Judy Wicks is studying her cellphone, checking the app that tracks the amount of electricity her solar panels are generating versus consumption.

She coordinates her activities based on what the graphs on the phone app show her.

"I cook when the sun is at its highest point," Wicks said, as a cloud moved in front of the main source of energy for her house in the city's Fitler Square neighborhood. Ditto using hot water for showers, dishwashing, and laundry.

Since March, rooftop solar panels have been generating enough electricity to keep her Peco Energy Co. bills down to about $7 a month, Wicks said.

Among her appliances is an induction cooktop, which replaced a gas stove removed "when I got rid of natural gas because of fracking," to which she is adamantly opposed.

Most chefs favor gas over electric, but "Marty Grims, who owns the Moshulu at Penn's Landing, told me about the induction cooktop, which he uses because gas cooking aboard ship is prohibited," she said.

"When I'm boiling water, I'll look at my phone to see how much electricity I'm using," she said.

Wicks has been so impressed that she wants to "solarize" Center City.

Now, unless you just arrived in Philadelphia from Mars, you likely have heard of Judy Wicks.

She is the activist, environmentalist, and former owner of the White Dog Cafe whose 2013 autobiography, Good Morning, Beautiful Business (Chelsea Green Publishing), says it all.

Wicks' home, and 10 others, will be featured on next Sunday's 58th annual Center City Residents' Association house tour. (For ticket and other information, visit www.centercityresidents.org or 215-546-6719.)

Among the stops on the tour will be two co-op apartments at the William Penn House and a two-parcel-wide townhouse built in 1829.

Wicks moved to Fitler Square more than six years ago, after selling the White Dog Cafe - which she had founded 26 years earlier on the first floor of her house in the 3400 block of Sansom Street - to Grims.

That house, part of a row of Victorian brownstones saved from a wrecking ball intending to make room for a shopping mall, had been her home for 40 years.

In the 1990s, Wicks said, she became more convinced of the realities of climate change and began looking to use alternative energy sources the same way she adopted sustainable-farming purchase practices for the White Dog. As a result, the restaurant was the first business in Pennsylvania to purchase its electricity from 100 percent renewable sources, mostly wind, she said.

The changes she has made in the Fitler Square house reflect her commitment to sustainability.

The house has central air conditioning, Wicks said, but she rarely uses it, except when the temperature climbs above 90.

"I removed all the interior walls between the front and back, and rely mainly on cross-ventilation," she said, adding, "It saves a lot of money."

But it is also much more than just an all-electric house running primarily on solar power. The floors are made of wood reclaimed from a barn. The kitchen cabinets were crafted from beams from the third floor.

The countertops and trim were created from wood from a cherry tree in Bucks County that was taken down after being struck by lightning.

A dining alcove, with fireplace, in the garden behind the house was made from redwood salvaged from the Ortlieb Brewery in Northern Liberties when it was razed a few years ago.

Some of the shelving comes from the Black Cat, the shop that featured locally made gifts for 20 years next door to the White Dog Cafe.

In a third-floor loft that has many uses, including bedroom and office - Wicks has had the rolltop desk there forever - is a massive black walnut armoire she found in pieces on two floors of the Architectural Antiques Exchange on Second Street and had reassembled.

All the windows in the house are double-pane, Wicks said, adding:

"I should have held out for triple-pane."