Passive Houses are often modestly sized; Under the Passivhaus, or Passive house concept, (explained here in 90 seconds) low levels of energy consumption or air leakage are permitted, and the high quality windows and doors are expensive. They are often simple forms, because every bump and corner is a possible source of heat loss; that's why consultant Bronwyn Barry calls them #BBB: Boxy But Beautiful™.
And then there is Serenity. No, not our favorite spacecraft, but certainly out of this world, landing somewhere in the Nottingham countryside to house an "affluent, twenty-something couple" who wanted an "Iron Man-style luxury home." Underneath those mushroom caps are an entertaining hub, a family hub, a games hub and an annex.
Using their guineas for good
Estimated to cost about seven million pounds (US$ 11,100,000, not including the collection of supercars stored behind the waterfall) this 16,000 square foot extravaganza would usually be on TreeHugger so that I could whine on about wretched excess while muttering "come the revolution...." However Baca Architects, Passivhaus consultant Etude and environmental engineer Kaizenge are using some of those guineas for good, aiming for ye olde European-style Passivhaus certification and level 5 under the British code for sustainable homes.
On top of the house, the roof is covered with building-integrated photovoltaics, enough to generate 15,000 kWh in a year. In the middle, it has acres of glass "solar oriented to provide a balance between passive solar gains and overheating."
Using the ground as a heat battery
Underneath, it has a ground source heat pump system, but not your garden variety; this one is designed to be a Borehole Thermal Energy Store (BTES)- In summer air conditioning mode, the rejected heat will be deposited into the ground, and banked for winter. Engineer Josh Bullard tells the CIBSE Journal that "it is, basically, a large, underground heat exchanger." So is every ground source heat pump system to a degree, but this is more elaborately managed with "borehole sequencing".
The heat pump system is good at moving the heat from one part of the house to another; you want your gym cool and your pool warm and your home theatre and music pod and guest wing just so. But if they can't get enough energy out of the heat pumps, there is always the 30 kW gas-fired combined heat and power unit to top it up.
In the end the cost of heating and cooling is supposed to be "a fraction of what it would be for a typical Georgian townhouse" or I suppose, Buckingham Palace. Apparently there are no worries here about the amortization costs of all the gizmo green that gets those bills so low.
Writing in CIBSE Journal, Liza Young concludes:
Many of the Passivhaus buildings in Europe are austere and simple in form. [see #BBB] Serenity has smashed this stereotype, with a design that closes the gap between pragmatic environmentalism and futuristic form.
The Downton Abbey of Gizmo Green
I am not sure anyone could call this "pragmatic environmentalism." I am also not sure it is in the spirit of the Passivhaus movement either, which usually starts with the idea of you know, a lot of insulation and not a lot of gizmo green. This seems more like a Net-Zero type project where you pile on the photovoltaics until it nets out, This is the Downton Abbey of Gizmo Green.
But I withhold the usual snark and give our affluent twenty-somethings a whole lot of credit for trying to build a pile like this in Passivhaus. It's pretty amazing. Don't miss the video: