Do Wall Units Work in Winter? Heating Options for Year-Round Comfort

Intro: The Winter Question

When summer’s over and the cold creeps in, most homeowners with a through-the-wall AC wonder:

“Can I keep using it in the winter — or do I need to shut it down?”

The answer depends on the type of unit you own. Some wall ACs are strictly cooling machines, while others are built with heating modes designed for year-round comfort.

Let’s break down how these systems work in cold weather, which models are made for winter, and how to protect yours when temperatures dip below freezing.

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1. Not All Wall Units Are Built the Same

Through-the-wall systems generally fall into three categories:

If you’re unsure which you have, check your model label or manual.
If it lists “heat mode” or “electric heat strip”, you’re good for at least shoulder-season warmth.

Jake’s tip: “If your remote has a ‘HEAT’ button, you’ve already got a winter-ready unit — the question is just how cold your winters get.”

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2. Electric Heat vs. Heat Pump: The Key Difference

Here’s the biggest distinction in winter performance:

Electric Heat (Resistance Heating)

These units use a heating element, much like a toaster or space heater.

• Produces instant, dry heat.

• Simple and reliable.

• Works even in freezing temperatures.

• Less energy-efficient (electricity converts directly to heat).

Example: GE AJEQ12DWJ 12,000 BTU with 3.5 kW Electric Heat

It’s ideal for mild or moderate winters — think southern states or rooms that need a quick warm-up.

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Heat Pump (Reversible Cycle)

This type uses refrigerant to move heat instead of creating it.

• Much more energy-efficient (saves up to 40% vs. electric heat).

• Works best above 25–30°F outdoor temps.

• Loses heating power as the temperature drops.

Example: Amana PTH093G35AXXX 9,000 BTU Heat Pump

In moderate climates, a heat pump wall unit can handle year-round heating and cooling seamlessly.

Jake’s rule: “If you live somewhere that gets light frost but not deep freezes, a heat-pump wall unit will cover you all year long.”

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3. How Heat Pump Wall Units Handle the Cold

Here’s how a heat-pump model works when you switch it to “Heat”:

• The refrigerant reverses direction.

• Instead of pulling heat from inside and dumping it outside, it extracts warmth from the outdoor air and brings it in.

Yes — even cold air has heat energy! But as outdoor temps fall, there’s less heat to pull, and performance drops.

Most heat pumps are efficient down to 30°F, but below that, you’ll notice the air feels cooler or the fan cycles longer.

If you live where winters dip into the 20s, look for models with electric backup heat — they automatically switch modes when it’s too cold for the heat pump alone.

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4. How Much Heat Can a Wall Unit Provide?

Let’s put real numbers on it.

That’s enough power to heat a bedroom, office, or small apartment comfortably.
Just remember, the output drops in colder air, so it’s best to size up slightly if you plan to rely on wall-unit heating.

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5. Using a Wall Unit in Freezing Temperatures

If your model includes electric heat, you can use it safely in winter.
If it’s cooling-only, never try to run it when it’s freezing outside — the compressor and coils aren’t built for it.

For heat pump models:
✅ Safe to operate down to ~30°F
⚠️ Efficiency drops below 25°F
🚫 Turn off in subzero weather

You can supplement with a small space heater or rely on central heat during the coldest nights.

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6. The Role of Wall Sleeves in Winter Protection

A wall sleeve isn’t just for stability — it’s your insulation barrier against cold drafts.

Make sure:

• The sleeve is sealed tightly with foam insulation.

• The rear grille blocks wind but allows drainage.

• Caulking around the sleeve is intact.

If you’re not using your wall AC for heat, add an insulated winter cover to block outdoor air completely.
Just don’t cover an active heat-pump unit — it needs airflow to function.

Jake’s advice: “Think of the sleeve as the window frame for your AC. If you feel cold air around it, you’re losing money.”

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7. Efficiency and Energy Costs in Winter

Here’s how the three common heating setups compare in energy use:

A wall heat pump costs roughly $0.10–$0.12 per kWh, translating to $50–$80 per month for average winter use — far less than baseboard heat or portable electric heaters.

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8. Best Practices for Winter Operation

If you’re running your wall unit in heating mode, keep these simple steps in mind:

✅ Clean your filter monthly — airflow is crucial for efficient heating.
✅ Don’t block the indoor grille with furniture or curtains.
✅ Keep the outdoor vent clear of snow or debris.
✅ Run in Auto or Energy Saver mode to prevent short cycling.
✅ Inspect seals and caulking before each winter.

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9. When to Add Backup Heat

If your winters routinely drop below freezing, consider combining your wall unit with:

🔥 A small space heater for spot warmth.
🔥 A baseboard or radiant heater for backup.
🔥 A central or mini-split heat pump for long-term efficiency.

Some homeowners even install a dual-unit setup — a heat pump wall AC for most of the year and a secondary electric heat model for deep winter.

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10. Best Winter-Ready Wall Units

Here are a few solid performers for 2025:

 

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12. Jake’s Real-World Experience

Last year, I installed a GE 12,000 BTU electric-heat wall unit for a client in Pennsylvania.
It kept their 400 sq ft office at a steady 72°F all winter — even when temps dipped to 20°F.
Their electric bill went up by just $35 per month, and they haven’t touched their baseboard heater since.

That’s the kind of performance that makes a wall unit a real four-season solution.

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Final Thoughts: Wall Units Aren’t Just for Summer

Modern through-the-wall air conditioners aren’t just cooling machines — many are full-fledged comfort systems that handle both heat and cold with ease.

If you pick the right model, seal it properly, and maintain it seasonally, your wall unit can serve as your primary comfort source year-round.

Jake’s closing tip: “If you’re still storing space heaters every winter, you’re missing out — a wall unit with heat can make your life a whole lot simpler.”

In the next Blog we will learn more about Is a Through-the-Wall Air Conditioner Right for Your Home?