Electrical contractors pursuing alternative-energy and efficiency-upgrade projects may have better business-development luck these days than some of their new-construction-focused colleagues. U.S. homeowners added 93.9 megawatts of capacity to their roofs in the first quarter of 2012 alone, according to the Solar Energy Industries Association, and utility and state incentives are making other efficiency upgrades more affordable for homeowners and businesses alike. Making this work easier are smartphone apps that can help answer installation questions and calculate savings on the fly.

The following are just a few of the more prominent solar, lighting and motor apps now available. Most are free, so trying them out won’t be a big investment.

Solar assistance
A successful solar-panel installation requires contractors to understand the sun’s relationship to the panel, both through the day and the entire year. Understanding the sun’s relative position also requires considering potential shade factors, such as nearby trees or neighboring buildings. The following apps can help make such calculations easier.

Solar Shading (Comoving Magnetics, $14, Android only) is the most expensive app on the list but also among the best reviewed. The developer offers a range of electrical-related apps. Using your phone’s compass, global positioning system and accelerometer, the program creates a complete solar-shading analysis in just a few minutes, including a graphical representation of the sun’s path and a chart illustrating the percent of daily hours lost per month because of shade. The calculations are done on your phone, so you only need a data connection to start the app.

PV Toolbox (Comoving Magnetics, $2, Android only) is a more basic version of the Solar Shading app, providing assistance with rudimentary string sizing and system characteristics. It also calculates sunrise and set times and the solar azimuth elevation. Users can add panels to their designs on the fly.

Photovoltaic Estimation Tool (Onyx Solar, free, Apple and Android) enables the user to estimate yearly kilowatt-hour (kWh) production and CO2 emissions avoided. Simply place the mobile device in the position and angle for the potential panel installation, and enter the installation’s square footage. Onyx manufactures both polycrystalline and thin-film photovoltaic products, but the production data should be fairly generic across manufacturers.

Lighting information
Lighting upgrades are among the most appealing for commercial building owners because they often offer quick payback, incentives often are available, and there’s a degree of both urgency and excitement in the lighting market as less efficient technologies exit and light-emitting diodes (LEDs) become more prevalent.

Light Bulb Finder (Eco Hatchery, free, Apple and Android) won last year’s Apps for the Environment Challenge, sponsored by the Environmental Protection Agency. It makes finding higher efficiency alternatives for incandescent lamps easy. It is of limited use in commercial projects—linear fluorescent lamps aren’t addressed at all—but it covers just about every other fixture style a residential contractor is likely to see. Results include payback times based on local kilowatt-hour rates and number of hours used per day.

LED Retrofit Savings Calculator (Philips Lighting, free, Apple and Android) draws heavily on Philips’ EnduraLED catalog of LED lamps, but it still can help you perform back-of-the-envelope calculations on potential energy savings when upgrading to a range of LED offerings. Users enter basic data, including existing lamp styles and wattages, the number of fixtures and current kilowatt-hour rates, and the app figures both kilowatt-hours and resulting dollar savings.

Classroom Lighting Calculations (Litecontrol, free, Apple and Android) also draws on a specific manufacturer’s catalog, but the calculations may be generalized to non-Litecontrol fixtures. Users can choose between three different classroom arrangements and two- and three-lamp fixture styles. Plug in the average kilowatt-hour charge, and you’ll get an output of that classroom’s annual lighting-energy cost, along with specifics on foot-candles, total wattage and watts per square foot.

OPTOTRONIC LED Power Finder (Osram Sylvania, free, Apple) brings the portfolio of power supplies to the fingertips of designers and specifiers. The app includes detailed product specifications, including regulatory and safety compliance information, for the full OPTOTRONIC portfolio. Furthermore, the LED Power Finder app has an LED Match function that identifies the best product for a given SSL system or application, and it allows users to tag products to a My Power Supplies list for easy access to frequently needed information.

Revving up motor savings
Fan and pump motors can largely affect a commercial or industrial facility’s electricity bill, especially if the owner hasn’t yet switched to variable frequency drives.

Rockwell Pump Energy Savings Calculator and Fan Energy Savings Calculator (Rockwell Automation, free, Apple, Android and Blackberry) both draw from the catalogs for Rockwell’s Allen Bradley PowerFlex drives, so the results may not be completely accurate for other makers’ drives; however, they could prove helpful for rough estimating. Users enter data on the existing fan or pump in use, along with annual operating time and kilowatt-hour costs to get results on potential savings and paybacks. The apps both offer basic, intermediate and advanced input levels, based on available current-equipment data.


ROSS is a freelance writer located in Brewster, Mass. He can be reached at chuck@chuck-ross.com.