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Mini Split for a Garage Apartment
Living above or beside a garage in Central Texas means fighting heat from every direction. A dedicated ductless mini split handles the heavy thermal load without overloading your main home HVAC system.
A garage apartment faces a double thermal assault during a Texas summer. Hot sunlight bakes the roof overhead, while radiant heat from the unconditioned garage bay below pushes right through the floorboards. Storing parked vehicles that radiate heat long after the engine turns off makes the floor behave like a radiator.
Standard central air conditioning units tied to the main house rarely balance this space correctly. The main house thermostat sits in a hallway far away, shutting the cooling off before the apartment ever reaches a comfortable temperature. Pushing cold air through long runs of ductwork into an isolated zone simply does not work.
Installing a wall mounted ductless heat pump gives the garage apartment its own dedicated cooling and heating source. Our crew installs these systems along the I-35 corridor, helping homeowners from Waco down to New Braunfels take complete control of their accessory living spaces.
The Price on the Card
That is materials and labor for a standard single zone mini split installation. One day every week is the Joker Day at $2,200. Which day it lands on changes week to week, and the current Joker Day is revealed on the home page.
A $400 materials deposit books the date. The balance is due on completion.
Call the crew: (512) 297-7493The Radiant Heat Challenge Below the Living Space
The concrete slab and air inside an unconditioned garage can easily climb past 110 degrees on a typical July afternoon. When you park a hot car inside, that metal engine block dumps substantial heat into the enclosed space. That heat moves upward through the joists and subfloor into the living quarters above.
Standard floor insulation helps delay the transfer, but over a long summer day, the floor itself becomes warm to the touch. The air conditioning unit inside the apartment has to continuously fight heat entering from both the ceiling and the floor simultaneously.
- Hot engine blocks trapped in the garage bay continue radiating heat into the subfloor for hours.
- Unconditioned air in the lower bay keeps the apartment floor constantly warm.
Independent Control Without Tying into Main House Ductwork
Trying to extend existing ductwork from the main home into a garage apartment usually creates major comfort problems. The main house thermostat senses temperature conditions in a completely different environment. When the main house hits its setpoint, the compressor shuts off, leaving the apartment stifling hot.
A mini split operates as a completely independent zone. It has its own thermostat, inverter compressor, and wireless controller. If you want the main house set at 75 degrees while keeping the garage apartment at 68 degrees for a tenant or family member, the ductless system operates without affecting the main house power usage or comfort.
Handling Stairwell Drafts and High Ceilings
Stairwells are famous heat traps in garage apartments. Warm air naturally rises up the stairwell, while cooler air dumps down to the landing near the outdoor entryway. If the indoor air handler is placed incorrectly, cold air leaks straight down the stairs while the main living area stays warm.
Our installation crew positions the indoor head unit to create efficient air circulation across the living area before air reaches the stairwell. Guide vanes on the wall unit are adjusted to push cold air horizontally across the ceiling space. This keeps the living area cool while keeping air moving, preventing pockets of stagnant heat from pooling near vaulted ceilings.
Sizing Rules of Thumb for Garage Apartments
Sizing a mini split for a garage apartment requires a different approach than sizing for a standard bedroom. As a general rule of thumb, spaces over unconditioned garages need roughly 25 to 30 BTUs per square foot, compared to the standard 20 BTUs used for normal rooms. A physical site visit by our crew confirms the exact heat load calculations before any equipment is selected.
Factors like window orientation, roof pitch, insulation depth, and whether the garage below is used for parking or active workout equipment all change the requirements. Getting the right capacity ensures the compressor ramps down smoothly during mild weather while having enough capacity when temperatures head well over 100 degrees outside.
Questions People Ask
Why is my garage apartment always hotter than the rest of the house?
Garage apartments take heat from two sides. The roof absorbs solar heat from above, while the unconditioned garage bay transfers radiant heat through the floorboards below. If your cooling is tied to the main home, the main thermostat shuts off before the apartment cools down. A dedicated mini split runs on its own thermostat to handle this extra thermal load.
Can I just run a duct from my main home AC into the garage apartment?
Connecting ductwork to the main home system usually leads to poor results. The main thermostat stays in the main house and will turn off long before the apartment reaches the desired setpoint. Tying the zones together also breaches air barriers, allowing fumes or garage air to mix into home air. A separate mini split keeps the air supplies completely separated.
Where should the indoor unit be placed relative to the stairwell?
The indoor unit should blow air across the main living zone rather than directly down the stairwell. If positioned right above the stairs, the dense cold air falls straight down to the entry landing, leaving the living quarters hot. Our crew mounts the unit on an exterior wall aimed across the main room so air circulates fully before reaching the stairs.
How many BTUs do I need for an apartment over a two-car garage?
A typical two-car garage apartment spans 400 to 500 square feet. As a general rule of thumb, these spaces often require between 12,000 and 18,000 BTUs due to the heat rising from the lower bay. However, ceiling height, insulation quality, and window exposure alter this figure. A site visit from our crew determines the precise sizing required for your space.
Will a mini split run efficiently during a hot Central Texas summer?
Yes, modern inverter mini splits adjust their compressor speed to match the cooling load. On days when heat sits well over 100 degrees, the compressor ramps up to full capacity to remove heat and humidity. During milder mornings, it runs at lower speeds to conserve energy while maintaining your exact thermostat setpoint continuously without cycling on and off rapidly.
Book the Job
If you have a garage apartment along the I-35 corridor that struggles to stay comfortable during the Texas heat, a dedicated ductless system is the practical solution. Our crew handles installations from Waco through Austin down to New Braunfels, evaluating your floor plan, stairwell placement, and lower bay conditions. Call or text our team to discuss your project and schedule a site visit.
Call or text the crew at (512) 297-7493. Tell us the room, the size and whether it is insulated, and send a photo of the wall you want the head unit on. Standard days are $2,400, materials and labor. The weekly Joker Day is $2,200, and the home page shows which day it is this week. A $400 materials deposit holds the date and the balance is due when the job is finished.
Call (512) 297-7493