Replacing a Through the Wall Air Conditioner with a Ductless Mini Split in Georgetown

Updated September 2026 · ATX Mini Split King, Austin and Central Texas

Many Georgetown homes, from mid century ranch houses near Southwestern University to garden homes in Sun City, were built with through the wall air conditioner sleeve units. When one of these aging units fails during a long Central Texas summer, a ductless mini split is often the cleanest permanent replacement. It lets you close up the wall opening and get efficient heating and cooling without adding ductwork to a home that never had it.

Flat pricing, everything included

Those are materials and labor together, wired to code by a TDLR licensed contractor. Anything non standard gets quoted first, before a single tool comes out of the truck: a very long line set, an electrical panel that needs work, a difficult mount, a roof or masonry penetration, disposal of the old equipment. You hear the number before we start, not after.

What a Through the Wall Sleeve Unit Actually Is

A through the wall air conditioner is a self contained metal box that sits inside a steel sleeve cut through the exterior wall. The entire refrigeration system, compressor, condenser coil, evaporator coil, and fan, lives inside that one box. The back half hangs outside to reject heat, and the front half blows cold air into the room. These are common in older Georgetown homes where central air was not part of the original build, particularly in smaller brick homes from the 1960s and 1970s, and in room additions or converted garages that were never tied into a central duct system.

These units cool only one space. They pull warm air from the room, pass it over a cold evaporator coil, and push the cooled air back out the front grille while dumping heat out the back. In winter, some have a resistive heat strip, basically a toaster element, that provides warmth. The sleeve itself is a permanent hole in the wall framed with a metal collar. The chassis slides in and out of that sleeve for service. Over time, the sleeve can rust, the seals around it degrade, and the unit becomes a major source of air leakage and outdoor noise.

Honest Pros of the Old Through the Wall Unit

There are real reasons these units stayed popular for decades. They are simple. One box, one power cord or hardwire connection, no refrigerant lines to run, no separate outdoor condenser to mount on a pad or bracket. For a small room, a working sleeve unit can cool the space quickly because it dumps conditioned air right where you sit. They are also cheap to buy off the shelf at a home improvement store, and if the sleeve is still sound, swapping in a new chassis is a half hour job for a handy homeowner.

In a home where the budget is genuinely tight, replacing like for like makes a kind of practical sense. You keep the hole, keep the sleeve, slide the new chassis in, and plug it in. No drywall work, no exterior patching, no electrician. For a rental property or a guest room used two weekends a year, that might be all you need. They also let you cool just one room without running a whole house system, which matters in a city like Georgetown where the cooling season runs from April through October and a single hot room can make a wing of the house unusable.

Honest Cons and Real Limitations

The biggest drawback is the noise. Because the compressor sits right in the wall, you hear every cycle start and stop from inside the room. There is no separating the noisy part from the quiet part. The second major issue is the permanent hole in your building envelope. Even a well installed sleeve unit leaks air around the edges, letting in dust, pollen, and humid outdoor air. In a humid climate like Central Texas, that constant infiltration makes the unit work harder and can lead to musty smells inside the chassis.

Efficiency is another real limitation. These units are designed to a lower standard than modern split systems. They also age quickly because the entire machine sits outside in the elements, even the parts that should be protected. The heat function, when it exists, is resistive electric strip heat, which is the most expensive way to warm a room. Finally, the sleeve itself becomes a liability. Once the metal collar rusts through or the surrounding framing gets water damage, a simple chassis swap is no longer an option. You are looking at structural repair regardless of what you replace it with.

Signs Your Sleeve Unit Is Failing

One clear sign is water where it should not be. If you find water pooling on the floor inside after a rainstorm, the sleeve seal has failed or the drain path is clogged and overflowing. Condensation dripping down the interior wall is another red flag. This means the insulation inside the chassis has deteriorated or the sleeve is no longer level, so condensate runs inward instead of out. You might also notice rust stains on the exterior wall below the sleeve, which tells you the metal collar is corroding and will eventually lose structural integrity.

Noise changes are a mechanical warning. A unit that suddenly rattles, grinds, or buzzes louder than it used to may have a failing compressor mount, a dying fan motor bearing, or loose internal parts that are no longer worth fixing. If the unit runs but the air coming out is barely cool on a hot day, the sealed refrigeration system may have a slow leak. These units are not designed to be opened and recharged economically. When the refrigerant is gone, the unit is done. Short cycling, where the unit starts and stops every few minutes, often points to a dying compressor or a control board failure.

What a Mini Split Replacement Actually Involves

Switching from a through the wall unit to a ductless mini split is more than a swap. Our crew removes the old chassis and the metal sleeve from the wall. The hole through the wall gets fully patched, inside and out. We frame in the opening, install new sheathing, match the exterior siding or brick as closely as possible, and finish the interior with drywall, tape, float, and texture. The goal is to make the wall whole again, as if the opening was never there. This is a skilled carpentry and finishing task, not just an HVAC job.

The indoor head of the mini split mounts on an interior wall, usually on an exterior wall to keep the line set short. A small three inch opening is bored through the wall behind the head for the refrigerant lines, the condensate drain, and the communication cable. The outdoor condenser sits on a pad or wall bracket outside, connected by that line set. Condensate drains by gravity to the outside through the same wall penetration. The electrical work includes a dedicated circuit from the panel to the outdoor unit, with a disconnect box mounted nearby. Most installations take a full day with a two man crew. If the existing circuit is adequate and properly grounded, we can sometimes use it, but many older Georgetown homes need a new home run back to the panel.

ATX Mini Split King does this work at a flat price. One indoor head, one outdoor condenser, all materials and labor including the wall patch: $1,500. Two indoor heads with one multi zone outdoor unit: $2,500. Three indoor heads: $3,500. Those prices assume standard installation conditions, an exterior wall mount, a line set run of fifteen feet or less, and an existing electrical panel with available space. Anything non standard, a long line set across an attic or crawlspace, a panel upgrade, a wall bracket on a tricky masonry surface, or an indoor head mounted on an interior wall with a condensate pump, is quoted before work starts. You always know the number before we begin.

When We Will Tell You to Wait

There are times when keeping what you have is the smarter move. If your sleeve unit is less than ten years old, the sleeve itself is solid and rust free, and the unit cools the room without complaint, run it until it dies. The most economical path in that situation is to buy a replacement chassis that fits the existing sleeve and slide it in yourself. You are not solving a problem you do not have yet. Similarly, if the room already has a ducted supply from a central system and the sleeve unit is just supplemental cooling for a chronically hot room, fixing the duct imbalance or adding a damper may be a better long term fix than adding a mini split to a home that already has working ducts.

If your home has a central furnace and air handler in good condition, and the sleeve unit is in a converted garage or addition that could be tied into the existing ductwork, extending your central system might make more sense. A mini split is the right answer when the space has no ductwork and adding it would be invasive and expensive. But if you have ducts already, use them. Also, if the wall around the sleeve has extensive water damage or the framing is compromised, that repair cost is separate and can shift the math. We assess the framing honestly and tell you what is structural work versus cosmetic patching. Finally, if your electrical panel is already full and would require a costly upgrade just to add one small mini split, waiting a season to budget for both the electrical work and the HVAC work together is a reasonable call. We never push a job that puts a customer in a bind.

Questions people actually ask

Can you just slide a new mini split into the old sleeve hole?

No. A mini split is a fundamentally different system. The indoor head and outdoor condenser are separate units connected by refrigerant lines. The indoor head is thin and mounts on the wall surface, not inside a sleeve. The old sleeve opening must be fully patched and sealed, and a much smaller penetration is made behind the indoor head for the line set and drain. Trying to force a mini split into an old sleeve would ruin the unit and leave the wall uninsulated. The whole point is to close up that large hole permanently and install the new system correctly.

How long does the whole replacement take, and what does the crew do?

A typical single zone replacement takes one full day. The crew arrives in the morning and starts by disconnecting and removing the old chassis and sleeve. They then frame, patch, and seal the wall opening. While the patching compound dries, they mount the indoor head, bore the line set hole, and set the outdoor condenser on its pad or bracket. The refrigerant lines are run, flared, and pressure tested. The electrician runs the dedicated circuit and connects both units. By late afternoon, the system is commissioned and running, and the wall patch is sanded and textured, ready for paint by the homeowner.

Does a mini split heat well enough for a Georgetown winter?

Yes. Georgetown winters are short and generally mild, with occasional overnight freezes. A modern ductless mini split in heat pump mode extracts heat from the outdoor air and moves it inside, working effectively even when outdoor temperatures drop well below freezing. This is far more efficient than the resistive electric heat strips found in old through the wall units. For the handful of genuinely cold nights Central Texas gets each year, the mini split will keep the room comfortable without the spike in your electric bill that a strip heat unit causes. You get one system that handles both seasons.

What happens to the brick or siding on the outside after the sleeve is removed?

We remove the old sleeve and any damaged framing, then fill the structural opening with matching sheathing, house wrap, and exterior finish. For brick homes common in older Georgetown neighborhoods, we source brick as close to the original as possible and mortar it in. The patch will be visible on close inspection, brick color and mortar age vary, but we aim for a clean, workmanlike match. For siding, we match the material and lap pattern. The exterior is then sealed and painted to blend. The goal is a weathertight closure that looks intentional, not a rough cover up.

Why are your prices flat instead of by the hour?

We price this work flat because we have done it enough times across Austin and Central Texas to know what a standard installation truly costs us in labor and materials. You know the total before we start, not an estimate that drifts upward. One indoor head is $1,500, two heads $2,500, three heads $3,500, all included. If your job needs something outside that standard scope, a long line set run, a panel upgrade, a difficult wall mount, we walk the job with you and hand you a written quote for the additional work before any commitment. No surprises at the end of the day.

Keep reading

Every replacement guide we have written is listed on the replacement guide hub. Next door to this page: replacing a through the wall air conditioner sleeve unit with a ductless mini split in pflugerville, replacing a through the wall air conditioner sleeve unit with a ductless mini split in kyle. Pricing, service area and the quote form all live on the ATX Mini Split King home page, and the Austin mini split cost guide covers what the rest of the market charges.