Passive House Simply Illustrated

We came across these wonderfully simple illustrations of the principles of Passive House design (Passive Haus) and thought they were well worth sharing.  They are by a U.S. firm, Albert, Righter and Tittman Architects. 

 The illustrations help make the case that green building in the new millennium should be about simplicity: weaving together and maximizing simple technologies rather than relying on fancy gizmos and complex systems.

The first image shows the evolution in building technology over the centuries, from wood-heated homes in the 19th century, to a complex jumble of building systems in 20th century homes, to the promise of simplicity presented by today’s Passive House standard:

It’s all about the envelope.  A central principle of Passive House design is to reduce heat loss by superinsulating homes, creating airtight building envelopes, and eliminating thermal bridges (elements or penetrations that allow heat or cold to leak through the fabric):

With a carefully-designed and executed building envelope in place, almost all the heating needs of a Passive House can be met by body heat, heat from lights and appliances, and solar gain:

The control of these solar gains can be easily regulated though a combination of well considered siting (along the east-west axis), shade-providing overhangs for the highest sun of the summer months, and the careful placement of high-performance windows.  All that’s left is to include heat-recovering mechanical ventilation, a simple system that exhausts spent air and brings in fresh air, all the while capturing and retaining the thermal energy of that exhausted air:

The end result is a comfortable, normal-looking home that saves 75-90% of the energy consumed by a conventional home.

Hofler Architects - Monkstown, Dun Laoghaire, Co. Dublin

Aggressive Passive House Strategies

Dún Laoghaire-Rathdown County Council is to make the Passive House energy efficiency standard compulsory for all new buildings – Dublin City Council to follow suit.

Passive House Diagram.

Dublin local authority Dún Laoghaire-Rathdown County Council has voted to make the passive house standard mandatory for all new buildings in the area as part of its 2016 Draft Development Plan. 

Council policy will be that all development in new buildings should be built to the Passive House standard. The motion also stated that Nearly Zero Energy Buildings (NZEBs) and other lower energy standards may be considered as appropriate alternatives.

Dún Laoghaire-Rathdown County Council has a record of requiring higher energy efficiency standards than the national Building Regulations demand.

It was one of the first local authorities, in 2007, to demand that buildings be constructed to higher energy efficiency standards than the national regulations, passing 40% energy and carbon reduction targets, along with mandatory renewable energy systems. 

Local authorities are permitted to set energy efficiency standards above levels in building regulations as a planning condition.

The current national Building Regulations require that anyone building a new home has to achieve a 60% energy reduction and install a renewable energy system to comply with building regulations anyway. Compliance with “Part L” of the regulations typically means an A2 or A3 BER [Building Energy Rating], bringing construction costs up to passive house levels, but with no guarantee that the building will actually work to Passive House certified standards – a standard that is firmly rooted in building science.

Assuming that the passive house clause makes it into the final version of the development plan, Dún Laoghaire-Rathdown County Council would become the first local authority in the world outside of continental Europe to make the passive house standard compulsory. 

Meanwhile, Dublin City Council seems set to follow Dún Laoghaire’s lead -

The Green Party group of councilors have proposed a motion, that states: "Unless exceptional circumstances apply, the council will require new buildings to reach the passive house standard or equivalent, with the exception of buildings that are exempted from BER ratings as defined by SEAI. By equivalent we mean approaches supported by robust evidence (such as monitoring studies) to demonstrate their efficacy, with particular regard to indoor air quality, energy performance, and the prevention of surface/interstitial condensation."

The new policy is to be included in a draft of the development plan due to be brought before the council in July, before a public consultation period begins in September.

Dun Laoghaire Rathdown Development Plan 2016

Hofler Architects