Like many major cities, London can be a very expensive place to live. However, local firm PUP Architects has a novel idea for low-cost housing in the form of a micro-house disguised as an air duct unit. The project, called H-VAC, skirts planning laws and could be installed atop existing rooftops.

H-VAC won a competition hosted by the Architecture Foundation charity calling for alternative low-cost housing ideas for London. According to PUP Architects, the impetus for the project came from the realization that local planning laws include a loophole for mechanical rooftop equipment to be built without planning permission.

Duly inspired, the firm set about constructing the cheeky shelter with help from structural engineers AKTii, some carpenters, and a team of willing volunteers.

The two-story structure gets its name from – and is styled to look like – the HVAC (or heating, ventilation, and air conditioning) units installed on some buildings, and is constructed from wood. Its silver cladding is made from Tetra Pak food and drink packaging. Though hardly a standard building material, the firm reports that Tetra Pak is actually pretty hard-wearing – a previous project using the stuff has been installed in Latvia since 2013 and still looks as good as new.

There's room for up to six people inside, though the interior is very simple and doesn't appear to function as a proper home as far as we can tell (no running water or toilet for example). It's clear that the architects intend the project more as food for thought rather than a practical dwelling anyway, much like the similar Tubular Living project we highlighted.

"The pavilion invites discussion about the occupation of the city's rooftops by highlighting relaxed permitted development rights," says the firm's press release. "It suggests that if dwellings could be disguised as air conditioning equipment, thousands of micro houses could be built across the city providing new homes."

If you'd like to check out H-VAC in person, it will be open to the public on September 17 and 18 in London's Hoxton Docks.

View gallery - 13 images