Sustainability: Part 7 - Laying the foundations

In the UK we often think more draughty and old when it comes to buildings, rather than something modern, temperature-controlled and made of sustainably sourced wood. But Passive House, a German building standard dedicated to energy conservation, has now hit the UK nursery market.

The Passive House or (Passivhaus) method originated in Germany in the early 1990s and has progressed from houses to offices, hospitals and now education facilities. It has been used in all of Frankfurt’s kindergartens since 2002.

The real secret of a Passive House nursery lies in the fact that the constant temperature and extremely high air quality are achieved without the need for expensive technical products such as photovoltaic panels or heat pumps. In fact, little heating is needed, as passive houses don’t leak – are not allowed, if they want to maintain their status – much air at all.

How is this achieved? It is not rocket science: the exterior of a passive house nursery is “super­insulated”. While many “sustainable” buildings have been proved to successfully keep warm in the winter, many suffer from overheating in the summer. Monitoring of Passive House kindergartens in Germany has shown that even when the outside temperature is over 30°C, the temperature inside does not exceed 22°C.

Windows are often large and are oriented towards the equator – to maximise exposure to the sun’s rays – or solar gain. Triple glazing means that there is virtually no temperature difference between the internal walls and the doors and windows. This means no draughts or cold spots.

It is not an airtight area, as while air cannot leak out, fresh, filtered air is delivered inside via a controlled ventilation system, removing stale air from the building. The large windows and doors are often opened. This has the added benefit of ensuring that CO2 levels are always kept low throughout the day – high levels of CO2 being proven to reduce attention spans.

Chris Hirst from Hooga, a Passivhaus design company, explains the costs needn’t be more than 5 per cent above a standard build. All the energy saving is achieved by the fabric of the building.

If you are interested in a build using the Passive House approach, the first step is to engage an architect and builder who are both registered with the Passive House Institute.

LINKS

An example of a Passive House building in Germany

Passive House Institute, www.passivehouse.com

Hooga, a Passive House design specialist, www.hooga-inc.com

Rocking Horse Nursery (see case study), www.abdn.ac.uk/rockinghorse/about

CASE STUDY: ROCKING HORSE NURSERY AT THE UNIVERSITY OF ABERDEEN

The first of its kind in the UK, the £2m Passive House Rocking Horse nursery at the University of Aberdeen opened in August 2015. The three-year build led to a single-storey, purpose-built design. It has an ‘Excellent’ rating from BREEAM, the world’s leading assessment method for sustainability in infrastructure and buildings. The nursery is open for up to 78 children aged three months to five years, and has been operating since 1989.

The aim is to have a building that maintains a comfortable temperature without the need for a heating system. Excellent air quality is provided thanks to a mechanical air-handler. The building design features quadruple-glazed skylights and triple glazing to the windows. There are solar panels to provide energy to heat the water supply, and the toilets are flushed using a grey-water harvesting system (where water used in one appliance such as a washing machine is cleaned and recycled for toilets, for example). A high level of insulation and ‘air tightness’ in the building is fundamental in reducing energy loss, though windows and doors are often opened onto outside areas for a period. Heating is provided by solar power, and by recycling energy, utilising body heat and appliances such as IT equipment. There is an underfloor heating system, but this is reserved for use in extremes of cold.

Sarah Walker, the manager, explains that the concept was driven by the University of Aberdeen’s desire to be a leader in environmental sustainability. She says, ‘The decision was taken by the university to develop a new nursery that would provide a modern facility which incorporated elements of early years best practice such as easy access to the outdoors.

‘We came from a very old grand building that was never designed to be a nursery to this, and it is absolutely fabulous.

‘The children were involved in the planning – we let them take photographs of things that were important to them. It was important it felt homely, so we had to think carefully about how to put that into the design.’