Even if you’re ready for an electric vehicle, your home may not be.
Many older homes have electrical panels and wiring that can’t safely deliver enough amps to power EV chargers and other household tasks at the same time. The necessary upgrades cost thousands of dollars.
Two companies with local roots, Stepwise and Savant, say they’ve got a better solution. They’ve developed devices that can automatically adjust the amount of electricity sent to the EV or to other household appliances, to ensure that multiple high-powered devices can coexist on low-capacity power panels.
Stepwise recently relocated to Buffalo, N.Y., after receiving a financial grant from New York state. But the company was born at Somerville-based Greentown Labs.
While earning a degree at the Massachusetts Institute of Technology Sloan School of Management, cofounder Jane Chen decided to launch a company to install EV chargers in homes. But she soon learned that many older buildings would first require electrical upgrades.
But a new high-capacity panel and new electric wiring from the house to the utility pole can cost as much as $10,000. “And so I started to ask,” said Chen, “is it actually necessary?”
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Chen and her cofounders, mechanical engineer Austin Hunt and master electrician Ethan Brewer, say it isn’t. The average home typically uses less than 10 percent of the capacity of an electrical panel because power-hungry devices such as water heaters, stoves, washing machines, and dryers run only intermittently, said Chen. So, 100-amp systems, which are commonly found in homes, can easily handle a 40-amp car charger most of the time. The challenge is knowing when.
So Stepwise developed a smart power monitor that sits between the electrical panel and the EV charger. It measures total amps flowing through the panel and can automatically keep the EV charger from exceeding the panel’s limits.
If the homeowner has a basic charger, Stepwise merely switches it off till overall household demand drops to a safe level. But there are also “smart” EV chargers that can be remotely controlled via the internet. Stepwise can order such chargers to keep charging the car, but at a lower power level — say at 20 amps rather than 40. This way the battery keeps charging, but more slowly.
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Stepwise has begun selling its system in Massachusetts and Rhode Island. A typical installation, performed by a licensed electrician, runs about $2,000, not including the cost of the EV charger. It’s a pretty penny, but much cheaper than the alternative.
Meanwhile Hyannis-based Savant will soon offer Savant Smart Budget, a system that can manage the power consumption of multiple household devices, not just EVs.
Savant has been in the smart home business since 2005, making systems to enable centralized control of home lighting, climate control, security, and entertainment systems. But they’ve also been working on power management solutions like Savant Smart Budget, which is to go on sale in September at $1,500 for a basic setup.
The system uses modules that act like smart circuit breakers. One of them monitors total household power consumption. The others are attached to the circuits controlling heavy-duty devices such as air conditioners or EV chargers. And all the modules talk to one another.
With Smart Budget, the customer can program the modules to manage power usage by specific devices at specific times. For instance, a user could set it up to automatically power down the water heater when the EV is charging. Or it could cut power to the air conditioner between 1 a.m. and 5 a.m. every day, to let the car charge up for the morning commute.
Royal Simmons, president of Savant’s power management business, estimates that as many as 50 million US households have electrical panels with a capacity of 125 amps or less. With the Biden administration pushing for regulations to make most new cars electric by 2032, that could mean a vast market for Savant Smart Budget and Stepwise.
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Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him @GlobeTechLab.