Image Credit: Octavia Housing (images 1-3), Paul Davis + Partners (images 4 and 5) A thermal image of the front of the house, which was built in the 1860s. When the remodel is complete, windows like this will have been replaced by custom made triple-glazed windows. Marion Baeli, a Paul Davis + Partners architect working on the project, explains that insulation will be added to the internal faces of the shell only, a process that likely will be followed in most of the U.K.’s historically significant buildings should they become candidates for deep energy retrofits. Paul Davis + Partners architect Marion Baeli notes that window replacement in the Victorian will follow a “to match existing” rule. Triple-glazed replacement windows have been specially designed for the project, which Baeli notes, is a first for the U.K.
There are so many Victorian-era homes still in service in the U.K., it is small wonder they’re among the prime targets for remodelers striving to increase the energy efficiency of Britain’s housing stock. So it’s no surprise the planned remodel of an 1860s Victorian row-house to Passivhaus performance standards has attracted the attention of many of the country’s residential retrofitters.
The renovation proposal for the building, which is part of London’s social housing network — that is, government-subsidized nonprofit housing — was among the 87 winners of a competition called Retrofit for the Future. The competition was an initiative of the U.K.’s Technology Strategy Board, a government-appointed group of executives whose mission is to stimulate innovation in areas that will encourage growth and productivity.
Led by social housing nonprofit Octavia Housing and several partners, the remodel project received $31,200 from Retrofit for the Future to test its strategy for retrofitting to Passivhaus standards and, upon being named a competition winner, another $234,000 to complete the retrofit.
A potential turning point in retrofits of hard-to-heat homes
The level of funding for the project is, of course, of considerable interest. As with many deep energy retrofits, challenges often extend well beyond meeting technical requirements and satisfying guidelines for historic preservation. The recent energy efficient remodel of a 1,075-sq.-ft. privately owned Victorian in London showed that the success of such projects can lean heavily on the client’s financial resources. The house ended up more than 70% more energy efficient than it had been before the remodel, but didn’t quite achieve Passivhaus performance. Still, the Passivhaus ambitions for the project added about $93,000 to standard renovation costs, which for a house of that size, the project architect noted, could fall between $180,000 to $280,000, depending on which luxury amenities the clients might choose.
Nonetheless, with $234,000 to spend, Octavia Housing and its partners sound confident they’ll reach their performance goal and make a case for the affordability of deep energy retrofits. The funding allotment is “not all that much more than a normal whole-house renovation,” Hamish Phillips of renewable-energy and Passivhaus specialist Green Tomato Energy, says in a news update on the Octavia website.
The renovation team – which also includes environmental consultancy Eight Associates, architects Paul Davis + Partners, and energy conservation specialist Ryder Strategies – says it aims to cut the building’s carbon dioxide emissions by 83% and its energy consumption by 94%, which would trim the home’s energy bills by about $1,420 a year.