Working towards energy efficiency in homes

Conservation of energy is the need of the hour and a vital step towards sustainable development. It is said that energy saved is rupees earned; electricity bills account for a significant portion of monthly household expenses, and wise homeowners are always looking for ways to cut their expenses. Here are some energy-saving solutions for multi-storied residential buildings.

Generally, residents in these buildings pay an electricity bill for their personal consumption along with added charges for common facilities.Tenants must focus on both these areas when they are looking to cut costs.

What does the data say?

To begin with, it is vital for a homeowner to determine the efficiency level of his/her unit’s construction. Usually, a green-certified residence will include a basic or better yet, an advanced level of energy efficiency measures. According to the data from the Green Business Certification Institute (GBCI) and Leadership in Energy and Environmental Design (LEED), certified homes will reduce energy consumption by as much as 40-50% over conventional homes.

This is done through insulation in walls and roofs, use of shaded windows with high-performance glass, ample day-lighting and ventilation. Provision for solar water heating systems and the use of LED lighting in common areas are some of the most effective energy-saving features.

The impact of including these measures can be substantial. It is imperative that the building is fully certified and not merely pre-certified. Pre-certification simply demonstrates the developer’s commitment to building green while certification ensures compliance with that commitment.

Appliances and fixtures offer another significant opportunity to save. Apartments either come pre-fitted with lights, air-conditioners and kitchen appliances, or the owner must select and install the said equipment.

If the equipment comes pre-installed, you should verify that it is Bureau of Energy Efficiency (BEE) star labelled. The greater the number of stars, higher the appliance’s efficiency. If you must buy new equipment, then purchase energy-efficient appliances only.

In addition, day-lit homes reduce lighting costs and well-ventilated homes have lower heating and cooling costs. Windows and fenestration are other sources of heat transfer. The use of external solar shading and insulated glazing are two highly effective ways to reduce heat gain.

Into the details

It is ideal to select an air-conditioning system based on room size, room orientation and building material. Existing residential high-rise buildings, particularly those that are older than 10 years have substantial scope for energy use reduction in common facilities. A considerable amount of electricity is used to light common staircases, basements, corridors, paths and roads, but LED lighting will lower these costs.

Also, pumping water to overhead tanks and operating lifts in high-rise buildings consumes considerable energy and can greatly inflate bills. As per a recent guidebook released by Maharashtra Energy Development Agency (MEDA), energy used to pump water, power lighting and operate elevators comprises 16% of total electrical consumption of a housing complex.

Common inefficiencies with conventional pumping systems involve oversized motors or pumps, inefficient motors and pump throttling controls, tank overflow, and the mismatch between pumping and pump ratings. Many such inefficiencies are found in low-cost and affordable housing, where developers feel the pressure to avoid any incremental cost. With some advanced planning, considerable savings can be achieved — without incurring added costs. Simple solutions include changing or trimming the size of pump impellers, installing lower speed pumps and motors, using variable-speed drives, or installing water-level based pump systems.

With research and planning, the results can be remarkable, savings of up to 30% have been reported by residential societies that implemented pumping efficiency measures. Typical payback is a short two to three years. In common areas, LED lighting and the use of occupancy sensors is enormously beneficial. Time-based controls are also very effective for areas with specific hours of usage, such as in building facades.

Though envelope retrofits are difficult to implement, there are some cost-cutting solutions that can be explored. These include roof insulation, cool roof or a shaded roof.

Since a horizontal roof receives maximum solar radiation, protecting the roof from heat ingress can help save a significant amount of energy, while also providing thermal comfort in low-rise homes and to the top floor of high-rise apartments.

Doing your bit

While all of the above measures will help cut energy use and generate savings, it is equally important to make lifestyle changes. Setting thermostats higher, switching off appliances when unused, and performing regular maintenance are all very simple, very helpful and very healthy measures to save energy.

If we work together, the people of India can make a tremendous difference — not only to our own homes and residences but for the greater good of the nation as well. Today, it is imperative that we all begin taking steps such as these for the future of our children and their children depend on it.

(The author is managing director, Green Business Certification Institute)