Most people regard electricity as a wonderful thing on most occasions. There are two exceptions: One is when it goes out, and the other is when we get the bill. In recent years, power and energy management have come to the fore as ways in which custom integrators can provide meaningful and actionable insights for their clients. Such systems not only monitor electricity usage so customers know where their utility costs are coming from in their homes, but also can be programmed to manage it all efficiently. 

Additionally, through networked power devices, dealers can tap into potential recurring revenue by delivering valuable data while also maintaining their systems without having to roll trucks all the time for service. Let’s take a closer look at this increasingly attractive category.

Doing Some Math on the Value of Power Management

The main reason it’s challenging to know exactly what we are paying for is a mysterious commodity called kilowatt-hours, or kWh. Kilowatt-hours are a difficult quantity to understand, and even harder to measure effectively.

Energy is generally measured in Watts (W), which are the product of Voltage (V) and Current (I). According to Ohm’s Law, W = V x I, so multiplying the Voltage (usually 120V or 240V in US residences) by the current usage in Amps gives us the Watts used by each device at that moment. 

But most devices don’t use full power all the time. Lights get turned on and off or dimmed; air conditioners and refrigerators cycle on and off; and most appliances and electronics are used intermittently. So, knowing how much electricity a device consumes at maximum power only tells half of the story.

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Measuring the operating cost of a device requires monitoring the power usage over a period of time and accumulating those readings for each device. For each home, the electric utility company provides a device that does exactly that, but for the entire home, and only for the duration of their “billing period.” The information is useful to the utility for billing purposes, but not particularly useful for consumers to manage and conserve their usage. 

Utilities bill for kWh, which is a calculation of the power drawn multiplied by the time it is drawn. So, a 100W light bulb burning for 10 hours at full brightness will consume 1kWh of power (0.1kW x 10hr = 1kWh). Calculating the total kWh for every electrical device in a home for an entire month would be a daunting task!

Fortunately, there are several solutions to this problem, at varying costs and features.

A Brief Look at Power Monitoring Devices

Power monitoring devices enable detailed views of electrical consumption by reading electrical current at your main circuit breaker panel. Although they don’t actually “save” energy, they deliver insights into usage that can save far more than their original cost.

For example, when I first installed an energy monitor in my home, I immediately saw that my old refrigerator I kept in my garage for parties and extra storage was not working properly and was using over 5x as much power as it was supposed to. It was an easy decision to replace it, and the new refrigerator paid for itself in about six months with the electric bill savings! 

It also showed that devices that I never considered as energy hogs, such as cable TV boxes, printers, and computers that were powered 24/7 used far more power than most of my home appliances like the dishwasher and washing machine, that draw power infrequently. And incandescent lights that were usually dimmed to low levels were not a significant contribution to my bills.

For customers of certain utility companies that use specific Zigbee meters, keeping track of electrical usage can be simple and inexpensive. The Emporia Vue: Utility Connect (emporiaenergy.com) simply plugs into any electrical outlet near the meter and receives the same data that is being sent to the utility. It converts the data to Wi-Fi and transmits it to Emporia’s cloud servers, making it available via phone or web app. The device needs to be registered with the utility (some offer a rebate that nearly covers the $40 cost of the device). 

The Utility Connect App shows power consumption every 10 seconds, and offers graphs detailing usage by minute, hour, day, week, month, or year. It reads in Watts, kWh, or actual cost.

Another approach is to attach current-monitoring transformer sensors to each main conductor in the circuit breaker panel and connect them to a power monitoring device. This will work regardless of the type of meter installed, but it requires physical attachment to the high-voltage conductors inside the panel and installation to a pair of breakers for power, which might require a licensed electrician.

It also requires room inside the breaker panel to install the device and sensors, or installation of another electrical box adjacent to the panel. For the normal single-phase split feed power (120v/240v) power found in the U.S., two sensors are required. For three-phase power, three sensors are needed. To monitor a system with solar production, an additional pair of sensors are used to measure the solar power feed.

You can see the result of turning a specific device on and off, but there is no breakdown by device, making it difficult to determine the actual monthly cost of individual devices. Typical home electricity usage involves multiple devices drawing power simultaneously, and many devices draw varying amounts of power over time, so it’s more difficult to separate the electric usage cost by device than it is with water usage.

Breaking down cost by device requires individual monitoring of each device. That can be done by attaching a current monitoring transformer to each branch circuit in the circuit breaker panel, or by plugging devices into an adapter that monitors (and often controls) that device.

The Sense Energy Monitor (sense.com) is a popular device for this purpose. It is available with one pair or two pairs of sensors — the one-pair unit is for single-phase split power up to 400A. The additional pair may be used for solar power monitoring, or to break out two specific circuits, such as HVAC or a refrigerator. It uses machine learning AI to differentiate between different types of devices. 

Sense is available as a standalone device, and it is integrated into other manufacturers’ systems, such as Schneider/Square D’s Smart Energy Center (se.com).

The Emporia Vue Home Energy Monitor is a similar device, with additional capabilities. It supports up to 200A single-phase split service or three-phase service. It’s available with up to 16 additional 50A sensors that can be used for solar or for monitoring specific circuits. Emporia also offers smart plugs that enable monitoring of specific devices and allow them to be remotely controlled. 

The Emporia App consolidates everything, letting customers see total consumption plus individual load and circuit consumption. Smart plugs can be defined as subzones of other circuits, so you can break out a home theater, home office, or a particular plug-in appliance from the branch circuit feeding it. This makes the data far more useful, especially if there are unrelated devices on a single branch. It can even use overall power data from the Emporia Vue: Utility Connect if attaching to the main conductors is difficult or hazardous. Emporia offers thin flexible sensors to make installation in tight panels easier.

Smart plugs are available from several manufacturers that also offer power monitoring. However, these are standalone devices that do not evaluate a circuit’s consumption relative to the entire home, and therefore the data that they provide is not particularly useful to understand overall consumption patterns. The Emporia devices are completely integrated via their App.

Combining Power Monitoring with Control

The next level up are systems that monitor and control power, integrating both functions to offer better performance and unique capabilities. While products like Sense and Emporia Vue are intended for simple retrofit installation, the integrated systems are generally more suitable for new construction, or when upgrading an existing electrical service. They usually require permits and installation by a licensed electrician.

SPAN.IO (span.io) offers the SPAN Panel, which is a 200A single phase split power 32-circuit smart breaker panel. It installs similarly to a conventional panel, but the current sensors and controls are built in, so the installation is much cleaner, and it has a very attractive appearance. If it resembles a Tesla car, it’s not surprising, since the founders of the company are former Tesla engineers. The panel even lights up to make it easier to find and reset a tripped breaker (your phone will probably tell you which breaker has tripped, although for safety reasons you can’t remotely reset a tripped breaker).

It is also designed to accommodate solar or wind production as well as a backup generator. This is one area where the combination of monitoring and control gets interesting. For traditional backup systems, the generator or battery pack is usually sized to only provide power to critical circuits during a mains power failure: refrigerators, a few lights, etc. This is because larger generators and batteries are far more expensive to buy and to run. 

To differentiate between “critical” and “non-critical” circuits, either separate electrical panels or multicircuit transfer switches are installed, and wiring is more complex. In addition, what is deemed to be “critical” might change over time; a new network device or health care product may be plugged into a circuit that was not originally designated as “critical”, or during a heat wave outage, you might really need a few minutes of HVAC while you keep the refrigerator doors closed. 

Since these smart panels have control of individual circuits, it is possible to reassign critical circuits dynamically, rather than by wiring. 

The apps for these panels make it all simple — they can automatically sense mains power outages and drop circuits as needed to prevent overload of generators or back-up batteries.

The SPAN panel has a capacity for 32 full-size circuit breakers of a variety of types and ratings up to 90A, from Eaton, Siemens, and Square D. With half-size breakers, more than 32 circuits may be accommodated, although the half-size breakers can only be controlled and monitored in pairs. 

Savant Power (savantpower.com) recently entered this category as a dedicated division of Savant Systems, mainly through strategic acquisitions and partnering with established companies, but its initial offerings are very exciting. Rather than a proprietary breaker panel, they offer a series of modules that resemble industry-standard circuit breakers and install in most standard load centers adjacent to the circuit breakers they monitor and control or in a standard subpanel. 

This presents a lot of cost savings and flexibility. The only requirement during rough-in construction is to install a larger load center panel than the expected number of circuits would require, to allow space for the control modules. Since this is just some extra sheet metal, the additional cost to prewire a home for the Savant Power system is minimal. The Power Modules can be installed as needed, so the cost is relatively linear as the number of monitored circuits increases. 

Each Power Module has a current sensor and a control relay, as well as a built-in OLED display that shows power draw, connectivity, and the name of each connected circuit. The modules communicate via Bluetooth Low Energy (BLE) with a Power Director Module located nearby, which connects to the network. This means multiple load center boxes can be combined into a single system.

In addition, Savant offers lighting dimmer modules that fit the same load centers, so lighting loads can be individually dimmed and monitored centrally, similarly to a Lutron HomeWorks installation, but within the same panel rather than requiring a separate enclosure for the dimmers. Everything is configured, controlled, and monitored in the Savant Power App, or with the same Savant Pro App used to control other AV and lighting devices.

They have established partnerships with several prominent manufacturers of battery systems, inverters, generators, and electrical products, and promise close integration with those products to create seamless power delivery and distribution.

Leviton (leviton.com) has taken the opposite approach — instead of creating a “smart” panel that contains traditional circuit breakers, it has integrated the electronics into the breaker itself. Their “smart breakers” plug into their traditional panels, although they have some sleek new panel offerings to match. You can mix Leviton smart breakers with their traditional breakers in a panel. A data hub within the panel connects the breakers via Ethernet or Wi-Fi to the App. The overall system is attractive and convenient but lacks certain features and integration support of SPAN and Savant. 

An interesting difference is that you can remotely trip any Leviton smart breaker (other than the main one) via their App, but you cannot remotely turn it back on, for safety reasons. With SPAN and Savant, the power relay is independent from the breaker, so you can turn circuits off and on remotely without tripping the actual breaker.

Schneider/Square D has created a new panel called Square D Energy Center that combines several devices under one roof — a load center, electric meter panel, Sense power management, critical load management, solar, backup, and a generator outlet and transfer mechanism into a single unit. It is a nice package, but with relatively traditional technology. 

They are also launching the new “Schneider Home” system later this year with more integration with solar and battery systems. Schneider Home (schneiderhome.com) will introduce the new “Schneider Pulse” panel which promises additional features and a more compact size to ease retrofitting in existing homes. The Schneider Home system will include solar, battery backup and EV charging.

Adding Alternative Energy Sources & Backup Power

Implementing local solar or wind power generation is an important component of any power management strategy. All these power management products are designed to support connection of local generated sources and properly measure their contribution and cost savings. 

In addition, by accumulating data over time, they can indicate if there are issues with the local systems that are reducing the output. Grid-tied solar installations are simple to attach and monitor. Solar installations that include battery backup are more complex. Different manufacturers support different battery systems, so coordination is crucial.

When it comes to backup power, while local uninterruptable power supply (UPS) systems have their place to protect small critical loads such as computers, security systems and network devices, whole-home battery backup systems will keep every device operating if mains power fails. Operating time varies with the load, but combined with solar power, indefinite operation is possible. 

To extend the operating time further, integrating with a smart load center allows some loads to be automatically disconnected or reduced during a mains power outage.

Savant has heavily invested in battery backup systems and offers close integration with their battery systems, enabling batteries to store and supply power as needed to manage consumption and demand, as well as prevent outages. 

As utility rates go up, and with utilities trying to limit peak demands to avoid new power plant construction, there is a need to adopt creative power management to manage costs. Batteries can be an important part of these strategies, but the overall management can be far too complex for most users. 

Integration of all sources and power loads into a single system can manage everything far better, deciding when to charge batteries and electric vehicles, when to reduce or cut off loads, and when to draw power from the grid automatically and dynamically.

Backup generators are another key component. They can provide large amounts of power for extended periods, relying on locally stored fuel or natural gas. Generator power is not dependent on sun or wind, so it is always available, but it is expensive and noisy to operate. It does not run in sync with the grid power, so it requires a transfer switch to isolate it from the grid. 

Backup generators can be permanently installed, or a portable generator may be plugged in when needed. Permanently installed units such as the Generac Guardian (generac.com) run on either natural gas or propane, while portable generators more often use gasoline or propane. Portable generators need to be started when power goes out, but most installed units will start and transfer automatically. 

Transferring from grid power to a generator may take a few seconds, and may be accompanied by surges, noise, and voltage fluctuations, so sensitive electronics may be affected adversely during the transition. A UPS or battery backup should be provided for sensitive electronics such as computers, network equipment, and AV devices.

Some of the smart breaker panels will support a variety of generator connections, but many offer only limited support. Homes that include grid power, solar/wind, batteries, and a generator require complex design engineering and management, but having the ability to manage them all allows for robust power availability at a minimum operating cost. 

How Power Quality Impacts System Design Decisions

With the proliferation of sensitive electronic components throughout most homes, especially high-tech homes, power quality is an increasingly vital issue. 

Surge protection is critical, but only solves part of the problem. Surge protection should be installed in layers, with primary protection at the service entrance to block and weaken major surges, then additional lower-threshold protection downline to protect more sensitive electronics. Whole-home surge suppressors are available from a variety of manufacturers and are also available to plug into many load centers.

Grid power, although generally reliable in most areas, can suffer from noise, surges, brownouts, and other more insidious disturbances that most surge protectors cannot protect against. Solar or wind power sources are variable by nature, and battery power and generators have limitations. In addition, switching between alternate power sources can induce serious glitches on the power feed to all devices. Most UPS systems, while protecting from complete loss of power to protected loads, only offer limited immunity to such spurious power issues. 

That’s why some companies offer management systems to completely isolate power within a home from these disturbances. Rosewater Energy Group (rosewaterenergy.com) has their SB20 Energy Hub (which CE Pro spoke to RoseWater about last year), for example, which has redundant power systems to provide high reliability and can be provided with extended battery packs for long outages.

They do it by creating a large online UPS system where the various sources of power are used to charge banks of batteries, then the battery power feeds inverters to regenerate 120v/240v clean 60Hz sine-wave power that is decoupled from the grid and other sources. They are designed to store enough power to prevent blackouts even under extended grid-failure conditions. 

The Tesla Powerwall (tesla.com), SonnenCore (sonnenusa.com), Kohler (kohlerpower.com) and other home battery systems do offer extended whole-home backup power, but do not include the robust isolation the Energy Hub provides.

Where Do Electric Vehicles Fit into the Mix?

When you add one or more electric vehicles to the system, there are even more advantages. Emporia Energy, SPAN, and Savant Power all offer electric vehicle charging systems that integrate with their power management products and are generally compatible with other brands as well. 

SPAN and Savant can not only monitor power consumption by an electric vehicle charger, but can also control it, so power is used when electric rates are lower, and when the grid is active. During a power outage, vehicles will not be charged — although the user can override that if it is an emergency. If there is more than one EV charger installed, the system can automatically switch between chargers to prevent high peak consumption or reduce the charging rates to allow both vehicles to charge at the same time. 

Savant and Emporia are promising an upgrade to allow some EV’s to even provide power to the home in an emergency through their charging port. 

Since this is all controlled by the Apps, it can easily be configured and reconfigured as needs change, and all the data is in one place and easily accessible to the owner.

Helping Your Customers Choose a Power Management Solution

Energy and power management is an exciting new industry and is still in its early phases. Most manufacturers offer vastly different solutions to overall power management, so matching a solution to each specific project is critical to offering the best value for the client. It also means that the stability of each manufacturer (and their commitment to their product lines) is just as crucial.

The market is a mix of new startup companies as well as traditional electrical manufacturers, many of whom have jumped into the market through acquisitions as well as traditional in-house research and development. 

Additionally, the federal Inflation Reduction Act of 2022 has brought billions of dollars to the energy market, bringing down costs and barriers to entry. Solar sales and installation companies are looking at power management systems as an add-on to solar sales. However, custom integrators are still in the best position to offer these systems to their clients, or as a way to attract new clients at all budget levels. 

For existing installations, the add-on monitoring products are a safe bet — they are low-cost solutions, quite easy to install in most cases (be sure to do a thorough site evaluation before committing to an installation), and the information provided to the client can be transformational. They are also especially useful if you have very different types of loads on one circuit, such as lights and a refrigerator, or to break out monitoring of different devices in a home theater or office.

Upgrading a main load center panel can be complex and expensive and will require the customer to be without power for a while. Generally, an upgraded panel will also need to comply with the latest electrical code requirements, such as GFCI and AFCI breakers, solar provisioning, etc.

For new construction, each product has advantages and disadvantages. Consider how each product and manufacturer matches with the clients’ needs and site issues. Many of the manufacturers will provide direct hands-on support for dealers to assist with marketing, sales, installation, and post-installation support.

How the product will match the workflow of the project architect, electrical engineer, and electrical contractor can also be decisive considerations. Decisions about load center locations, circuiting, lighting control, EV charging, solar and backup systems will impact the design of a power management system and influence the choice of products. For the best power management options, provision as many circuits as practical, rather than combining multiple loads into a single circuit. It’s best to get involved early in the design process.

ORRIN CHARM (orrincharm@gmail.com) has been in the smart home industry since 1989 as a system designer and engineer. His consulting company, Charm & Imagination, is based in Simi Valley, Calif. 

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