The residential sector is a large consumer of electrical energy. Green Homes can reduce energy consumption through energy efficient lighting, air conditioning systems, motors, pumps, etc., the rating system encourages green homes, which select and use BEE labelled equipment and appliances. The energy savings that can be realized by adopting this rating programme can be to the tune of 20 – 30%.
Reduced Use of Fossil Fuels
Fossil fuel is a slowly depleting resource, world over. The use of fossil fuel for transportation has been a major source of pollution. The rating system encourages the use of alternate fuels for transportation and captive power generation.
Reduced Dependency on Virgin Materials
The rating system encourages projects to use recycled and reused material and discourages the use of virgin wood thereby, addressing environmental impacts associated with extraction and processing of virgin materials. Reduced usage of virgin wood is also encouraged.
Health and Well-being of Occupants
Health and well-being of occupants is the most important aspect of Green Homes. IGBC Green Homes Rating System ensures minimum performance of day lighting and ventilation aspects, which are critical in a home. The rating system recognizes measures to minimise the indoor air pollutants.
- Stockpile top soil and reuse later for landscaping purpose or stockpiled soil can be donated to other sites for landscaping purpose.
- Open areas can be landscaped (e.g., grass, trees, shrubs). Paved areas can be installed with permeable paving. For impermeable surfaces direct all runoff towards storm water collection pits.
- Avoid disturbance to site by retaining the natural topography of the site and / or design landscape for at least 15% of the site area.
- Parking areas, walkways etc., are considered as site disturbances.
- Landscape refers to soft landscaping which include only vegetative materials.
- Natural topography in its broad sense means preserving natural features of the terrain.
- Landscaped areas over built structures such as roofs, basement etc., cannot be considered for the purpose of calculation of landscaped area.
- Potted plants will not be considered as landscape.
- Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimise impact on microclimate.
- Use material with high solar reflectance and thermal emittance (such as, white china mosaic or white cement tiles or any other highly reflective material) and / or provide vegetation to cover at least 50% of the exposed roof areas.
- To maximize energy savings and minimise heat island effect, select materials that exhibit high reflectivity and high emissivity. Consider providing green roofs or using highly reflective materials over roofs to reduce the heat island effect. Typical materials with high reflective properties include china mosaic, white cement tiles, paints with high Solar Reflective Index (SRI) values etc.
Provide rainwater harvesting or storage system to capture atleast 50% of the runoff volumes from the roof surfaces.
In coastal areas where the groundwater table is shallow and water percolation is limited, collection tanks may be provided meeting the above requirement.
Capture rainwater from roof top for reuse. The design should also include flushing arrangement to let out impurities in the first few showers. Such pollutants and impurities include paper waste, leaves, bird droppings, dust, etc.
Water Efficient Fixtures:
To minimise indoor water usage by installing efficient water fixtures.
- While selecting water fixtures, look for the efficiencies. The product catalogue or the brochure may detail the flow rates at various pressures.
- Fixtures are available with ultra high efficiency which can reduce substantial quantity of water consumption.
Baseline Flow Rates / Capacity for Water Fixtures in a Typical Household
||BASELINE AVERAGE FLOW RATES / CAPACITY
* At a flowing water pressure of 3 bar
- Flow fixtures include faucets, basin mixer, taps, showers, shower mixers.
- The baseline flows can be demonstrated at flowing water pressure of 3 bar. Flowing water pressure of 3bar does not mean that the water supply in the building is at 3 bar. The building fixtures can operate at lower pressures but to show compliance under this credit, the design flow rates are to be submitted at 3 bar.
- The average flow rate is a simple arithmetic average of all the respective flush / flow fixtures.
Drought Tolerant Species:
Landscape to be designed to ensure minimum consumption of water. Ensure that atleast 25% of the landscaped area is planted with drought tolerant species.
- Applicable only for those projects which have atleast 15% of the site/ plot area landscaped.
- Drought tolerant species are those species that do not require supplemental irrigation.
- Generally, accepted time frame for temporary irrigation is one to two years.
To avoid the use of such refrigerants and ozone layer depleting gases which will negatively impact the environment.
- Refrigerants used in Heating, Ventilation & Air-conditioning (HVAC) equipment and unitary air-conditioners installed must be CFC-free.
- Survey the market for all CFC-free HVAC systems. Such systems are also available in smaller capacities. Install HVAC equipment, which does not use CFC based refrigerant.
- Optimise energy efficiency of the building to reduce environmental impacts from excessive energy use.
- Consider a holistic energy efficiency approach to include the building orientation, envelope, systems, lighting and other equipment.
- Identify the materials and equipment available in the market and their properties with regard to energy performance. While selecting these material and equipment, consider their associated environmental impacts.
- Decision making with respect to selection of materials can be based on the life cycle assessment approach rather than the initial cost.
- Determine the applications where automatic controls can help in energy savings. Obtain details of the controls and ensure proper installation.
To encourage the use of energy efficient appliances to reduce energy consumption in the proposed building.
- Appliances installed/ used must be rated atleast three stars under BEE labeling or equivalent.
- List of Appliances rated by BEE can be referred from the BEE website http://www.bee-india.nic.in/
Solar Water Heating Systems:
To encourage use of solar energy for water heating applications in the building.
- Provide solar water heating system to satisfy hot water requirement for domestic purposes. The minimum hot water requirement for domestic purposes should be calculated for 25 liters per person per day.
Efficient Luminaries & Lighting Power Density:
To encourage use of energy efficient lighting systems to reduce energy consumption within the home.
- Install energy efficient internal and external lighting luminaires (as applicable) which are atleast three star rated under BEE labeling programme or luminaires which are more efficient.
- Following are some of the energy efficient light fittings: efficient tubular fluorescent light fittings with electronic ballasts, T5 lamps, Compact fluorescent light fittings, Light emitting diodes etc.
- Level controllers in overhead water tanks.
- Minimum 60% efficiency for pumps of capacity greater than 3 HP and ISI rated water pumps for others.
- Minimum 75% efficiency for motors of capacity greater than 3 HP and ISI rated motors for others
- ISI rated gas burners in kitchen/ cafeteria.
- Movement sensors for lighting control to cover the following areas: toilets, study, staircases, stair cabins, corridors, garage, balconies, wash and storage areas.
- Dimmer controls / daylight cut-off sensors for internal and external lighting, as appropriate.
- Sleep mode control for air conditioners in bedroom.
Separation of Wastes:
To facilitate segregation of waste at source to prevent such waste being sent to landfills.
- Provide separate bins at individual house level to collect organic waste, plastics and paper.
- In multi dwelling units, in addition to the above, also provide a common facility to collect waste which should cover the following:
- Metals (tins and cans)
- 'e' waste
Allocate suitable site for sorting out dry and wet wastes. Examine the scope for recycling items of waste collected from building debris and residential wastes. Locate local dealers of waste material such as glass, plastic, paper, newspaper, cardboard, organic wastes and 'e' wastes & batteries.
Waste Reduction during Construction:
- Minimise construction waste being sent to and fills. Avoid atleast 75% of the waste generated during construction from being sent to landfills and incinerators.
- Collect all construction debris generated on site. Segregate these waste based on their utility. Examine means of sending such waste to manufacturing units which use them as raw materials. Typical construction debris in residential projects could be broken bricks, steel bars, broken tiles, glass, wood waste, paint cans, cement bags, packing materials etc.,
Materials with Recycled Content:
To encourage the use of products that contain recycled materials to reduce environmental impacts associated with the use of virgin materials.
- Some of the materials with recycled content are Fly ash blocks, Tiles, Steel, Glass, Cement, False Ceiling, Aluminium and Composite Wood.
Rapidly Renewable Materials:
- Maximize the use of materials which are rapidly renewable. Use rapidly renewable building materials and products (made from plants that are typically harvested within a ten-year cycle or shorter) such that the renewable material content constitutes at least 2.5% of the cost of the building materials.
- Consider materials such as bamboo, wool, cotton insulation, agrifiber, linoleum, wheat board, strawboard and cork. During construction, ensure that the specified rapidly renewable materials are used.
Encourage the use of building materials available locally thereby minimising the associated environmental impacts. Ensure atleast 50% of the total building materials by cost used in the building should have been manufactured within a radius of 500 Km.
Reuse of Salvaged Materials:
- Encourage the use of salvaged building materials and products to reduce the demand for virgin materials thereby minimizing the impacts associated with extraction and processing of virgin materials.
- Ensure atleast 2.5% of the total building materials by cost used in the building is salvaged, refurbished and reused. Identify opportunities to incorporate salvaged materials into building design and Consider salvaged materials such as flooring, paneling, doors, frames, furniture, brick etc.,
- To minimise the usage of virgin wood thereby avoiding deforestation.
- Minimise exposure of non-smokers to the adverse health impacts arising due to passive smoking, post occupancy. Smoking should be prohibited in the common areas of the building.
- Prohibit smoking in common areas like corridors, lobby, lifts etc., Design the building to eliminate or minimise tobacco smoke pollution in the common areas. Occupant guidelines can also specify that smokers should ensure that tobacco smoke does not leak into common areas or other dwelling units. Signages can be placed at several places in the building campus to educate occupants and visitors.
To ensure connectivity between the interior and the exterior environment, by providing good daylighting:
- Achieve a minimum glazing factor of 2% in each of the living spaces. 50% of the total floor area of all regularly occupied spaces which include kitchens, living rooms, bed rooms, dining rooms and study rooms. Average glazing factor can be calculated using the formula given below: Glazing Factor = Window Area (SF) / Floor Area (SF) x Actual Visible transmittance x Constant
- Windows on wall : 0.2
- Window on roof (skylight) : 1.0
For living spaces which are large in size, part of the areas which have access to daylighting can be factored in the calculation.
Living spaces which are used for multi-purposes such as dining and drawing can be considered as separate spaces based on the function. The separating boundary need not be a physical boundary.
Fresh Air Ventilation:
To avoid indoor pollutants affecting indoor air quality by providing adequate outdoor air ventilation.
Install openable windows or doors in living spaces, kitchens and bathrooms such that the openable area is designed to meet the criteria as outlined in the table below: Design Criteria for Openable Windows and Doors
||Openable area as a percentage of total carpet area
- Having adequate window openings will help in bringing in fresh air into the building, thereby ensuring good air quality. The approach would be to have large openings on atleast two different directions to allow cross-ventilation.
To ensure that kitchens and bathrooms are better ventilated to improve indoor environment:
- Exhaust from bathrooms and kitchens are very vital in preserving the indoor air quality within homes. It is not just adequate to install exhaust fans, but sizing these systems to purge out sufficient quantities of indoor air will determine the performance and thereby the indoor air environment.
Minimum Intermittent Exhaust Flow Requirements
||For < 9.3 sq.m (100 sq.ft) floor area
||For > 9.3 sq.m (100sq.ft) proportionally increase air flow
||For < 4.64 sq.m (50 sq.ft) floor area
||For > 4.64 sq.m (50sq.ft) proportionally increase air flow
Low VOC Materials:
To encourage the use of materials with low emissions so as to reduce adverse health impacts for building occupants:
- Before the building is occupied and after paints, adhesives and sealants have been used, a building flush out needs to be carried out for ten days by keeping all windows open. This ensures the premises free from air borne contaminants before occupying.
- Adequate spaces between dwelling units is important to ensure cross ventilation. Many a time, this aspect is neglected which can lead to poor indoor environment both in terms of indoor air and the daylighting aspect. Narrow corridors can impact the indoor environment as well.