Replacing Gas Wall and Floor Furnaces in Killeen

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

Many older homes in Killeen, especially around historic downtown and established neighborhoods near Fort Cavazos, still rely on gas wall furnaces or floor furnaces for winter heat. While these simple heaters served families well for decades, they do not provide cooling during intense Central Texas summers. ATX Mini Split King helps homeowners transition from outdated gas heaters to modern heat pump systems that handle both summer heat and winter cold.

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.

How Gas Wall and Floor Furnaces Work

A gas wall furnace is a self-contained heating unit recessed directly into an interior or exterior wall cavity. A floor furnace sits suspended below the floor joists in homes with crawlspaces or pier and beam foundations. Both systems burn natural gas or propane to heat a metal heat exchanger. They operate primarily on natural gravity convection rather than forced air blowers. Cooler air near the floor enters the bottom of the heater, warms up across the metal combustion chamber, and rises naturally into the living room without any ductwork.

Wall heaters exhaust combustion gases through a dedicated metal flue or chimney rising through the ceiling and roof. Floor furnaces exhaust through piping run under the floorboards to an exterior vent. Most of these units utilize a standing pilot light and a simple mechanical wall thermostat or built-in control valve. Because they lack motorized fans and duct runs, they heat only the immediate space around them, leaving distant bedrooms and closed areas significantly colder than the central room where the heater is located.

Honest Pros of Keeping a Wall or Floor Furnace

The greatest advantage of a traditional gravity furnace is its ability to operate during electrical outages. Many of these older units use a self-generating millivolt gas valve powered by the heat of the pilot flame. Because they do not need household electricity to ignite or circulate air, they continue providing warmth when Central Texas winter storms take down the power grid. For homeowners in older Killeen properties who worry about freeze events, this standalone heating ability provides genuine peace of mind.

These heaters also have very few moving parts. Without blower motors, electronic control boards, or complex sensors, they require minimal maintenance and can last for decades. They generate fast radiant heat that warms a single room quickly on chilly mornings. In a climate like Killeen where cold weather lasts only a few weeks, an existing gas furnace that is already paid for represents an inexpensive heating method, provided the unit remains structurally sound, properly vented, and free of gas or exhaust leaks.

Honest Cons and Limits of Gas Gravity Heaters

The most obvious limitation is that wall and floor furnaces do not provide air conditioning. Summer in Bell County brings months of intense heat and high humidity, making cooling a necessity. Homeowners with floor or wall heaters must purchase and install noisy window air conditioning units to stay comfortable. Window units block natural light, create security concerns, and struggle to cool multi-room layouts evenly, leaving some parts of the house stuffy while others remain freezing cold.

Safety and space constraints are also major drawbacks. Floor furnace grates reach high temperatures during operation, presenting burn hazards for small children and household pets. You cannot place rugs or furniture over a floor unit, which reduces usable square footage in smaller homes. Older combustion chambers can crack over time, raising the risk of carbon monoxide entering the living space. In damp crawlspaces, floor furnace casings frequently rust from the exterior inward, compromising system integrity without showing clear signs from above.

Signs Your Gas Heater Is Failing

Visible physical damage is a primary indicator of end of life for wall and floor units. Flaking rust around the cabinet, soot deposits on the wall above the heater, or corrosion on the exhaust flue mean combustion gases are not venting cleanly. If the pilot light frequently blows out, produces a lazy yellow flame instead of a sharp blue cone, or will not stay lit, the burner assembly or thermocouple is failing. Any faint odor of raw gas or burnt metal requires immediate shutoff.

Lack of replacement parts is another clear sign that it is time to replace the unit. Many manufacturers stopped producing components for older floor furnaces decades ago. If a gas valve, burner tray, or safety switch fails and cannot be sourced, the heater cannot be made safe. Structural degradation under the house, such as rusted-through bottom pans in crawlspace units, also indicates that the heating equipment has reached the end of its serviceable lifespan and should be retired.

The Ductless Mini Split Replacement Process

Replacing a gas furnace begins by safely shutting off and capping the gas line to TDLR code standards. The crew removes the old wall or floor heater completely. For a wall furnace, the open wall cavity can be sheetrocked flat or turned into a recessed shelving niche. For a floor furnace, the floor opening must be framed and patched with matching subfloor. Our team drills a three-inch pass-through hole in the exterior wall to connect the new indoor unit to the outdoor heat pump.

We mount the indoor air handler high on the wall, run insulated refrigerant line sets and condensate drain lines through the wall opening, and set the outdoor compressor on a level ground pad. Our crew handles the required electrical work, including installing a dedicated disconnect switch and outdoor circuit. Pricing is straightforward: $1,500 for one indoor head, $2,500 for two indoor heads, and $3,500 for three indoor heads, with all standard materials and labor included. Anything non standard, such as long line sets, a panel upgrade, or awkward mounting, is quoted before work starts.

Most installations are finished in a single day. The homeowner decides the exact placement of each indoor head based on room layout and daily habits. Once the system is installed, our technicians test the refrigeration lines under pressure, pull a deep vacuum, and release the refrigerant. The resulting mini split provides whisper-quiet cooling for hot Killeen summers and reverse-cycle heating for winter, controlled by a handheld remote or wall thermostat without requiring ductwork.

When Not to Switch to a Mini Split

A ductless mini split is not always the right choice for every property. If your home already has an existing, functional central duct system that simply needs a furnace swap, replacing the ducted equipment is often more economical than installing individual ductless heads across multiple rooms. If you plan to sell the home in the immediate future, making an equipment switch might not return its cost compared to a modest repair on the existing gas heater.

If off-grid winter survival is your highest priority and you do not have a backup generator, keeping a functional millivolt gas heater may be preferable. Mini splits require continuous electricity to run their compressors and fan motors, so they will not heat during an electrical blackout without a backup power source. If your current gas unit is safe, passes inspection, and you are content using window units for cooling, keeping your current setup for another season can be the sensible financial move.

Questions people actually ask

What happens to the hole left by an old floor furnace?

When a floor furnace is removed, it leaves a large rectangular opening in your floorboards. Our crew removes the furnace equipment and caps the gas line safely. The homeowner or a carpenter then frames across the floor joists, lays matching subfloor plywood, and installs new flooring over the patch. This eliminates the hot metal grate and frees up usable floor space for furniture placement.

Can a ductless mini split handle both Killeen summers and winters?

Yes. Ductless mini splits are complete heat pumps that provide both powerful cooling and heating from the same equipment. During long, humid Killeen summers, the system cools the home quietly and efficiently. During short Central Texas cold snaps, the system reverses its operation to pull ambient heat from outdoor air and deliver warm air indoors, eliminating the need for a separate gas heater.

Do I need to upgrade my electrical panel before installation?

Not always, but older homes in Killeen sometimes have crowded electrical panels that lack space for a new dedicated 240-volt circuit. During our initial assessment, ATX Mini Split King inspects your main panel to verify available electrical capacity. If your panel requires an upgrade or subpanel to support the heat pump safely, we identify that need and quote the work before any installation begins.

How much does ATX Mini Split King charge for ductless installation?

Our standard flat installation pricing is $1,500 for one indoor head, $2,500 for two indoor heads, and $3,500 for three indoor heads. These rates cover standard labor, mounting equipment, refrigerant lines, and basic electrical hookups. If your project involves non standard conditions like long line set runs, difficult outdoor mounting, or an electrical service upgrade, we provide a complete quote before work starts.

Will my mini split keep working if the power grid goes down?

No. Mini splits rely on electrical power to run the outdoor compressor, indoor fans, and electronic controls. Unlike gravity gas wall or floor furnaces that use millivolt valves without electricity, a mini split will stop running during a blackout unless you connect it to an appropriately sized home generator or battery storage system. Call ATX Mini Split King at (512) 297-7493 with any questions.

Keep reading

Every replacement guide we have written is listed on the replacement guide hub. Next door to this page: replacing a gas pack all in one heating and cooling unit with a ductless mini split in austin, replacing a gas pack all in one heating and cooling unit with a ductless mini split in round rock. 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.