A pair of rundown warehouses in south Minneapolis that were recently converted into apartments are on the National Register of Historic Places. And now, they've been equipped with the latest in renewable energy technology.

Dominium, a Twin Cities-based apartment development and management company, transformed the buildings along the Hiawatha Corridor into Millworks Lofts, a 78-unit income-restricted rental building that opened this month.

Those buildings, and a third one that wasn't redeveloped, were built for the Lake Street Door and Sash Company and are on the National Register of Historic Places. Because of that designation, Dominium was able to use federal historic tax credits to help finance a historically sensitive rehab, including the preservation of several features, such as the original windows. Paint was removed from the exterior brick and the lumber shed was restored to its original cedar look.

Lake Street Sash and Door Company was a notable millwork company established in 1916. The company's original factory was in the 3200 block of Hiawatha Avenue and has since been razed.

The buildings were submitted to the National Register in 2016 as an intact representative of Minneapolis' sash and door industry during the early-to-mid-20th century, according to the nomination application.

The three-story brick and timber building houses the bulk of the apartments, while the adjacent lumber sheds house a couple apartments, building amenities and indoor car and bike parking.

An adjacent surface lot is atop the primary infrastructure for the ground source heat pump system, including 96 wells that are about 225 feet deep. They form a network of tubes that are capable of heating and cooling the building depending on the season, a system that eliminates the need for natural gas heating, said Dominium developer Nick Andersen. While the parking lot behind the building provided space for the loop system, the soil conditions were also suitable.

"It was the best long-term decision to make for this project," Andersen said, noting that it's likely the first affordable development in south Minneapolis to have such a system.

In addition to those federal historic tax credits, Dominium also used low-income housing tax credits to finance the purchase and rehabilitation, enabling them to them to offer the units at more affordable rents than typical.

Andersen said that all of the units are spoken for, but a waitlist is developing. To qualify, renters cannot earn more than 60 percent of the area median income. Rents will range from $1,000 for a one-bedroom unit to $1,387 for the project's single three-bedroom apartment.