Dream homes become reality

Stevie Emilia ,  The Jakarta Post ,  Copenhagen   |  Tue, 06/30/2009 9:30 AM  |  Environment

Setting good example: Suburban resident Charlotte Hjelm (photo right, below) washes in her kitchen in their home (photo above) in Stenløse, some 30-minute drive from Copenhagen.

At first glance, green homes appear expensive, but over time, owners get their money back.

Charlotte Hjelm knew this well. The mother of two did not mind paying extra to build the dream home she wanted her two children – four-and-a-half-year-old Andrea and eight-month-old Jonas – to live and grow up in.

The nurse and her husband Peter Hans Jensen spent DKK3.15 million (US$587,000) building their home three years ago on a 400-square-meter block of land in the town of Stenløse, about 30 minutes’ drive from the Danish capital Copenhagen.

The price, she said, was some DKK150,000 more they would have had to pay to buy an ordinary home.

“It’s true that building a new house more expensive than buying an old house, but we don’t have to do any maintenance work for 10 years and we pay less for heating and electricity,” she said, showing details of the three-room house to visiting journalists.

Large windows in the Hjelm house, protected by thick insulation panels, allow sunlight to enter freely, reducing the use of electricity in the process.

The house is also installed with equipment to recycle warm air, which automatically happens every hour.

“But the air is recycled every 15 minutes when more people are inside the house to prevent us from feeling ‘stuffy’,” she smiled. “By recycling warm air, it becomes cheaper for us to heat up the house, meaning we’re using less gas.”

Rain harvesting is another prominent feature of this “green” house.

Good cover: Flower bed serves as reservoir to harvest rain.

Rainwater is collected from the roof and stored in a reservoir in the garden. The water is treated before use.

“We use the water to do our laundry, flush the toilet and wash dishes. Since the water contains no chloride, I only have to use a little detergent so it does not take time to do the laundry, meaning I use less electricity.”

Currently, the family pays 25 percent less for their heat and electricity than usually paid in an ordinary home. Their heating, for example, comes to about DKK6,000 a year – less than $100 a month.

Charlotte’s house is not the only green home in the area. Several such houses were built following the introduction of the 2001 Stenløse town regulation by its then mayor Willy Eliasen.

The town regulation required that houses built in designated areas should be 50 percent more energy efficient than required by the Danish government’s building codes.

Denmark introduced a building code in 1979 that obliged people to build their houses with thicker insulation and more tightly sealed windows in order to conserve energy.

The codes – which are periodically updated – helped lower the country’s heating bill by 20 percent from 1975 to 2001. The codes also aim to reduce energy demand by 25 to 30 percent from the 2006 level of 5.5 liters of oil per square meter.

With transportation and industry grabbing the headlines for their high manmade CO2 emissions, which are blamed for causing climate change, it is less well known that our homes consume vast amounts of energy.

Constructing, heating, cooling and supplying electricity to our homes altogether account for a massive 30 percent of the total global energy consumption. The percentage is even higher in highly developed countries.

“By improving the energy efficiency of existing housing using available technologies, we can reduce energy consumption by up to 45 percent by 2015,” Ole Michael Jensen, senior researcher at the Danish Building Research Institute, was quoted as saying in the Denmark: Key Developer of Climate Solutions report.

“Domestic housing accounts for 40 percent of total energy consumption in Denmark. However, the fact is, these costs can be eliminated if we build intelligently.”

The new low-energy houses are not only more efficient and healthier but, when a lifecycle calculation is made, are also considerably cheaper than regular housing.

Currently, architects, construction companies and building materials manufacturers are exploring these developments, described as “the new industrial revolution” by German chemist Michael Braungart.

Germany is spearheading the developments, experimenting increasingly with “Passive Houses” – a rigorous voluntary standard that results in ultra-low energy houses – and even building houses that produce more energy than they consume.

The Danish government has also passed the world’s toughest energy-saving legislation, making its housing sector now one of the most energy efficient in the world.

The secret behind zero-energy consumption is the use of high insulation standards combined with intelligent hi-tech systems, such as wireless interior lighting control and automatic heat recovery from ventilation and hot water systems. Windows and building envelopes that absorb more heat than they release should be installed.

Calculations show that over 30 years, the energy produced by a house’s solar panels will offset all the energy that went into the building, the report said.

Ellen K. Hansen, the architect responsible for an experimental building project, said in the report that improving ventilation and indoor climate means this type of housing is simply healthier and more pleasant to live in.

“Just like green office environments, green housing will save society huge amounts of money,” Hansen said.

As for Charlotte Hjelm, she is just thinking of her children. “I don’t mind the trouble in building the house,” she said. “We have to do it if we want to preserve the environment and our future, for our children.”

Photos by Stevie Emilia

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