Perry Pear Orchard - NPPF Para 55 - Passivhaus Premium
A new build six bedroom family house in the Cotswolds Area of Outstanding Natural Beauty.
The house has a private, agricultural appearance on approach, while a more transparent treatment is given to the south elevation, with lots of glazing to maximise solar gains and views out to the surrounding countryside.
Since the site was outside of the local village development boundary and has not previously been developed, the project was assessed under paragraph 55 of the National Planning Policy Framework (NPPF Para 55).
In November 2013, the project gained the support of the MADE Design Review Panel.
Due to the sensitive location, the house was designed to sit into the natural slope of the site, with only the contemporary roof profile of the south elevation visible from a nearby public footpath, which could be read by a passer-by as a collection of agricultural sheds.
We felt that the entrance to the house need to feel like a farm yard, albeit with a stylish modern cor-ten weathered gate.
While clearing the site of the brambles, weeds and fallen trees we discovered apple trees and a Perry Pear Tree which we didn’t know were there, hence the name. The design of the house was orientated carefully within the landscape and uses the existing fruit trees as focal points. The site is surrounded on three sides by established deciduous trees, the southern side opens up to the wonderful Cotswolds AONB landscape. West side of the site has a small pond and a six foot waterfall.
Following on from our success of building the first Passivhaus in England, this new country house aims to go far beyond the previous Passivhaus standard. We designed it to be the first Passivhaus Premium house in the country. What does that mean? We aim for the building to produce more energy than it uses on a yearly cycle. You can read more at the Passivhaus Trust.
To achieve Passivhaus Premium is not rocket science, Passivhaus uses hardly any energy already and using our previous experience we have developed a novel approach but using off the shelf solutions.
We are using super insulated and air tight envelope, Southern orientation with solar shading, photovoltaics for electricity, solar thermal for hot water, thermal store for storing hot water, MVHR (Mechanical Ventilation & Heat Recovery) for ventilation, bore hole for water and the innovation was a ground source heat pump (GSHP) connected to a thermal bank and solar thermal.
What is a Thermal Bank?
In simple terms it is a borehole connected to a GSHP, but there is bit more technical stuff happening. The Thermal Bank is fed from the solar thermal on the roof during the summer months when there is excess energy. It is pumped underground via a borehole for storage. The heat is then pumped back up in the winter months via a ground source heat pump (GSHP) which because the ground temperature is raised above it’s normal level is now working at a much higher coefficient of efficiency which means a lot less electricity is required to run it. The output is used for hot water or some top up heating for the house. From our own experience of living at Underhill House the system only needs to top up the thermal store from the thermal bank between November and March, after that the sun is strong enough to do the rest on its own. Effectively the system is acting as a thermal flywheel, taking energy from the summer for use in the winter.