The Oil Drum

Hello jmgygann

"Green" homes can be built at costs comparable to traditional homes- or far lower if you want a straw bale - or Earthship buildings. What makes a building "green" is often a minor extra cost, compared to total cost.

The concept of "green" has to be defined also. Some green concepts are based on using recycled materials, others on using nature materials and yet other on reducing the resourse use and impact on nature. So make your pick.

To me a green Home is a building that has the lowest resource use and impact on nature through the building life 50-75 years. This includes maintenance.
With a tool called Life cycle assessment (LCA) you can actually calculate the Energy use and the emissions produced for making the building materials, for building the home and the energy and emissions produced during the building use during 25,50,75 or more years including maintenance.

The LCA shows that for almost all possible building types, the energy consumption during use ( heating, cooling, hot water and electricity) is the dominating impact on nature, regardless of the climatic conditions. In Europe this is some 40% of all energy use.
In Europe, the tradition is mostly Brick, concrete, expanded concrete and in Scandinavia some wooden houses.

Some LCA numbers can illustrate this. (Forgive me for not using btu and ft2- but they can easily be converted). Brick cavity wall home weigh approx. 1 ton/m2 and consume 1 barrel of oil energy/m2 floor area for producing and installing materials. Maintenance during 50 years (10-25% add on- fx window double glazing replaced each 20 years.)
A wooden home cost some 20% less energy for building materials and installation. A higher replacement rate and maintenance usually evens this out during the 50 Years of use.

The average energy use for heating in EU homes is 150 kwh/m2/year = 15 liter fuel oil/m2/year. In 50 years this alone is close to 5 barrels of oil energy.
So building materials for 1 m2 = 1 barrel, Building heating of 1 m2= 5 barrels. Add to this cooling and hot water and electricity. So the "green" basically means reducing heating/cooling energy use. So how is this done in green building?

With EU numbers.
First the heat loss must be reduced. Then we can later add solar heaters and PV etc. But the base consumption must come down.
Of the 150 kwh/m2/year heating energy some 55 kWh/m2/year is heat loss from cracks and ventilation. So seal the cracks. The rest - 90-100 kWh/m2/year should be reduced with a combination of insulation 250-500 mm depending on climate, better insulated windows - trible glazed windows with insulated frames and doors and ultimately ventilation systems with heat recuperation. Add good workmanship and your heating energy use will go down to 15 - 50 kWh/m2/year. 1.5 - 5 liter oil energy. A solar heat panel of 1.5 m2 per person will suffice for 70% of all hot water, and PV panels can be added for electricity. Cooling is not used videly in EU today, so it is not included.
In environmental (LCA terms) the energy payback time (Energy saved/energy invested) is approx 1 year for solar heat and 1-6 months for Insulation, depending on thickness. Energy payback for PV elements is 3-5 years- and as comparison large wind generators (>1 MW)have a energy ( and emission) payback time of 8-12 months.

The most optimized "green building" concept today is the German Passivhaus - concept (passive house - less than 15 kWh/m2/year for heating). Some 6-7000 have been built today and several houndred have measured data, available on the internet. The Passive house concept can also be used in renovation of old buildings, but heating energy use will end higher.
The extra cost for a Passive house is plus 10-15% for a single family home. Less than a new kitchen or a new bathroom. This is usually saved within a few years in heating costs.
Needless to say that smaller and compact buildings have lower energy use.
An average Danish family home is approx 110 m2 today and in the US it is 230 m2.

Wikipedia has a couple of nice overall papers which I would recommend.
http://en.wikipedia.org/wiki/Low-energy_house
http://en.wikipedia.org/wiki/Passive_house
If you follow the links you will see most of the green solutions available.
Re. Passive houses
If you need more info, you could Google "passive house" or "Passivhaus". If you want to see how they look use google images.
There is a ton of info available- also in English.

jmygann,

I built about 15 spec homes over the last 4 years, and have many friends in the business. At the end of the day, its all about profit. I am not building any more homes for anybody. Most people do not care about energy use or green building, just square footage and cost.

I am currently designing my personal Chesapeake Bayfront home now. Will be about 900 square feet, and it will be simple.

Building green is somewhat of a nebulous proposition. The article above talks about ICF construction, and there is nothing green about concrete. IMO, the best thing anyone can do is to design and build around the idea of minimal energy use.

I have been somewhat freaky about energy use for about 20 years, and learned alot. The most important thing is your/family personal habits. For example: I moved in with a women and her two teenage daughters. Average electricity use was about 2200Kwh per month. Now its about 800. This was accomplished by using the woodstove that was already installed, using an Energy Star window shaker for A/C, CFL's for general lighting, low flow shower heads, eliminating the use of the electric clothes dryer, not using the oven to cook a frozen pizza when its 90F outside, etc,etc,etc. Most people do not think.

As far as building goes, the most important lessons I have learned that impact energy use:

- Central A/C and heat is NOT as efficient as point of use.

- Energy Star appliances make a big difference.

- Proper building techniques. Control moisture.

- House orientation on the building lot and taking advantage of solar gain or keeping trees that block western sun exposure for warm climates.

- Use the best materials available that last, and install them correctly.

- For the green side, use natural materials instead of synthetics. (Wood siding, wood flooring, etc)

I could really go on for a hundred pages about this topic. The reality is that most people can build (or retrofit) a house that is enviromentally friendly and energy efficient for a small cost premium ,today. Energy is just way to cheap to force the mainstream to move in that direction.

Personal habits make a big difference, no matter how green or efficient a home is. Robert Rapier posted a nice article about his friends green house in the Colorado hills. He was using a gas fired clothes dryer in a desert climate!

Having built several passive solar houses, there is no need for movie star incomes.
In my experience, keys to low-cost are:
1) Use recycled materials where possible. I built a passive solar studio using almost exclusively wood rescued from construction site dumpsters. In Boulder, we have Resource 2000 which is a construction material recycling yard with prices often 70% below retail.
I just added a layer of insulation in my attic that I got for free from a dumpster I noticed as I was biking by.
2) Simple design means low-cost. Minimize complicated roof-lines, window layouts, wall framing, etc.
3) Fund operations out of income if possible. Better to build as you can afford over a longer time period than to pay lots of interest. This also synergizes well with used materials which can take a while to acquire and stockpile.
4) Many construction tasks are reasonable do-it-yourself jobs. Figure out the difference. Framing, painting, window/insulation installation, trim, concrete are the parts I do myself. I usually hire out electrical, plumbing, drywall.
5) Proper site orientation and window placement add nothing to project cost, but have a major impact on building thermal performance
6) Learn to operate any building for energy efficiency. Manual thermostat setbacks at night or during unoccupied periods, plus using window coverings according to solar gain, along with hot water conservation/setpoint reduction can reduce energy use by up to 50% without any remodel or green building technologies.