Straight answers for North Texas homes.

The most common causes are a failed capacitor or contactor at the outdoor unit, a tripped breaker, a frozen indoor coil, or low refrigerant from a leak. Check that the thermostat is set to Cool, the filter is clean, and the outdoor unit’s fan is spinning.

If the outdoor fan isn’t turning but you hear humming, shut the system off at the thermostat. Running it that way can overheat the compressor. That symptom is very often a bad capacitor, which is a quick repair for a technician.

A healthy system usually cools the air about 15–20°F below the temperature of the air going into the return. If your house is 76° and the vents are blowing 58–61°, that’s normal.

A much smaller difference points to low refrigerant, a dirty coil, or airflow problems. A much larger one can mean low airflow or a coil starting to freeze. You can check it with any kitchen thermometer held at a return grille and then at a nearby supply vent.

Yes, on the hottest afternoons a correctly sized system may run almost continuously and still let the house drift up a degree or two. Systems are designed around typical peak temperatures, not record highs.

What isn’t normal is a house that keeps climbing into the 80s, ice on the refrigerant lines, or a system that never shuts off even in the evening. Those point to a problem worth a service call.

Heat rises, and upstairs rooms sit right under an attic that can pass 140°F in a Texas summer. Long attic duct runs, too few return vents and an undersized or poorly balanced upstairs system make it worse.

The fix is rarely just a bigger unit. Balancing airflow, adding or enlarging returns, repairing attic ducts, adding insulation and checking the upstairs system’s charge often close most of the gap. Zoning or a dedicated upstairs system are options when the house needs it.

Ice usually means the indoor coil is getting too cold, almost always from restricted airflow (a dirty filter, closed vents, a weak blower) or low refrigerant. Turn the system to Off, set the fan to On to help it thaw, and replace the filter.

Don’t chip at the ice. If it freezes again after thawing and a new filter, call for service. Low refrigerant means there’s a leak, and topping it off without fixing the leak only delays the problem.

Turn the system off at the thermostat right away to stop more condensate from forming, then call for service. Most leaks come from a clogged condensate drain line, a full or rusted drain pan, or a frozen coil that’s thawing.

Many attic systems in this area have a float switch that shuts the AC off when the pan fills. If your AC shut off and there’s water in the pan, that switch did its job. The drain still needs clearing before the system runs again.

Around 76–78°F when you’re home is a good balance of comfort and cost in North Texas. Raising it a few degrees when you’re away saves energy, but don’t turn the AC off completely during the day in July and August.

Letting the house soak up heat for eight hours means the system has to fight humidity and heat stored in walls, furniture and the attic all evening. A moderate setback recovers faster and is easier on the equipment.

First check the easy things: the thermostat setting and batteries, the breaker for both the indoor and outdoor units, and the filter. Reset a tripped breaker once; if it trips again, leave it off and call.

Close blinds on sunny windows, run ceiling fans, avoid the oven and dryer, and drink water. If anyone in the house is elderly, very young or has health conditions, go somewhere cool. Signs of heat stroke such as confusion, hot dry skin or fainting are a 911 emergency.

A dusty, burning smell for the first few minutes of the season is normal: dust that settled on the heat exchanger over the summer is burning off. It should fade within an hour.

A smell that lingers, a hot electrical or plastic odor, or a rotten-egg (gas) smell is not normal. For gas, leave the house and call your gas utility or 911 from outside.

Common causes are a dirty flame sensor, a failing hot-surface ignitor, a pressure switch or inducer motor problem, or a clogged condensate line on high-efficiency furnaces. The furnace is designed to shut down safely when it can’t confirm a flame.

Many furnaces flash a diagnostic code on a small light inside the panel. Note the pattern before you call; it helps the technician bring the right part.

Yes. Any home with a gas furnace, water heater, fireplace or attached garage should have CO alarms on every level and near sleeping areas. Carbon monoxide has no smell.

If a CO alarm sounds, get everyone outside and call 911 or your gas utility. Annual furnace checks look at venting, the flame and the heat exchanger, the places CO problems start.

Both work well here. Modern heat pumps handle Collin County’s mild winters efficiently, while a gas furnace delivers hotter air on the rare hard freezes. The right answer depends on whether you have gas service, your electric rates and how your current system is set up.

A dual-fuel setup (a heat pump paired with a gas furnace) uses the heat pump most of the winter and switches to gas when it gets very cold. We’ll walk through the options honestly for your house.

Light frost on a heat pump’s outdoor coil in cold, damp weather is normal, and so is the steam you see when it runs a defrost cycle to melt it. Defrost usually takes a few minutes and repeats as needed.

A unit encased in thick ice, or one that never seems to clear, needs service: it can point to a failed defrost control, low refrigerant or a fan problem.

Auxiliary heat is the backup electric heat strip in a heat pump system. It kicks in automatically during defrost or when the heat pump can’t keep up. Emergency heat forces the system to use only those strips.

Electric strips cost far more to run than the heat pump, so use Emergency Heat only if the heat pump has failed. If AUX is on constantly in mild weather, have the system checked.

Keep the heat on and set to a steady temperature, keep the outdoor unit clear of ice and snow buildup, and make sure the furnace or air handler closet isn’t blocked. Never wrap a heat pump in a tarp or cover while it’s running.

If the power goes out, switch the thermostat off until it’s restored, then turn the system back on. That avoids a surge of everything starting at once. Have a backup heat plan that doesn’t involve a gas oven or unvented heater indoors.

Around 10–15 years is typical here. Long, hot cooling seasons put more hours on a system than in milder climates. Gas furnaces often last longer, 15–20 years, because they run fewer hours.

Regular maintenance, clean filters and a properly sized system push toward the long end of that range.

Repair usually makes sense for a newer system with a single failed part. Replacement starts to make sense when the system is 12–15+ years old, needs a major repair like a compressor or coil, uses R-22 refrigerant, or has needed repeated repairs.

A common rule of thumb: if the repair costs more than about half the price of a new system, or the age multiplied by the repair cost passes the price of a new system, it’s time to look at replacement. We’ll give you both numbers and an honest recommendation.

Yes, but R-22 hasn’t been produced or imported in the U.S. since 2020, so only recycled and stockpiled supply is left and it’s expensive. Small repairs that don’t need refrigerant are still worth doing.

If an R-22 system has a leak or needs a major part, replacement is usually the better investment.

SEER2 measures how efficiently an air conditioner or heat pump cools over a season, under more realistic test conditions than the older SEER rating. Higher is more efficient.

Texas is in the Department of Energy’s South region. Since 2023, new central air conditioners there must meet at least 14.3 SEER2 for most home-sized systems (13.8 SEER2 for systems 45,000 Btu/h and larger), and new heat pumps nationwide must meet 14.3 SEER2.

New residential systems are moving from R-410A to lower–global-warming refrigerants such as R-454B and R-32, under the EPA’s HFC phasedown. Existing R-410A systems can still be repaired and serviced.

If you’re replacing a system, the indoor and outdoor equipment need to be matched to the same refrigerant, which is one more reason to replace them as a set.

No. An oversized system cools the air quickly and shuts off before it removes enough humidity, leaving the house cold and clammy, and the constant short cycling wears it out sooner.

The right size comes from a load calculation that looks at square footage, insulation, windows, sun exposure and ductwork, not from the size of the old unit or a rule of thumb.

In most cities, yes. McKinney, Frisco, Allen, Plano and other area cities generally require a mechanical permit and inspection for system replacements. A licensed contractor pulls it as part of the job.

Permits protect you: the inspection checks electrical connections, refrigerant lines, condensate drainage and, for gas, venting. Be wary of anyone who suggests skipping it.

Check it monthly and replace standard 1-inch filters every 1–3 months. Change them more often in peak summer, during construction dust or pollen season, or with pets. Thicker 4–5 inch media filters often last 6–12 months.

A clogged filter is one of the most common causes of frozen coils and high bills. When in doubt, hold it up to the light: if you can’t see through it, replace it.

Twice a year is ideal here: the AC in spring before the heat arrives, and the heating in the fall before the first cold snap.

A tune-up catches weak capacitors, dirty coils, clogged drains, worn contacts and safety issues while they’re inexpensive fixes, not emergency calls on the hottest day of the year.

A good tune-up checks electrical components (capacitors, contactors, connections), refrigerant performance, the outdoor and indoor coils, the condensate drain and safety switch, blower operation, thermostat function and the filter.

It should end with a clear report of what was found and anything that’s close to failing, not a high-pressure sales pitch.

Musty smells usually come from moisture: a dirty evaporator coil, a slow drain pan, or mold growth in the ducts or air handler. In humid weather, an oversized system that short cycles can add to the problem.

Cleaning the coil and drain and fixing the source of moisture usually solves it. Sprays and fragrances only mask it.

Generally no. Closing more than a couple of vents increases pressure in the ductwork, which can reduce airflow, increase duct leakage and, in cooling season, help freeze the coil.

If certain rooms are always too hot or cold, it’s a balancing or ductwork issue worth fixing properly.

Not routinely. Duct cleaning is worth it if there’s visible mold, pests, or heavy debris after construction or a remodel. For most homes, good filtration and sealing duct leaks do more.

Leaky or disconnected attic ducts are a bigger problem in North Texas. They pull hot attic air into the system and waste cooling you’re paying for.

A breaker that trips when the AC starts can mean a failing capacitor, a compressor straining to start, a shorted fan motor, loose wiring, or a breaker that’s worn out. Reset it once.

If it trips again, leave it off and call for service. Repeatedly resetting a breaker on an electrical fault can damage the compressor or create a fire hazard.

Use the Texas Department of Licensing and Regulation (TDLR) license search and look for an Air Conditioning and Refrigeration Contractor license. TDLR licenses and regulates HVAC contractors in Texas.

4Square Heat and Air’s license number is TACLB108423E. A Class B license covers systems up to 25 tons of cooling and 1.5 million Btu/h of heating, which includes residential systems and many light commercial ones.

They’re Texas air conditioning contractor license prefixes. TACLA is a Class A license with no size limit. TACLB is a Class B license for systems up to 25 tons of cooling and 1.5 million Btu/h of heating.

The letter after the number shows the endorsement, such as environmental air conditioning. Either class covers typical homes.

The equipment brand, model numbers and efficiency ratings, the size (tons and Btu), what’s included (thermostat, line set, pad, drain, electrical, permit, haul-away), labor, warranty terms and the total price.

Comparing quotes is much easier when they’re itemized. Be cautious of a price given over the phone without anyone looking at the house.

Call (469) 556-0507 and we’ll give you an honest arrival time. Neighbors on Nextdoor mention same-day and same-morning fixes, and we always work to get your home comfortable as quickly as possible.

Tell us what the system is doing when you call, such as no cooling, water leaking, or a breaker tripping, so we can bring the right parts.

We’re based between McKinney and Princeton and serve Collin County, including McKinney, Princeton, Frisco, Allen, Plano, Murphy, Melissa, Anna, Wylie, Prosper, Fairview, Lucas and Farmersville.

Not sure if you’re in range? Call and ask.