Conditioning a Converted Attic or Bonus Room in Austin
Updated September 2026
A converted attic or bonus room is one of the hardest spaces to keep comfortable in Central Texas. The existing HVAC system usually was not sized for that square footage, the ductwork rarely reaches it properly, and the roof load means that room swings hot in August and cold in January. A ductless mini split is the most direct fix, because it puts heating and cooling exactly where the problem is, without asking the rest of the house to carry the load.
Old West Minisplits installs these systems at flat, posted prices across Austin and the I-35 corridor. One zone is $2,000, two zones are $3,700, and three zones are $5,400. That includes equipment, labor, line set, standard electrical, refrigerant, testing, cleanup, and even a Home Depot run for touch-up paint. You know the number before we show up.
Why a bonus room fights the rest of the house
Bonus rooms and finished attics sit above the insulation line and often have three or four exterior surfaces. That means they gain heat faster in summer and lose it faster in winter than a normal bedroom. The main system's thermostat is usually downstairs, so by the time that hallway feels fine, the upstairs room is already ten degrees off. Running more ductwork to that space is expensive, leaky, and still limited by the capacity of the original unit.
A ductless unit solves the room, not the whole house
A mini split is a heat pump sized for the actual load of that one room or zone. It cools hard through brutal Central Texas summers and handles our mild winters without a furnace. The indoor unit mounts high on a wall or ceiling, the outdoor unit sits on a pad or bracket outside, and a small line set connects them through a three-inch hole. No ductwork. No closing off other rooms. No running the big system all day just to make one space usable.
What the flat price actually covers
Our posted pricing is honest. A one-zone attic or bonus room install is $2,000. Two zones are $3,700. Three zones are $5,400. That covers the equipment, labor, line set, standard electrical, refrigerant, system testing, cleanup, and touch-up paint. We tell you the exceptions up front, never after the work starts: a very long line set, a panel upgrade the house already needed, or unusually difficult mounting. If your install is standard, that is the price you pay.
How we compare
| Factor | Old West Minisplits | The usual |
|---|---|---|
| Installed price for one zone | $2,000 flat, posted online | Often $3,700–$6,000 per zone on a custom quote |
| How you get a price | Flat price, no in-home sales visit required | Free estimate that requires a sales appointment |
| Surprise add-ons | Exceptions stated before work begins | Change orders or added line items after the quote |
| Cooling and heating | Heat pump handles Texas summers and mild winters | Often cooling-only window units or portable ACs |
| What you are left with | Permanent system, no blocked window, no condensate tray | A loud unit in the window that drips and blocks light |
Straight answers
Will one zone handle a finished attic or bonus room?
Yes, in most cases. We size the indoor unit to the room's square footage and heat load. If the space is very large or split into two distinct areas, a two-zone system at $3,700 usually makes more sense.
Do I need to upgrade my electrical panel?
Maybe, but we tell you before we start. Standard electrical is included in the flat price. If your panel was already undersized for the house and cannot accept the new circuit, that is one of the few honest exceptions we state up front.
Can you install in a room with no attic access above it?
Usually yes. The line set runs through a small exterior wall penetration, not through ductwork. As long as we can mount the outdoor unit on a pad or bracket near the room, the install is straightforward.
What about the mild winter? Do I need a furnace too?
No. A mini split is a heat pump, so it heats as well as cools. It handles Austin-area winter temperatures without a furnace or backup heat strips in nearly all cases.
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