Energy Efficient Home
Most owner builders want to build an energy efficient home. Energy efficient construction is the wave behind the "green" movement in home building today.
So what is energy efficiency?
Efficiency is the degree to which a certain action or level of work can be effectively produced for the least expenditure of effort or fuel. For instance, a light bulb that uses 15 watts of electricity to produce 900 lumens of light would operate with much greater efficiency than one that required 60 watts to produce the same light level.*
In other words, building an energy efficient home means heating or cooling your home for the least cost.
Of course that's a little over simplified. If you live in a forest, the cheapest way to heat may be by burning wood.
But you may be unwilling or unable to cut and burn wood. And there's all that soot . . . not to mention the carbon footprint! So there are trade-offs. It's a balancing act.
The U.S. Department of Energy says, "Homeowners can achieve energy savings of 30 percent or more while improving the home's comfort level by adopting energy-efficient building practices. Substantial savings are possible whether building a new home or renovating an existing one.
So what is energy efficiency? There are many, many things that can be done to conserve energy and/or increase energy efficiency. Building an energy efficient home is said to include active and passive elements. An active element may be a solar water heater.
Passive features may include the design of the roof overhang which will allow the winter’s warming rays, but exclude the summer sun, or the orientation of the home on the lot - again to take advantage of the suns influence on the home.
One of the surprising benefits of building an energy efficient home is that you will find that you have a quieter, more comfortable home! The added insulation and minimized infiltration, reduces hot and cold spots and outside noise.
The first real push for energy efficiency construction came after the big oil crunch in the mid 1970's. Gasoline prices rose precipitously form 32.9 to 74.9 cents a gallon! During this period Owens Corning Fiberglas sponsored a number of studies and built some test homes to try out a number of energy saving techniques.
The really neat thing about these projects is that they featured mainly low-tech, easy-to-implement ideas that are still very effective today.
All of the things done to build energy efficient homes
fall into one of three categories:
1. Control heat gain and heat loss - caulking, sealing, insulation, vapor barriers, window and door design, etc.
2. Make use of free energy - solar, hydroelectric, thermal, etc.
3. Make the best use of purchased energy - heat pumps, high efficiency appliances, good controls (thermostats), etc.
Back in the 70's most people were just trying to save some money, These days, everyone is trying to save the planet!
What's your goal? If you're like most of us, it's probably a little of both.
What is energy efficiency? In addition to the components of energy efficient construction mentioned above, the actual implementation of building an energy efficient home involves several actions. These are Research (which you are doing now!), Design, Specifications, and Construction Quality Control.
Research and the actual steps involved in building a home and ask yourself this question:
A good way to proceed is to look at our pages on the different parts of a home
For example, the "parts" page starts with your lot. Haven't bought a lot yet? If you live in a warm climate that emphasizes the air conditioning more than the heat, you may want to look for a lot with some trees that can provide some shade to reduce the A.C. load.
Looking at the "Steps" page, you see that the very first step is to rough stake your lot. Have you considered the orientation of your new home with reference to the sun as it moves across the sky each day? Could make a big difference in your heat gain/heat loss calculations.
Once you've asked these questions for each part and for each construction activity, you can begin your research in earnest.
Many design elements of your home will have energy implications. You have started with the question, "What is energy efficiency?" Now, with some of the answers in hand, you're ready to incorporate a few them into your plans and build an energy efficient home!
If your home if to be built on a slab, how that slab is to be insulated is an example. Will your exterior walls be built from 2x4's or 2x6's? How wide will your roof overhangs be? How many windows? What size will they be?
What are the dimensions of your new home? A 20x200 and a 40x100 and a 80x50 home all have the same square footage: 4,000. The first has 480 linear feet (LF) of exterior wall. The second has 280 LF. The third has 260.
Do you think the ratio of heated space to exterior walls has an energy impact? You bet! A two story house has half the roof exposure (an hence potential heat loss) of a one story house of identical square footage.
See what I mean? Almost every design decision has an energy consequence! There isn't one big thing that will bring success in building an energy efficient home. It's an accumulation of many features and details - doing a lot of things right - that brings success in energy efficient construction.
You'll remember from the Plans and Specifications page that the specifications are the documents where you "specify" everything that you can't or don't show on your plans.
For example, you would want to spell out the type of insulation you want used throughout your home. You'll want to give details on the kind of heating system, windows, exterior doors, and so forth to be used. Be diligent.
Don't leave anything to chance. If you don't decide, someone else will decide for you. It's your home. You make the decisions. Energy efficient construction is all about attention to details.
Construction Quality Control
Insulation workers are often paid by the number of pieces they stuff in a wall.
When we built our first "energy efficient home" in 1976, we made a deal with out insulation supplier to pay his guys by the hour instead of by the piece on the first house they did for us.
After all was said and done, we figured we had them tear it all out and redo it three times before they got it like we wanted it - perfectly tight at the top and bottom plates and to each stud, and no compression (which reduces the insulating value of fiberglas).
The point is that if we had not been watching closely, we wouldn't have gotten the job we wanted. The old saying is true: you get what you inspect . . . not what you expect!
Then, of course there are those of you who want to be totally energy independent and produce your own energy.
Building a new home is a terrific opportunity to
"get it right" from the start.
Here is a look at some of the things you may want to consider.
- Orient your home on your lot to take the best advantage of the sun andshade your lot and its vegetation afford.
- Design overhangs to allow the sun into your home in the winter and exclude it in winter.
- Use a "house wrap," glued on siding, and plenty of caulk and "'Great Stuff" to minimize air infiltration.
- Increase the thickness of exterior walls (2x6 instead of 2x4) and use higher R-Value insulation.
- Reduce the percentage of the area of your exterior walls devoted to windows and doors.
- Use energy efficient exterior doors and windows.
- Install energy efficient appliances.
- Consider heat pumps, radiant heat, and solar solutions (active and passive).
Of course there are many, many other things you can do to increase your energy efficiency. You'll discover them easily as you begin your research into building and energy efficient home.
Building an energy efficient home always involves trade-offs. You have to weigh the cost vs. benefit of all your choices. Some will be easier than others - low cost vs. obvious long term benefit. Others will be more of a challenge.
Solar photovoltaic panels (the kind that produce electricity) and other tech-heavy energy solutions may have extensive, even unacceptable "pay-back" periods.
What does that mean? Say you spend $1,200 on a device that promises to cut your home heating energy bill by 20%. If your heating costs are $2,400 a year, and you actually save 20%, you'll save $480 a year. Your "pay-back" comes in only 2-1/2 years ($1,200 ÷ $480)! After that, it's pure savings. Pretty good, huh?
But what if you are paying $20 a month to produce hot water with natural gas and someone wants you to spend $15,000 to install solar water heater panels. At $240 a year (12 months x $20 per month), it'll take you over sixty-two years to recoup your investment ($15,000 ÷ $240).
Of course there are other factors that may come in to play, like a tax credit for the investment in solar energy or what $15,000 would be worth if invested at 8% for 62 years ($1,771,593.59)!
Building an energy efficient home is a worthy goal. Do your research, get all your plans for energy efficient construction into your plans and specifications, and then plan to be vigilant in making sure your plans are implemented to perfection.
You'll have a quiet, comfortable home that will be much more affordable in its month-to-month operation. And you will be doing your part to save the planet!
*from City Water, Light & Power, serving Springfield, Ill.
For additional insight into Energy Efficiency,
see Lesson Five of our online course
Successful Home Contracting.
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