Energy Efficient Homes



Today energy efficient homes are the need of the hour. We are faced with environmental challenges of immense proportions.

Humans have inhabited homes on this planet green for centuries without any problems. This was because traditional homes were usually made with materials using natural resources taken from immediate surroundings.

Energy Consumption

Homes, as they are designed and used today, contribute to serious environmental problems because of excessive consumption of energy and other resources. energy use in energy efficient homes

Modern homes consume energy in several ways. And they do so in five phases.

The first phase corresponds to the manufacturing of building materials and components.

The second and third phases correspond to the energy used to transport materials from production plants to the building site and the energy used in the actual construction of the home.

Fourthly, energy is consumed at the operational phase, which corresponds to the running of the home when it is occupied.

Finally, energy is consumed in the demolition process of homes as well as in the recycling of their parts, when this is promoted.

Energy Efficiency

To construct a home and meet its demands for heating, cooling, ventilation, and lighting cause severe depletion of invaluable natural resources.

Energy resource efficiency can be effected by adopting an integrated approach to energy efficient homes design. The primary steps in this approach are -

  • Incorporate solar passive techniques in a building design to minimize load on conventional systems (heating, cooling, ventilation, and lighting).
  • Design energy-efficient lighting and HVAC (heating, ventilation, and air-conditioning) systems.
  • Use renewable energy systems (solar photovoltaic systems / solar water heating systems) to meet a part of building load.
  • Use low energy materials and methods of construction and reduce transportation energy.

To create energy efficient homes and draw green home plans, we have to first discern in detail different aspects of energy use in a home. For that it is important to understand the concept of carbon footprint.

Carbon Footprint

A carbon footprint is a measure of the impact of any activity on the environment. It relates to the amount of greenhouse gases produced in our day-to-day lives through burning fossil fuels for electricity, heating and transportation etc.

A carbon footprint can help measure and keep track of changes in your daily activities. It can let you know how much a particular event or activity contributes to your energy use and carbon dioxide output. It can also help you figure out what changes in your lifestyle may make the biggest impact.

To use energy more wisely and build energy efficient homes, the following aspects of energy use in a house need to be considered -

Lighting

The lighting you choose can have far-reaching effects on how much energy is used and how much you pay for it. Energy efficient homes use lighting plan that maximizes energy savings through the implementation of low-cost compact fluorescent lamps, solar lights, skylights, and other natural light sources.

Incandescent lights, in principle, are electric space heaters that give off light as a byproduct. They waste most of the power they consume as heat.

For best efficiency, use standard fluorescents in workspaces and compact fluorescents in living spaces for a warm ambiance.

Use halogen lighting for outdoor applications where temperature causes problems with fluorescents.

Install white LED lighting for applications that require less light like task lights, night lights, pathway lights, exit signs, and flashlights.

Use these tips for efficient use of lighting as a first step to making energy efficient homes -

  • Natural light should be used maximum as it is the most energy efficient lighting source.
  • Turn off lights when not needed.
  • Replace standard incandescent bulbs with energy saving compact fluorescent lamps and make sure you use the lowest wattage lamp needed.
  • To control outdoor and security lighting use programmable timers, daylight sensors or movement sensors.
  • Use solar-powered light for outdoor garden lighting.

Water

Water is one of the most precious resources on this planet.

Energy efficient homes use water wisely. Water efficiency in the home means using less water to provide the same level of service or to get the same result.

One way to achieve water efficiency is by using water efficient bathroom fixtures, for example water-efficient shower heads, taps and toilets.

Another way is to use water-efficient appliances like washing machines and dishwashers. Water-efficient models will get your clothes and dishes as clean by using less water.

If you use less heated water, you will be saving energy as well as water.

Energy efficient homes have many features for efficient use of water. These actions should be taken to avoid wasting water, both in the house and in the garden.

  • Install water-saving shower heads, faucets, and toilets.
  • Replace single-flush toilets with a more water-efficient dual flush model.
  • Fix leaking pipes and plumbing fixtures at the earliest.
  • Have a water-efficient dishwasher and washing machine.
  • Collect and use rainwater for toilet flushing, laundries or for watering the garden.
  • Use wastewater to flush toilets, water the garden and even to wash clothes. Greywater which is wastewater from non-toilet fixtures such as showers, basins and taps can be used for this purpose.
  • For efficient water use in the outdoors, minimize lawn areas.

Over one third of the water savings will come from more efficient showers, about 34 per cent from washing machines and 23 per cent from toilets and urinals.

Heating

Very little energy is required to make a well designed house comfortable. Highly energy efficient homes may need no non-renewable energy inputs for heating and cooling.

Mechanical heating and cooling should never be used as a substitute for good design. It is better to invest more money in building energy efficient homes than spend it on heating and cooling.

Use passive design principles to increase comfort and reduce the need for heating. Insulate the roof, walls and floor, seal draughts, let in winter sun and draw curtains at night. This applies to existing homes as well as new homes.

See environmentally friendly houses for more information on the use of passive design principles to achieve comfortable environments in a home.

Solar Heating

In well-designed energy efficient homes, solar energy is able to provide sufficient warmth day and night, throughout most or all of the year.

The sun's energy can be harnessed to provide free home heating. How well your home catches the sun's energy will depend on factors such as size and orientation of windows, insulation, use of materials such as concrete which can store heat in the day and release it at night etc.

Insulation

One of the most efficient and cost-effective ways to make your home warmer is to insulate. Internal space is protected from outside cold by insulation. It works by trapping layers of still air to minimize heat transfer.

Although it is easier to install insulation when you are building or renovating, there are ways to improve the insulation in your existing home. For example, thermal drapes will prevent heat escaping from windows. Further, energy efficient windows with double-glazing will retain heat within the home.

Energy efficient homes using additional insulation feel more comfortable as it keeps the interior wall at a stable temperature. The indoor humidity is also better controlled, and drafts are reduced.

Heaters

When you are choosing a heating option, it is worth considering whether you want to heat a single room or the whole house. There is no point heating the whole house if you will only be using one room.

In the same vein, it is better to use space heating than central heating. Space heating heats only the rooms that are in use. Central heating heats the whole house whether the rooms are occupied or not, consuming lot more energy.

A thermostat turns the heating system on and off as the room temperature rises and falls. Installing it can save energy by ensuring the heating system is not run more than it needs to.

Wherever possible, use gas heaters as those produce only one third the amount of greenhouse gas emissions of standard electric heaters.

Water Heating

Whether you are choosing a new hot water system or using the one you already have, there are two easy ways to reduce your energy use without compromising on convenience.

  • Cut your hot water use with some simple, everyday actions like using less water for bathing, using cold water for washing clothes and rinsing dishes.
  • When it is time for a new one, choose a hot water system that uses renewable energy sources like the sun (solar hot water or a heat pump) or wood (a wetback or wood boiler).

Around 80% of a home's hot water is used in showers, but many showers use a lot more water than they need to - which means wasted energy, water and money. Get a shower head with a lesser flow rate.

Ventilation

Ventilation is about helping air to circulate in your home. It allows moisture and airborne pollutants to escape, and fresh, clean air to be drawn into your home. Well-designed ventilation in a passive house will provide cooling in summer. In winter, it will let stale air out but keep warmth in.

Effective ventilation depends to a large extent on the size, placement and type of windows, doors and other openings in your home. With good design, air will be circulated without creating draughts.

You will need extractor fans to expel moist air from the kitchen, bathrooms and laundry outside.

Energy efficient homes strike a balance between the need to introduce fresh, healthy air in the home and the need to maintain comfortable temperatures. Hence ventilation should be considered alongside passive heating and cooling options.

Passive Ventilation

Passive ventilation uses doors, windows, vents, louvers and other openings to bring fresh air in eco homes and let stale air out. The size and placement of these openings guide air into and through your home.

Active Ventilation

Active ventilation is ventilation provided mechanically - for example, by fans and forced air ventilation systems. The bigger the system with more components, the more power it will use.

Well-insulated energy efficient homes may only need to use active ventilation for rooms where moisture is generated (bathroom, kitchen and laundry), while passive ventilation will be sufficient for maintaining air quality through the rest of your home.

Cooling

It is better to use passive design principles to minimize the need for cooling by mechanical means. Refer environmentally friendly houses for more information on that aspect.

Points to consider when choosing cooling systems:

  • Does the air requires cooling or will creating a breeze be enough?
  • How big an area needs to be cooled?
  • How often and for how long is cooling needed?
  • Is space cooling sufficient or central cooling is required? Central cooling is more expensive to buy, uses much more energy, cools more areas than required and costs more to run.

The three major methods of mechanical cooling are fans, evaporative coolers and air conditioners.

Fans should be the first choice for mechanical cooling. With good design and insulation, fans can often provide adequate cooling.

Fans are the cheapest to run and have the least greenhouse impact.

Your second choice for mechanical cooling should be evaporative coolers.

Evaporative coolers work best in low humidity as the air has greater potential to absorb water vapor. They are significantly less effective in climates with high humidity.

While normally giving a higher degree of comfort, air conditioning consumes more energy and creates more greenhouse gases than fans and efficient evaporative coolers.

For efficient air conditioning, the house or room should be sealed and highly insulated. Windows must be shaded from the summer sun.

Appliances

By choosing energy-efficient appliances, both energy and water can be saved.

Key things to consider while sourcing appliances for energy efficient homes are whether you really need the appliance, the right sized model for your house, and the amount of energy and water it will use.

Ongoing running costs can easily exceed the original purchase price of an appliance so consider the full lifetime cost when choosing an appliance. Using efficient appliances can save you hundreds of dollars each year in running costs.

Consider the following points while choosing appliances for energy efficient homes -

  • Look for the Energy Rating Label that shows the star rating and other useful information about energy consumption. Choose an appliance with a high star rating as they use less energy and generate fewer greenhouse gas emissions.
  • When designing a new kitchen or laundry, plan for the best layout and placement of appliances to maximize efficiency.
  • Refrigerators and freezers should be located out of direct sunlight and away from other sources of heat such as ovens and stoves.
  • Hot water service should be located as close as possible to the appliances that require hot water to reduce heat losses in pipes.
  • Where possible choose appliances that have a high rating for water efficiency.


Apart from the discussed elements, energy efficient homes use eco furniture and other eco friendly products and materials that do not require too much energy to manufacture, transport, maintain or dispose.

For in-depth information on different aspects of energy efficient homes, visit this website by U.S. Department of Energy - Energy Savers .

By incorporating all or most of the elements of energy efficiency you will be well on your way to creating energy efficient homes.

Next step to energy efficient homes is zero energy homes and energy surplus homes. That is when the house is producing more energy than it is using.

Let us aim for a future where all homes are energy surplus homes, where we give more than we take from this earth.





Go to Eco Homes hub page Eco Homes;
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Sushil Wadhwa

Sushil Wadhwa
Architect, Interior Designer, creator of Homes and Interiors... more.