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

When you think of a through-the-wall air conditioner, you probably imagine it humming away on a hot July afternoon — not warming your living room on a January morning. But here’s the truth: many modern wall units can heat and cool your space year-round, saving you the cost and clutter of a separate system.

Whether you live in a mild climate or face frigid winters, there’s a through-the-wall solution built for your needs. In this guide, we’ll break down how these systems perform in winter, which models handle the cold best, and how to choose one that keeps your home comfortable and efficient 365 days a year.

💬 Mark’s Perspective:
“I’ve installed wall units from Texas to Michigan, and every climate tells a different story. The right unit can handle both summer heat and winter chill — but you have to know which type fits your weather.”

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🧊 1. Can Through-the-Wall Air Conditioners Really Heat Your Home?

The short answer: yes — many can.

But it depends on the type of system you have. Some wall units only cool, while others include heating features powered by either electric resistance elements or heat pump technology.

Two Common Types:

1. Electric Resistance Heat – like a built-in space heater.
   Simple and reliable but uses more electricity.

2. Heat Pump Heating – reverses refrigerant flow to absorb warmth from outdoor air and move it indoors.
   Far more efficient, but performance drops in extreme cold.

Most newer wall units — especially PTAC (Packaged Terminal Air Conditioner) models — use both technologies: they act as heat pumps in mild conditions, then automatically switch to electric backup heat when it’s freezing outside.

💡 Mark’s Take:
“If your winters are moderate — say 35°F and up — a heat pump unit can handle the job alone. But if you get snow every year, you’ll want one with a dual heating system.”

Learn more: Energy.gov – Room Air Conditioners

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⚙️ 2. How Each Heating Type Works

Let’s dig into the mechanics so you can decide what’s right for your climate and budget.

🔌 Electric Resistance Heating

This method converts electrical energy directly into heat using metal coils inside the unit — much like a toaster.
It’s simple, dependable, and works in any weather.

Pros:

• Works even in freezing temperatures.

• Simple design means fewer components to fail.

• Instant, steady warmth.

Cons:

• Uses more electricity than heat pumps (less efficient).

• Can dry out air faster in small rooms.

• Better as a backup or zone heater than a primary source.

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🔁 Heat Pump Heating

A heat pump works by reversing the refrigerant flow used for cooling. Instead of removing heat from inside and releasing it outdoors, it captures available heat from outside air and transfers it inside.

Pros:

• Up to 3x more efficient than resistance heat.

• Quieter, smoother operation.

• Provides both heating and cooling in one system.

Cons:

• Efficiency drops below 30°F.

• Requires proper installation and wall insulation.

• May need an electric backup in very cold climates.

💬 Mark’s Tip:
“If your winters are mild to moderate, a heat pump model is your best friend. It costs less to run and keeps your temperature stable without drying the air.”

Learn more: HowStuffWorks – How Heat Pumps Work

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⚡ 3. Heat Pump vs. Electric Heat: Efficiency Comparison

Here’s a quick breakdown of how both systems perform in real-world conditions:

In most climates, the heat pump model pays for itself within two to three winters due to energy savings — especially if you use it daily.

Learn more: ENERGY STAR – Room Air Conditioners

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🧱 4. Inside the Tech: How Wall Heat Pumps Handle Winter

When temperatures dip, wall-mounted heat pumps rely on a few clever engineering tricks:

🌀 Reversing Valve

This component allows the refrigerant to flow backward, turning your AC into a heater.

🧊 Defrost Cycle

In cold weather, frost can build up on outdoor coils. The defrost cycle briefly switches the system into cooling mode to melt the ice — you might feel a temporary burst of cool air indoors, which is normal.

🔋 Backup Electric Heat

Many wall units automatically switch to electric heat when outdoor temps fall below ~30°F. You won’t notice the change — just steady warmth.

💡 Mark’s Insight:
“When your unit blows cool air for a few minutes in winter, don’t panic. It’s defrosting — a sign it’s protecting itself to keep working all season.”

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🧊 5. What Happens When It’s Too Cold?

In extreme cold, there’s simply not enough outdoor heat for a heat pump to draw in — which is where electric backup heating comes to the rescue.

If you live in regions like the upper Midwest or New England:

• Expect your system to switch to electric mode when temps drop below 28°F.

• For subzero temperatures, supplement with a small space heater or baseboard unit.

• Proper wall insulation and weather-sealed sleeves help retain heat efficiently.

🧠 Mark’s Advice:
“Think of your through-the-wall heat pump as your main heater nine months of the year — and your backup unit as insurance for the deep-freeze weeks.”

Learn more: Energy.gov – Heat Pump Systems in Cold Climates

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🌡️ 6. Real-World Heating Performance: Top Brands Tested

Here’s how popular models from GE, Amana, Friedrich, and LG perform when it comes to heating power and cold-weather reliability:

💬 Mark’s Verdict:
“If you’re below the Mason-Dixon line, LG and GE are perfect. Up north, Amana or Friedrich give you reliable heat even when it’s freezing.”

Learn more: Consumer Reports – Best Wall and PTAC Units

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🔇 7. Comfort Features That Matter in Winter

A good heater is about more than just temperature — it’s about comfort and consistency.

Look for these features when buying or upgrading your wall unit:

• Thermostatic Control: Maintains steady room temps.

• Auto Fan Mode: Adjusts airflow to prevent drafts.

• Defrost Protection: Prevents icing during long cold spells.

• Smart Scheduling: Start heating before you wake up.

• Filter Check Reminders: Keeps efficiency high all season.

💡 Mark’s Note:
“I love models that let you preheat rooms from your phone — it’s like having a programmable thermostat built into your wall.”

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🧰 8. Installation Tips for Year-Round Use

If you’re planning to run your through-the-wall system in winter, proper installation makes all the difference.

✅ Mark’s Checklist:

1. Seal the wall sleeve — Use foam insulation or weatherstripping around the edges to prevent heat loss.

2. Check the tilt angle — The unit should slope slightly outward to drain moisture.

3. Clean both coils before the heating season — dirt acts as insulation and blocks heat transfer.

4. Inspect electrical load — Ensure the circuit can handle both heating and cooling amperage.

Learn more: GE Appliances – Through-the-Wall Sleeve Maintenance

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🔋 9. Pros and Cons of Using Wall Units All Year

🧠 Mark’s Tip:
“If you only need to heat one or two rooms — like a bedroom or den — a wall unit beats installing new ducts any day.”

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🧾 10. Seasonal Maintenance for Winter Mode

Keeping your unit clean and protected ensures it stays efficient through the coldest months.

💬 Mark’s Tip:
“I run my unit in Fan Only for 10 minutes before switching to heat. It burns off dust so I don’t get that musty smell.”

Learn more: Family Handyman – AC Maintenance Guide

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🌍 11. Understanding Heating Efficiency Ratings (HSPF & COP)

📊 HSPF (Heating Seasonal Performance Factor)

Measures total heat output over electricity consumed during the heating season.

• 8.0+ = Very efficient.

🔋 COP (Coefficient of Performance)

Represents how many units of heat you get per unit of electricity.

• COP 3.0 = 3x efficiency over electric resistance heat.

Most through-the-wall heat pump units have:

• HSPF: 7.5–9.0

• COP: 2.8–3.2

Meaning they deliver reliable warmth for less than half the energy cost of standard electric heaters.

Learn more: Energy.gov – Heat Pump Ratings

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🧠 12. Mark’s Real-World Winter Test

“I installed an Amana heat pump wall unit in a customer’s sunroom in Columbus, Ohio — 250 square feet, lots of windows. It ran all winter long, down to 15°F, without needing a space heater. Energy bills dropped about 30% compared to the old electric baseboard.

When you install right and keep it clean, these systems can outperform expectations — even in the Midwest.”

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🧊 13. Best Use Cases by Climate

💬 Mark’s Rule of Thumb:
“If it rarely drops below freezing, heat pump. If it snows every winter, combo system. If you live in Florida — you’ll never need backup heat at all.”

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🏁 14. Final Thoughts: Year-Round Comfort in One Smart System

Today’s through-the-wall air conditioners aren’t just for summer cooling anymore. With efficient heat pump and electric backup systems, they’ve evolved into true year-round comfort machines that can handle almost any weather.

✅ Key Takeaways:

• Heat pump wall units save the most energy in mild to moderate climates.

• Dual systems (heat pump + electric heat) offer all-season reliability.

• Insulation, cleaning, and installation make or break winter performance.

• Smart thermostats and ENERGY STAR models cut utility costs even further.

💬 Mark’s Final Word:
“The right wall unit won’t just get you through the winter — it’ll make you wonder why you ever bothered with a separate heater.”

In the next topic we will know more about: How to Size a Through-the-Wall AC: BTUs, Square Footage & Efficiency