

It supports and enhances design processes involving:

  • Building forms
  • Optimal building orientation
  • Shading systems
  • Solar collecting systems (passive, active, and photovoltaic)
  • Day-lighting (direct beam component)
  • Landscape designs that welcome the winter sun and reject the summer sun


- Conceptually Clear
Architectural models tested on the Model 126 Heliodon are not rotated or tilted, but remain fixed on a horizontal ground plane. This fixed-earth design simulates one's perspective, from Earth, of the sun's motion across the sky, resulting in exceptional conceptual clarity.

- Easy to Operate
The Model 126 Heliodon requires minimal training for use and is very easy to operate. Just plug it in, unfold the table, place your model on the table, and go!

- Simple Model Construction and Adjustment
The model is placed on a flat table and kept stationary; the sun lamps are the only things in motion. Therefore loosely constructed study models may be easily used on this device. This allows for quick, simple changes to be made to the model during testing.

- Mobile
The Model 126 Heliodon is set up on locking castor wheels and designed to fit through standard doorways when folded, thus it can be easily moved from location to location, or stored away when not in use.

- Weather Independent
The Model 126 Heliodon is weather independent, as it is used indoors and doesn't rely on actual sunlight for use.


  • 48" (1.2 m) diameter Formica covered table
  • Seven lamp hoops for all 12 monthly positions
  • Hoops are manually rotated to hourly positions
  • Lamp/month-selector switch on a 12' (3.6 m) remote cable
  • 5' (1.52 m) diameter equinox hoop for high accuracy
  • Calibrated latitude adjustment with 0 to 90 degree positioning
  • Locking brake for latitude adjustment
  • Welded steel frame with durable powder coating and locking castor
  • Overall dimensions: 28" (.71 m) deep, 76" (1.93 m) long, 70" (1.78 m) high
  • Total weight: 285 lbs. (130 kg)
  • Low voltage (12 VDC), 24° flood, MR-16 halogen lamp
  • Input power requirement: 110/220 VAC, 50/60 Hz
  • Crated and ready for shipping
  • One year warranty, excluding bulbs


HPD's Model 126 Heliodoon is your choice for solar energy modeling and education


"The HPD Model 126 Heliodon is conceptually simple to understand and easy to operate. It is an exceptional tool for teaching the principles of solar energy utilization in building design."

  ~Prof. Norbert Lechner, Architect
  Building Sciences Department, Auburn University

"The HPD Model 126 Heliodon is a very high quality instrument. It is well designed and exceptionally well crafted."

  ~Prof. Robert Koester, Architect
  Director, CERES Center, Ball State University

"The Model 126 Heliodon is a great teaching instrument that has generated a lot of interest among students and faculty. It is especially well made and attractive. Overall, the Heliodon is an A."

  ~Prof. David Ogoli
  Department of Architecture, Judson College, IL
   (Courtesy of Environmental Building News,
   Volume 12, Number 9, September 2003)

The Model 126 Heliodon sun emulator:
A powerful tool for building planners, teachers and architects.

Contact HPD for a price quote...

High Precision Devices, Inc.
4601 Nautilus Ct S Boulder, CO 80301 USA
Phone: +1-303-447-2558 Email: