Newsflash: There are a lot of great (and free) online resources for design professionals. When I am having exchanges about energy and environmental design analysis with colleagues and students, it seems like I am constantly referring them to any number of small, accessible online utility programs for performing simple — yet highly sophisticated — functions. Some would refer to these small programs as applets.

Below, I have endeavored to compile a collection of several applet resources that have proven valuable to me. These applets cover a range of energy and environmental design concepts. I hope this list serves you well!

I would like to begin by highlighting three particularly useful sites for energy and environmental design applets.

AndrewMarsh.com

Dr. Andrew Marsh, a former Senior Principal Engineer at Autodesk and creator of Ecotect (which makes him a rockstar in my book), graciously shares a collection of applets which he personally developed. The applets address a wide range of concepts including weather data visualization, the Earth and Sun's orbital relationship, dynamic shading and shadows, Sun-path diagrams, refraction effects and surface reflectance and incidence.

Energy Design Tools

UCLA Professor Murray Milne curates a number of applets which are highly regarded throughout the sustainable design community:

• HEED: Home Energy Efficient Design
• SBEED: Small Building Energy Efficient Design
• Climate Consultant
• Opaque (for wall/roof U-value, Time Lag, and Decrement Factor)

Center for the Built Environment

UC Berkeley's Center for the Built Environment (CBE) hosts several online tools for assessing thermal comfort and energy loads. Three of their applets are particularly worthy of mention:

• MRT Calculator - for assessing mean radiant temperature in a basic rectangular room.
• Setpoint Calculator -  for estimating potential energy savings from expanded thermostat setpoints.
• Thermal Comfort Tool - for evaluating comfort according to ASHRAE Standard 55.

More Applets for Energy and Environmental Design

The following list is a alphabetical list of other applets for energy and environmental design:

Cool Roof Calculator by the Oak Ridge National Laboratory

Calculates cooling and heating energy cost savings for putting a cool roof on small and medium-sized facilities. 

Degree Days.net by BizEE Software

Calculates custom degree-day data from Weather Underground temperature data.

Dew Point Calculator by Image Permanence Institute

User-friendly dew point calculator complete with long-term preservation evaluation.

Flash Tools by Lighting Analysts

Web-based calculation tools for indoor and outdoor lighting analysis.

SRI Calculator by LBNL, hosted by USGBC

This simple Excel-based applet allows users to determine the Solar Reflectance Index (SRI) of a surface simply by inputting the solar reflectance and thermal emittance.

Project Sunroof by Google

A solar calculator that uses Google Maps to help determine a roof's solar savings potential.

Reverberation Time Calculator by Georgia State University

Calculates the approximate reverberation time for a simple rectangular room based on user inputs.

SunCalc by Vladimir Agafonkin

Illustrates the Sun's movement and sunlight phases for any day at a specified location using Google Maps.

PVWatts Calculator by NREL

Estimates the production and cost of energy of grid-connected photovoltaic (PV) systems.

Windows for High-Performance Commercial Buildings by the Efficient Windows Collaborative

This site features the simple Facade Design Tool to help designers and/or contractors specify windows for high-performance commercial buildings. 

Window Selection Tool by the Efficient Windows Collaborative

This web-based tool can help designers and/or contractors specify new or replacement windows for residential buildings. 

Zero Tool by Architecture 2030

Calculates building energy use baseline and target data based on a few simple inputs.

What did I miss?

Please reach out to me if I should consider adding other applets to this list!