Very hot or cold, darker, rainy days – all these climatic conditions add substantially to your monthly electricity bill. As utility bills recur, it can eat into your disposable income. Not only does saving power add to your kitty, it also helps the country and the earth — housing accounts for 22 per cent of the current electricity use and is expected to grow to 39 per cent of the demand by 2047. Lower energy use can save capital spent on power plants and emissions. Some simple ideas — when building a home or by upgrading it — can help you save on utility bills.
If you are buying or building a new home, maximum savings come from an energy-efficient design. Studies show a 30 per cent savings from often simple features such as ensuring natural ventilation and lighting.
Materials make the next big difference. For instance, for roofing, good material choice can ensure insulation when it gets hot and cool roof materials deflect sunlight and reduce the temperature of the roof. Thermoplastic, one such material, is said to reflect 80 per cent of the sun’s rays — much higher than the 30 per cent for asphalt roof. This can save 15 per cent of energy use in a building. Other materials are terra cotta and clay tiles as well as white or light-coloured glazed tiles.
A renovation idea is to paint the roof. A simple coat of white limestone can reduce temperature inside the home by 3 degrees and only costs under ₹30 per sq ft. There are also special reflective coatings that can be applied; while costs may be higher, these can also provide UV or water-proofing to the roof. A white or reflective roof can potentially save 15 per cent of air-conditioning energy use.
While roofs are important in an independent or low-rise home, windows are effective in reducing heat across the board. Installing double-glazed windows, which trap air between them, can save 20 per cent energy costs (based on the ambient climate). You may pay 30-40 per cent more upfront, though.
There are also simple add-ons to invest in. One example is installing solar panels which absorb heat and generate power that can be used to reduce your grid electricity usage. Study data showed that a building’s ceiling was 2-3 degrees Celsius cooler with solar panels compared to an exposed roof. Capital cost of the solar panel, based on data from government solar calculator, is about ₹60,000 per unit of power (based on ₹500-per-sq-ft cost and 120 sq ft of space needed to generate 1 Kilo-Watt). There are subsidies of up to 40 per cent available (for capacities up to 3 kW) and recently the application process was made online.
If you have interest in gardening, you can create a green roof by growing plants in the terrace. The idea has been extended beyond roofs to walls also. One caution is to ensure that the plants you pick do not wilt easily or consume too much water and the surface is water-proofed.
Likewise, with windows, you can use sun control films – simple plastic ones similar to what is often pasted on car windows. They can reduce nearly 80 per cent of the heat coming through the windows and can save 5-10 per cent of your electricity bill. Even using simple blinds can reduce both light and heat, saving cooling cost.
Other ways to invest capital to lower monthly bill include switching to LEDs and green-rated electrical appliances. Newer models of fans – such as brushless DC motor models – consume up to 60 per cent lower power compared to regular fans. Likewise, Inverter ACs are about 7 per cent more power efficient than non-inverter version.
One, often overlooked, power hog is motors for water. Grey water (from showers, baths, basins, and washing machines) after simple treatment can be reused in toilets, garden and other non-potable consumption. This reduces power used for pumping fresh water and in sewage treatment plants.
Besides traditional solutions, there are many smart devices and mobile apps that can help you understand your usage and act towards trimming it. For example, sensors can detect that rooms are not occupied and turn off devices. Smart-blinds with sensors can adjust the opening based on ambient conditions. Philips Smart Lighting has products that can be controlled via a mobile app or voice assistants such as Alexa and Siri. Users in the US have reported power saving of 10-20 per cent with smart devices such as Google Nest, which control lighting and heating/cooling.
Some smart-home systems provide analysis on potential power savings for, say, increasing the temperature by 2 degrees (typically 10 per cent of cooling cost). Such quantification can provide much-needed nudge towards behaviour change.
The author is an independent financial consultant