Sunday, February 7, 2010


Energy efficient homes are composed of a network of elements working together to reduce the overall amount of energy consumption. This section will help you understand what makes a home more energy efficient, how to test your home’s energy efficiency level, why insulation and ventilation are key ingredients, and how you can start making your home more energy efficient.



So How can you design my home or house to be Energy Efficient?

Elements and Factors to be considered

1) Insulation
2) Beginning a Project
3) Orientation & Siting
4) Wall and Roof Assemblies
5) Ventilation/Draught Proofing
6) Foundations and Slabs
7) Windows/Shading/Landscaping
8) Heating and Cooling Requirements

Insulation

An energy-efficient house has much higher insulation R-values than required by most local building codes. For example, a typical house in New York State might have haphazardly installed R-11 fiberglass insulation in the exterior walls and R-19 in the ceiling, and the floors and foundation walls may not be insulated. A similar, but well-designed and constructed house's insulation levels would be in the range of R-20 to R-30 in the walls (including the foundation) and R-50 and R-70 in the ceilings. Carefully applied fiberglass batt or roll, wet-spray cellulose, or foam insulations will fill wall cavities completely.

Beginning a Project

Houses incorporating the above features have many advantages. They feel more comfortable since the additional insulation keeps the interior wall temperatures more stable. The indoor humidity is better controlled, and drafts are reduced. A tightly sealed air/vapor retarder reduces the likelihood of moisture and air seeping through the walls. They are also very quiet because of the extra insulation and tight construction.

There are some potential drawbacks. They may cost more and take longer to build than a conventional home, especially if your builder and the contractors are not familiar with them. Even though their structure may differ only slightly from conventional homes, your builder and the contractors may be unwilling to deviate from what they've always done before. They may need education or training if they have no experience with these systems. Because some systems have thicker walls than a "typical" home, they may require a larger foundation to provide the same floor space.

Before beginning a home-building project, carefully evaluate the site and its climate to determine the optimum design and orientation. You may want to take the time to learn how to use some of the energy related software programs that are available to assist you. Prepare a design that accommodates appropriate insulation levels, moisture dynamics, and aesthetics. Decisions regarding appropriate windows, doors, and heating, cooling and ventilating appliances are central to an efficient design. Also evaluate the cost, ease of construction, the builder's limitations, and building code compliance. Some schemes are simple to construct, while others can be extremely complex and thus expensive.

An increasing number of builders are participating in the federal government's Building America and Energy Star Homes programs, which promote energy-efficient houses. Many builders participate so that they can differentiate themselves from their competitors. Construction costs can vary significantly depending on the materials, construction techniques, contractor profit margin, experience, and the type of heating, cooling and ventilation system chosen. However, the biggest benefits from designing and building an energy-efficient home are its superior comfort level and lower operating costs. This relates directly to an increase in its real-estate market value.


Orientation & Siting

By carefully considering the position of your house on your chosen block, you can maximise the passive solar design advantages that can make your home more comfortable all year round.

The following points should be considered when selecting a block of land:

-Size and orientation of the block (having sufficient space to allow sum entry when required)
-Solar access to the north side of the house (for winter sun entry)
-Slope of the block (to enable sun entry)
-Tree coverage and height (to avoid too much shading)
-Height and proximity of surrounding buildings (to avoid overshadowing)

The orientation and siting of your home can make a huge difference to your energy bills and your comfort. The 'ideal' home is sited with the daytime living areas facing north with the long axis of the house running east-west (Opportunities for this are fairly rare, and the good news is that variations on the orientation can be up to 30 degrees to the east and 20 degrees to the west of true north, with no major effects on the solar advantage. Bear in mind that some extra sunshading may need to be considered however).

Large windows on the north side of the house let the sunshine in during winter, but can be easily shaded from the summer sun. This will make the house warmer in winter and cooler in summer.

To prevent overshading from neighbours, allow a set back of at least 6 metres from a single storey house to the north, and at least 11 metres from a double storey house. If this is not possible, you might be able to use a clearstorey window to allow adequate sunlight into the home. Note that this window will require sufficient shading for summer comfort.


Wall and Roof Assemblies

There are several alternatives to the conventional "stick" (wood stud) framed wall and roof construction now available and growing in popularity. They include:

Optimum Value Engineering (OVE.) This is a method of using wood only where it does the most work, thus reducing costly wood use and saving space for insulation. However, workmanship must be of the highest order since there is very little room for construction errors.

Structural Insulated Panels (SIP.) These are generally plywood or oriented strand board (OSB) sheets laminated to a core of foamboard. The foam may be 4 to 8 inches thick. Since the SIP acts as both the framing and the insulation, construction is much faster than OVE or it's older counterpart "stick-framing." The quality of construction is often superior too since there are fewer places for workers to make mistakes.

Insulating Concrete Forms (ICF.) These often consist of two layers of extruded foamboard (one inside the house and one outside the house) that act as the form for a steel reinforced concrete center. This is the fastest and least likely technique to have construction mistakes. Such buildings are also very strong and easily exceed code requirements for tornado or hurricane prone areas.

Ventilation & Draught Proofing

In summer, a cool breeze flowing through the house helps cool down the house and it's occupants at night. The house need not face directly into the prevailing summer breeze, but can be offset at an angle of up to 45 either way.
While adequate controllable ventilation is essential to provide fresh air, prevent condensation, and help cool a house on summer nights, draughts can create discomfort and lead to energy losses in both summer and winter.
In winter, draughts can account for up to 25% of heat losses. Reducing these draughts can be a cheap and cost effective way of reducing heating and cooling costs. New houses should be built to minimise draughts, by avoiding gaps at construction joints between different wall materials, and where walls join or meet the ceiling and the floor, and by ensuring that doors and windows fit snugly in their frames. Draughts can be further reduced by:
Draught proofing doors and windows
Sealing up cracks and gaps
Sealing unnecessary vents
Sealing exhaust fans and outlet grills
Sealing unused fireplaces
Sealing vented skylights
Covering ceiling evaporative ducts during the colder months

Foundations and Slabs

Foundation walls and slabs should be at least as well insulated as the living space walls. Uninsulated foundations have a negative impact on home energy use and comfort, especially if the family uses the lower parts of the house as a living space. Also, appliances that supply heat as a by-product, such as domestic hot water heaters, washers, dryers, and freezers, are often located in basements. By carefully insulating the foundation walls and floor of the basement, these appliances can assist in the heating of the house.


Windows

The sun's rays pass easily through normal windows. This can provide welcome heat in winter, but can lead to overheating in summer, as the heating power of sunlight shining directly on east and west facing windows is around 1,000 watts per square metre (the amount of heat from a one bar radiator). About 88% of this heat will pass through a window made of 3mm float glass.
Double-glazed windows however, while they are good at reducing conducted heat transfer, do not significantly reduce radiant heat transfer, and they need to be used with effective external shading in summer. (Double glazed windows can have some treatments applied that allowed them to perform well in reducing heat transfer, but the extra cost tends to be only financially viable in larger commercial buildings that have high airconditioning costs. They are very effective at slowing heat losses to the outside, and so they are very popular in very cold climates.
Ideally all north facing windows should be full length, so when the winter sun is low in the sky, the heat will penetrate well into your home. Use minimum or zero glass on the east and west sides, and small glass areas on the south side of the house.
The total window area should be less than 25% of the total floor area of the house (these proportions are a guide only, as new energy rating software for houses considers this and a range of design features when assessing the overall rating of the house). If windows are made too large they can make the house uncomfortably hot in summer and hard to keep warm on cloudy winter days and nights.

Shading

The shading of sun is vital in keeping your house cool in summer.
Well designed shading greatly reduces heat entry, adding significantly to summer comfort in the home. It can also significantly reduce the need for, and running costs of, airconditioning equipment. The most effective way to keep summer heat out of the house is to use adequate external shading. North facing windows can be easily shaded with fixed shading devices, such as an eaves overhang, horizontal shade or awning, and pergolas.
These shading devices must be designed so that they allow sun entry in winter and totally shade the windows in summer. In Adelaide, to achieve this, the width of the fixed shading on the north side should be 0.5 times the vertical height of the window (at the top of the window). Attention should be paid to adequately shading east and west facing windows; whilst south facing windows generally do not need shading.
Whilst important, internal shading such as curtains and blinds will never be as effective as external shading because the radiant heat from the sun has already passed through the glass. To get the best performance from curtains and blinds you need to ensure that they should be opaque and of light colour, to maximise the reflection of sunlight. Pelmets are a good way to reduce heat loss. Tinted or reflective glass should be used where it is not desirable to obstruct the view, and internal shades with a reflective backing should be used where it is not possible to install external shading devices.

Landscaping

Landscaping can enhance your property and provide benefits to you in maintaining more comfortable conditions in your home. By carefully planning the landscaping around your home, you can control the entry of heat, as well as the quality and direction of the breezes you allow to blow through it.
Breezes entering your house will be cooler if they have passed through gardens or courtyards that have shade, pools or shrubs and lawns. The layout of your garden can also be used to screen or direct breezes.

Heating and Cooling Requirements

Houses incorporating the above elements should require relatively small heating systems (typically less than 50,000 Btu/hour even for very cold climates). Some have nothing more than sunshine as the primary source of heat energy. Common choices for auxiliary heating include radiant in-floor heating from a standard gas-fired water heater, a small boiler, furnace, or electric heat pump. Also, any common appliance that gives off "waste" heat can contribute significantly to the heating requirements for such houses. Masonry, pellet, or wood stoves are also options, but they must be operated carefully to avoid "back drafting."

If an air conditioner is required, a small (6,000 Btu/ hour) unit can be sufficient. Some designs, like the ACT2 houses in arid Davis, CA use only a large fan and the cooler evening air to cool down the house. In the morning the house is closed up and it stays comfortable until the next evening.

*********NOTE**********

But with the newest technologies and breakthroughs that some innovators and inventors have done to help us, we can’t help but also consider them to even save more money and costs to renovating our house to become energy efficient home.

Building a solar panel is very helpful considering that it will definitely lessen ones power bills because of your less energy consumption from power lines and more consumption from your solar panels. Actually these solar panels are also built at home.

There is also the magnetic energy motor that can also be made at home. Its very effective and very cheap that one can considerably do away from your power line subscription.

But most importantly, our attitude towards our energy consumption should always be in mind. Discipline and thoughtfulness for the other members of the house is very essential in maintaining low consumption on energy. This is making everyone in the house feel responsible.

CLICK HERE - Build Solar Panels at Home at the Cheapest Cost to save Energy and Completely Reduce or Eliminate your Power Bills!


CLICK HERE - The Ultimate Guide to not paying your Power Bills anymore, but dont get me wrong, it is just that you are going to build your own electricity, FREE electricity that is!
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