Licensing, diagnostic method, pricing transparency, and what happens after the invoice. Those four separate a company that will fix your furnace from one that will sell you a new one.

Verify Licensing and Insurance

Ask for a license number and check it with the state. In Texas, HVAC contractors are licensed through the Texas Department of Licensing and Regulation, and verification takes a minute online.

Ask for a certificate of insurance showing general liability and workers’ compensation. Liability covers damage to your property. Workers’ comp matters because if an uninsured contractor’s employee is injured in your attic, the exposure can land on your homeowner’s policy.

These are not rude questions. Any legitimate contractor expects them, and hesitation is itself an answer.

Ask How They Diagnose

This is the question that separates technicians from parts changers.

A proper furnace diagnosis involves measurement: gas manifold pressure, combustion analysis at the flue, temperature rise compared against the rating plate, static pressure, and amp draw on motors.

A company that arrives, listens to the furnace, and quotes a part has guessed. Sometimes the guess is right. Often it means you pay for a part that was not the problem, and then pay again.

Ask what they will measure. The answer tells you a great deal.

Watch for the Replacement Reflex

The economic pressure in this industry runs hard toward replacement, because a system sale is worth many times a repair.

Be cautious with a technician who recommends replacement without showing you why. If a heat exchanger is cracked, you should see the crack — photographed or on camera. If combustion readings are out of range, you should see the numbers.

A red-tag on a furnace is a serious call, and a legitimate one comes with evidence. Some companies red-tag aggressively as a sales tool, and it is worth a second opinion if the finding does not come with something you can look at.

Pricing Before Work Begins

You should have a price in writing before anyone starts, and you should know what the diagnostic fee is and whether it applies toward the repair.

Ask whether pricing is flat-rate or hourly. Flat-rate is common and fine, but you should see the number before agreeing.

Be wary of a quote given over the phone without anyone seeing the system. It will change.

Ask About the Warranty on the Repair

Two questions: how long is the labor warranty on this repair, and is the part covered separately?

Also worth asking — will they check whether your equipment is still under manufacturer warranty? Heat exchangers frequently carry long terms, and homeowners often pay for repairs that should have been covered. A company that checks is one that is not optimising against you.

Availability When It Matters

Hill Country freezes arrive abruptly, and when one does every heating call in the county lands within about eighteen hours.

Ask whether they offer emergency service, what the after-hours policy is, and whether maintenance customers get priority. That last one is the practical reason many households join a maintenance plan — standing in the queue on the day everyone calls.

Local Track Record

A company that has worked in the same market for a long time cannot outrun its reputation, because it lives on repeat business and referrals.

We have been serving the Hill Country since 1986, our technicians are NATE-certified, and we are BBB accredited. What customers say is on our reviews page.

Whether They Look Past the Furnace

A good diagnosis considers the whole system. Many furnace complaints are actually ductwork problems — undersized returns, leaking supply ducts — and no repair to the equipment fixes them.

A company that measures static pressure and tells you duct sealing is the real answer is giving you the smaller invoice and the better outcome.

For furnace repair, contact 72 Degrees or call (830) 468-5316.