iW Solar builds the SD-P pressurized double inner tank solar water heater in Taian City, Shandong Province — from 15 to 30 vacuum tubes and 130 L to 240 L net capacity. Mains-pressure hot water without a circulation pump, a SUS304 double inner tank and 0.6 MPa working pressure — B2B manufacturing and OEM & ODM for importers and distributors since 2013.
An integrative high pressure solar water heater is a compact, all-in-one system where the collector and the storage tank are mounted together as one unit — but unlike a non-pressure heater, the water your customer actually uses stays at mains (tap) pressure, up to 0.6 MPa. That means strong showers straight from the city water line, with no booster pump and no separate circulation loop.
iW Solar manufactures the SD-P series on the “two inner tanks, double comfort” design: a non-pressurized inner tank works as the heat exchanger, wrapped around a pressurized inner tank that supplies the user. It is the natural upgrade for markets where customers have used non-pressure heaters but now expect mains-pressure comfort.
Solar energy heats one tank; your customer draws from the other. The two never mix — and that is exactly what makes the system both simple and pressurized:
Four standard configurations; tank and frame dimensions scale with the tube count.
| Model | Vacuum tubes | Net tank capacity | Gross capacity |
|---|---|---|---|
| SD-P-15 | 15 pcs | 130 L | 165 L |
| SD-P-20 | 20 pcs | 165 L | 215 L |
| SD-P-25 | 25 pcs | 205 L | 265 L |
| SD-P-30 | 30 pcs | 240 L | 315 L |
| Item | Specification |
|---|---|
| Working pressure | 0.6 MPa (mains pressure, no circulation pump needed) |
| Inner / outer tank diameter | Φ360 mm / Φ470 mm |
| Inner tank material | SUS304; middle (exchanger) tank SUS304 |
| Outer tank material | Colour steel |
| Insulation | Polyurethane, high-pressure foaming |
| Vacuum tube | Φ58 × 1,800 mm, high borosilicate glass 3.3 |
| Frame | Stainless steel / galvanized steel, 2 feet or 3 feet |
| Mounting angle | 45° |
| Backup heating | Electric heater; automatic operation |
| Quality control | Full-process inspection; tank pressure test; AQL 2.5 packing check; third-party inspection welcome |
Offer the SD-P pressurized series when your customers have reliable city water pressure and expect a strong shower — it is the closest thing to a “normal” water heater experience powered by the sun. Offer the non-pressure solar water heater when price decides the sale, mains pressure is weak or intermittent, and gravity flow is acceptable.
If your market has hard freezing winters or customers want the tank hidden indoors, step up to a split system instead: see our heat pipe solar collector for the collector half of a split installation. For a side-by-side view of all main system types, read the different types of solar water heaters.
iW Solar is a B2B manufacturer, not a retail shop, so the heater is built around your business:
See the full solar water heater product range for the copper coil, split and flat plate options that complete a catalogue.
The design uses two inner tanks. Solar heat goes into the open, non-pressurized tank first; your customer's water sits in a separate sealed SUS304 inner tank inside it and is heated indirectly. Because the user-side tank is sealed, it holds full mains pressure up to 0.6 MPa.
No. The system connects directly to the city water line and runs on natural thermosiphon circulation, so there is no pump and no separate station to install — that is one of its main selling points over a split system.
No. The two inner tanks are completely separated. The user never touches the solar-heated water directly; it only transfers heat through the tank wall, which also means scale and water quality issues stay out of the user side.
An electric heater inside the tank provides backup heating under automatic control, so the household always has hot water regardless of weather.
Yes. Logo printing on the outer tank, custom cartons and manual branding are standard OEM services, and the colour-steel outer tank can be finished to your market preference.
MOQ starts from 1 set for market testing. Production takes 18–25 working days after order confirmation, and we reply to every enquiry within 12 hours.
Tell us your target market, target retail price and estimated annual quantity. Our engineers will come back with the right tube and tank configuration, and a price, within 12 hours.
Request a quotation See all solar water heater productsCompetitive pricing, exceptional quality — get a factory quote within 12 hours.
If you are looking for an experienced and reliable factory for your OEM custom solar water heaters and bespoke solar equipment in China, iWSOLAR is your best choice. We offer the most reasonable price with the finest quality to support your business.
Markets: South Africa