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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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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Cold is not the whole story – what the health services need to know about housing

An AECB consultation response

This document was written in response to a NICE (National Institute for Health and Care Excellence) 2014 consultation on producing guidelines for health authorities on tackling excess winter deaths and illnesses. It was written (mainly) by me, on behalf of the AECB, teaming up with Severn Wye Energy Agency and the STBA (Sustainable Traditional Buildings Alliance) – who also contributed information.

While at the time of this consultation the deleterious impact of cold living conditions on health were well known – prompting the consultation – poor indoor air quality was less discussed.

Yet of course, air quality can be very poor in cold homes: people will block out any draughts they can – including the intended fresh air supply from a ventilation fan or vent – especially if they are in fuel poverty. This only increases the risk of condensation and mould – already high in a dwelling with cold, uninsulated surfaces. And more and more evidence is piling up of just how bad mould in particular is for people’s health and wellbeing. Continue reading

A look at the evidence on mechanical ventilation

Natural ventilation often fails – but what is the evidence that mechanical ventilation succeeds? – Investigation for Passive House Plus

There have been a number of studies showing that natural ventilation, dependent as it is on random gaps in the building fabric and the vagaries of wind and weather, is not a reliable source of fresh indoor air. (see here for my article on this)

In theory, mechanical ventilation is under more control, and should work more reliably. But does the evidence bear this out? Does mechanical ventilation deliver good air quality in practice?

I looked into the research to find out whether MVHR, in particular, lived up to the ideal. Continue reading

Deep retrofit – the big prize?

Simple home energy efficiency improvements (such as new boilers, cavity wall insulation etc) can bring valuable comfort and health benefits to the occupants of inefficient homes – especially those in fuel poverty – as the last article revealed (see here). However, energy, carbon and bill savings tend to be modest, rarely topping 15% or 20% – and sometimes energy use actually increases!

If housing is to contribute its share of the 80% cuts in carbon emissions this country is committed to, in order to play is part in tackling climate change, retrofits will need to go deeper – a lot deeper. But will occupants benefit from the extra work? And is it affordable?

In the first part of this article we looked at the damage fuel poverty and cold homes do to occupants’ health, and found good evidence that when these twin evils were tackled, occupants could enjoy measurable improvements in their health. Encouragingly, some local health bodies are recognising this and investing in home retrofit to help improve people’s health.

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Ventilation – presentation for AECB

Slides from my presentation to the 2014 AECB annual conference on ‘Natural ventilation – does it work?’.

Download pdf – Natural Ventilation – talk for AECB 2014

Cold bridging, condensation & mould CSE

Failure of ventilation? Photo courtesy of the Centre for Sustainable Energy

For my article on the same subject, see this link:

Natural Ventilation: Does it Work? Article for Passive House Plus magazine

 

Overheating – how can we avoid it?

Jump straight to article in html Overheating – how can we avoid it?

There is a lot of concern that modern, airtight, well-insulated buildings might be more prone to overheating than older, leakier ones. However, the worst-offending buildings for overheating (and there are some shockers) are as often old as they are new. Overheating buildings just tend to be all-round bad buildings: often cold in winter, as well as hot in summer.

It looks as though buildings with too little insulation, too much glazing, not enough shading, and inadequate provision for purge ventilation are at risk of overheating – as are buildings with badly designed and inadequately insulated heating/hot water/community heat systems. Extravagant use of glazing, in particular, seems to have a great deal to answer for. Continue reading

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

 

Healthy buildings – feature in Green Building magazine

Most people spend 80 – 90% of their time indoors, which means the indoor environment is where people meet many of the influences that affect their health and wellbeing, for good or ill. The impact is serious: just one condition affected by the indoor environment, asthma, kills three people a day and costs the country millions of pounds annually.

We all want the buildings we create and  occupy to be healthy, and the sustainable building world often makes special claims to be creating healthy spaces. But are we directing our attention the right way? Which hazards are most important – and which can we actually do anything about?

In this article for the Spring 2014 issue of Green Building magazine, I have a look at the indoor hazards that might affect out health, and consider which ones we can do anything about – and how they might be tackled.

Download the article in pdf, for references and links: Healthy Buildings