Guides · Faisalabad, Lahore, Punjab
Heating Your Home in Winter With Solar: Can You Run a Heater on Solar?
Short answer
Yes, you can run a heater on solar, but only some heaters make sense. An inverter AC in heat mode is usually the best electric choice, because it moves heat in from outside and gives roughly two to three times more heat than the electricity it uses; oil-filled, fan and halogen heaters turn each unit of electricity into only one unit of heat. Run heating in daylight, when your panels are producing, and do not plan on heating through the night from a battery.
This guide compares the three common options in Punjab homes, inverter AC heat mode, electric room heaters and gas heaters, with plain arithmetic so you can judge what your solar system can carry.
Winter is when solar is weakest
Heating is needed in the very months when panels produce least. December and January bring short days, a low sun, fog and smog. In the seasonal data behind our guide to how many units a solar system produces in Punjab, a winter day gives roughly half the output of a spring day. Our guide to solar in fog and Lahore smog explains why.
There is a helpful side too. In winter the summer AC load disappears, so a system sized for summer cooling often has spare midday output on clear winter days. The question is how best to use it.
Winter heating on solar
Heat pump AC
Most heat per unit
Resistive heater
Heavy load, low efficiency
The three ways to heat a room
1. Inverter AC in heat mode
Many inverter split ACs sold in Pakistan are heat-and-cool models; check for a heat mode on the remote or in the manual. In heat mode the unit works as a heat pump: it pulls heat from the outdoor air and pumps it indoors. The US Department of Energy notes that a properly installed air-source heat pump can deliver up to three times more heat to a home than the electrical energy it uses. Real results depend on the model and the outdoor temperature; efficiency falls on the coldest, dampest nights, and the outdoor unit pauses now and then to defrost.
Because it is an inverter unit, it also starts gently, without the hard motor surge of a fixed-speed AC. Our guide to inverter AC vs non-inverter AC on solar explains why that matters for your inverter and battery. A non-inverter "heat and cool" AC also heats, but its starting surge and higher draw make it a weaker match for solar.
2. Electric room heaters (oil-filled, fan, halogen, ceramic)
All of these are resistance heaters. One unit (kWh) of electricity gives one unit of heat, whatever the design. An oil-filled radiator is not more efficient than a fan heater; it simply releases heat more slowly and quietly. Typical ratings are about 1 to 2.5 kW. They are cheap to buy and simple, but they are the most expensive way to make heat from electricity.
3. Gas heaters
Gas heaters use no electricity, so they do not load your solar system at all. Their problems are supply and safety. Piped gas has become less dependable in many Punjab areas in winter, and LPG has to be bought and carried in; our guide to the all-electric home covers that shift. Flueless gas heaters also burn the oxygen in a room and can produce carbon monoxide. Rescue 1122 repeats the same advice every winter: keep a window or vent open, switch the heater off at intervals, and never sleep with a gas heater running.
Comparing them on solar
| Point | Inverter AC (heat mode) | Electric room heater | Gas heater |
|---|---|---|---|
| Heat per unit of electricity | Roughly 2 to 3 units (varies with model and weather) | 1 unit | Uses gas, not electricity |
| Load on the inverter | Moderate, soft start | High, constant while on | None |
| Suits daytime solar | Yes, well | Yes, but uses a lot of output | Not relevant |
| Suits night battery | Only lightly, for short periods | Poorly | Not relevant |
| Safety notes | Normal electrical safety | Keep clear of curtains and bedding; use a proper socket and circuit | Ventilation, carbon monoxide risk, never while sleeping |
| Also useful in summer | Yes, cooling | No | No |
The arithmetic: how many units does heating use?
All figures below are round illustrative numbers to show the method, not measurements or promises.
Electric room heater. For example, if a 2 kW oil-filled heater runs for 5 hours in an evening on its highest setting, it uses about 2 × 5 = 10 kWh (10 units). With a thermostat cycling it on and off, the real figure might be lower, say 6 to 8 units.
Inverter AC in heat mode. For the same warmth, a heat pump giving about 2.5 units of heat per unit of electricity would need about 10 ÷ 2.5 = 4 units over those 5 hours. On a very cold, foggy night the ratio falls, so allow more.
Your winter solar output. For example, our guide to units per kW gives an indicative yearly average of roughly 36 to 44 units a day for a 10 kW system in Punjab, with winter days around half of spring. A clear winter day might therefore give somewhere around 18 to 25 units, and a foggy day far less. From that you still run the fridge, lights, fans, water motor, possibly an electric geyser and cooking.
What this tells you:
- One inverter AC heating a living room for a few midday and afternoon hours fits comfortably inside a typical clear-day winter output.
- Two or three resistance heaters running all evening can use more than the panels made that day.
- Overnight heating from a battery is rarely practical. In the example, 10 units for one room heater is more usable energy than many home batteries hold, and the battery would then be empty for the rest of the night. See our battery size guide for how usable kWh is calculated.
How to heat with solar sensibly
- Heat in solar hours. Run the AC in heat mode from late morning into the afternoon, while panels produce, to warm the rooms you use most. Our solar load management guide explains how to shift loads into the sunny window.
- Keep the heat in. Close doors to unused rooms, use curtains after sunset and seal obvious draughts. Heat you keep costs nothing to replace.
- Use the inverter AC as the main electric heater. Keep resistance heaters for small spaces or short bursts.
- Do not stack heaters on backup. During load-shedding, two heaters plus a kettle or iron can overload the inverter. Our inverter overload guide explains the warning beeps.
- Protect the battery. Set the inverter so heating does not drain the battery you need for lights, fans and the fridge at night. If you heat at night, accept that most of it will come from the grid.
- Use solar for self-use first. Under net billing, a unit used at home saves your full tariff, while an exported unit earns much less. Midday heating is one of the better winter uses of your surplus. See sizing under net billing.
- Keep any gas heater safe. Ventilate, switch it off at intervals, and never leave it running while anyone sleeps.
Should you size your system for winter heating?
Usually, no. Sizing a system to cover full winter heating means many more panels and a much larger battery that sit underused for the rest of the year. Most homes are better served by a system sized for the year as a whole, with winter heating added in daylight and the grid or gas covering the rest. Our guide to running your whole house on solar explains why winter is the hardest season to cover fully.
If you are planning new appliances, it is worth choosing heat-and-cool inverter ACs, which give you summer cooling and efficient winter heating from the same unit. Water heating is a separate decision; compare options in our solar geyser, heat pump and electric geyser guide. For cooking, see induction cooking on solar.
How Solar Works Pakistan sizes for winter loads
At the site survey we list every heavy load, including ACs, heaters, geysers and cooking appliances, and ask which must run in winter, during outages and at night. Our in-house engineers then size panels, inverter and any battery for your real year, not just the summer peak, and the quotation names each component's brand and model with the manufacturer's warranty per product given in writing. We design systems from about 6 kW upward. For a first estimate, try the solar calculator, and see current package rates on our solar system price page.
Get today's price or a free site survey
Send us your last 12 months of bills, a list of your ACs (inverter or not, heat-and-cool or cool only) and any heaters you use.
- WhatsApp or call: 0336 666 4321
- Email: info@solarworks.pk
- Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
- Lahore branch: 2nd Floor, Jeff Heights, Gulberg, Lahore
- Hours: 9:00 AM to 6:00 PM, daily
We serve all of Punjab, and site surveys are normally free. See our Faisalabad and Lahore pages, or contact us online.
Frequently asked questions
Can I run a room heater on solar panels?
Yes, during the day if your system has enough spare output, because a heater is just an electrical load. A 2 kW heater uses about 2 units an hour, so a few heaters can use most of a winter day's production. Running them at night from a battery is rarely practical.
Is an inverter AC in heat mode better than an electric heater on solar?
Usually yes. In heat mode the AC works as a heat pump and gives roughly two to three units of heat per unit of electricity, depending on the model and the weather. A resistance heater gives one unit of heat per unit of electricity.
Is an oil-filled heater more efficient than a fan heater?
No. Both turn electricity into heat one for one. An oil-filled heater gives a gentler, quieter heat and holds warmth after it switches off, but it does not use fewer units for the same heat.
Can my solar battery run a heater all night?
Not sensibly. A single 2 kW heater running for several hours can use more energy than many home batteries store, leaving nothing for lights and fans. Use the battery for essentials and let night heating come from the grid or another source.
Do solar panels produce enough in winter to heat a house?
On clear winter days they can usually run an inverter AC in heat mode for some hours alongside normal household loads. Winter output is roughly half of spring in Punjab, and much lower on foggy days, so full-house heating from solar alone is not realistic for most homes.
Is a gas heater safe to use?
It can be used safely with care: keep a window or vent open, switch it off at intervals, and never leave it running while anyone sleeps, because flueless gas heaters can produce carbon monoxide. If you smell gas, shut off the supply, open windows and leave the room.
Sources
- US Department of Energy, Energy Saver, "Air-Source Heat Pumps"
- APP, "Rescue 1122 issues safety guidelines for gas heater use" (22 December 2025)