When Melbourne architect Charles Justin retired, it was an opportunity to spend more time with his art collection.

“We had this big collection and we didn’t know what to do with it,” says Charles. “We knew we should do something more than just let it sit stacked away in the spare bedroom.”

Charles and his wife Leah, both in their sixties, had also outgrown the house they were living in. They saw the Lyon Housemuseum in Kew and travelled the world looking at private collections that had been opened to the public. They knew what they wanted to do next.

Leah’s career as an education coordinator at St Kilda’s Jewish Museum and Charles’ as an architect gave them the ideal starting point. Designed by their daughter Elisa (also an architect), the Justins’ new house is part home, part gallery – but they don’t draw a sharp line between the two. The top floor is the Justins’ apartment: spacious, homey, with walls lined with art. But the real attractions are downstairs – the lower two floors are dedicated exhibition spaces, which opened to the public on April 3.

A visit to the Justin Art House Museum takes roughly two hours. Visitors are met by Charles and Leah at the front door, and personally guided through the gallery. After, they invite you upstairs for a cup of tea, and if you’re lucky, poppyseed cake (I give Leah’s poppyseed cake five stars), where the art chat continues. It’s the most important part of the visit. Without being didactic, the tours offer potential explanations for the work that may or may not be what the artist intended.

“We’re saying there’s no right or wrong way to read art,” says Charles. “Your interpretation is as good as anyone else’s.”

Their inaugural exhibition, Divine Abstraction, is a contemplation on God and the divine through a series of abstract works, including paintings and video art from artists such as Peter Daverington, Ash Keating and PJ Hickman. The works are arranged into categories, such as “mystery”, “ephemeral”, “eternity” and “chaos”. It’s a big idea, but the Justins’ approach is to provide multiple interpretations and get you thinking. Adding another voice into the mix, Rachel Kohn, presenter of ABC Radio National’s religion program The Spirit of Things, has written a catalogue essay and a blurb for each of the works.

“House museums are all different,” Charles says. “They reflect the persona of the collector.” Just like the furniture in their house and the books on their shelves, the Justins’ art collection is a catalogue of their lives.

45 years ago, while still an architecture student, Charles was asked to design a house for a friend. In place of pay, his client offered to buy him a painting of his choice. That first piece, an abstract landscape in blacks and silvers and golds, had pride of place in the Justins’ home for four decades. Charles still doesn’t know anything about the artist, but that work began a lifelong habit of collecting art, buying on instinctive, emotional reactions to work. The result is an expansive survey of the Justins’ life-long love of art. There are more than 250 pieces in the collection, which they’ll rotate regularly.

“One of the differences between having art in a home and in a gallery space is that in a home, the works just go where they fit. In a gallery they can be curated, sequenced,” says Charles. “Here it’s a bit of a hybrid experience. Upstairs is our home. The work upstairs is just for the pleasure of having art around us.”

The art the Justins buy isn’t particularly expensive. They buy a lot of emerging artists, and the future value of the work isn’t a consideration. They buy out of passion, and it’s that passion they want to share with visitors. “For many people contemporary art is quite intimidating. It shouldn’t be,” says Charles.

“We’ve been living with art for more than 40 years, and we have a close relationship with it,” says Charles. “We just want to be advocates for it.”

The Justin Art House Museum is at 3 Lumley Court, Prahran.

The museum offers tours twice a week at various times. Visitors can register at jahm.com.au.