It only takes a winter spent in an old house to convince anyone of the benefits of living in a healthy home. Cold, draughty, and more often than not full of dust mites and even toxic substances such as asbestos or toxic mould, they epitomise the worst of historical building practices.

It is no secret that New Zealand’s pre-2000 housing stock is generally considered to be of a poor standard. Since 1998, a large body of work has gone into identifying the causes and looking for remedies. In 1998, the National Health Committee released a benchmark report which identified the impact poor housing had on the health of many New Zealanders, in particular overcrowding and the contribution cold houses made to respiratory-related hospital admissions.

The Department of Public Health at the University of Otago, Wellington research group, led by Professor Philippa Howden-Chapman, has also undertaken extensive research into the links and associations between housing and health over a number of years. This work has underpinned national and local policies for healthy homes. The research showed that 14 percent of children between two and fourtenn years old, and 11 percent of all New Zealanders aged fifteen years or older have been diagnosed or had symptoms consistent with asthma.

These are some of the highest rates in the world.

The main issue is that many houses in New Zealand are simply too cold and damp, poorly oriented to the sun, and badly insulated. Of the 1.5 million private houses in New Zealand, 1.3 million were built before 2000. During winter the temperatures of living areas and bedrooms of many New Zealand homes have been shown to be up to 6°C below the World Health Organization suggested minimum indoor temperature of 18°C. The average winter temperature in New Zealand living rooms is 13.5°C in winter. More than 75 percent of New Zealand homes have insufficient ceiling insulation and 70 percent where the floor could be insulated, have no underfloor insulation at all.

Why is our housing stock so bad? Even Nick Collins, general manager of Beacon Pathways, an organisation that has been researching ways to improve the performance of homes and neighbourhoods for the last eight years, is not altogether sure. “It is partly that pioneering ethnic that leads to the response of ‘harden up or put on another jersey’ mindset. With the house it seems to be similarly cosmetic in terms of location and appearance, yet we are not concerned about safety, and performance,” he says.

Ironically, says Collins, Howden-Chapman’s research has shown that the cost of treating one patient in the A&E department for a respiratory illness is about the same as insulating an entire house. Beacon Pathways has been at the forefront of healthy-home research since it was formed in 2004 as a government consortium investigating ways to improve New Zealand’s homes and neighbourhoods for the Foundation for Research, Science and Technology. Collins says that for the first 18 months it was mainly desktop research. However, they realised that they weren’t going to change the sector unless they could demonstrate what could be achieved.

“It wasn’t about just about new houses; it became apparent the challenge was the existing housing stock.” It is a view shared by many and one of the main government policies introduced to address the issue has been the Warm Up New Zealand: Heat Smart campaign for homes built prior to 2000, which has been run by the Energy Efficiency and Conservation Authority (EECA) since July 2009. The subsidised scheme aims to retrofit more than 188,500 New Zealand homes over a four-year period, with a government spend of $347 million. The policy also had its beginnings in the 2001 National Energy Efficiency and Conservation Strategy which identified more energy-efficient housing stock as key to helping achieve a more sustainable energy future for New Zealand.

“New Zealanders don’t respond unless you give them incentives,” says Collins. “The Warm Up New Zealand campaign has been a really successful driver because middle-income New Zealanders have seen they can get something for nothing, so they have been prepared to take some steps. “My concern is that it will end next year and where is the next incentive? It has only covered 20 to 30 percent of our homes, so to stop there is a pretty pointless exercise. We have done the easy ones, the hard ones are the private landlord rentals and the ones where people are really struggling financially.”

Therein lies the crux of the problem; the risk of serious injury, toxic exposure, and illness from living in an unhealthy home is often higher among those who are least able to find and afford a healthy one. According to a submission by researchers from the He Kainga Oranga Housing and Health Research Programme in the Department of Public Health at the University of Otago, Wellington, “The affordability of housing has significant implications for the health and wellbeing of families”. They cite the lack of housing affordability as an increasing problem in New Zealand.

Since 1988, the percentage of households paying 30 percent or more of their net income for housing has increased from 12 to 30 percent in 2008. Increasingly, access to affordable quality housing and home ownership is beyond the reach of many, particularly low- to middle-income families, Maori and Pacific Islanders. They say that for households struggling to make ends meet, there is little choice but to opt for poor-quality housing and sacrifice the basic necessities which include adequate heating and space. “In other words, for those on a low or even a middle income, an ‘affordable’ house will all too often mean something dilapidated, damp, uninsulated, unheated and smaller than ideal. Households that are crowded raise the risks of infectious diseases.”

This is why one of the major drivers for Beacon’s work is to demonstrate that high-performing houses can be built for the same costs as a conventional home while conserving energy and water, says Collins. “There are lots of high-performing homes at the top end of the market that because of the size of the house and the way they are designed and built, are enormous consumers of energy in spite of the fact that they might be well specified.” The group has developed performance benchmarks for healthy and sustainable homes and built two demonstration houses – called the Waitakere NOW and Rotorua NOW homes – to show that these houses can be built now with current products and materials.

“The new housing stock is better,” says Collins, “but as the building code sets minimum performance standards, so the industry tends to gravitate to minimum standards rather than high-performance standards.” The NOW home in Waitakere had interior temperatures that were between 16°C to 18°C for most of the year, and there were only three nights when it dropped below 16°C in a building that has no heating. They achieved this through careful design, Collins says.

“Healthy homes and energy efficiency are inextricably linked. Firstly it is about good design, it is about appropriate location and orientation and in some ways it is about the basic things our forebears understood, that if you wanted sunlight you have to oriente your house to the sun. We had verandahs to shield us from the hot summer sun and they were cleverly designed so that the lower winter sun would stream through the window. Intuitively, that was understood a long time ago. I think what we didn’t understand was around thermal mass and insulation, more efficient space and water heating.”

The Waitakere house has big windows to the north, concrete floors that are insulated, relatively high levels of insulation in the ceilings and the walls, and small windows to the south. “It performed incredibly well,” says Collins, “but that is not the standard to which houses are normally built. And the costs were on par with a standard three-bed home in west Auckland. We achieved that by making the house a bit smaller, 142 sq m, three bedrooms and no hallway.”

Retrofitting existing houses presents different challenges. There are very few opportunities in the life of a house to actually intervene and upgrade, and those opportunities normally happen within the first two years of a house being bought. “It’s often around additions to a family such as the first child is coming and they have to have a nursery,” says Collins. “Hopefully they don’t just paint the walls but put some insulation in behind them.”

Insulation levels in the building code should be considered as the minimum acceptable levels, and higher insulation levels should be encouraged for new homes and retrofit where possible. In recent years steps have been taken to introduce rating systems for healthy and efficient homes and a recent survey found that New Zealand home buyers want to see energy and cost-of-living ratings on the homes they look at. The Nielsen Annual Real Estate Market Report, based on a survey sponsored by realestate.co.nz – the country’s largest real estate website – says that two-thirds of those surveyed wanted information on environmental performance of homes made available online.

One such system is Homestar, developed by the New Zealand Green Building Council and BRANZ. Alistair Helm, of realestate.co.nz, says that Homestar is only going to grow in terms of its recognition by consumers as the defining measure for home environmental performance. “We are now including certified Homestar ratings on property listings on the realestate.co.nz website,” says Helm. “New Zealand now has a robust, government- and industry-backed home rating tool that aims to help New Zealanders create healthier, more comfortable and energy-efficient living spaces.” Director of Homestar Krista Ferguson says that consumer demand for the rating tool is growing substantially.

“We are delighted to now have homes with Homestar certified ratings viewable on realestate.co.nz, and to see consumer demand reported in this survey reinforces Homestar’s commitment in improving the health and quality of New Zealand homes. This represents an important step in the process towards improving the overall stock of New Zealand homes,” says Ferguson. Beacon’s HomeSmart Renovation programme sought to find out what it took to get consumers retrofitting to improve their homes’ performance. Based on individual assessments, 430 participating homeowners were given renovation plans that would bring their homes up to Beacon’s high standard of sustainability.

The project focused on whether homeowners, provided with independent advice on achieving an affordable and effective retrofit, would use that advice to make the changes needed. The results were somewhat surprising. Although 65 percent of homeowners installed or upgraded their insulation as a result of their renovation plan, only 18 percent enquired about the EECA Warm Up New Zealand subsidies and only 13 percent took advantage of them. The trend seemed to be saving power at the expense of health and comfort. Although around half of the homes in the study met the benchmarks for energy, only 3.6 percent of monitored homes had temperatures in both the bedroom and living rooms that met World Health Organization minimum standards.

“Those of us who have lived in a warm,dry house will never go back but how do you encourage other New Zealanders, how do you get them to share that?” Collins asks. “You have to change a mindset of a nation, and part of that is the people who live in the homes, the regulators, central government. We have to have high standards around building performances.”

So what makes for a healthy home? First, adequate heating and insulation to ensure a warm, dry house and good ventilation that prevents toxic mould and moisture build-up and reduces allergens. Removing potential toxic substances such as lead paint and asbestos is important and the installation, maintenance, and consistent use of safety devices – along with good design – will eliminate potential health and safety hazards.

Energy-efficient heating systems Healthy heating systems go hand in hand with energy efficiency, but some systems also have significant health risks. Research has shown that unflued gas heaters generate significant amounts of moisture and nitrogen dioxide. However, modern flued gas appliances offer a fast and efficient heat source with a wide range of options from small heaters through to central heating.

Open fires may be popular but they also produce smoke and have been banned in many cities and towns. Modern enclosed woodburners are more efficient but still emit tiny particles of smoke which, if inhaled in sufficient quantities, can cause respiratory disease. All woodburners sold since September 2005 for urban use have to comply with national environmental standards. Heat pumps are among the healthiest and most energy-efficient forms of heating available. They can warm a single room or an entire house and in summer, they can be used to cool. Underfloor heating is gaining popularity in New Zealand and can be easily installed in a new house.

It can either be embedded in a concrete slab or laid under the flooring of a new or existing home. As it is slow to warm a house, it is a good option for buildings where the occupants are home a great deal. However, once the floor is heated, it acts as a low-temperature radiator.

Dealing with toxic mould One of the major symptoms of leaky buildings is ugly black mould growing in the cladding and corners of houses. As well as being unsightly, mould spores can cause health problems such as allergic reactions similar to hay fever, breathing difficulties, eye irritation, skin rashes and occasionally, more serious symptoms.

Some types of moulds produce toxic compounds. Stachybotrys chartarum is a toxic mould that is associated with leaking buildings, and is caused by leaks that originate outside the building and from leaks within wet areas in buildings. Finding Stachybotrys in a building does not immediately mean that the building occupants have been exposed to allergens or toxins. While it is growing, a wet slime covers the spores, preventing them from becoming airborne. Exposure will only occur when the mould has died and dried up.

The building code has minimum requirements for ventilation: all the air in a house should be changed every three hours, the air in kitchens should be changed every hour and in bathrooms every two hours. To achieve this, extractor fans should be installed in kitchens and bathrooms – and windows should be opened elsewhere – to bring in fresh outside air. To control condensation that leads to mould growth it is necessary to address all the contributing factors – heating, ventilation, insulation and lifestyle – and to reduce the production of water vapour within the dwelling. Installing an automatic ventilation system is a good long-term solution, while dehumidifiers offer an immediate solution.