Introduction
Hey, Mike Sanders here. If you’re considering a through-the-wall air conditioner, you’ve likely heard the big question: “Can I install it myself, or should I call a pro?” It’s an important decision that affects your comfort, safety, and wallet.
I’m here to help you figure out what’s right for your home. In this guide, I’ll cover everything from the tools and skills you need for a DIY install, to when it makes sense to call in a professional HVAC technician. I’ll also walk you through the installation process step-by-step, so you know exactly what to expect.
By the time you finish reading, you’ll have a clear understanding of your options and feel confident about your next move.
🔧 Understanding Through-The-Wall AC Installation Basics
Installing a through-the-wall air conditioner isn’t like sliding a window unit into place. It involves cutting into your wall (if not already prepped), securing a wall sleeve, and properly sealing the unit to prevent air and water leaks.
Here’s a quick overview of what installation usually entails:
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Measuring and preparing the wall opening (or using an existing sleeve)
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Installing or fitting the wall sleeve
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Mounting the AC unit securely into the sleeve
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Sealing around the unit to ensure weatherproofing
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Connecting electrical wiring safely to power the unit
If your home doesn’t already have a wall sleeve, creating the opening requires tools like a saw, drill, level, and possibly a stud finder to avoid cutting into electrical wiring or plumbing.
For a detailed look at the step-by-step installation, Family Handyman’s guide to through-the-wall AC installation is a fantastic resource.
🛠️ DIY Installation: What You Need to Know
Pros of DIY Installation
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Cost savings: You avoid professional labor fees, which can add up to hundreds of dollars.
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Satisfaction: Completing a home project yourself can be rewarding.
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Flexibility: You set your own schedule and pace.
Cons of DIY Installation
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Skill requirements: You need basic carpentry skills and electrical know-how.
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Tools: You’ll need saws, drills, levels, screwdrivers, sealants, and possibly electrical testers.
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Risk of mistakes: Incorrect installation can lead to leaks, poor performance, or electrical hazards.
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Time-consuming: If it’s your first time, expect the project to take longer than a professional.
Key DIY Installation Steps
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Check your wall: Verify the wall material and ensure there’s no wiring or plumbing where you plan to cut. A stud finder can help locate framing.
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Measure and mark: Accurately mark the cutout area to match your wall sleeve size.
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Cut the opening: Use the appropriate saw to cut through drywall, siding, and studs if needed.
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Install the sleeve: Insert the sleeve into the wall opening and secure it firmly. Make sure it’s level and properly sealed against water intrusion.
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Wire the unit: Connect the AC’s power wiring to the existing electrical circuit or install a dedicated outlet as required by your unit’s specs. This step must follow local electrical codes for safety.
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Insert the AC unit: Slide the AC into the sleeve and secure it according to manufacturer instructions.
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Seal and insulate: Apply caulking or weatherproof foam around the sleeve to prevent drafts and water leaks.
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Test the unit: Turn on power and verify the unit runs smoothly, cools effectively, and that all controls respond properly.
If electrical work makes you uneasy, you might want to hire a pro just for the wiring — it’s safer and keeps your installation code compliant. The U.S. Department of Energy has great tips on safe AC installation and electrical best practices.
👷 When to Hire a Professional
Sometimes, DIY isn’t the best choice. Here are situations where a professional installation is strongly recommended:
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No existing wall sleeve or difficult wall material: Cutting through brick, concrete, or stone requires specialized tools and skills.
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Electrical wiring work: If you’re not licensed or experienced, handling 240V circuits or installing new dedicated breakers can be dangerous.
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Complex framing or structural issues: If your wall has unusual framing, plumbing, or other obstructions, pros can navigate these challenges safely.
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Local code compliance: HVAC professionals know local building and electrical codes, ensuring your installation passes inspection.
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Warranty requirements: Some manufacturers require professional installation for warranty validity.
Hiring a licensed HVAC technician may cost more upfront but saves headaches and ensures your unit runs safely and efficiently. The Air Conditioning Contractors of America (ACCA) is a great place to find qualified installers near you.
⚙️ What to Expect From a Professional Installation
Professional installers typically:
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Perform a site evaluation to ensure your wall can accommodate the unit
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Verify electrical supply and recommend upgrades if necessary
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Cut the wall opening with precision and install proper support framing
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Mount the sleeve and air conditioner securely, ensuring weatherproof sealing
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Test the unit’s operation and explain maintenance tips
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Provide documentation for code compliance and warranty
Professionals also clean up the worksite and handle any unforeseen issues like hidden pipes or wiring.
🕒 How Long Does Installation Take?
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DIY installation: Depending on skill and tools, expect 6-12 hours, possibly longer if it’s your first time.
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Professional installation: Usually 3-5 hours for a typical installation with an existing wall sleeve; longer if structural modifications are needed.
💡 Tips for a Successful Installation
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Prepare your tools and workspace in advance.
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Read the manufacturer’s installation manual carefully.
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Have a helper available to assist with lifting and leveling the unit.
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Double-check measurements before cutting.
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Wear proper safety gear: gloves, goggles, dust masks.
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Ensure your electrical circuit can handle the unit’s power requirements.
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Seal around the unit thoroughly to prevent drafts and water intrusion.
For more on installation safety, check out OSHA’s guidelines on construction and electrical safety.
🔍 Common Installation Mistakes to Avoid
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Cutting an opening too large or too small for the sleeve
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Failing to level the sleeve, causing drainage issues
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Improper sealing leading to water leaks and drafts
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Using the wrong circuit or inadequate wiring
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Not following manufacturer specs, voiding warranty
🔄 Post-Installation Maintenance
Whether you DIY or hire pros, regular maintenance extends your AC’s life:
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Clean or replace filters monthly during heavy use
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Check for air leaks and reseal as needed
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Schedule annual professional tune-ups to keep everything running smoothly
The EPA’s guide on maintaining your HVAC system is a helpful resource.
Final Thoughts
DIY installation can save you money and give you a sense of accomplishment — but it requires time, tools, and skills. For many homeowners, especially those without carpentry or electrical experience, hiring a professional HVAC technician is the safest, most reliable choice.
Your home’s comfort and safety are worth the investment. Whether you go DIY or pro, following the right steps and safety precautions will ensure your through-the-wall air conditioner keeps you cool for years to come.
If you’re ready to shop for a through-the-wall AC unit or want help finding a qualified installer, check out the full range at The Furnace Outlet.
