Installing a GE 12,000 BTU Through-the-Wall Unit: What Homeowners Should Know

If you’ve decided on the GE 12,000 BTU 208/230 Volt Through-the-Wall Air Conditioner with Electric Heat (Model AJEQ12DWJ), congratulations—you’ve selected a highly versatile unit ideal for cooling and supplemental heating. But before you enjoy year-round comfort, you’ll need to plan for a smooth installation.

This in-depth guide walks you through everything homeowners like Mark need to know before, during, and after installation—from wall sleeve selection and electrical requirements to sealing, insulation, and troubleshooting.

📦 What Comes in the Box—and What Doesn’t

The GE AJEQ12DWJ includes:

• The AC/heater unit

• A front grille

• Mounting hardware for connecting to the sleeve

• Installation manual

Not included (but required):

• Wall sleeve (recommended: GE RAB46A or compatible)

• 208/230V power source

• Wall support brackets (if required)

• Weatherproofing materials (foam tape, sealant)

🧱 Step 1: Choosing the Right Wall Sleeve

A through-the-wall AC unit cannot be installed directly into drywall or studs. You need a metal wall sleeve that provides structural support and protects the unit from weather.

✅ Compatible Sleeves

• GE RAB46A: Official GE sleeve, weather-sealed, powder-coated for rust resistance

• Friedrich USC Sleeve: Fits many GE models if dimensions match (26"W x 15 5/8"H x 16 3/4"D)

⚠️ What to Avoid

• Old sleeves with rust or improper drainage

• Open-back sleeves designed for window units

Need help picking a sleeve? Read our full Wall Sleeve 101 guide.

📐 Step 2: Planning the Opening

📏 Unit Dimensions

• Width: 26 inches

• Height: 15 5/8 inches

• Depth: 21 13/16 inches

🔨 Wall Opening Guidelines

• Frame an opening with 2x4 studs or steel framing

• Add 2 inches clearance around for sleeve installation

• Ensure interior framing is level to prevent water intrusion

🪚 Wall Type Considerations

• Vinyl siding: Use j-channel or drip flashing for waterproofing

• Brick: Use a diamond blade masonry saw

• Stucco: Cut carefully and use sealant around sleeve

Always verify structural integrity and check for wiring or plumbing behind the wall.

⚡ Step 3: Electrical Requirements

The GE AJEQ12DWJ requires:

• 208/230 Volt power supply

• Dedicated 15-amp or 20-amp circuit (check label)

• A NEMA 6-15P or 6-20P receptacle

⚠️ Important Safety Tips

• Never plug into a 120V outlet

• Confirm ground wire connection

• Use a licensed electrician if you’re unsure

🧰 Step 4: Sleeve Installation

1. Insert the wall sleeve into the framed opening.

2. Make sure the rear end of the sleeve is pitched slightly downward to allow condensation drainage.

3. Secure sleeve to wall studs with mounting brackets or screws.

4. Seal around the outside using weatherproof caulk and foam backer rod.

5. Inside, apply insulating foam or spray foam around gaps.

Use this opportunity to clean the sleeve if it’s reused from an older unit.

🌀 Step 5: Installing the Unit

1. Slide the AC unit into the wall sleeve. It should fit snugly.

2. Align locking brackets and tighten mounting screws.

3. Snap on the interior front grille.

4. Plug into the correct electrical outlet.

5. Test operation in both cool and heat modes.

Check:

• Air blowing steadily from vents

• Drainage is clear (outside water drip OK)

• No rattling or vibration

🧽 Step 6: Weatherproofing & Noise Control

Weather resistance is crucial for long-term performance.

✅ Seal the following:

• Around sleeve exterior using caulk

• Inside gaps with foam insulation

• Rear drainage holes—ensure they remain unblocked

🔇 For Noise Reduction:

• Ensure unit is level

• Tighten all screws and brackets

• Place rubber pads between sleeve and wall if needed

🧑🔧 DIY or Professional Installation?

You can DIY if:

• You’re comfortable with basic framing and electrical work

• You have a pre-existing wall sleeve

Hire a professional if:

• You’re cutting a new wall opening

• You need a new 230V circuit installed

• Your home has complex siding or masonry

For best results, use a licensed HVAC or general contractor.

🧊 Testing Heating and Cooling Modes

After install:

• Run the unit in cooling mode for 15 minutes

• Test heating mode on a cold day (or override sensor for testing)

Common Troubleshooting:

• No power: Check breaker, verify voltage

• Dripping inside: Drainage slope may be wrong

• Weak airflow: Clean filters and confirm unobstructed vents

Full troubleshooting guide available at GE Appliances Support.

🛒 Must-Have Accessories

• GE RAB46A Wall Sleeve

• Weatherproof caulk (silicone-based)

• Foam insulation tape

• Drainage kit (for high-moisture environments)

• Smart plug or GE-compatible thermostat

🧠 Maintenance Tips from Mark

• Clean the filter monthly during heavy use

• Check for mold or debris in the wall sleeve

• Ensure vents are never blocked by curtains or furniture

• Test heating mode at least twice each year

🔗 Verified External Resources

1. GE Product Page – AJEQ12DWJ

2. National Electrical Code (NEC)

3. Home Depot – Wall Sleeve Buying Guide

4. Energy.gov – Efficient Room Air Conditioners

5. GE Appliances Support

6. Building America Climate-Specific Guidance

🏁 Final Word

Installing the GE AJEQ12DWJ through-the-wall unit is well within reach for experienced DIYers and straightforward for professionals. The key is proper wall preparation, correct electrical supply, and a sealed, secure sleeve. With a little planning—and a few pro tips from Mark—you’ll have reliable year-round climate control in no time.

In the next topic we will know more about: What’s the Ideal Wall Sleeve for Your GE Through-the-Wall AC? A Compatibility Guide