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                                           Small, Eco Friendly, Zero Bills Home In Austin, Continued

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After the home was framed out,  the exterior walls and roof were covered with OSB (oriented strand board) which is more environmentally friendly than plywood. Walls were then wrapped with Tyvek moisture barrier to prevent air infiltration, and the roof decking was covered with heavy felt paper. To reduce home insurance costs, maintenance costs, and add fire resistance to the home, cement based, James Hardie Hardiplank siding was used on 3 sides of the Austin "zero energy home". Each piece of Hardyplank siding was caulked where it met the next one, and all cracks around the exterior of the home were either caulked or spray foamed. Elastomeric stucco was applied to a foam base on the front side which faces the street and accented by local rock. 24 gauge, highly reflective Galvalume metal roofing was used to reduce heat gain and avoid fire danger.

Insulation: The exterior walls and attic were insulated with open cell spray foam insulation which was applied by a local firm, Foam Home Solutions. Phone: (512-844-8437). Please let them know that you read about the project on Savegreenly.com  Since the home is insulated all the way up to the top of the roof trusses, enveloping the entire structure, this allows the HVAC unit in the attic to operate more efficiently. On a typical summer day when the outside temperature is over 100 degrees, the 2 ton unit only runs for a few hours a day.  More than 4 inches of foam were applied to exterior walls and about 6 inches of insulation were sprayed on the the underside of the roof decking. Spray foam insulation can help reduce a home's energy use by up to 65% or more, compared to conventional fiberglass insulation. Spray foam insulation, combined with Low-E windows and a solar power system, were some of the key features in making this small home "zero energy" and almost "zero bills".  By totally encapsulating the structure in foam insulation and controlling and filtering all air that comes inside, indoor air pollution is nearly eliminated. The fact is, spray foam insulated homes have much better indoor air quality that fiberglass insulated ones, which reduces allergy problems and the need to dust so often.

Windows: Those used in our Austin "zero energy" home were made by Ringer Windows Inc, a local Austin company. All windows and doors featured a solar heat gain coefficient of 0.22, U-Factor of 0.30 and visible transmissance factor of 0.52.  Solar screens were applied to west facing windows and white faux wood blinds were used on the inside of the home's windows to reflect solar heat.

HVAC Unit: The HVAC unit used in the Austin zero energy home was a Carrier 2.0 ton heat pump with a SEER rating of 15.25. The outside compressor  unit was situated in a shady spot outside the home with good ventilation. Because the home is essentially "air tight", a controlled amount of fresh air is brought into the home each time the HVAC system turns on, in a regulated manner, free of dust, bugs, etc.

Appliances:  Due to space limitations, which prevented having a propane tank on the property, and the lack of city gas service, the home is all electric. It features an Energy Star rated Whirlpool microwave, High Efficiency Bosch Washer and Dryer, Energy Star rated GE fridge, and an Energy Star rated 40 gallon hot water heater, which was further insulated with two fiberglass blankets. All hot water pipes in the home, including those running through the slab, were insulated with foam sleeves.

Lighting: All lighting in the home is provided by high efficiency 6 to 8 watt LED bulbs made by EarthLED. (See LED Bulbs vs. CFL's)  Lighting cost for the home is currently about ten cents per day. Most of the energy in the home is consumed  by the electric water heater, heat pump, electric range and washer and dryer.  Lights in bathrooms operate on push - button light timers, which reduce the time lights are accidentally left on.

Solar Power System:

Solar power, provided by a 4.5 KW photovoltaic system on the south facing side of the  roof, provides all the energy that the home uses on an annual basis. Should extra energy be required, a track type system and over-sized inverter will allow for another 1 KW of panels to be installed.  In summer and winter months, Austin Energy bills average from $10 to $20 a month. In the fall and spring months, more power is sold back to the utility than is used by the home, yielding an annual  "zero  net energy bill".  Below is a photo of the solar panel system being installed. ( I have detailed information about a number of Austin solar power companies, their prices,  the types of solar panels that they use and warranties, consumer satisfaction ratings, etc.)  For details on the solar installer that we used for this project, please contact us here: Contact   Generous rebates from Austin Electric and federal rebates of 30% brought the total system cost down to around $6,000.  Below, a  worker installing one of the  180 watt Schuco solar panels.

Additional Energy Saving Measures Used In The Zero Energy Austin Home:

In addition to the 4.5 KW solar power system, a programmable thermostat was used to reduce heating and cooling costs. Line drying of some clothes items, such as heavy bedspreads is used at times. Items such computer and entertainment center peripheral devices were put on "smart power strips". Smart power strips turn off the electronic items such as DVD players, which are not needed when the main device, such as the PC or TV is off. This prevents "phantom loads" from wasting energy. For more about phantom loads see: What Are Vampire Or Phantom Loads?  Low flow showerheads are used to reduce hot water consumption and overall water use.  Deciduous shrubs and trees were planted around the exterior of the home, which will help save energy by reducing solar heat gain in summer. In winter these same trees will lose their leaves and allow for solar heat gain.  Unrelated to the home's energy use, but in keeping  with the green nature of the home, the lawn is xeriscaped with low water use plants.  Household food waste that can be composted is done so in a tumbler type composter.  A rainwater collection system is planned for the future, which will provide water for an organic vegetable garden and ornamental plants.

The Bottom Line, Not Zero Bills, But Close To It. The net energy cost for this 1303 square foot home in Austin Texas is zero. Water bills average $25 a month, which is the city's minimum rate. Entertainment programming from "over the air",  local HDTV stations, received with a small outside antenna, along with free web - based TV sites such as Hulu.com, is used to avoid a cable bill. The owner uses a  cell phone and "magic jack" type device for phone service, resulting in monthly "non energy" bills of around $75. Because of discounts for the metal roof, monitored security system, masonry siding, and proximity to a fire hydrant, insurance rates are less than $30 a month.

For seniors living on a fixed income, or anyone else, a zero energy home makes sense. For information on the builder of this home, contact us here: Contact

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