Sanctuary: Modern green homes

Open Plan Gone Mad?

This is an excerpt from an article in Sanctuary magazine issue 16.

Open-plan living has many benefits, but also potential drawbacks in loss of control over noise, heating and cooling, says building designer Dick Clarke.

Words Dick Clarke

If there’s one idea that has permeated contemporary home design more than any other, it would be “open plan”. Open-plan living has many tangible benefits, but also some serious drawbacks if not done well. Combined living, kitchen and dining areas should be no larger than 70 or 80 square metres – any bigger and things get out of control. It’s reasonably well known that houses with large living areas and circulation spaces which connect the house from one end to the other have poor thermal control, but if they have lots of exposed thermal mass inside, such as concrete floors and masonry walls, they may also have extremely poor acoustics.

The concept of open-plan living comes from our love of big living areas with plenty of light, where all household activities happen in close proximity. This is in stark contrast to houses built before the 1950s, where kitchen, lounge and dining activities each had their own separate room, quite disconnected from the rest, and certainly disconnected from the outside world. During the 1950s and 1960s, lounge and dining often came together in one larger space, with direct access to the kitchen. Then during the 1970s the kitchen was liberated from its second-class status, freed from isolation and brought joyfully into the core of the household.

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Cleaner, Greener Hot Water

This is an excerpt from an article in Sanctuary magazine issue 15.

Close coupled or split system? Gas or electric booster?
Solar hot water presents some intriguing choices.

Words Sarah Robertson

Misty Cronin and her family recently built a townhouse in an inner suburb of Melbourne. Solar hot water was just one of a number of sustainable features incorporated into the design by Breathe Architecture’s Jeremy McLeod. With water heating accounting for about 25 per cent of household energy use and solar capable of supplying from 50 to 90 per cent of household hot water demand, Misty was sold.

“It just makes sense, why not? The sun’s out there, why wouldn’t you? It was kind of a no-brainer,” she explains.

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Building your sustainable dream home

From Sanctuary issue 10. More articles like this

By Alan Strickland with Judy Celmins

Excerpt: Wanting to live sustainably is not a fringe occupation. Millions of Australians want to make a difference to their homes and lives. But as a member of the Alternative Technology Association and an organiser of Sustainable House Day the question I am constantly asked is: “Where do I start?”

Many people come away from Sustainable House Day fired with enthusiasm. They see homes that are warm in winter and cool in summer, without the need for large heaters or airconditioning. They see water-wise homes that gather rainfall and greywater and use these to produce wonderful, food-producing gardens. They want that for their own home. The problem is that visitors only see the finished house. Time doesn’t usually allow visitors to ask the owners about how they went through the whole saga of planning and creating a sustainable home. The wondering, the indecision, the frustration and dead ends, and the many stages of learning they had to go through.

This article aims to help fill that gap. The more you learn before you start, the easier the process will be and the less the likelihood of repeating the mistakes that others have made before you.

Further information

This article is the combination of two online posts at shmeco.com: “I’d like a sustainable home but where do I start?” by Alan Strickland and “Building the self-sufficient dream” by Judy Celmins. Alan Strickland is the Alternative Technology Association’s South Australia Branch Treasurer. Judy Celmins is a director and co-founder of shmeco.com. shmeco.com invites people to exchange their ideas, stories and experience on sustainable living choices. shmeco are managers of Sustainable House Day.

www.ata.org.au
www.shmeco.com
www.sustainablehouseday.com
www.yourhome.gov.au
www.sanctuarymagazine.org.au

Free home health checks

This is an excerpt from an article in Sanctuary magazine issue 8.

The Australian Government’s Green Loans program, launched on July 1 2009, aims to help homeowners improve their existing home. As part of the program, more than 1000 people will undertake Home Sustainability Assessor training to become accredited Green Loans assessors.

A tailored home sustainability assessment, coupled with access to a four-year interest-free loan of up to $10,000, will enable homeowners to make immediate energy and water-saving changes, from draft-sealing to installing solar panels and greywater systems.

Getting a free home sustainability assessment is the first step to qualifying for a Green Loan of up to $10,000. To find out if you are eligible for a Green Loan or to register for a home sustainability assessment, go to www.environment.gov.au/greenloans.

Apart from reducing your carbon footprint, making your home more environmentally friendly is a timely investment. The next 10 years will see the housing market shift towards environmentally friendly homes in response to pricing shifts for water and energy, smarter environmental building regulations and consumer demand.

Choosing a heater

This is an excerpt from an article in Sanctuary magazine issue 3.

The type of heating you need depends on the size and function of the space to be heated and how often and how many people use the space. When looking for a heater find out how much energy a heater will use, its long term running costs and how much pollution it will create.

Unless you create your own energy from a renewable source or purchase GreenPower, the energy used by your electric heater is sourced by greenhouse gas producing fossil fuels. Efficient gas heaters and reverse cycle airconditioners produce one third the amount of greenhouse emissions of standard electric heaters. They also have energy labels to help you choose the most efficient model. If looking for a space heater choose a 5-6 star natural gas heater or a 4-6 star reverse-cycle airconditioner. For central heating, zoned 4-5 star natural gas ducted heaters and zoned natural gas hydronic systems are the most economical.

Wood can be a good fuel source if the wood is sustainably harvested and sourced locally. However, the smoke from wood fires is a major source of pollution, and open fires lose 90 per cent of their heat up the chimney. If using wood make sure it is sustainably sourced and use a slow combustion heater to the manufacturer’s instructions.

Solar heaters

Almost all of the energy available on the planet today comes or has come from one place—the sun. Yet, very little of it is used directly by people. There are two forms of active solar heating available in Australia; flat plate collectors and solar boosted hydronic heating.

Flat plate collectors consist of a large flat glass covered box used to heat air which is then pumped into the home using a fan. Small (approximately 1 x 2 metres) flat plate heaters can be used to heat individual rooms, while larger (approximately 3 x 4 metre) roof-mounted collectors can heat an entire home, at least when the sun is shining.

You can also use the sun’s heat to provide some (or sometimes all) of the heat to a storage-type hydronic heating system. Indeed, some hydronic systems that use solar evacuated tubes are designed to be primarily heated by solar, with gas or electric boosting as a backup.

Whatever system you choose, remember that the best way to save energy, money and reduce your greenhouse emissions is with good house design. By reducing heat loss you can maintain a comfortable temperature inside, regardless of the temperature outside.

A naturally warm home

This is an excerpt from an article in Sanctuary magazine issue 3.

By making a few changes to your home you can considerably reduce your heating bills and stay comfortable in the process.

Design for warmth

The cheapest way to heat your home is to use the warmth of the sun. If you are building or renovating, include passive design principles in your plans to let the winter sun in and keep the summer sun out. Position the daytime living areas so that they face north, with windows strategically placed to let in the winter sun and shaded by eaves, sails or external blinds during summer.

In cooler climates, thermal mass can help regulate the temperature inside the house, especially when there is a big difference between day and night outdoor temperatures. Use building materials that have high thermal mass such as concrete, bricks and tiles to absorb heat during the day and radiate the warmth back into the home during the night.

Changes around the home

Even if you are not building there are some measures that you can take to stop heat escaping from the house. Good insulation is a must. Insulation is like a barrier, preventing heat passing in and out of the house and can be placed in the ceiling, walls and floor. When looking for insulation check its R-value; the higher the value the greater the level of insulation.

Do a walk around your home with a candle, using the flame to show if there are any drafts. Place draught excluders, such as under-door strips, and foam door and window seals around doors and windows. They are low cost, very effective and are one of the simplest ways to reduce energy use. Replace or seal off open air vents and exhaust fans that allow warm air to escape into the roof cavity or the outside air. Don’t forget gaps between walls and skirting boards, and even the gaps between floorboards—these gaps may be small, but put together they can make for a great deal of cold air entering the house, especially when it is windy outside.

Fireplaces

This is an excerpt from an article in Sanctuary magazine issue 7.

In the latter half of the twentieth century, many Victorian houses had their draughty and notoriously inefficient fireplaces sealed up and plastered over, cast-iron insert and all, as gas heaters found favour over wood fires.

This may have improved thermal efficiency, but it came at a cost to charm and heritage appeal. For all their problems, fireplaces with ornate surrounds are one of the principle features of a Victorian home. If you wish to keep or restore your fireplace, there are ways to do it energy-efficiently.

Ninety per cent of heat from a woodburning open fireplace goes up the chimney. Replacing your woodburning fire with a fireplace-fitted gas heater will be more efficient than a wood-burning fire, but a regular flued gas heater will still allow a draught up the flue. It will also burn oxygen from within the home, which may necessitate a wall vent (unventilated rooms with gas heaters are a serious hazard).

Maurice Beinat of Ecomaster recommends that “heaters should be fitted with a balance flue, also known as a power flue, which draws the air used for combustion from outside the home. These have no possibility of draught as the combustion chamber is fully isolated from the air within the home.”

When they’re not being used in winter, open fireplace flues should be sealed. Sealing a fireplace, says Andreas Sederof of Sunpower, “can be as simple as stuffing a hessian bag into the throat of the chimney or (for more control) having a damper fitted into the flue”. In summer you should keep your chimneys open, as they can act to vent hot air out of the house.

Design for climate

This is an excerpt from an article in Sanctuary magazine issue 6.

One size does not fit all. Australia has eight climate zones, ranging from tropical to alpine. Make sure you employ a designer who is familiar with your zone and who designs climate-appropriate buildings (for instance light-weight and ventilated in hot, dry climates, well insulated and with good solar access in cool climates).

In tropical and hot, dry climates, orientate the house to exclude the sun year-round and to maximise cross-ventilation. In all other climates, your aim should be to minimise the summer sun and maximise the winter sun, which basically means a northern orientation.

Couple your “passive solar” design with thermal mass (materials that absorb heat energy) to retain the warmth of winter sunlight and/or the cool of summer shade.

Hot sun, cool house

This is an excerpt from an article in Sanctuary magazine issue 6.

The sun is beating down on the roof. The garden is wilting and so are you. Wouldn’t it be nice to turn some of that heat against itself?

You may be surprised to know, it’s actually possible to convert heat on the outside of your house into a cooling breeze inside. Solar airconditioners are coming your way.

The models in development now mostly use evacuated solar thermal tubes, like the ones used in many solar hot water systems. Instead of drawing on mains power on the hottest days, pushing power grid peak loads into the red, these systems would just hum along on solar energy. And the hotter it is, the better they work.

Consensus is that solar aircon for homes could be only a couple of years away. Currently there are several types of system in development.

How will they work?

One of the most promising systems uses evaporation. The system uses a desiccant to remove humidity from the air, which is then re-humidified using wet pads so the air delivered to the building is both cool and not too humid. The desiccant is then solar-heated to remove the moisture it has collected, so it’s ready to work again.

These systems are very far down the track in terms of technical development and will probably be among the first to be commercialised for domestic use. They’re efficient, robust and easy to maintain. A slight downside with desiccant-evaporative systems, however, is that they use a fair amount of water: CSIRO has estimated 30-50 litres on a hot day for a residential system (that’s about as much as a four-minute shower with a low-flow showerhead).

Another exciting technology, though not as far along as evaporative systems, uses ejector jet pumps, which rely on heat energy to circulate a fluid through a cycle of condensation and evaporation. The principle has been known for around 100 years, and Dr Mike Dennis, who heads the Australian National University’s solar ejector jet program, believes it has the potential to be more reliable, cheaper and smaller than comparable systems. The ANU is working with commercial partners to develop a prototype.

A winning design

Dr Paul Kohlenbach of Solem Consulting is a former research scientist with CSIRO and an expert in residential-scale solar aircon. Dr Kohlenbach says that to succeed in the residential market, manufacturers “need to develop a plug-and-play solution, pre-packaged and ready to use”.

Dr Kohlenbach believes the future for solar aircon is bright. “The CSIRO is currently researching a small solar cooling system which could be market-ready in two to three years. Overseas manufacturers have realised that the Australian market has huge potential and have started to establish themselves here.”

Probably the single most exciting thing about solar technology, he says, is that it has the potential to not only offer airconditioning, but heating and hot water as well. “A possible solar cooling kit can therefore provide all the thermal needs of a residential house.”

The ANU’s Mike Dennis agrees that a system that both cools and heats is the holy grail of solar climate-control technology. “Consider that most of Australia’s population live in a temperate climate that hardly requires airconditioning – in fact requiring a lot more heating than cooling,” he says.

If we allow climate change to continue, of course, more Australians will be concerned about summer cooling than winter heating. Even so, whichever system prevails, the winning design will almost certainly offer year-round comfort and a hot shower.

Soak up the sunshine

This is an excerpt from an article in Sanctuary magazine issue 5.

If you want to keep your home warm during winter the first step is to consider good passive solar design and high levels of insulation. If extra heating is required for comfort, solar hydronic heating is often a good option. Solar hydronic heating warms your home by taking advantage of an environmentally friendly energy source—the sun. Hydronic heating systems are typically gas-fired and have been used in Europe for almost a century. Solar hydronic heating systems that use evacuated tube solar collectors as the primary method of heating the water needed for the hydronic circuit are now available on the market.

How does it work?

Solar collectors capture energy from the sun and heat the water in a storage tank to the required temperature via a coil in the top of the tank. If the solar system does not heat the water in the pipes sufficiently, a backup boiler comes on and boosts the temperature. A pump circulates the hot water through pipes around the hydronic circuit, and the heat is transferred into the room through wall mounted panel radiators or through piping laid in a concrete slab floor during house construction. A separate heat exchange coil in the tank can provide domestic hot water for household use.

The backup burner can be run off natural gas, solid fuel or LPG. If you live in an urban area the most economical and environmentally friendly fuel for the backup is natural gas. Solid fuel can be labour intensive and LPG can be up to two and a half times more expensive than natural gas and will significantly increase the running costs of the system.

The components that make up a solar hydronic system are:

• an evacuated tube solar collector to capture energy from the sun
• tanks to store the hot water that is heated during the day
• backup burner which can heat water to a thermostatically-controlled temperature
• a pump to circulate water through the hydronic circuit
• piping that carries the water from the boiler to the panel radiators or to the in-slab pipes and back again for reheating.

A crucial component of the system is the mixing valves, which regulate the water temperature. The evacuated tubes are capable of producing high temperatures, so for safety and reliability reasons it is essential that these temperatures are controlled.

Getting the heat out

Panel radiators are most commonly made of pressed steel and can be installed in existing homes or during the building process. Each panel can be controlled independently, which gives you the benefit of being able to shut off heating in rooms that are not being used.

In-slab piping or ‘foil coils’—made from polyethylene—are generally installed during the building process, but a concrete slab can sometimes be introduced to an existing home during renovations. When considering in-slab piping for your home talk to a concreter who is familiar with your area to ensure that your slab is not likely to shift or crack. The piping can tolerate some kinks and movement, but in-slab piping will not be suitable for all land areas. The piping is usually laid out in a minimum of three zones, which gives you the benefit of controlling heating to only the rooms which are being used. Once heated, the concrete slab floor converts into a radiant heat bank that releases heat evenly throughout an area.

In-slab floors can be tiled or the slab can be finished as a polished concrete floor. Carpet is generally unsuitable, due to the carpet underlay acting as an insulator and preventing the heat being released, but floor rugs can be an option. Timber floors can be laid over in-slab piping. However, the thickness of the wood can impact on heat transference and may also affect the warranty on the timber as the wood may shrink and buckle if it is not already kiln dried.