No matter how carefully you plan for the operation of your homes, the occupants’ lifestyles and habits determine the buildings’ ultimate performance. Energy management systems can help customers achieve the energy efficiency they thought they would get from a green home.
Beyond basic whole-house monitors, installers can turn to packaged monitoring systems that offer more detailed feedback or to control systems that let homeowners automate energy-saving tasks.
While simple, whole-house monitoring can lead to proven energy savings, builders and remodelers can help homeowners fine-tune their homes further with energy management systems, such as Agilewaves or EcoView, that give feedback on individual systems or resources like gas and water. Agilewaves, for instance, has a resource monitor that can track individual electric loads, rooms, or floors of the home, or alternative power generation, in addition to gas and water.
For example, one Agilewaves customer installed a powerful solar array and discovered his inverter was failing at peak production—data he most likely never would have seen otherwise, says company chief technical officer David Brock.
Adding to the options are home control systems and intelligent HVAC controllers that not only monitor the energy a system uses, but also control settings based on occupancy, temperatures, or the cost of energy at a given time. Such systems, including Control4 and Crestron, are better known for their home theater and “smart home” controls, but some are now set up to integrate energy monitoring features, and at a more reasonable cost than luxury systems of the past, acccording to Bill Ablondi, director of home systems for research firm Parks Associates.
These systems build off such useful but underused technologies as programmable thermostats and lighting controls to also monitor the energy used by the products they control and provide feedback. In short, they make it easier to operate the home at peak performance. While they face many of the same challenges as home automation systems—builders may be unwilling to add to the home’s initial cost, and the systems might intimidate less tech-savvy homeowners—they can be a differentiator.
Homeowners can now operate and manage control and monitoring systems in a variety of formats, from the traditional wall-mounted touchscreen to a Web application to mobile phones or devices. Many of the companies offer e-mail or text alerts when certain energy or carbon footprint thresholds are met and can automatically take action, such as setting back the temperature, to decrease the load.
The systems vary in how they monitor usage. Some use individual load sensors that track the electrical draw of a device—a more accurate but more expensive method. Others simply calculate predicted energy use based on runtime and settings for a device.
Proving a return on investment is still an obstacle. At $500 for an entry-point controller and several thousand dollars for a full home control system, payback at current energy prices is six to eight years, says Eric Smith, chief technology officer of Control4, though he adds the company is working on a basic package that would cost less than $250. Agilewaves’ typical whole-house gas and electric monitoring system with details on seven circuits retails for $7,500, and prices can range higher or lower depending on capabilities.
Home energy hypermilers also will ask about the systems’ own energy use, which varies depending on the device. Brock says Agilewaves has been conscious about the resource monitor’s energy draw, and that the system pulls up to 30 watts at maximum.