Kaldor ETC & FPC solar water heaters deliver 70–90°C hot water daily — engineered for diverse climates and hard water conditions across the globe.
Kaldor solar water heating systems are built on one principle: harness the sun with maximum efficiency, store heat with minimal loss, and deliver hot water every single morning. Our ETC and FPC systems are engineered for climates worldwide — from humid tropical coastlines to arid desert environments.
German Porcelain Diamond Glassline coating. TATA Steelium inner tanks. Copper riser pipes with ultrasonic welding. These are not claims — they are specifications. Distributed across India by Hydrolux Solutions, authorized Kaldor distributor.
The ETC system uses high borosilicate vacuum tubes with 3-target coating (Aluminium/Copper/Nickel) for maximum solar absorption. Performs in diffuse light and works with hard water up to 3000 PPM. Available in Diamond Glassline, Prime Ceramic, and Eco Deluxe variants.
The FPC uses a selective-coating absorber plate with copper riser pipes (12.5mm) brazed to a 25mm header, enclosed in toughened frosted glass (97% transmittance). Ideal for pressurised systems. Available in pressurised and non-pressurised variants with Diamond Glassline or SS 304 inner tanks.
Both systems are built to Kaldor's exacting standards. The right choice depends on your water type, pressure requirements, and climate.
| Feature | ETC — Evacuated Tube | FPC — Flat Plate |
|---|---|---|
| Collector Technology | High borosilicate vacuum tubes (58×1800mm) | Copper riser & header with selective absorber plate |
| Water Hardness | Up to 3000 PPM ✓ | Up to 200 PPM (soft water) |
| Pressurised Supply | Non-pressurised (gravity feed) | Both pressurised & non-pressurised ✓ |
| Performance in Diffuse Light | Excellent — works in cloudy/diffuse light ✓ | Good — requires direct sunlight |
| Maintenance | Zero maintenance — sealed tubes ✓ | Periodic cleaning recommended |
| Tank Inner Coating | Diamond Glassline / Ceramic / SS 304 | Diamond Glassline / SS 304 |
| Max Capacity | Up to 500 LPD (38 tubes) | Up to 1000 LPD (8 collectors) ✓ |
| Output Temperature | 70–90°C | 70–90°C |
| Insulation | 50mm High Density PUF | Fiber wool / Rock wool |
| Working Pressure | 1 Kg (non-pressurised) | 3 Kg (pressurised) ✓ |
| Best For | Homes in hard water areas, arid & semi-arid climates | Apartments, hotels & commercial — pressurised supply |
Your water is hard (above 200 PPM), you don't need pressurised supply, or you're in a region with occasional cloudy days. The sealed tube design also means you'll never need maintenance.
You need pressurised hot water, you're on a soft water supply, or you need large-capacity systems above 500 LPD for hotels, apartments, or commercial applications.
The outer glass tube is made from high borosilicate material — thermally shock-resistant, with transmittance exceeding 91%.
Aluminium, Copper, and Nickel layers in the absorber achieve absorptivity of 0.097±0.02 — the highest available commercially.
The evacuated annular gap between tubes eliminates convective heat loss entirely — a principle borrowed from thermos flask technology.
Hot water rises naturally from tube to tank by density difference — no pump, no electricity, no moving parts to maintain.
97% light transmittance. Hi-efficiency frosted toughened glass minimises reflection losses while providing weather and hail protection. Collector size: 1030×2030mm.
12.5mm copper riser pipes brazed to a 25mm header. Ultrasonic continuous welding bonds riser to absorber sheet for zero-gap heat transfer. Brass flanges at inlet and outlet.
Absorptivity of 0.097±0.02. The dark selective coating maximises absorption across the solar spectrum while minimising thermal re-emission — engineered for peak efficiency in direct sunlight.
Collector box in extruded aluminium channels with polyester powder coating (off-white). Aluminium foil interior finish and fiber wool / rock wool backside insulation. EPDM rubber gaskets seal the unit for decades.
The inner tank is the most critical component — it's what your water actually touches for decades. Kaldor uses Wendel (Germany) Porcelain Glassline coating on TATA Steelium enamel-grade CR steel.
Heat-treated at 850°C, the glass coating bonds permanently to steel — corrosion-resistant even in hard water up to 3000 PPM.
Glass acts as a natural insulator, compounding the PUF foam layer. Water stays hot from morning through next morning.
Non-reactive glass surface prevents mineral and bacterial buildup. Every litre delivered is clean, safe, and odour-free.
| S.No | Capacity | Tube Size | No. of Tubes | Inner Tank |
|---|---|---|---|---|
| 01 | 100 LPD | 58×1800 mm | 10 Nos | CR + Diamond Glassline |
| 02 | 150 LPD | 58×1800 mm | 15 Nos | CR + Diamond Glassline |
| 03 | 200 LPD | 58×1800 mm | 20 Nos | CR + Diamond Glassline |
| 04 | 250 LPD | 58×1800 mm | 25 Nos | CR + Diamond Glassline |
| 05 | 300 LPD | 58×1800 mm | 30 Nos | CR + Diamond Glassline |
| 06 | 500 LPD | 58×2100 mm | 38 Nos | CR + Diamond Glassline |
| S.No | Capacity | Tube Size | No. of Tubes | Inner Tank |
|---|---|---|---|---|
| 01 | 100 LPD | 58×1800 mm | 10 Nos | CR + Fusion Bond Ceramic |
| 02 | 150 LPD | 58×1800 mm | 15 Nos | CR + Fusion Bond Ceramic |
| 03 | 200 LPD | 58×1800 mm | 20 Nos | CR + Fusion Bond Ceramic |
| 04 | 250 LPD | 58×1800 mm | 25 Nos | CR + Fusion Bond Ceramic |
| 05 | 300 LPD | 58×1800 mm | 30 Nos | CR + Fusion Bond Ceramic |
| 06 | 500 LPD | 58×2100 mm | 38 Nos | CR + Fusion Bond Ceramic |
| S.No | Capacity | Tube Size | No. of Tubes | Inner Tank |
|---|---|---|---|---|
| 01 | 100 LPD | 58×1800 mm | 10 Nos | SS 304-L Air Vent System |
| 02 | 150 LPD | 58×1800 mm | 15 Nos | SS 304-L Air Vent System |
| 03 | 200 LPD | 58×1800 mm | 20 Nos | SS 304-L Air Vent System |
| 04 | 250 LPD | 58×1800 mm | 25 Nos | SS 304-L Air Vent System |
| 05 | 300 LPD | 58×1800 mm | 30 Nos | SS 304-L Air Vent System |
| S.No | Capacity | No. of Collectors | Inner Tank | Type |
|---|---|---|---|---|
| 01 | 100 LPD | 1 Nos | Diamond Glassline / SS 304 | Non-Pressurised |
| 02 | 200 LPD | 2 Nos | Diamond Glassline / SS 304 | Non-Pressurised |
| 03 | 300 LPD | 3 Nos | Diamond Glassline / SS 304 | Non-Pressurised |
| 04 | 500 LPD | 4 Nos | Diamond Glassline / SS 304 | Non-Pressurised |
| 05 | 1000 LPD | 8 Nos | Diamond Glassline / SS 304 | Non-Pressurised |
| S.No | Capacity | No. of Collectors | Inner Tank | Type |
|---|---|---|---|---|
| 01 | 100 LPD | 1 Nos | Diamond Glassline / SS 304 | Pressurised |
| 02 | 200 LPD | 2 Nos | Diamond Glassline / SS 304 | Pressurised |
| 03 | 300 LPD | 3 Nos | Diamond Glassline / SS 304 | Pressurised |
| 04 | 500 LPD | 4 Nos | Diamond Glassline / SS 304 | Pressurised |
| 05 | 1000 LPD | 8 Nos | Diamond Glassline / SS 304 | Pressurised |
Enter your household usage and current energy costs. The calculator estimates your monthly savings and full payback period based on Kerala average solar irradiation.
* Calculation assumes 5.5 peak sun hours/day (global average for sunny regions), 80% solar fraction, and a temperature rise of 40°C. Actual savings vary by location, climate, and usage pattern.
Talk to a Kaldor specialist. We'll recommend the right system for your climate, water type, and requirements.
