Beautiful Innovative underground Luxury House is Bright and Light
The Client thought her home would look like an underground bunker. She was pleasantly surprised
By Bridget Puszka, BP Architects
What is an Earth Shelter?
An earth shelter is an underground house. It has earth against the walls and on the roof. Some earth shelters are entirely underground.
Why have an earth shelter house?
In an earth shelter house, the earth acts as a thermal mass. The earth maintains a constant temperature of around 14°C, three metres below the surface.
So if the earth’s temperature around your house is staying at this temperature, this means two things. It is warmer than the air temperature in winter, which could be zero or below. So you heat your home not from zero or below. You heat from around 14°C. So you don’t need that much heat to warm from 14°C to a comfortable 20°C to 25°C. The second thing is that the earth is colder than the air in summer.
So you can use both the thermal mass and the temperature of the earth to your advantage. It will help keep your house to a set temperature of around 14°C in winter. Then with a bit of heat from the sun or a heat source, you can keep your home comfortable during the colder months. In summer, the earth will keep your home cool. The earth will shade your house from the hot summer sun. And the earth will absorb some of the heat from the air in the house and keep your home cooler. So you cut any required heating and cooling.
The earth shelter house can also provide efficient fire protection from bushfires. If you build a bushfire shelter, you have to build to the Australian Standards. The Australian Building Codes Board produced design and construction standards in 2014. This was for private bushfire shelters. You can read the standard and find out the requirements for a private bushfire shelter.
Are underground houses cooler?
In summer, the house stays cool because the cooler ground around the house absorbs the heat as the ground stays a cool 14°C.
Suppose you think of Coober Pedy in northern South Australia. Coober Pedy has a hot desert climate with a gibber desert not far from the township. The temperatures in Coober Pedy can go up to the high 40°C during summer. Guaranteed year in year out.
The people of Coober Pedy have adapted and resorted to living in below ground or underground houses. Called dugouts, they are comfortable in the hot summer. Dugouts stay around 23degC all year round. Without electricity or air conditioning.
What is a berm house?
A berm house is an earth-sheltered house with walls and a roof covered by earth.
What is an Autonomous house?
An autonomous house is a house designed to be independent. It doesn’t need any infrastructure support. It is a house with no bills. The house generates its own electricity. There is no gas used in the house. It collects its own rainwater for household use and treats its owns sewerage. So it is entirely independent of the infrastructure. Such as the power supply from the electric power grid. Independent of Gas supply, mains water, the sewerage system, or Stormwater. In 2002 British architects Brenda and Robert Vale said
“It is quite possible in all parts of Australia to construct a ‘house with no bills’, which would be comfortable without heating and cooling, which would make its own electricity, collect its own water and deal with its own waste…These houses can be built now, using off-the-shelf techniques. It is possible to build a “house with no bills” for the same price as a conventional house, but it would be (25%) smaller.”
Earth shelter underground House in Carrajung, Gippsland, Victoria, Australia
The Carrajung underground house is located in the highest bushfire zone, the BAL FZ or flame zone.
The Country Fire Authority CFA downgraded the bushfire requirements. This was because of the bushfire safety house design. Even so, the roof construction is to BAL FZ requirements. And the windows and doors have bushfire shutters. The wine cellar in the house doubles as a safe room in case of an emergency in a bushfire.
The Carrajung underground house is a berm building built into the side of an existing hill. The house is on a rural allotment of over 100 acres. It is an autonomous house. It generates its electricity from a photovoltaic power supply with battery storage. Evacuated tube solar hot water system heats the water. It does not use gas in the house. The water supply is from rainwater and stored in 120,000L rainwater tanks. A 60,000L reserve is for bushfire fighting purposes in the event of a bushfire. There is a backup diesel generator if required. A worm farm composting system manages household waste. And a roof garden and berm building keep the house comfortable all year round.
BP Architects specialize in designing homes that can reduce your ecological footprint.
Find out how we help our Clients with their architect house designs. If you are planning a new home and would like to talk to an architect about your future home, drop us a line.
Sketch Design, North Elevation, Carrajung Underground House