The Zetland Passive House was originally built in 1894. This photo from 1905 shows a house on the street with stained glass windows and an interior which housed high ceilings decorated with plaster coving and cornicing. It would have been a very comfortable home for a family in the Victorian era.

By 2016, when the property was purchased by Ecospheric, the homes had been used as shared rental housing for decades. Years of renovations meant the original stained glass and Victorian decorative features had been removed.

These Victorian houses are just one of the 8 million pre-1930's homes in the UK which will need retrofitting to meet zero carbon targets. Ecospheric's vision was to show how far we could push the boundaries of sustainable retrofit, while also preserving the homes' architectural heritage.

As much as possible, existing materials were preserved and reused. Roof timbers, floor joists, floorboards, the staircase and over 200 tons of bricks were saved from landfill.

Thermal bridging is a source of heat loss when heat transfers from one material to another. We installed thermal breaks on the end of this steel beam to prevent heat loss from the timber A frame which would be attached to it.

Going Passivhaus can mean a lot of insulation. These homes required 2 arctic lorry loads - about 100 pallets - of insulation! We used blown cellulose insulation made from recycled newsprint as well as wood fibre insulation.

The original floor joists have been preserved with wood fibre and cellulose insulation put below and between joists.

The floor joists were covered with an airtight, breathable membrane.

In order to preserve the front bay walls, they had to be painstakingly dismantled brick by brick and rebuilt in order to accommodate the large amount of cavity wall insulation

Blown cellulose insulation is a great option for retrofits as it can fill the awkward spaces in older buildings and is relatively economical.

Chimney voids were used to house ventilation ducting and electrical wiring to maximise space.

Airtightness tape is used to seal up the opening around the ventilation ducting to ensure an airtight seal which prevents heat loss.

Hidden in the roof and wall build up, the Siga Majrex intelligent building membrane provides an airtight barrier whilst adopting biomimicry; using cactus inspired technology to keep the building fabric dry.

Every roof, wall, and floor build up required careful design and consideration resulting in 106 separate detailed drawings

The Zetland Passive House is one of the first installations of the Mixergy hot water tank. A novel technology that is powered by solar technology and heats only the amount of water needed. This smart tank is also app enabled so the amount of water it heats can be controlled from a phone.

The Paul Novus 300 MVHR (mechanical ventilation and heat recovery) system is able to maintain an even temperature throughout the home by capturing heat and redistributing it. The 2kw post heater which sits atop the MVHR is able to heat the air flowing through on particularly cold days.

The filtration system in the MVHR means that dust and pollen are filtered out, so air within the house stays clean and fresh.

Aiming for EnerPHit Plus certification means these homes also produce energy. That energy comes from solar PV panels on the roof which power the home's appliances as well as the Mixergy hot water tank and the MVHR system.

Lime plaster was used to finish internal and external walls. It has a number of benefits including moisture buffering, crack resistance, breathability, and the absorption of carbon dioxide during the curing process

Traditional handmade plaster cornicing and ceiling roses produced in Yorkshire by The Coving Warehouse restore the Victorian charm to these homes

Floorboards were pulled up, cut up and relaid in a chevron pattern. The floors were sanded and finished with a natural wax.

Ultra durable copper guttering and downpipes are expected to last 120 years, keeping maintenance to a minimum

These two homes have achieved a 95% reduction in space heating demand and an air pressure test result of 0.86 air changes per hour. On top of that, there are zero energy bills.

From the street the building looks classically Victorian with its decorative path, finials, stone steps and ornate porch

The interior walls have been finished with a lime paint formulated with graphene technology. Graphene is a nobel prize winning super material which is 200 times stronger than steel and extremely flexible, making this paint incredibly crack resistant.

For this project, we needed to develop triple glazed stained glass windows and doors that met the Passivhaus standard. We think this is the first example of exterior stained glass used in a Passivhaus.

Space has been maximised by removing the chimney breast and moving the bay walls out to accomodate insulation

For this project, we partnered with lighting designers Agapanthus Interiors in Stockport. This family business lovingly refurbishes beautiful antique chandeliers and light fixtures which are rewired for LED bulbs.

The space-saving toilet recycles grey water by storing dirty hand wash water in the basin and using it to flush the toilet. Such a simple way to save on water!

All the kitchen cabinetry has been handmade using locally sourced hardwood by John George Fine Cabinetry. The timber is waste-wood harvested from local parks and green spaces where trees needed to be removed. The worktops are made with Welsh slate and all appliances are triple A rated for energy efficiency.

The V and A timber supports are one of the most distinctive features of this house and something we get asked about a lot. We wanted to avoid using steel beams which have a very high embodied carbon with inherent thermal bridging issues. Timber is a renewable material with better thermal performance. And, triangles provide a much stronger support, so that’s why they’re there. Plus, we think they look really cool.

The lounge features a DiBT accredited wood stove. This stove draws air from outside the building envelope which means it won't create draughts. This sofa and armchair are by Ecosofa. They are handmade using natural materials and organic fabrics with no fire retardant chemicals.

There are no extensions on this house. Building extensions means using more materials and always results in more envelope by which to lose energy, so we’ve adopted tiny house principles to maximise space and utilise it to the greatest effect. We lowered the floor to create double height space and offer Al-fresco access to the garden, without need for an extension.

The back of the house has a completely different style from the front. We worked with Guy Taylor Associates to design the modern rear elevation. Exterior wall insulation has been clad with pre-fossilised timber which is designed to last up to 50 years without maintenance.

Windows on the back of the property are angled southward to maximise solar gain. The size of windows are smaller on the top floor to avoid overheating.

The master bedroom in Woodleigh features a handmade bed by John George Fine Cabinetry. The headboard is made with French walnut and inlaid brass. John George also designed the William Morris armchair. The antique chandelier is by Agapanthus Interiors.

Ecospheric developed these Passivhaus standard stained glass windows to complement the style of neighbouring homes on the street.

The master bedroom in Ingleside features the Ecobed by Longbeds.com. This is organic, vegan upholstered bed was designed with sustainability in mind using FSC certified timber, and organic flax, linen, and coconut fibre produced in a carbon neutral factory.

We have partnered with a number of environmentally sustainable companies and artisans to furnish the home. A full list can be viewed on our suppliers page.

This contemporary styled bedroom overlooks the back garden and features recessed LED lighting.