Diagram Architects

Rule 2: Stop fighting the universe.

The universe wants you to design an energy-efficient house. No, seriously; it does. Why else would so many things, from the tilting of the earth to the laws of thermodynamics, give you the tools to heat or cool your house for free?

More energy lands on the roof of your house than you’ll ever need to heat it. Last summer’s heat lies stored only a few metres under your feet, and last winter’s ‘coolth‘ only a short distance below that. Hot air rises, where it can be recirculated as required or vented to the sky at night. The evaporation of water draws latent heat, cooling the air. Glass transmits light (short wave radiation) but traps heat (long wave radiation). Light-coloured surfaces reflect. Mass provides thermal capacitance, carrying the day’s heat into a colder evening. Heat travels from warm to cold, but at different speeds through different media.

These basic physical laws give us passive solar heating, earth-coupled heat storage, night-time heat purging, subsidence (cool) towers, sunrooms, reflective foil and bulk insulation and the many other tools we can use for energy efficient house design.

The same tilting of the Earth on its axis which gives us winter also sets the sun lower in the sky, allowing heat and light to pass under deep eaves and further into a north-facing room (south-facing in the northern hemisphere). The increased azimuth of the sun in summer allows it to be screened, provided you calculate your sun angles and eave dimensions carefully. (Pritzker-winner Glenn Murcutt calls this “Letting the planet do all the moving”.)

These are not new discoveries. Xenophon of Thebes wrote about passive solar design in his Memorabilia (3.8.8-10) in 371AD, but the 20^th Century experience of cheap ,easily accessible fossil fuel has allowed us to heat and cool our buildings through the application of brute force.

Now, brute force is a fantastic thing if you’re planning to wrestle a gorilla or launch a payload into orbit, but using it to warm or cool your house is just pure bloody-mindedness if there are cheaper and easier options available.

So before you turn the first sod or draw the first line for your new, energy efficient house, we recommend you ask yourself (or your architect/designer) the following questions:

• Are we best using the house’s environment, climate and conditions?

• Is there a path of lesser resistance to achieve the same levels of comfort and delight?

And my personal favourite:

• What is the universe trying to give me for free?

By all means, create an energy efficient house because you’re concerned about energy independence, peak oil or climate change. But personally, I like energy efficient design because any other choice is just beating your head against the laws of the universe. 

Tags: , eco, energy efficient, green, green design, house design

This entry was posted on Monday, December 1st, 2008 at 6:25 pm and is filed under 10 rules for energy efficient house design, energy efficiency, green house design. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.