Retrofitting existing buildings consists of making modifications that may improve energy efficiency or decrease energy demand. But one may ask why care about decreasing energy demand when you can just pay extra to get all the energy one needs? However, a holistic perspective that surpasses mere monetary considerations is required for a transition towards energy-efficient spaces.

An assessment by the International Energy Agency (2021) indicates that energy demand in buildings in India has grown by 40% since 2000, mostly on account of growing appliance ownership, especially air conditioners, and increased access to modern cooking fuels. The direct use of fossil fuels in the building sector resulted in over 160 MT (1, 60, 000 kg) of CO2 emissions in 2019, with a further 460 MT (4, 60, 000 kg) of indirect emissions coming from the use of electricity.

New construction activity and the replacement of traditional structures with new buildings constructed from energy-intensive materials such as cement, bricks and steel are other significant factors resulting in increasing demand for energy.

Based on the current scenario, it is predicted that air conditioning (AC) units will see faster growth than any other household appliance by 2040, becoming the key driver of energy demand growth in buildings. The increasing uptake of household appliances would mean that the share of electricity in total energy demand in buildings will rise from 20% in 2021 to almost 50% by 2040.

About 55% of India’s energy needs are met by coal. And the pollution emitted from coal-powered electricity generation will linger in the atmosphere for years, worsening the already ballooning climate crisis. Also, given that coal is a fossil fuel, limited in availability, it is vital for us to pull the brakes on the use of this resource.

There is talk of increasing the use of solar, wind, and hydroelectric power. However, it is vital to recognise that the price paid for any source of large-scale electricity production is the destruction of life-supporting habitats.

Mindful consumption of electricity is thus not just a cost-saving step, but a necessity to ensure a minimal negative impact on our planet.

‘Retrofitting’ is one key pathway to addressing this issue. Retrofit is defined as ‘to install, fit, or adapt for use with something older’. In recent times, retrofitting also encapsulates the addition of new technology or features to older systems.

This article provides some guidelines that can facilitate the process of ensuring that already existing multi-storeyed buildings and individual house structures move towards energy efficiency.

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Retrofit guidelines for an energy-efficient building

The guidelines focus on retrofitting methods, use and maintenance techniques for ‘building envelope-related thermal retrofits’, which include installing thermal comfort solutions on the exterior surfaces of the building like walls, roofs, windows etc.’ and ‘appliance retrofits’. It is vital to note that the guidelines only share an overview of ideas to facilitate energy efficiency. Readers will need to identify suitable options based on the context of their house structure, monetary capacity, and other relevant aspects through further research and discussions with individuals experienced in built-space work.

1. Building envelope-related thermal retrofits:

Building envelope-related thermal envelopes include outer walls, roofs, foundations, windows, and doors. The purpose of the thermal envelope is to prevent or facilitate heat transfer from the interior of a house to its exterior whenever it is beneficial to do so.

2. Retrofitting methods:

• Undertake window glazing.
• Install static insulation material such as eco board and wood wool panels under the roof of the topmost floor of the building/house.
• Install a radiant barrier, such as a static alufoil sheet under the roof of the topmost floor of the building.
• Install radiant barriers using mechanisms, such as sliding, chain-sprocket, and pipe-motor above the roof which also enables cooling at night due to night-sky radiation.
• Install water-filled pet bottles on the rooftop to increase thermal mass
• Create a green roof by growing vegetation on the roof.
• Install a dormer window for enhanced stack ventilation.
• Incorporate jaalis at the highest point of the house to enable stack ventilation.
• Install a chimney to facilitate ventilation.
• Install shading devices such as fins, light shelves, external shutters, canvas awnings, solar screens, automatic shades and blinds, and/or incorporate landscape features such as mature trees or hedgerows.
• Apply reflective paint to the exterior of the house.
• Apply light-coloured paints inside the house.
• Use low-emissivity plasters like barite plasters and cow dung plasters.
• Use thick curtains at the windows.
• Install a structure cooling system on the entire roof slab.
• Install a radiant cooling system.
• Install an Indirect Direct Evaporative Cooling (IDEC) system.

3. Building envelope use guidelines

• During the summer season, keep the draperies and shades on south-facing windows open during the day to allow the sunlight to enter and keep them closed at night.
• Keep doors and heating/cooling vents in unoccupied rooms closed.

4. Maintenance guidelines:

• Clean all external building envelope elements every year.
• Check/repair air leakage inside the building.
• Check/repair air leakage outside the building i.e. repair all cracked or missing exterior caulking.
• Check for holes or cracks around walls, ceilings, windows, doors, lights and plumbing fixtures, switches, and electrical outlets that can leak air into or out of the home. Caulk and insulate wherever needed.
• Clean all interior surfaces of the building every six months.

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Appliance retrofits:

1. Lighting
   • Install a Solar PhotoVoltaic system of the required capacity.
   • Install 5-Star labelled Energy Star LED light fittings for indoor lighting.
   • Install LED lamps in all display/ exit sign boards.
2. Water Heaters
   • Install a solar water heater
   • Look for ENERGY STAR-certified water heaters, since they use 50% less energy than other models.
   • Get a tankless water heater. These are more energy efficient because they only warm up the water one needs when needed.
   • Make sure that the water heater is the right size for your home.
3. Refrigerators:
   • Install ‘Direct Cool’ and ‘Frost Free’ Refrigerators with at least a three stars rating under Building Energy Efficiency (BEE) labelling or equivalent.
   • Buy the right-sized refrigerator for your household’s needs. Overfull or almost empty refrigerators will not perform at the rated efficiency.
4. Gas burners:
   • Use Indian Standards Institute (ISI) rated gas burners in the kitchen.
5. Cooling Devices
   • Use coolers instead of air conditioners in places with hot-dry climates
6. Solar PV
   • Install a Solar PhotoVoltaic system of the required capacity.

Appliance use guidelines:

1. Dishwasher:
   • Use the dishwasher only when it is at full load.
   • Air dry dishes instead of using the washer’s drying cycle.
2. Lighting:
   • Turn off lights when not in use
3. Washing Machine:
   • Wash only full loads of clothes.
   • Switch the washing machine water settings from hot water to warm or even cold, which can reduce energy consumption by about half.
4. Fans:
   • Turn off kitchen and bathroom exhaust fans within 20 minutes of cooking or bathing.
   • Turn off the ceiling or table fan when not in use.
5. Refrigerator:
   • Set your refrigerator’s temperature to 4.44 degrees Celsius. According to the FDA, this is sufficient to keep your food safe, and will also help reduce energy use.
   • Turn off the automatic ice maker.
   • Place the fridge in a cool space i.e. keep it away from heat sources like the stove.
   • Keep the refrigerator organised so that things can be found more quickly without leaving the door open.
6. Computers:
   • Turn computers off at night. Computers in energy-saving mode still use a lot of energy.
7. Water Heater:
   • Turn down the thermostat of the water heater by 10 degrees if it is set at the default temperature of about 54.44 degrees Celsius. This can conserve unexpectedly high amounts of energy and money.
   • Insulate the water tank and pipes to reduce heat loss before it even reaches the faucet.
   • Monitor and clean the sediment buildup at the bottom of the tank.
   • Take shorter showers.
8. General guidelines for all electronic devices:
   • Unplug devices when not in use.
   • Plug electronics into power strips. Turn the power strips off when equipment is not in use. This will help reduce phantom loads meaning energy that appliances continue to draw when they are turned off.

Appliance maintenance guidelines:

1. Washing machines:
   • Clean the lint screen after every use.
   • Clean the washer’s interior and rubber seals.
2. Refrigerators/Freezer:
   • Check and clean the gaskets regularly to ensure a tight seal.
   • Set the temperature as recommended by the manufacturer.
   • Clean dust from the coils.
   • Check the door’s seal. You can do this by checking if a piece of paper closed in the door pulls out easily. If it does, replace the gasket.
3. CookTops/Stoves
   • Clean with a recommended over-the-counter cleaner. Do not use harsh abrasives unless specified.
   • Clean all filters regularly.
4. Microwaves:
   • Clean the range hood fan filters regularly by soaking the filters or lightly brushing them in hot soapy water. Make sure the filters are dry before reinstalling them for better efficiency
5. Water Heater:
   • Insulate the electric hot-water storage tank and the first couple of feet of hot and cold water pipes connected to the heater.
   • Drain a quart of water from the water tank every three months to remove sediment that impedes heat transfer and lowers the efficiency of your heater.
   • Keep radiators and vents unobstructed by furniture, rugs, etc.
6. Solar panels:
   • Monitor the inverter display on the panels daily to ensure that it is working correctly and that the green light is on.
   • Keep a daily record of the system’s output to be able to monitor performance over a long period of time. Most modern inverters and their monitoring software will do this automatically.
   • Clean the glass on the solar panels with a soft cloth or wash rag or biodegradable soap, monthly. Clean solar panels are important to maximise the panel’s energy output.
   • Run a hose pipe with water over the panels in case of dust accumulation under and around the PV rays.
   • Check the panels to ensure that they are free of fractures, scratches, corrosion, moisture penetration, and browning, annually.
   • Conduct an annual general performance check of the system by reviewing the daily performance data to detect any major changes in the output
   • Check the cabling annually to ensure that it is secure and the voltage of strings is within the stipulated tolerance.
   • Check the mounting hardware annually to ensure it is in good condition and the earth connection is continuous
   • Check the junction boxes annually to ensure there is no water accumulation and that the integrity of lid seals, connections, and clamping devices is intact.
   • Check the breakers annually for any damage, and to verify that the isolation devices are working correctly
   • Check the fuse boxes annually for water damage and resistive joints on connections.
   • Inspect the inverters annually to assess any damage, checking for any resistive joints on connections and verifying the DC voltage coming into the inverter.
7. Lighting:
   • Use only ENERGY STAR‐labelled lighting, if replacing lights.
   • Check if interior automated lighting controls are working. If the motion control detector stops working, have the detector fixed or replaced so that you can continue to save energy when lighting is not needed.
   • In cases where you feel that some continuous lighting is needed for safety reasons in rooms, install a low level of light, with a sensor to trigger a high level of light when motion is detected.
   • Clean the light bulbs and fixtures – indoors and outdoors (annually).
   • Check the light bulbs and fixtures for damage.
8. Water Heating System Maintenance:
   • Turn off the system when not in use.
   • Check for water leakage in hot water pipes and repair as needed.
   • Check the insulation of hot water pipes, and repair the insulation of pipes if necessary.
9. Electrical Maintenance:
   • Check that cables and conductors are clearly grouped, bundled and labelled.
   • Ensure cable wiring, terminals and devices are free of damage, wear and tear, and corrosion.
   • Ensure cable wiring, terminals, and devices are free of overheating.
   • Ensure cable wiring, terminals and devices are disconnected and redundant.
   • Check that the interior of the cabinet is free from condensation, water leakage and poor drainage.

Also read:

• Co-creating cooling solutions for the homes of Bengaluru’s poor
• How to save electricity intelligently and smartly