The 3kW heating element is standard for instant geysers in India, but you should check the type and material of the heating element. Incoloy or copper heating elements are known for their durability and efficiency. Otherwise glass coated heating elements are the best. Only AO Smith provide glass coated heating element in Instant geysers in India.

Instant geyser must have safety features like a thermostat to prevent overheating and a pressure relief valve to release excess pressure. As the 3kw is considered high power which put a lot of load on wiring of the house specially old houses with decade old wiring. An ELCB inbuilt instant geyser are also need of the hour to avoid electric shock. Better to connect elcb plug/top separately to geyser.

Racold Pronto Pro 3L 3KW Vertical Instant Water Heater (Geyser) | Faster Heating | Suitable for High Rise Buildings | Italian Design|3 Levels of Safety|Convenient for Kitchen & Bathroom Applications
  • PUF INSULATION: the dense and thick insulation in the tank effectively retains heat, improving energy efficiency and lowering electricity costs
  • FASTER HEATING: the high-capacity heating element ensures rapid access to hot water
  • AUTO CUT OFF: the stem-type thermostat and cutout feature provide automatic temperature control and added safety for your water heater
  • NO BACK FLOW: the anti-syphoning system prevents water from flowing back into the container, thus avoiding dry heating
  • HIGH PRESSURE RESISTANCE: the water heater has high pressure withstanding capacity, which makes it suitable for high-rise buildings and high pressure pump applications
Racold Svelto 3L 3KW Vertical Instant Water Heater(Geyser) White | Free Electric Plug | Faster Heating |3 Levels of Safety |Italian Design| Convenient for Kitchen & Bathroom Applications
  • High Pressure Resistance: Your water heater has high pressure withstanding capacity, which makes it suitable for high-rise buildings and high pressure pump applications
  • Safety Plus: Three levels of safety against high temperature and pressure, provided by a hightech adjustable thermostat, cut-out and multi function safety valve according to international standards
  • Faster Heating: The high power heating element ensures you get hot water in minimum time
  • Anti-Siphon : The back flow of the water from cold inlet pipe is prevented by anti-siphoning system from inner tank of the water heater,Avoids dry-heating incase of no or less water inside inner tank due to back flow of water
  • Rust Proof Body : This water heater have rust proof body to prevent corrosion leaving no room for rust, ensuring, also its longer life Improves aesthetics in the bathroom
POLYCAB Intenso 5 litre, 3 KW Electric Instant Geyser (Water Heater) For Home & Kitchen | Efficient Heating Element | Enhanced Safety Measures| 5 years tank & 2 years product warranty【White】
  • ✅【Efficient Heating Element】Experience instant hot water with the highly efficient heating element.
  • ✅【Special Grade Heating Element 】Rapid heating, extended tank durability. Efficient performance meets lasting reliability.
  • ✅【Advanced 5 layers safety】 Advanced Thermostat and Thermal Cut-off. Advance Pressure Release Value. Anti-Siphon Protection. Shock-proof Plastic outer body. Multi-Layered Protection against Corrosion.
  • ✅【Versatile Usage】 POLYCAB’s compact Water Heater design is perfect for both Bathroom & Kitchen applications.
  • ✅【Durable Engineered Plastic Body】Our Water Heaters boasts a rust-proof engineered plastic body that ensures prolonged durability.
AO Smith EWS-5 White Instant Geyser 5 Litre With 3kW Express Heating | High Rise Building Bathroom & Kitchen geyser | UL Rated Wiring & Pressure Relief Valve For Ultimate Safety | 5 Year Tank Warranty
  • INSTANT HOT WATER HEATER FOR YOUR HOME: Experience the comfort of instant water heater technology with our 3000-watt element. Whether for your bathroom or kitchen, this instant water heater delivers hot water in seconds, perfect for cold mornings.
  • DURABLE STAINLESS STEEL GEYSER 5 LTR: Our geyser 5 litre with a stainless steel tank is built to resist corrosion even in hard water. Designed for long-lasting performance, this 5 litre geyser ensures you enjoy dependable hot water every day.
  • ADVANCED SAFETY FEATURES FOR YOUR FAMILY: Stay protected with our electric geyser featuring a 5-level safety shield. From overheating control to a rust-proof body, this instant water heater for bathroom guarantees total peace of mind for you and your loved ones.
  • HIGH-PRESSURE READY FOR HIGH-RISE HOMES: Perfect for high-rise living, our water heater 5 litre handles up to 6.5 Bar pressure effortlessly. This hot water geyser for bathroom ensures consistent performance, even in multi-story buildings.
  • WORRY-FREE WARRANTY FOR YEARS TO COME: Invest in confidence with a 5-year tank warranty and 2-year product warranty by AO Smith. Our instant water heater is backed by comprehensive coverage, ensuring you get the best experience without worry.
Havells Instanio 3L Instant Water Heater(Geyser)| Temp. Sensing LED Indicator| Rust & Shock Proof Body| ISI Marked|Warranty: 5 year on Inner Tank| High Rise Compatible (White Blue)
  • LED Indicator: Colour-changing LEDs that change from blue to amber to indicate the hotness of the water
  • Outer Body: Rust and shock proof ABS outer body for long life
  • Inner Tank: Stainless steel inner tank of 304 grade
  • Power Cord: Fire retardant power cord for maximum safety
  • 0.65 MPa Bar Pressure: Suitable for high rise buildings and pressure pump applications
Crompton Solarium Vogue 3-Litre, 3KW Instant Water Heater/Geyser with free Installation & Pipe (White and Turquoise Blue)
  • Premium Finish ABS Outer Body that compliments your interiors
  • Food Grade Inner Tank: 304 Grade Stainless Steel Inner Tank; also suitable to be used in the kitchen
  • Color changing LED Indicator: LED Indicator for power on & heating function
  • Powerful Heating: 3000-Watts Copper Heating Element for 33% faster heating
  • Withstands a pressure of 6.5 Bar: Suitable for high rise buildings and pressure pump applications
Crompton Solarium Neo 3-Litre, 3KW Instant Water Heater/Geyser with Rust Free ABS Body (Ivory)
  • PRODUCT: Crompton’s energy efficient instant water heater with rust proof ABS body
  • TECHNICAL SPECIFICATIONS: Wattage: 3000 W; Capacity: 3L; Pressure 6.5 bar
  • 4 LEVEL SAFETY: Capillary Thermostat, automatic thermal cut-out, pressure release valve and fusible plug
  • ANTI-SIPHON PROTECTION: Designed to prevent any backflow of water and protect the heating element from dry heating damage
  • QUALITY COMPONENTS: ISI marked nickel coated special element to provide resistance against scale formation
NEXOMS Cup Type Heating Element ISI Marked 3KW Compatible for 3 Litre – 6 Litres Instant Geysers
  • Tube Material: Anti-Corrosive Copper
  • Power: 3KW
  • Heavy Quality ISI Marked Element
  • Compatible for Portable Geysers and Instant Geysers 3 Litre to 6 Litres

Another thing to check is pressure bar capacity of inner tank specially if you like high rise buildings as water pressure can be much more for tank to withhold. You can also consider 4.5kw instant geysers if the house is fairly new with new wiring.