Can Solar Power a Mini-Split? Heat Pumps for Off-Grid and Backup Heating

If you've looked into heating or cooling a home, cabin, or addition with solar power, you've probably hit the same wall most people do: electric heat uses a lot of energy. Plug a space heater into a power station and watch the battery percentage drop.

A ductless mini-split heat pump changes that math. Instead of making heat from electricity, it moves heat from outside air into your home, so each kilowatt-hour you put in delivers several kilowatt-hours of warmth. That efficiency is what makes solar-powered heating and cooling realistic, and it's why mini-splits have become a go-to for off-grid cabins, garages, additions, and homes that want heat during an outage.

So can solar power a mini-split? Yes. The better question is how much solar and battery it takes, and the answer depends heavily on whether you're heating or cooling. Let's work through it.

Why a Heat Pump Beats a Space Heater on Battery Power

A resistance space heater turns one unit of electricity into one unit of heat. A heat pump uses a compressor and refrigerant to pull heat from outdoor air, even cold air, and move it inside.

Heat pump heating efficiency is rated in HSPF2 (BTUs of heat delivered per watt-hour used over a season). The MRCOOL DIY 12K 5th Gen, for example, is rated HSPF2 10 in the national-average climate region. That works out to roughly 2.9 units of heat for every unit of electricity, about three times what a space heater delivers from the same battery.

Two more things make modern mini-splits battery-friendly:

• Inverter-driven compressors ramp up and down to match demand instead of cycling hard on and off, which is easier on backup power systems.
• Cold-climate operation. The MRCOOL DIY 5th Gen units heat down to -13°F outdoors, according to the listings.

Cold-climate note: efficiency drops as temperatures fall. The 12K's HSPF2 rating is 10 for the national-average region but 7.5 for the colder northern region, so budget more power if you live in the Northeast or upper Midwest.

How Much Power Does a Mini-Split Use?

Mini-split listings give efficiency ratings and circuit sizes, not a single "watts" number, because an inverter unit's draw changes constantly. You can estimate it from the ratings. Here's the math for the MRCOOL DIY 12K BTU 5th Gen (115V):

These are estimates calculated from the listed ratings. Your actual use depends on insulation, room size, outdoor temperature, and thermostat setting. The colder the weather, the higher the draw.

The pattern is clear: heating a room through a winter day can take five times the energy of cooling it on a summer afternoon, and heating demand peaks at night, when solar produces nothing. That's the core challenge of solar heating.

On the electrical side, the 12K runs on 115V with a 20A maximum breaker and 18A minimum circuit ampacity. Whatever powers it has to supply a dedicated 120V circuit.

Three Ways to Power a Mini-Split With Solar and Batteries

1. Outage Backup With a Portable Power Station

The Jackery HomePower 3600 Plus delivers 3,600W of 120V power, comfortably above what a 115V 12K mini-split needs. Connected through a manual transfer switch, it can keep one room warm during an outage.

Estimated runtime: at a 600W average heating draw, the 3,584Wh base battery runs for roughly 5 hours. Jackery's expansion batteries can take the system up to 21kWh, which stretches that to more than a day. Pair it with solar panels, and daytime sun can buy back some of the overnight use.

Best for: keeping one heated room livable through a typical outage without a permanent installation.

2. Whole-Home Backup With a Large Battery System

The EcoFlow DELTA Pro Ultra offers 7.2kW of output per inverter with both 120V and 240V power, enough to run a 115V 12K unit or a larger 230V mini-split alongside the rest of your essentials.

Estimated runtime: each 6kWh battery adds roughly 8–9 hours of heating at a 600W average draw, and the system scales up to 90kWh. It accepts 5.6kW of solar per inverter, and it can also recharge from a gas generator, a useful fallback during a cloudy, multi-day winter outage.

Best for: homes that want heat plus the fridge, lights, and well pump through a long outage. Our Nature's Generator vs. EcoFlow vs. Jackery comparison covers these systems in depth.

3. A Permanent Solar System With a Hybrid Inverter

For daily solar heating and cooling, not just backup, a permanent system built around a hybrid inverter makes the most sense. The EG4 18kPV (12,000W output, up to 18,000W of solar input) and EG4 FlexBOSS18 run on 48V battery banks and provide 120/240V split-phase power for mini-splits of any size. See our hybrid inverter guide for how these systems work.

Estimated winter solar: covering 14.4 kWh per day of heating in a Northeast winter, where peak sun is often only around 2–3 hours per day, takes roughly 6–7kW of panels plus enough battery to carry you overnight and through cloudy stretches. Covering 2.6 kWh of summer cooling takes a small fraction of that.

Best for: off-grid homes, cabins, and homeowners who want to cut heating and cooling costs with solar. Add 48V batteries from home battery storage and panels from Rich Solar or Renogy.

Choosing a Mini-Split for Solar and Backup Power

The MRCOOL DIY 12K 5th Gen is a strong fit for solar and battery setups:

• 12,000 BTU of heating and cooling, with SEER2 22.7 and HSPF2 10
• 115V power (20A breaker), so it runs from 120V power stations, not just 240V systems
• Heats down to -13°F with a DC inverter rotary compressor
• True DIY installation with a pre-charged QuickConnect line set; no vacuum pump or specialized HVAC tools required
• ENERGY STAR certified, with built-in Wi-Fi and a 7-year compressor / 5-year parts warranty (plus a registered limited lifetime compressor warranty)

MRCOOL also offers the DIY Select and Easy Pro lines in 9,000 to 24,000 BTU sizes, at both 115V and 230V. For solar and battery use, compare the SEER2 and HSPF2 ratings on each listing, since higher ratings mean less battery drain. Browse all mini-split systems.

Sizing tip: match the unit to the space. An oversized mini-split cycles more and wastes energy; an undersized one runs flat-out in cold weather. Smaller, efficient 115V units are the easiest to run on backup power.

Tips to Stretch Your Battery

• Heat one zone, not the whole house. Close off the room you're using during an outage.
• Hold a steady setpoint. Inverter units are most efficient running steadily; big overnight setbacks force hard recovery runs.
• Pre-heat while the sun is out. On solar, warm the space during the day and let the thermal mass carry you into the evening.
• Seal and insulate. Every draft you stop is battery you save. Our off-grid cabin winterization guide covers the basics.
• Plan for the worst week. Size for a cold, cloudy stretch, not an average day, and keep a generator or grid fallback.

Preparing for winter outages more broadly? See our winter storm power outage checklist. For summer cooling with smaller units, read Can a Solar Generator Run a Window AC? To size batteries and solar for your whole home, use our whole-home sizing guide or the off-grid inverter and battery calculator. Planning a small space? Our tiny home energy budget shows a full-system example.

Frequently Asked Questions

Can a portable power station run a mini-split?

Yes, if it supplies enough continuous power at the right voltage. A 115V unit like the MRCOOL DIY 12K needs a 120V source rated for its 20A circuit; a 230V unit needs 240V output. Mini-splits are hardwired, so connect through a transfer switch installed by a licensed electrician.

How long will a battery run a mini-split in winter?

It depends on how much heat your space needs. As a rough estimate, a 12,000 BTU unit averaging 600W runs about 5 hours on a 3.6kWh battery and about 8–9 hours per 6kWh of battery. Colder weather and poor insulation shorten that.

Is a mini-split better than a space heater during an outage?

For battery runtime, yes. A heat pump rated HSPF2 10 delivers roughly three times the heat per watt-hour of a resistance space heater.

Can I heat a house all winter with solar and a mini-split?

It's possible, but short winter days mean you'll need a large array and battery bank. Most homeowners use solar to offset most of their usage and keep grid or generator backup for the coldest, cloudiest stretches.