This issue’s international selection of passive and low energy building includes two homes built for retirement —one in Austria, one in New Mexico — a striking house in a Romanian forest, and an out-of-this-world passive-certified dome in tropical south-west China.

Low energy building isn’t complicated, but it’s easy to get wrong. Since Irish house builders downed tools en masse when the last boom ended, energy efficiency standards for new homes have seen unprecedented rises of 40% in 2008 and 60% in 2011, shooting far ahead of the UK. But with signs of a new boom emerging, can the industry get to grips with this brave new world of insulation, airtightness and thermal bridging and deliver healthy low-energy homes — or are damp and mould set to become the norm in new build?

The Passive House Institute’s announcement of new classes of passive house certification – including renewable energy generation – at this year’s International Passive House Conference caused something of a stir. Dr Benjamin Krick, the institute’s head of component certification sheds some light on the new classes and explains the rationale behind proposals which may set up passive house for a fabric first approach to near – and sub – zero energy building.

A passive retrofit in Co Meath offers a template that could be applied across much of the Irish housing stock: a long, dark, 1970s bungalow was transformed into a bright modern home that’s now warm and comfortable.

When Sjölander da Cruz Architects sought to turn an old abestos-clad shed into the firm’s new studio, it offered the perfect opportunity to put an enthusiasm for passive house design into practice.

A new development in Tipperary aimed to combine excellent levels of airtightness and insulation with generous glazing and natural ventilation to deliver ultra-modern, comfortable, low energy offices. How did it work out?

The eco-village at Cloughjordan, Co Tipperary is no stranger to low energy buildings, and with this passive house, architect Paul McNally of The Passivhaus Architecture Company set out to prove that energy efficiency and good architecture go hand-in-hand.

For Ruth Busbridge and her builder Mike Whitfield, aiming for the passive house standard was just one part of an environmentally conscious approach that put natural, healthy materials to the fore.

Three award-winning affordable homes in scenic North Norfolk have achieved passive certification while embracing a unique local style of architecture.

This issue’s selection features ultra low energy buildings from Mexico, Germany, New Zealand and Italy, and illustrates how widely the energy efficiency specification can vary in different climate zones.

A building’s airtightness test result isn’t just an indicator of its energy efficiency – it’s an unambiguous indicator of build quality. With a little care in design and on site, airtightness targets that may seem impossibly tough are anything but, argues leading architect and certified passive house designer Simon McGuinness.

If you’ve ever wanted to take a passive house for a road test, one holiday letting on the coast of west Cork may be too good an opportunity to turn down. The aptly named Sea Spray – an as yet uncertified Enerphit upgraded bungalow – is a bona fide triumph in the face of adversity.

Hitting Enerphit – the passive house standard for retrofits – wasn’t challenging enough for one Yorkshire retrofit project. The team also had to stop the building falling down, and avoid wholesale changes to the building’s external appearance.

How can a house embrace passive solar principles when all the sun’s heat and light is to the south — but all the best views are to the north? This striking home on the Connemara coast employed some clever solutions.

A simple building form, few junctions and minimal surface area are some of the cornerstones of passive house design — but as this spectacular certified passive house in Co Meath proves, rules are made to be broken.

One third of the units at a new social housing development in the East Midlands have met the passive house standard— but the entire project was inspired by fabric first, low energy design.

Anyone who thinks the passive house standard isn’t relevant to non-domestic buildings is missing a trick. One certified passive office in Leicester reveals the significant benefits companies can yield in terms of saving energy, increasing productivity and improving the bottom line.

The latest in a string of passive house projects by social housing providers, Octavia’s Housing’s new mixed-use development at Sulgrave Gardens embraced fabric first design on an awkward London site to help protect occupants against rising fuel costs.

This issue’s Eurocentric selection is drawn from the International Isover Energy Efficiency Awards, including a German renovation that generates an energy surplus, a Danish nature reserve, a Romanian Solar Decathlon entry and a Polish church.

It’s sometimes said to be hard – perhaps too hard – to get a small house to meet the passive house standard. But a small house will have small heating bills, so why is it hard for a small house to be a passive house? Leading passive house consultants Alan Clarke and Nick Grant delve into the passive house software to find out what’s going on.

Britain and Ireland’s post-war social housing blocks are seen as ugly and uncomfortable, and suffer from high energy bills, damp and mould. But three ambitious renovation projects show the answer doesn’t always lie in demolition.

There was a time when insulating an historic property meant treading lightly on its building fabric. But today, guided by building physics, passive house designers continue to push the boundaries of retrofit by bringing old homes up to modern standards of super-insulation. This project is the third such deep retrofit to an historic London property by Green Tomato Energy.

The general consensus is that it’s not appropriate to upgrade historic buildings to avant garde energy efficiency levels, creating a sense that conservation of the natural and built environments may be mutually exclusive concerns. Not so, argue Arboreal Architecture’s Harry Paticas and passive house engineer Alan Clarke in an updated version of a paper presented at the 2014 International Passive House Conference, about a highly experimental upgrade to a London townhouse that may point to a sustainable solution.

For self-builder James Byrne, building to the passive house standard was just one element of an approach that aimed to drastically reduce the environmental impact of his house — built from a hemp and lime system, it also features solar collectors, rainwater harvesting and natural wastewater treatment.