Saturday, May 24, 2008

How To Choose A House Plan - Part 8 of 10

If you're not yet giving much thought to how much energy your new house is going to use, and how much it's going to waste, then it's time you started. It should be one of your top priorities - if for no other reason than your own pocketbook.

Energy used for heating and cooling homes is going to continue to get more expensive and as we've seen recently, world politics can quickly and dramatically affect your access to cheap energy.

I'll get to the part about house plans in a minute, but first...

A Little History

This isn't the first energy crunch we've had. In the 1970's - when I was a college student studying Environmental Design - world events conspired to create an American energy crisis. It was an interesting time to study Architecture, because the buildings we designed were required to respond to the environment - to use natural energy sources as much as possible.

The homes we created used technology and inventive design to give them form - we designed solar homes, earth-sheltered homes, thermal-mass homes, and other types in a wide variety of shapes and sizes. They collected heat from the sun and the ground and held it inside as long as possible. They blocked excessive solar radiation with deep overhangs and shading devices, and they were very carefully oriented to the angle of the sun and prevailing winds.

Sure they looked a little weird (some were downright ugly) but we designed homes that stayed warm in the winter and cool in the summer and used almost no energy at all.

A Little More History

But then in the 1980s energy got cheap again, and everybody forgot about low-energy homes (see I told you - just a little more history).

Where We Are Now

Fast-forward to the twenty-first century and suddenly energy is on the front page again. And again homes are responding to pressure to reduce energy usage, but in a curiously different way - through envelope and mechanical technologies.

Envelope Technology

The "envelope" of your home is its wrapper - the roof, walls, windows, and foundation. It's what keeps the outside out. There was a time when heat flowed rather freely through the envelope; windows were single-pane thickness and walls and roofs had little or no insulation.

Today, wall and roof assemblies can be very high-tech. New types of insulation, sheathing, and siding slow heat flow to a crawl. Infiltration barriers (Tyvek, Typar for example) stop excessive water vapor migration and seal the outside more tightly than ever. Houses can be sealed so tightly in fact, the trapped moisture can accelerate mold growth (that's a subject for another time).

Windows and doors have also gone light-years beyond the old wood-framed putty-glazed sashes of the early twentieth century. Windows today are offered with multiple panes of glass sealed together to create an insulating layer within; often that "airspace" is filled with inert Argon gas - which has a higher resistance to heat transmission than air.

The framing of the windows is far better sealed, and the installation methods are much improved. Even plain old glass isn't what it used to be - now it's coated with a microscopic layer that allows sunlight in, but block Ultraviolet rays and keeps heat from escaping.

Other high-tech wall technologies include ICFs (Insulated Concrete Forms), and SIPs (Structural Insulated Panels).

Mechanical Technology

The other area of big change is mechanical technology, including groundwater-source heating and cooling systems, active solar collection panels, and on-demand water heaters.

Furnaces, heat pumps, heat exchanges, boilers, and air conditioners are more efficient that ever and work hard to squeeze every BTU of energy out of the fuels they use. And sophisticated computer control systems manage the distribution of heat throughout the house.

Back To House Plans!

Envelope technology and mechanical technology are two good ways to make any house plan more energy efficient. High-technology energy management systems can be added to any house plan, and most plans can be easily modified to include the latest in envelope technology. Some house plan sites even sell versions of their plans with ICF wall detailing already included.

Take advantage of high-tech energy-saving technologies wherever you can. With increasing energy costs, more sophisticated systems will be paid for with savings in fuel usage.

But envelope and mechanical technologies aren't the only way to create a more energy-efficient home. "Back in the day" we did it with old-fashioned good design - by paying attention to solar orientation, window quantity and location, and house shape and size. An Architect or a qualified Residential Designer can help you choose and/or modify a house plan to better fit your concerns with energy usage.

So choose carefully - a good looking house isn't necessarily an energy-efficient one.

Richard L. Taylor, AIA is a published author and recognized expert in Residential Architecture. He is President of Richard Taylor Architects, a 5-person firm in Historic Dublin, Ohio. Residential Architect | Luxury Home Plans

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