Most replacements are done in a day. Here is what that day actually looks like, so you know what to expect and what is expected of you.
Before the Crew Arrives
Clear a path from the entry to the furnace and a few feet of working space around it. If the unit is in a closet or garage, move stored items out the night before — this is the single thing that most often delays a start.
Plan for the heat to be off during working hours. In Hill Country weather that is usually a non-issue, but if a cold front is forecast, tell us when scheduling and we will plan around it.
Secure pets. There will be doors propped open and people moving equipment.
Morning: Removal
The crew protects floors along the work path, then shuts off gas and electrical to the unit and verifies both.
The old furnace is disconnected — gas line, electrical, venting, and duct connections — and removed. On attic and closet installations this is the physically demanding part of the day, and it is where access limitations show up.
The old unit goes with us. So does the packaging from the new one.
Midday: Installation
The new furnace is set and secured, then connected in sequence: duct transitions, gas line, electrical, venting, and on a condensing unit the condensate drain.
This is where a replacement becomes more than a swap. Code has changed since most existing furnaces were installed, and venting, clearances, and gas connection requirements may all need bringing current. That is not optional work and it is not padding — we identify it during the estimate rather than discovering it now.
If your old furnace shared a flue with a gas water heater and the new one does not, the water heater’s venting has to be corrected so it is not left on an oversized flue that will backdraft.
Afternoon: Commissioning
This is the part that separates a good installation from a fast one, and it is the part you cannot see.
Gas pressure is measured and set to the manufacturer’s specification. Combustion is analysed at the flue. Temperature rise is measured and compared against the rating plate — a furnace running outside that range has an airflow or firing rate problem that will persist for its entire life if nobody checks.
Safeties are tested, not assumed. Airflow is verified. The thermostat is configured for the actual equipment staging.
An installation that wraps up unusually early has almost certainly skipped this.
Before We Leave
We run the system through a full cycle with you, show you where the filter goes and which size it takes, walk you through the thermostat, and explain what maintenance the warranty requires.
You get the model and serial numbers, warranty registration handled on your behalf, and the permit documentation.
What Extends It Past One Day
Moving from standard to condensing efficiency, which changes the venting entirely. Gas line upsizing where the new unit demands more volume. Significant ductwork corrections. Difficult attic or crawlspace access. Or a system change — going to a heat pump or a hybrid fuel system involves outdoor equipment and refrigerant lines as well.
We tell you which category your job falls into before you schedule, not after.
The Inspection
Permitted work is inspected after installation. That happens on the municipality’s schedule and does not affect your heat — the system is in service from the day we finish.
If It Cannot Wait
When a furnace fails during a cold snap, no heat also puts your plumbing at risk in a Texas home, where supply lines often run through unconditioned attics. That makes a no-heat call more urgent here than the temperature alone suggests.
Our emergency heating repair line runs around the clock, and in many cases a repair gets you through until a replacement can be scheduled properly.
Details are on our furnace replacement page. Financing is available.
Contact 72 Degrees or call (830) 468-5316.
