In some of the hottest US housing markets, 3D-printed houses are competing against traditional wood-frame houses with developers touting "cheap", "safe" and "eco-friendly" features.

The US housing market has flourished since the COVID-19 pandemic depressed housing inventory last year, and new buyers are driven by low mortgage rates and the ability to work remotely.

In Riverhead, New York, on Long Island, a 3D-printed house with three bedrooms, two bathrooms and a 2.5-car detached garage is listed for sale through Zillow with an asking price of $299,999. 

The house will be built with concrete by SQ4D, a New York-based construction technology company using an "Autonomous Robotic Construction System". 

It is touted on the company's website as "the first 3D-printed home slated to receive a certificate of occupancy" in the US. 

The company said its patent-pending technology lays concrete layer by layer, robotically building the footings, foundations, interior and exterior walls on site. It offers a 50-year limited warranty on the 3D-printed structure.  

Stephen King, the Zillow agent who has the listing, said the price is 50 percent below the cost of "comparable newly-constructed houses" in the area, according to SQ4D's promotion on its website. 

In Austin, Texas, another construction technology company, ICON, also claims to have America's first 3D-printed homes for sale. Partnering with Kansas City developer 3Strands, the company is building two-to-four-bedroom homes in Austin, the Texas capital.

ICON's 3D printer — "Vulcan" — is almost 12 feet tall and is 33 feet wide. It can print walls up to 8 feet, 5 inches tall and foundations up to 28 feet wide.