Hot and cold ACs: what heating mode is worth in an Indian winter

Updated August 31, 2026 · Claude AC · 2 sources cited

North India spends eight months worrying about heat and about six weeks worrying about cold. In Delhi, Chandigarh, Lucknow and the Punjab plains, January mornings routinely start near single digits, and every winter the same purchase question returns: the shop is offering a « hot and cold » model for a few thousand rupees more than the cooling-only one — is the heating mode a genuine feature or a sticker?

It is a genuine feature, and physically it is the most efficient electric heating most Indian homes can buy. Whether it is worth paying for depends almost entirely on where you live and how many weeks a year you would actually press the button.

Moving heat beats making heat

A resistance heater — the rod heater, the halogen bar, the fan blower, the oil-filled radiator — converts electricity into heat at a ratio of one to one. A kilowatt-hour in, a kilowatt-hour of heat out. That is the ceiling, and no brand can beat it.

A hot and cold AC does not make heat at all. It runs the refrigeration cycle backwards: the outdoor coil becomes the evaporator, absorbing heat from winter air that still contains plenty of it, and the indoor coil releases that heat into the room. Because the machine is transporting energy rather than creating it, one unit of electricity delivers roughly two and a half to three and a half units of heat in mild conditions. That ratio, the coefficient of performance, is the whole argument.

Read the last row carefully: the AC both draws less and delivers more. For the same warmth in the same room, the heat pump path typically costs a fraction of what the blower costs — and the gap compounds over a season of nightly use. Converting that into rupees for your own tariff slab is the same arithmetic as summer, described in our guide to what an AC really adds to an Indian electricity bill.

What happens when it actually gets cold

The COP figures above carry a condition: they assume mild cold. Heat pump output falls as outdoor temperature falls, because there is less heat in the air to collect and the machine has to work harder to move it. That decline is gentle at 10 °C, noticeable at 5 °C, and steeper below freezing.

For the Indian plains this rarely matters. A Delhi or Chandigarh January morning near 5–8 °C sits comfortably inside the range where a modern inverter machine still returns two to three units of heat per unit consumed. Where it does matter is the hill stations and the higher parts of the north — Dehradun and above — where sub-zero nights push the machine towards the part of its curve where an auxiliary heater starts to look reasonable.

Two behaviours surprise first-time users and are entirely normal:

• The defrost cycle. In cold, damp air the outdoor coil frosts over. The machine periodically reverses briefly to melt it, during which the indoor fan stops and the room gets no heat for a few minutes. Water dripping and steam rising from the outdoor unit afterwards is defrost water, not a fault.
• The slow start. A heat pump warms a room gradually, while a blower feels hot within seconds because it is throwing radiant heat at you directly. The AC wins on room temperature over an hour; the blower wins on the first thirty seconds. Judging the machine on that first minute is the commonest reason people wrongly conclude « it does not heat ».

Does the extra purchase price come back?

Hot and cold models cost more than cooling-only equivalents — a modest premium relative to the price of the machine, and one that varies by brand, tonnage and season, so treat any figure as indicative until you have two real quotations in front of you. The payback question is simply how many hours of heating you would displace.

One more consideration favours the AC where it is close: an existing hot and cold split gives you a single serviced appliance instead of a second one stored eleven months a year, and it does not consume oxygen or scorch dust the way an open-element heater does. Against that, a heat pump dries indoor air further in an already dry north Indian winter, which is why users often run a bowl of water or a humidifier alongside it.

Using heating mode well

• Point the louvres down. Warm air rises. In cooling you aim high; in heating you aim at the floor, or the heat collects at the ceiling and the room never feels warm.
• Set 22–24 °C, not 30 °C. A higher setpoint does not heat faster, it simply overshoots and costs more — the same logic as the summer setting discussed in our note on what temperature to set your AC to in India.
• Service before winter, not only before summer. A clogged filter throttles heating exactly as it throttles cooling, and the outdoor unit needs clearance for airflow in both directions.
• Give the outdoor unit drainage. Defrost water has to go somewhere; a unit sitting in its own puddle on a balcony is a slip hazard and a corrosion problem.
• Close the room. Heating a bedroom with the door open to an unheated flat is the fastest way to make an efficient machine look inefficient.
• Do not judge it in the first five minutes. Start it half an hour before you need the room, as you would a geyser.

What to check before buying

The star label on the box rates cooling: the ISEER framework described in our guide to BEE star ratings is a cooling-season metric, and a five-star machine is not automatically the better heater. Ask instead for the declared heating capacity and input power, and for the lowest outdoor temperature at which the manufacturer still declares output. Inverter machines hold their heating capacity in the cold far better than fixed-speed ones — the reason is in our explainer on how inverter ACs work. And if the room is small and the budget tight, note that hot and cold window units exist too, with the trade-offs set out in our window versus split comparison.

Frequently asked questions

Is a hot and cold AC cheaper to run than a room heater?

Substantially, in the conditions found across the Indian plains. A resistance heater returns one unit of heat per unit of electricity by definition; an AC in heating mode moves roughly two and a half to three and a half units of heat for the same unit consumed. Over a winter of nightly use in a Delhi bedroom, that difference is the largest single saving available on a winter bill.

Can I convert my existing cooling-only AC to heat?

No. Heating requires a reversing valve and a circuit designed for it; the hardware either exists in the machine or it does not, and it is not a retrofit. The decision belongs to the purchase, not to the service visit.

Why does my AC blow cold air in heating mode?

Most often because it is in a defrost cycle or a start-up delay: the machine pauses the indoor fan rather than blowing unheated air, and it resumes within minutes. If genuinely cold air continues, check that the remote is in HEAT and not FAN or AUTO, then treat it as a fault — the ordered diagnosis in our guide to a split AC that is not cooling applies equally in reverse.

Does heating mode damage the air conditioner?

No — it is a designed operating mode on machines built for it, and running it does not shorten the compressor’s life. What does cause damage is running an unserviced machine hard in either direction: a blocked filter, a fouled coil and a starved evaporator strain the compressor whichever way the valve is pointing, which is why the routine in our maintenance guide matters twice a year rather than once.

Read next

• AC annual maintenance contracts in India: what an AMC really covers
• Renting an AC in India: what a summer on rent really costs
• Dry mode in the monsoon: what the water-drop button really does
• What an AC really adds to an Indian electricity bill
• Where the outdoor unit goes: placement, piping and the cooling you lose

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