Six objections to industrial heat pumps in India, answered one at a time

Six objections come up in almost every Indian plant conversation about industrial heat pumps. Five of them have answers. One of them is correct as stated. They are taken here in the order they usually arrive.

1. “It cannot reach my temperature”

It is often true. Here is the limit, and the list of duties above it.

An industrial heat pump delivers continuous output up to 120°C. Above that it does not, and here is what sits above the line:

Duty	Temperature
Retort sterilisation	121°C saturated steam at pressure
Autoclave and sterilise-in-place	121 to 134°C pure steam
Bake ovens	140 to 200°C
Electrodeposition cure ovens	190°C
Powder cure ovens	177 to 204°C
Alkyd polycondensation in a resin reactor	150 to 280°C
Spray dryer inlet air	180 to 200°C
Frying and baking	160 to 220°C
Zinc galvanising kettle	445 to 465°C
Annealing	650 to 850°C
Reheat furnace	1,200°C

So the objection is right for every one of those. The useful question is what share of your heat bill sits below 120°C. On most Indian sites that share is larger than the plant expects. It includes wash tanks, degrease baths, pasteurisation loops, CIP circuits, jacketed aqueous vessels, drying air and HVAC reheat.

Work out the share before dismissing the machine. A project that takes 40% of the fuel bill and leaves the furnaces alone is still a project.

2. “Electricity costs more than gas in India”

Per unit of energy bought, that is correct. Per unit of useful heat delivered, it is wrong.

Buying energy and delivering heat are two different transactions. A gas boiler turns roughly 85% of what you buy into useful heat. A heat pump turns one unit of electricity into two to five units of heat, because it moves heat that already exists.

Heat source	Per useful kWh thermal
Light diesel oil	₹12.58
Electric resistance, Maharashtra HT-I	₹8.70
Furnace oil	₹7.70
PNG, Gujarat industrial	₹7.24
Heat pump at COP 2.5, Maharashtra HT-I	₹3.38
Heat pump at COP 3.5, Maharashtra HT-I	₹2.41

The test that settles it on your own plant takes one division. Breakeven COP is your electricity price per kWh divided by your fuel’s cost per useful kWh thermal. Against gas and furnace oil it lands at 1.0 to 1.2, which any working machine clears. The full arithmetic with every assumption printed is here.

There is one caveat. If your gas is cheap enough and your electricity dear enough, the answer changes, and the division above will tell you that before anyone quotes.

3. “It will derate in a 45°C summer”

This one is backwards.

The objection is borrowed from cold-climate residential heating, where a heat pump has to extract heat from freezing air and struggles. In that setting, colder ambient means worse performance, and the concern is real.

Indian industrial heating is the opposite situation. A heating heat pump works harder when its source is colder, because the lift from source to output is greater. A 45°C afternoon is a smaller lift to a 70°C wash tank than a 15°C January morning. Hot ambient is the easy case.

There are two qualifications. This applies only to air source machines, and most industrial installations are water source or waste-heat source, for which ambient is close to irrelevant. And the design condition that matters is the worst case, which in India is a winter morning start, not a summer afternoon. Size on that.

4. “My grid supply is not reliable enough”

It is a fair concern, but a fired boiler depends on the grid too.

A boiler needs electricity for feedwater pumps, forced and induced draught fans, fuel handling, burner controls and instrumentation. A plant with no power is not making steam from that boiler. Both depend on electricity. The real question is how much backup generation each one needs.

A heat pump draws roughly its thermal duty divided by the coefficient of performance it holds at your output temperature. A 500 kW thermal duty at COP 3.5 draws about 143 kW. That calls for a materially larger generator than a boiler’s auxiliaries require. It is still materially smaller than the thermal duty itself.

Three things make this manageable in practice. One is retaining the existing boiler through the first year, which is normal practice. Another is buffer storage, which carries a short interruption without the process noticing. The last is putting the heat pump on the same essential supply as the rest of the plant’s critical load. The heat pump is not a special case.

5. “The payback will not clear our hurdle”

The objection usually rests on a hurdle rate that is not applied consistently.

Indian industrial buyers state a preference for payback in one to three years. Realised payback across a World Bank study of 224 Indian MSMEs came in at 44 months. So the stated preference works as a screening filter, not as a hurdle rate. A project at 30 months is well inside the payback those plants actually realised.

Two things move the number more than the equipment does. The fuel being displaced, because the saving against LDO and the saving against briquette are different projects. And the output temperature, because the COP falls as it rises and the saving falls with it. There is no single payback figure, and a supplier offering one has not asked enough questions.

Two things are also often left out of the capital side, and they pull in opposite directions. The first is the electrical connection work and any load enhancement, which is covered here. Leaving it out makes the payback look better than it is until the first bill. The second is accelerated depreciation at 40%, which applies to heat pumps and is named explicitly in the Income Tax rules. Leaving it out makes the post-tax case look worse than it is.

Payback depends on the quotation and the duty. Put the quotation you are holding over the annual saving the calculator computes on your own fuel price and tariff.

6. “It will not beat my coal boiler”

This objection is correct.

The breakeven coefficient of performance against delivered coal is 3.3 to 6.5, so on grid power a heat pump generally loses. Delivered coal costs about ₹1.94 per useful kWh thermal against ₹2.41 for a heat pump at COP 3.5 on the Maharashtra tariff. On running cost the heat pump is about 24% dearer. Against biomass briquette the heat pump saves only 5%, and that will not survive a bad month on the tariff.

So a plant on solid fuel deciding purely on fuel cost should keep the coal boiler.

There is still a case against coal, and it is a different one. A heat pump has no stack and no particulate emissions, no ash handling and no fuel handling labour. It has no exposure to coal availability, and it gives a clean answer when a customer audits your scope 1 emissions. Those are real, and for some plants they are decisive. They weigh most where a pollution control board direction or an export customer has already set a date. But it is a compliance and air quality argument.

On a levelised basis, an industrial heat pump is roughly at parity with coal on grid power. On captive renewables it is clearly ahead. So a plant with a captive solar plan is in a different position from one buying at the industrial tariff.

What to do with this list

Take the six in order on your own plant. First, find what share of your heat sits below 120°C. Then find what a useful kilowatt-hour of heat costs you today. Check whether your source is air or a process stream, and what your essential supply already covers. Ask what hurdle your finance team applies in practice, not the one it states. Last, note which fuel you are burning.

Five of those six are answerable from your own bills and instruments in an afternoon. The hurdle question is a conversation with finance. The cost-of-heat page has the arithmetic, the calculator runs it on your numbers, and the specification page sets out exactly where the equipment stops. When you have the six answers, send them to us.