As electricity supply from renewable sources continues to grow, and electricity grids gradually decarbonise as dirtier fossil fuels are phased out, heating homes with electrical technologies like heat pumps starts to make more sense. And in the mild, temperate climate of Britain and Ireland, air source heat pumps are particularly suitable — especially as new build standards of energy efficiency continue to tighten, meaning new homes need less and less energy to achieve comfortable indoor temperatures. But how do air source heat pumps work, what types are there, and how much do they cost to run? Our in-depth guide attempts to answer the key questions.

Architect Tom Duffy has long had an interest in green design, and working on a self-build project for himself and his wife he was able to prove a point: making a modest family home to the highest standards need not cost the earth.

Assessment of thermal bridges is the low hanging fruit lining the path to passive house and low-energy building, according to leading thermal modeller Andy Lundberg of Passivate, who says that taking the time to understand thermal bridging and to minimise and calculate it properly is essential to delivering cost optimal low energy buildings without an Achilles heel.

Rising from the shell of the stalled riverside headquarters of Anglo Irish Bank, Ireland’s financial regulator could be accused of insensitivity for choosing as its new home a site that became a toxic symbol of the banking crisis, but the building is not without virtue: it comfortably surpasses the proposed nearly zero energy building standard while achieving the onerous Breeam ‘Outstanding’ rating for sustainability.

A selection of passive & eco builds from around the world, this issue features a rustic holiday home in New Zealand designed using the key principles of passive house design, and the 26-storey House at Cornell Tech, New York, now the tallest certified passive building in the world.

Even in the era of climate change, there still appears to be something of a split in the world of architects between those who prioritise sustainability, energy efficiency and occupant health, and those who put design and aesthetics first. So it’s refreshing to find that the designer of this contemporary Dublin home put so much attention on insulation, airtightness and indoor air quality — as well as good looks.

Almost a decade after the economic crash, every political party in Ireland now recognises the country is in the middle of a full-blown housing crisis. Similar problems exist in the UK market, but for different reasons. Now, if the political will to fix things has finally arrived, the question remains — what can actually be done about it?

This unique sports and drama hall, inspired by the architecture of local buildings, was built to a new standard that aims to ensure buildings deliver all round health and comfort to their users.

Two spectacular low energy social housing units looking out over Ulva Ferry’s breath-taking surroundings prove to be a superb response to local problems of fuel poverty and lack of affordable family housing.

With low electricity and gas bills and a feed-in tariff from its solar photovoltaic array, this simple, ecological timber frame passive house near the Welsh border manages to make about a £50 profit on annual energy costs.

Set on a picturesque coastal plot in north County Dublin, this eye-catching home was built from clay blocks and strives to balance energy efficiency and comfort with expansive sea views.

Homeowners Michael and Paula Sheridan say that, living in their farmhouse-inspired Mayo passive house — which includes a highly unorthodox heating system — it’s easy to completely forget how cold it is outside.

Simultaneously tackling fuel poverty and climate change requires drastic action on deep retrofitting the existing housing stock – and fast. Dún Laoghaire-Rathdown’s deep retrofit and renovation of Rochestown House may be Ireland’s most significant retrofit to date – a fact reflected in the project picking up the sustainability award at the 2017 Irish Architecture Awards.

Building physics take no prisoners. Anyone designing, constructing or upgrading the thermal envelope of a building to modern energy performance levels is duty bound to understand and minimise thermal bridging, or suffer the consequences. One-man thermal bridging encyclopaedia Andrew Lundberg of Passivate, who teaches thermal bridging analysis at Dublin Institute of Technology, gives some practical advice on why and how to tackle thermal bridging head on, and describes some of the leading innovations in thermally broken components.

As of 16 April, owners of pre 2011 Irish homes are now eligible for generous grants to retrofit heat pumps, and in so doing help to create comfortable, economical, low carbon homes. But what’s the thinking behind the scheme, and what results can participating homeowners expect?

Unclear definitions for nearly zero energy buildings are confusing the building industry and distracting from delivering better buildings, says architect and DIT lecturer Simon McGuinness.

Homeowner Brendan Murphy started self-building his Cork passive house way back in 2010, long before the standard was trendy, and even chose to completely forgo a water-based heating system. So what did he learn from the experience — and how has the house been performing since?

This ambitious experimental retrofit of a Victorian barn high in the hills of West Yorkshire has turned a cavernous, draughty space into a comfortable low energy period home — and cut its heating bills by over 80%.

A new development of passive housing on the outskirts of Norwich shows how to combine energy efficiency, ecology and affordability on one exemplary site — and why the city continues to be an unlikely leader in pushing passive house construction in the UK.

This cellulose-filled timber frame house in the Suffolk countryside combines a rustic timber aesthetic with a simple contemporary form to rest lightly on the land.

In the first in a new series of technical articles on some of the key technologies in sustainable building, John Hearne makes the case for wrapping buildings in an external insulation layer, and describes some of the main issues to watch out for.

The first social housing scheme of any kind to top Ireland’s BER scale, this project is a timely reminder that in the midst of a national housing emergency, it is possible to tackle climate change and blitz the forthcoming nearly zero energy building targets, while housing the most vulnerable in society in healthy, fuel poverty-proof homes predicted to incur zero heating cost.

If the reduce, reuse, recycle mantra has a built embodiment, it’s arguably the recently completed Rediscovery Centre in Ballymun, Dublin – a 1960s boiler house for a much maligned early district heating system that’s been transformed into a sustainability education centre, and that makes use of a remarkably large palette of green materials and sustainable technologies.