London passive house demonstrates that you don't have to trade BTUs for beauty
There are a lot of architects and designers who are not crazy about the Passivhaus or Passive House concept. It's based on hitting difficult targets of energy consumption and air leakage that some consider arbitrary. Others complain that they are stuffy inside, that windows are a problem, and that they are often ugly. Designer and builder Michael Anschel once complained:
Buildings should be designed around occupants. That's who they are for! They should be comfortable, full of light, grand or quaint, they should resonate with our souls. Passivhaus is a single metric ego driven enterprise that satisfies the architect's need for checking boxes, and the energy nerd's obsession with BTUs, but it fails the occupant.
To once and for all prove Michael wrong, let's look at this house by Justin Bere, the Camden Passivhaus, the first urban passive house in London. Screw the BTUs, it resonates with my modernist soul. It's a modest 1300 square feet and it certainly doesn't look or feel like it was designed around some obscure energy standard.
One complaint that is often made about Passivhaus is that they are boxy; there is some truth to this. That's because every jog and corner can create a thermal bridge or an increase in surface area, all of which has to be calculated and shown in the big spreadsheet used to figure out the heat losses. It's hard to rely only on proportion and detail, but I think Bere pulls it off in a clean, contemporary design here. Passive House consultant Bronwyn Barry has a hashtag for it: #BBB or Boxy But Beautiful.
Another complaint is that the windows are often limited in size because of the heat loss (and heat gain). But it doesn't have to be. The architect explains:
The final design of the house provides bright and airy rooms with large, tilt and slide, draught-free triple-glazed windows to the south and west. Summer shading is provided by means of retractable external venetian blinds with automatic solar control, whilst inward-tilting windows provide secure summer night-time purge ventilation .
They have also been called stuffy. But as consultant Monte Paulsen explains in Green Building Advisor,
Passive House buildings are ten times more airtight than typical new buildings. But this does not mean they feel “stuffy.” A Passive House window opens like any other. And because the Passive House is better insulated, its residents may choose to leave windows open more days per year than the resident of a code-minimum home. It’s when the windows are closed that the Passive House excels, however. Stale indoor air is continuously exchanged for fresh outdoor air through a high-efficiency heat recovery ventilator. The New York Times recently described the resulting air quality of a Passive House this way: “The air inside the house feels so fresh, you can almost taste its sweetness.”
In fact, the owner tells Home and Property, " there are no more old-sock bedroom smells, and the air is cleaner inside than out."
I look at the Camden Passivhaus and I see a house that's bright and airy and open. It's not just about the BTUs either; There's a lot more going on here in terms of healthy materials, water and biodiversity.
The house uses non-toxic materials to avoid polluting the air and, together with a heat recovery ventilation system (saving ten times the energy it uses) air quality is very high. A water filtration system ensures perfectly clean water for both drinking and bathing. Mains water use is reduced by an underground rainwater-harvesting tank, which provides water for the garden.
Biodiversity was very important for this project which incorporates two, wild flower meadow, green roofs, a south facing garden and, as planned, an ivy covered gabion stone wall.
Not everyone loves austere, minimalist modern design as much as I do, but I think anyone would have to admit that this house does not look dark, stuffy, and more concerned about BTUs than beauty. More at Bere Architects.