Uni teaching block launches large Passivhaus in the UK

Case studies for Passive House Plus: new build

UK’s largest passive building opens to 2,400 students and staff

University of Leicester – the new Centre for Medicine

Completed early this year, the new Centre for Medicine at the University of Leicester is by far the largest single building in the UK to meet the passive house standard — and not surprisingly, its design and construction posed tough new challenges on how to meet the rigorous low energy standard on such a large, complicated building. December 2016

 

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A healthy retrofit scheme for London residents

Retrofit case studies for Passive House Plus

South London scheme delivers better health for residents

The original houses, with the new build homes beyond

A sensitive development of social housing in Lambeth combines three new passive houses with six low energy flats carefully constructed inside an old Victorian terrace. With the emphasis on good indoor air quality, residents are already reporting improvements in health & well-being since moving from their old accommodation. Oct 2106

 

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Post-war housing retrofit

How to save social housing blocks

The colourful timber -built external cladding in place on the block at Parkview

Post-war social housing blocks are often seen as both ugly and uncomfortable. They frequently suffer from high energy bills, damp and mould. But three ambitious renovation projects show the answer doesn’t always lie in demolition. Oct 2015

 

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Victorian Passive Retrofit

Sensitive passive retrofit transforms Victorian North London home

The all-new, Victorian-feel facade of this deep deep retrofit

Upgrading a historic home to the passive house standard typically means leaving the façade untouched to preserve the building’s historic appearance, but the team behind this fully passive retrofit in Kensal Green took a totally different approach. Oct 2016

 

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Archive keeps its cool the Passivhaus way

Hereford archive chooses passive preservation

Hereford County Archive

Safeguarding historic documents and other artefacts requires super-stable environmental conditions. This has usually been achieved by using masses of expensive and energy-hogging heating and cooling plant, but a new approach for Herefordshire Council used the passive house approach to conserve energy, money — and the county’s precious historical archives. Nov 2015

 

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Passive school learning refines the design

Building a better passive school

Wilkinson School, Wolverhampton

The team behind a series of passive house schools in Wolverhampton have used the lessons learned from in-depth monitoring of the first two buildings to make the third even better — and cheaper to build. Oct 2015

 

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Natural materials make a warm, homely Passivhaus

Ledbury passive house embraces warmth, wood & light

The ‘modern organic’ style of the Ledbury Passive House

For the builder and his client, aiming for the passive house standard was just one part of an environmentally conscious approach that put natural, healthy materials to the fore.

The style of the house inside and out is what the owner calls ‘modern organic’ – white paint and render, and lots of natural wood. The carpentry is beautifully finished, with charming bespoke touches. Not everyone expects a passive house to be like this…Nov 2015

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Does Natural Ventilation Work? – References and Links

I’ve had a couple of requests for links to the sources for “Natural Ventilation – does it work?”, my article for Passive House Plus Issue 6 (start of 2014), so here is a list of most of them – live as at the time of posting in April 2014, but no guarantees they will remain so of course.

My apologies where (a few) refrences are behind a paywall – it usually means either that I’ve wriggled my way behind it somehow (though if your subscriber-only publication is on here, not yours, obviously 😉 ) – or a helpful academic has supplied me with a copy. Or alternatively, it means that I’ve only referred to the abstract.

The references are roughly in order of their appearance in the article. Here you go:

The NHBC Foundation’s commendably honest account highlighting a string of concerns in the design, specification, installation,  commissioning and operation of MVHR systems in 10 ‘zero carbon’ homes: Assessment of MVHR systems and air quality in zero carbon homes NHBC Foundation August 2013 (Greenwatt Way study) http://www.nhbcfoundation.org/Researchpublications/MVHRsystems/tabid/585/language/en-US/Default.aspx (NB you have to register to download this, but registration is free)

Neil Jefferson, director of the NHBC writing in Building magazine, questioning whether MEV, PSV or natural ventilation are exempt from the performance issues that NHBC uncovered with (non-Passivhaus) MVHR installations in the study above: http://www.building.co.uk/we-need-to-know-all-ventilation-systems-are-safe/5062555.article

Bob Lowe’s 2000 modelling study investigating the “under-ventilation index” for naturally ventilated dwellings (the proportion of the heating season for which a dwelling will be underventilated without additional window opening). His results suggested that even for leaky buildings that lose heat unnecessarily in very cold or windy weather, and are generally over-ventilated (draughty!),  under-ventilation for a proportion of the time (in mild and/or still weather)  “is almost assured”: Building Services, Engineering, Research & Technology 21 (3) 179-186 R. J. Lowe: Ventilation Strategy, Energy Use and CO2 Emissions in Dwellings – a Theoretical Approach http://bse.sagepub.com/content/21/3/179.abstract (abstract)

Simon McKay & David Ross (AECOM), and Ian Mawditt & Stuart Kirk (Building Services Ltd) carried out a small study (of 22 homes of different types)  for DCLG, to investigate whether Part F 2006 was providing adequate ventilation and IAQ in homes, and whether it should be uprated at the review in 2010. They found that all of the flats and 40% of the houses failed to achieve the recommended background ventilation rate; NO2 and volatile organic compound levels exceeded guidelines in a number of dwellings – and this was with all vents open and fans running. When the researchers arrived however they had found 60% of vents were closed and many extract fans disabled. Six of the 22 households didn’t use their kitchen and bathroom extract fans at all, and five said they used the isolator to control some of their fans  – though in fact many more actually did so: Ventilation and Indoor Air Quality in Part F 2006 Homes BD 2702 DCLG 2010 http://www.scribd.com/doc/43637758/Ventilation-and-Indoor-Air-Quality-in-Part-F-2006-Homes, and  Ian Mawditt’s  presentation on the findings, showing the position of vents and fans as normally used by occupants http://www.goodhomes.org.uk/downloads/members/ian-mawditt-operation-and-behaviour.pdf

Stirling Howieson of the University of Strathclyde has reported on the basis of his recent research that “technical standards prescribed by the Building Regulations are not being enforced”. He also found that natural ventilation tends not to be used as intended and fails to give good IAQ. Howieson and colleagues looked at 24 new-build homes constructed to  2010 regulations, where trickle vents in the windows provided the only source of background ventilation.  CO2 levels measured in occupied bedrooms “were found to be at unacceptable concentrations” (occupied mean peak of 2317 ppm with a maximum of 4800 ppm): “Are our homes making us ill?”, Stirling Howieson, University of Strathclyde. Perspectives in Public Health 2014 in press, abstract at https://pure.strath.ac.uk/portal/en/publications/are-our-homes-making-us-ill%280b8ce07f-b36d-499f-8caa-08c249f241ac%29.html

Derrick Crump, Sani Dimitroulopoulou and colleagues at BRE carried out a study of ventilation and indoor air quality in 37 homes in 2002;  although the sample were approximately as leaky as the average stock,  the majority (68%) of the sample had below the recommended design air change rate of 0.5 ach. And some suffered indoor air pollution issues: in winter 18% of the homes during winter had kitchen CO levels above WHO guidelines, and even in summer, 13% of them did.  In winter the kitchens of six homes also exceeded NO2 guideline values: VENTILATION AND INDOOR AIR QUALITY IN NEW HOMES Crump, Dimitroulopoulou et al BRE, Watford, http://www.umad.de/infos/cleanair13/pdf/full_104.pdf. The study is also summarised here

A Good Homes Alliance report presenting examples of good ventilation practice in low energy homes highlights only a few projects with natural ventilation (three with vents plus humidistat-controlled extract, two with passive heat recovery, and one with a passive stack system). Even so, two of the six dwellings had had poor IAQ , which was attributed to occupant behaviour: in both cases, occupants said they had closed vents/shut off fans because of noise or draughts. IAQ was poor in both cases.  (Air quality in the other four of the six naturally ventilated dwellings was good): http://www.goodhomes.org.uk/downloads/news/VIAQ%20final%20120220%20-%20PUBLICATION.pdf

Contrary to general expectation, buildings may become more airtight as they age – which may also present an issue for ventilation design recommendations. In one NHBC study,  eight of 23 homes became more airtight 1-3 years after completion. And in the NHBC’s Greenwatt Way study (see link above), 9 out of 10 homes became more airtight. http://www.insidehousing.co.uk/eco/room-to-breathe/6514729.article

Some research suggests that in order to reduce the risk of house dust mite problems (mites are known to exacerbate asthma in particular) relative humidity below 60, or even lower, should be sought: Lawrence Berkeley National Laboratory, http://www.iaqscience.lbl.gov/dampness-impacts.html

 

Passive House goes large

Passivhaus is no longer just the preserve of the self-builder: more and more large Passivhaus schemes are being announced. These include both non-domestic buildings, for example in schools and universities,  and multi-housing schemes, generally in the social rented sector, though sometimes with a portion for private sale.

In this article for Passive House Plus magazine I looked at some of the economies of scale available on larger Passivhaus projects, and some of the obstacles that larger schemes may run into. Also, following from my previous article on the cost of Passivhaus, I looked a bit further into the economics of Passivhaus from the point of view of developers and owners – in both the domestic and the non-domestic sectors.

Read the article in pdf here: Passive House goes large

My thanks to Passive House Plus for the use of this document.

The cost of building passive

Passivhaus (Passive House) is often thought of as being “too expensive” for the mainstream. There are some designers and developers however who are managing to shave the capital cost premium down to just a few per cent – or even zero.

In researching this article for Passive House Plus I learned that the extra costs, where they are incurred, seem to derive from two main sources:

  • Passivhaus components tend to be more expensive than the “conventional” alternatives – though this difference is diminishing all the time; and
  • There is a “learning curve” in first (and probably second and third) Passivhauses for any team, where designers and contractors alike need to spend a bit longer working out how to co-ordinate their activities to ensure that details are buildable, and that built quality matches up to the standards sought.

The extra costs are mainly up-front; looked at over the building’s first decades of lifetime, running cost savings – including maintenance, and even cost associated with tenant dissatisfaction – start to pay back the initial investment. Continue reading