Passivehaus homes often have a distinctive look but with the help of a few new technologies and materials such as graphene there’s now more variation in shape and style than ever before – even Victorian-era townhouses are getting the Passivehaus treatment.
Europe’s first retrofit of old townhouses to Passivhaus standard opened on 18 January and immediately wowed viewers who came to see them.
Located on Zetland Road in Manchester, UK, the two large semi-detached homes are traditional Victorian solid walled structures of the type that are notoriously hard to heat and renovate. They are accredited to the EnerPHit standard, which is issued by the Passivhaus Institute and adapts the Passivhaus standard for eco-retrofit projects.
The green building consultancy responsible for the work, Ecospheric, claims that from now on they will need no central heating and save homeowners £5000 [AUD $8979] a year in bills and maintenance combined (based on an average yearly £3500 [AUD $6285] in energy bills for a large townhouse maintained at around 22 degrees Celsius and £1500 [AUD $2692] in maintenance).
Furthermore, they will generate more power than they use, so the occupants can sell excess electricity to the National Grid.
The homes will outperform the vast majority of new build properties. This is not just because of their design but because of the deployment of numerous technologies including the novel Nobel prize winning material, graphene.
They will also be healthier than most houses, because the system that controls the ventilation-with-heat-recovery also cleanses airborne germs and particulates from the air, controls humidity and minimises the danger of mould, which is a frequent problem with old buildings in this climate.
Passivehaus refits are becoming more affordable
It’s often said that the cost of a deep retrofit to Passivhaus standard of an old house is prohibitive – around £60,000 [AUD$107,751].
In response, founder of Ecospheric Kit Knowles said: “True, but as homeowners will generally use the opportunity of a deep retrofit to also install new kitchens, bathrooms and extensions, the typical spend for such a project is often double that – up to £160,000 [AUD$287,336]. This means for an average £250,000 [AUD$448,963] house, the costs for retrofitting are around 25 to 50 per cent of the value of the building. Of course, as the property value increases, so that percentage drops. Also, the cost savings achieved by passive houses continue forever.”
He added that the costs of all the technologies used in the houses are dropping. “A new UK program based in Norwich has managed to build 100 Passivhaus units for the same price as normal new build houses,” he pointed out.
“Period semi-detached properties represent a huge portion of the UK’s housing stock, yet they are one of the trickiest formats to upgrade,” he continued. “It’s critical that planners, architects and builders explore and define appropriate methods to tackle them. The UK housing stock of today will account for over 80 per cent of the stock in 2050. New build solutions do not tackle this, it is sustainable retrofit that is critical to meeting the Government’s 2050 greenhouse gas emission targets.”
Recycled newspaper insulation and a drainage system made from old car tyres
Photovoltaic (PV) panels on the roofs not only power the homes’ lighting and appliances but also heat the hot water tank – apparently the first in the world with a thermocline control.
The insulation is mostly made of recycled newspapers. This helps maintain an even temperature all year round even in hot summers; a thermostatically controlled roof light with a rain sensor supports the effective passive cooling.
The vapour control membrane around the building not only provides an airtight barrier but adapts biomimicry by using technology inspired by cacti to keep the building fabric dry.
Toilets are flushed with dirty hand wash water, and outside, a Sustainable Urban Drainage System (SUDS) made from recycled car tyres not only reduces stress on the surface water drains and replenishes the water table, but keeps the drive weed free.
To make them last as long as possible, the properties have been specified with durable materials. Graphene, the strongest material known to science at 200 times stronger than structural steel, has been formulated into the interior paints, which prevents cracking.
The wooden external cladding is resistant to rot and UV degradation. The copper guttering and downpipes are expected to last over 100 years.
The care in the selection of materials extends to the choice of lime plaster, which also helps control humidity and minimise mould. The building fabric is intentionally petrochemical free, focusing on natural, breathable materials that avoid harmful off-gassing and are intrinsically low carbon.
High-tech credentials almost invisible
An estate agent, Martina Harrison, a partner at Jordan Fishwick, praised the result. “To have the Victorian charm without the maintenance, draughts and bills is the dream! Ecospheric have created something truly special with Zetland Road. What really struck me is the meticulous attention to detail and the simple fact that so many of the house’s features work better than what we consider ‘normal’.”
She continued, “Ecospheric have achieved a pristine period finish on Zetland Road, even incorporating stained glass in a passive house, which is a world first. From the street the building looks classically Victorian with its decorative path, cast stone steps and ornate porch.
“The only hint of the wealth of technology within is a subtle copper strip that blends into the traditional Victorian brickwork to disguise a super-insulated sidewall.”
In the four-metre-high rear living area sits a wood burning stove. Although it is not needed to heat the property it does add a little winter luxury. By drawing its air from outside, it avoids the draughts typically caused by chimneys and made worse by lighting fires.
The beautiful kitchen was handcrafted using locally grown timber. It is complemented by hand brushed brass splashbacks, Welsh slate worktops and A+++ rated appliances.
Other beautiful features to complement the properties’ heritage include period-style features such as elaborate plaster cornicing and ceiling roses. The latter sport refurbished LED chandeliers. The taps are gold plated, baths are iron roll top design and some floors are marble.
To achieve all this within the project cost is remarkable and must surely hugely increase the properties’ market value.
We’ll soon find out. The properties are for sale.
The result certainly impressed Jon Bootland, chief executive of the Passivhaus Trust: “The properties combine the beauty and character of a period property with the world’s highest standards of energy efficiency.” He called them “a great addition to the UK’s Passivhaus portfolio”.
[The buildings were certified by Kym Mead (Mead Consulting), The Fifth Estate was advised]
Passivhaus is growing around the world. Over 65,000 buildings have now been designed, built and tested to this standard. Their distinguishing features are defined by the use of careful modelling in software to ensure they provide a high level of comfort while using very little energy.
David Thorpe is the author of Passive Solar Architecture Pocket Reference, Solar Technology, and Sustainable Home Refurbishment.