beginings:- Thermal mass and earth coupling

Hi all,

Well it all started watching Better Homes and Gardens a few of months back, we saw a house a couple built themselves. It was an underground house that had good earth coupling which meant that it kept cool in the summer and warm in the winter.

We started to question the wisdom of the current style of house that we lived in, especially when these guys said that with their solar power and water harvesting they had "no bills".

I started investigating other styles of house design. After making a few inquiries, we decided that earth covered wasn't really and option, its quiet an engineering feat especially if you want to cover your house with 2000 tonnes of earth.

What we did find out was that current building styles of houses are inside out. Meaning that all the solid walls are on the outside and light weight walls are on the inside. The problem with this is that there is very little thermal mass to help regulate the temperature of the inside of the house. The correct style of house is called a "Passive Solar House". This uses the correct placement of the windows and eaves of the house and proper use of thermal mass. In the winter as the sun shines through the windows it warms the solid mass inside your house and absorbs the thermal energy during the day which is released though out the night. In the summer the eaves or verandas are designed in such a way that the sun doesn't hit the floor. Your house is cooled at night by the cool air and because of the thermal mass the house doesn't heat up quickly during the day but maintains a cooler temperature inside.
The key to make all this happen is to have a high thermal mass inside the house. This can be achieved through a number of means, and it really doesn't matter what is on the outside of your house, it can be clad in a lightweight material. What matters is having dense materials internally, without insulation eg carpets getting in the way. Materials that work with this are; reverse brick veneer, solid brick, mud brick, and rammed earth. Light weight and insulated materials like heable block and gyprock and stud walls don't really work in a passive solar house as they don't help regulate the temperature.

Wendy and I decided that we liked the look of rammed earth and have started to investigate plans that utilize them. After looking at the videos at this site: http://www.rammedearthhomes.com/ we also decided that we liked the idea of playing in the dirt, rammed earth certainly fits the criteria of passive solar.

More to come later, I need to sign off now :)

Darrin