Thermal energy as a service

Solar heat, without buying the system

Greentek funds, installs, owns and operates a solar thermal plant at your facility. You buy the heat it delivers — metered, integrated with your existing boiler. Zero capital cost, zero process change.

In short: for industrial process heat and boiler feed water, Greentek will fund, install and operate the system and charge only for the useful thermal energy delivered. The plant integrates with your existing boiler rather than replacing it, so there is no change to your process and no capital on your balance sheet.

ZeroCapital cost to you
MeteredPay for heat delivered
Boiler staysSolar pre-heats the feed
1997Manufacturing since
In-houseFins · collectors · tanks

The model

What does "heat as a service" actually mean?

Under a conventional purchase you pay the full system cost upfront and carry the maintenance risk. Under heat-as-a-service, Greentek carries both. We design, fund, install and operate the solar thermal plant at your site, and invoice only for the useful thermal energy actually delivered — measured at the heat meter, not estimated. Every degree the sun provides is fuel you do not burn.
No capex

We own the asset

Greentek funds, installs, owns and maintains the plant. You approve the roof area and the tie-in point.

Metered

You pay for heat delivered

Billing is against useful thermal energy actually supplied — not installed capacity, not sunshine hours.

Non-disruptive

Your boiler stays

Solar pre-heats the feed; the existing boiler carries the rest and remains the guaranteed source.

Four steps

How the commercial model works

01 · Assess

Site assessment

We profile your heat load, fuel bills, roof or ground area and water quality, and confirm the duty suits solar thermal.

02 · Invest

Greentek funds and builds

The system is designed, manufactured — fin, collector and tank, in-house — and installed at zero capital cost to you.

03 · Meter

You buy the heat

Billing is against useful thermal energy actually delivered, measured at the heat meter — not installed capacity, not sunshine hours.

04 · Operate

Greentek operates

Monitoring, maintenance and performance risk stay with Greentek for the term of the agreement. Your team provides site access, nothing more.

Integration, not replacement

Why the boiler stays

The plant is a fuel-displacement layer, not a boiler replacement. Solar delivers pre-heated water — typically 60–80 °C — into your existing line; the boiler covers night, monsoon and peak loads and remains the guaranteed source. No process re-engineering, no redundancy risk, and no downtime beyond the tie-in.
Schematic of a forced-circulation solar thermal plant pre-heating boiler feed water — collector array, storage tank, heat meter and tie-in to the existing boiler line.
A forced-circulation plant pre-heating the boiler feed. The heat meter at the tie-in point is what you are billed on.

Best suited to continuous hot water or low-temperature process heat loads — dairies, food processing, textiles, plating, hotels, hospitals and laundries.

Who runs on Greentek thermal

Proven at institutional scale

The engineering behind this offer already runs at some of India's most demanding institutional sites — AIIMS Gorakhpur, Guwahati, Bathinda and Bilaspur; the Indian Institute of Science; IIT Jammu and Bhilai; IIM campuses; and industrial clients including Flipkart, L&T and Lodha. Systems from 2,000 to 1,00,000 LPD, engineered per site.
Institutional-scale Greentek flat plate collector array delivering hot water at a large campus site.
Flat plate collectors at institutional scale — the same manufacture behind the heat-as-a-service offer.

Why we can offer this

The economics work because we manufacture

Heat-as-a-service only pays when the operator controls system cost and longevity. Greentek makes the absorber fins, flat plate collectors and storage tanks in-house — SS 304, TIG-welded, PUF-insulated tanks with sacrificial anode protection — as one of India's top five manufacturers of solar flat plate collectors, producing the equivalent of 2,00,000 litres per day of hot-water capacity every month, BIS-licensed to IS 12933.

See how the collectors, fins and tanks are made →

Questions buyers ask

Heat as a service — frequently asked questions

Further reading

More on solar thermal

Solar water heating systems

The full range — FPC, ETC, heat pipe and heat pump — and the manufacturing behind it.

Cutting boiler fuel cost without capex

The case for displacing boiler fuel with solar heat, without capital expenditure.

Inside the factory

Fins, collectors and tanks — how the hardware behind the service is made.

Send us a fuel bill. We'll price the heat.

Share your monthly fuel or electricity spend on hot water, your daily demand and your location — we'll return a feasibility view and what the heat would cost you delivered.

Request a site assessmentSee the systems