For more than 30 years, Sher Polvinale and her husband, Joe, took in as many unwanted dogs and cats as they could rescue and devoted their lives to finding them loving new homes.

Then, as the Polvinales grew older and their pace became a bit slower, they noticed something: Many of the dogs and cats they took in from shelters and the streets were older too, and harder to place in energetic homes with young families. So in 2006, they came up with a plan. They would turn their Gaithersburg, Maryland, home into a non-profit retirement home, where older pets could live out their twilight years in dignity and comfort.

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Eleven years later, Sher, 69, now runs House With a Heart with help from a loyal group of volunteers, since Joe died of lung cancer in 2008.

“I miss him every day, but I know he’d be proud that we’re still taking in as many senior pets as we can and treating them with compassion in their final years,” she tells PEOPLE. “In order to feel happy and fulfilled in life, everyone needs a passion. This has become mine.”

Funded entirely by donations, House With a Heart has dog beds in almost every corner and steps leading up to the sofas and daybeds.

Pets from age 12 and up (mostly dogs) are referred to Sher’s four-bedroom retirement home by animal shelters and private requests, with about 30 at a time living at the sanctuary until they die.

Image zoom Courtesy Sher Polvinale

“It’s a wonderful place of hope and love that I’ll always hold dear to my heart,” says Lisa Browning, who brought her dad’s elderly and blind dog, Max, to Sher’s place when her family could no longer give him proper attention and care.

“Sher taught Max to use a doggy door and gave him his own bed in the foyer, where he soon became the official greeter at House With a Heart,” she tells PEOPLE.

“What was really cool was that my dad was able to visit the sanctuary on several occasions and hang out with Max,” she says. “He was so grateful that Sher was with his dog when he died. When my dad died soon afterward, he was content, knowing he’d be reunited with my mom and with Max.”

Many of the animals that end up at Sher’s house are disabled from being run over by cars or abused by owners, who then abandoned them. At House With a Heart, they find full kibble dishes, full hearts, and nobody shouts at them to stay off the furniture.

With help from a rotating staff of 60 volunteers, pets are regularly groomed and exercised and have plenty of playtime, indoors and out.

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“The satisfaction I get from caring for them in their golden years is priceless,” volunteer coordinator Martine Ferguson tells PEOPLE. “Seniors are the last to get adopted in shelters and are too often overlooked — so trust me when I say that they are extra grateful for the love you provide.”

“We start caring for our pets at 6 in the morning and finish at midnight,” adds Sher, who sleeps on a couch downstairs so that she can get up to help several dogs that need assistance going outside at night.

“They’re like old people in many ways, with some of them having cardiac issues, dental problems, incontinence or blindness,” she says. “We make a lot of trips to the vet.”

Image zoom Courtesy Sher Polvinale

Some trips to the vet are more difficult than others, with the knowledge that a dog or cat is suffering and will need to be put down. After they die, Sher has casts made of their paw prints and buries their ashes in a flower garden in her back yard.

But once her pets are gone, they are not forgotten.