Why solar water heating
Hot water heated by the sun, with backup only when you need it.
Heat from the sun
Flat plate collectors turn sunlight into hot water. The sun's heat itself costs nothing.
Less electricity or fuel
On sunny days the sun does most of the heating, leaving your geyser, boiler or heat pump less to do.
Pressurised or gravity-fed
Non-pressurised systems run from an overhead tank; pressurised systems suit homes with a pressure pump or high-pressure supply.
Stored until you need it
Heated water is held in an insulated storage tank, ready for use when you need it.
Pairs with a heat pump
For cloudy days and the monsoon, a Rudhra Solar heat pump can take over from electric backup.
Sized and installed by our team
Our engineers size the collectors and storage from your daily hot-water use and roof space, and our team installs the system, with AMC support available.
How it works
- 1
Collect
Sunlight falls on the collector's dark absorber plate and heats it.
- 2
Transfer
Water in the collector's tubes carries that heat away from the plate.
- 3
Store
The heated water moves into an insulated storage tank.
- 4
Top up
On cloudy days a backup heater or heat pump makes up the difference.
From our installations
Rudhra solar water heaters on Indian rooftops
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Find your model
How much hot water do you need each day?
Solar water heaters are rated in litres of hot water per day (LPD). This picks the smallest model that covers your daily use; an engineer confirms it on site.
- Collectors need a shade-free roof or terrace, facing south for most of the day.
- Size for winter, when days are shorter and incoming water is colder.
- In hard-water areas, scaling can affect the collector; a heat exchanger or water softener may be advised.
Specifications
RSFPC-200 technical data
System
- Capacity
- 200 LPD
- System type
- Non-pressurised
- Circulation
- Thermosiphon (no pump)
Collector
- Collector type
- Flat plate collector (FPC)
- Number of collectors
- 2
- Collector size (L × B × H)
- 2030 × 1020 × 100 mm, 45 kg dry
- Area per collector
- Gross 2.132 m², absorber 2 m²
- Total absorber area
- 4 m²
- Absorber
- Aluminium–copper or copper–copper, black chrome selective coating
- Optical properties
- Absorptivity 0.96, emissivity 0.12
- Header and risers
- Copper: Ø 25 mm header, Ø 12.5 mm risers, 9 fins
- Glazing
- 4 mm toughened glass, transmissivity above 0.85, EPDM sealed
- Collector box
- Aluminium, rockwool insulated (50 mm back, 25 mm sides)
Storage tank
- Tank
- MS, SS 304 or SS 316; PUF 50 mm insulation
- Cladding and backup
- Aluminium or powder-coated cladding; backup electric heater available
- Operating pressure
- 1 bar
- Mounting and connections
- Powder-coated MS or galvanised (GI) structure; ¾-inch inlet/outlet
Installation & service
- Installation
- By the Rudhra team
- Service
- Annual maintenance contract (AMC) available
Performance & warranty
- Typical hot-water temperature
- 60–65 °C on a sunny day
- Warranty
- 2 years
Source: Rudhra Solar flat plate collector technical specification and Rudhra Industries product data, October 2026. Values at rated test conditions; specifications may change without notice.
Compare
Compare up to three non-pressurised models
| Specification | RSFPC-100 | RSFPC-200 | RSFPC-300 |
|---|---|---|---|
| Capacity | 100 LPD | 200 LPD | 300 LPD |
| System type | Non-pressurised | Non-pressurised | Non-pressurised |
| Number of collectors | 1 | 2 | 3 |
| Total absorber area | 2 m² | 4 m² | 6 m² |
| Tank | MS, SS 304 or SS 316; PUF 50 mm insulation | MS, SS 304 or SS 316; PUF 50 mm insulation | MS, SS 304 or SS 316; PUF 50 mm insulation |
| Operating pressure | 1 bar | 1 bar | 1 bar |
| Warranty | 2 years | 2 years | 2 years |
Applications
Where Rudhra Solar water heaters are used
- Residential
- Hotels & hospitality
- Hospitals
- Hostels
- Process pre-heating
Downloads
Documents
- Technical datasheetPending · request a copy
- Installation & user manualPending · request a copy
- BrochurePending · request a copy
FAQ
Common questions
How is a solar water heater different from a heat pump?
A solar water heater collects heat from sunlight, so its output depends on the weather. A heat pump draws heat from the air using a compressor and works day and night. Many sites use both: solar for the daytime load and a heat pump in place of electric backup.
What happens on cloudy days or during the monsoon?
Output drops when there is less sunlight. A backup electric heater or a heat pump keeps hot water available; we size the backup together with the system.
Pressurised or non-pressurised: which do I need?
If your bathrooms are fed by gravity from an overhead tank, a non-pressurised system fits. If you use a pressure pump or a high-pressure supply, choose a pressurised system. Our engineers confirm this on site.
How much roof space does it need?
It depends on the capacity and the number of collectors. We confirm the layout and space during the site survey.
What maintenance does it need?
Keep the collector glass clean and follow the periodic checks in the manual. Our team installs every system, and annual maintenance contracts (AMC) are available.
Request a Custom Proposal
Get a proposal for RSFPC-200.
Tell us your daily hot-water use, number of bathrooms and roof details. An engineer confirms the model and layout before we quote.
Chat with an engineer on WhatsApp