Solar Water Heater vs Heat Pump vs Electric Geyser (2026): Which Suits Your Home?

Quick answer: Heating 100 litres of water by 30°C takes about 3.5 units of energy, whatever heater you use. An electric geyser takes all of it from the grid, plus a little extra to keep the tank warm. A heat pump moves heat from the air and, at the 3 to 4 times efficiency CLASP cites, needs roughly 0.9 to 1.2 units. A solar water heater takes most of it from the sun: HAREDA estimates a 100 litre system can save about 1,500 units a year compared with an electric geyser. For a family with a sunny, shade-free roof, solar is usually the cheapest to run; a heat pump suits homes without roof access; a small geyser still makes sense for a single bathroom with light use.

Hot water is one of the largest electricity loads in many Indian homes, especially in winter. This guide compares the three common options on running cost, roof needs, rules and upkeep, using Hyderabad's climate as the example.

The physics that decides the bill

Water needs a fixed amount of heat to warm up: about 1.16 units (kWh) to raise 1,000 litres by 1°C. So 100 litres heated from 25°C to 55°C needs about 3.5 units. In December and January, when tap water is colder, the same bath needs more. What changes between heaters is where that heat comes from:

• Electric geyser: a resistance element turns one unit of electricity into one unit of heat. Every unit of heat is a unit on your bill.
• Heat pump water heater: works like an air conditioner in reverse, pulling heat from the surrounding air. CLASP, which is supporting BEE on a future label, says heat pumps can provide 3 to 4 times more heat per unit of electricity, a 60 to 80% saving.
• Solar water heater: collectors on the roof absorb sunlight and heat the water directly. Electricity is used only by the backup element on cloudy days, and by a pump if the system has one.

Side-by-side comparison for 100 litres a day

To put a rupee value on it, multiply the units by what you pay per unit. Every 1,500 units saved is worth Rs 1,500 for each rupee of your tariff.

What the 2026 rules say

• Electric geysers carry a mandatory BEE star label. Storage type electric water heaters were already under mandatory star labelling before BEE added more appliances from 1 January 2026 (PTI, December 2025). The label rates standing loss: the energy the tank uses in 24 hours just to stay hot, tested at 45°C above room temperature. In BEE's 2023 to 2025 table, a 5 star 100 litre heater could lose no more than 0.796 units a day, against up to 1.164 units for 1 star. Check the band on the label of the model you are buying.
• Heat pump water heaters have no BEE label yet. In 2026, CLASP invited consultants to recommend a star labelling programme to BEE, and noted that Indian standards for heat pump water heaters were still being developed, and that about 90% of heat pumps in India are imported from China. Until a label exists, ask for the tested efficiency (COP) and the conditions it was measured at.
• Solar water heaters must carry the BIS mark. Under the Solar Thermal Systems, Devices and Components (Quality Control) Order, 2024, flat plate collector systems (IS 12933) and all-glass evacuated tube systems, with their storage tanks, need the BIS Standard Mark from 13 April 2025. Greentek's flat plate collectors are made under BIS licence CM/L-6557382.
• GST on solar water heaters is 5%. The rate on "solar water heater and system" came down from 12% to 5% from 22 September 2025.

How solar water heating fares through a Hyderabad year

The good news for Hyderabad is that the months when you want the most hot water are also the sunniest. WMO climate normals for Hyderabad Airport show only about 4 mm of rain in December and 8 mm in January, so winter mornings follow clear days that have already filled the tank. The weak months are July and August (about 158 mm and 205 mm of rain), when cloud cuts collection; that is when the backup element earns its place. Our kW vs units guide shows the same seasonal pattern for rooftop solar power.

Before you buy: a short checklist

• Size by use, not by bathrooms. HAREDA puts domestic systems at 100 to 300 litres a day. Count baths, the kitchen and any washing machine on hot water.
• Hard water. If your home runs on hard borewell water, it can leave scale in tubes and tanks. Ask whether the system suits hard water (for example an indirect, heat exchanger design) and what descaling schedule is recommended.
• Roof and warranties. Check roof strength and pipe runs. Collector, tank and backup heater are often covered separately. Our solar warranty guide explains what to look for.

Frequently asked questions

Will a solar water heater work in the monsoon?

It still collects heat on bright overcast days, but on long rainy spells the water may not reach the temperature you want. That is why home systems include an electric backup element. In Hyderabad, the rainy months are July to September, and the dry winter months are the strongest for solar heating.

Is a heat pump better than solar?

On running cost, solar usually wins where there is a good roof, because the sun does almost all the work. A heat pump wins where there is no usable roof, and it keeps working at night and through the monsoon.

Can rooftop solar panels run my electric geyser instead?

Yes, a grid-connected solar PV system with net metering offsets the geyser's units along with the rest of your load. As a rough guide, the 1,500 units a year a 100 litre solar water heater saves is about what 1 kWp of rooftop PV produces at the Indian average of 4 to 5 units per kWp a day (CSE India). Which option is better depends on roof space, your other loads and whether you also want power for the rest of the home.

Does PM Surya Ghar subsidise solar water heaters?

No. PM Surya Ghar Muft Bijli Yojana gives central financial assistance for rooftop solar PV, not for solar water heaters. Check with your state nodal agency for any local scheme.

Rules can be revised. This guide is current as of November 2026; check the latest BEE, BIS and MNRE notifications, and the label on the model you buy, before relying on it.

Thinking about switching from a geyser?

Greentek has been working in solar from Secunderabad since 1997 and makes BIS-marked flat plate collectors. If you are weighing solar, a heat pump or simply a better geyser for your home, our team is happy to help you size it.