How to Prepare Your HVAC System for DFW’s Hot Summer Days

When the Texas heat shows up, your air conditioner doesn't just need to run. It needs to run hard. If you want cool, consistent comfort without unexpected breakdowns or spiking energy bills, early-season prep is essential. But despite all the DIY guides out there, the truth is proper HVAC prep isn’t something most homeowners can or should handle on their own.

Here’s what you can check and do for yourself and what should always be left to the pros.

Swap Out Your Filter—and Set a Reminder to Keep It Fresh

One of the AC maintenance tasks the vast majority of DFW homeowners can handle on their own is replacing their air filter. A clogged filter doesn’t just reduce airflow; it can cause your evaporator coil to freeze and your system to work much harder to cool your home, especially in extreme heat.

We recommend setting a calendar alert or phone alarm for every 30, 60 or 90 days depending on your preference and household needs. If you're unsure what size or type of filter your system needs, or whether the higher-end filters are worth the price, our team at Tom’s Mechanical can point you in the right direction.

Give the Outdoor Unit Some Breathing Room

Leaves, grass clippings and weeds crowding your condenser can reduce airflow and cause your system to run less efficiently. Homeowners can gently remove this debris with a gloved hand or light brush—but avoid using a hose or trying to clean the fins yourself. Those components are delicate and easily damaged without the right tools.

What’s That Smell? It Could Be a Warning Sign

If you notice a faint burning or “hot plastic” smell when your AC turns on for the first time this spring or summer, don’t ignore it. While a brief odor could be harmless, a persistent burning smell may point to fraying wires, an overheating motor or other electrical problems inside your system. These kinds of issues can escalate quickly, and they’re definitely not a DIY fix. If something smells off, it’s best to shut the system down and call a professional to inspect it safely.

At Tom’s Mechanical, we treat emergency calls as actual emergencies and go the extra mile to dispatch a technician fast and provide solutions to restore your home’s temperature control and safety.

When Something Sounds Off, It Probably Is

Your ears are often the first line of defense against serious HVAC problems. You’ve likely grown familiar to the sound your AC makes when it cycles on and off, and the steady hum it produces when cooling your home. That familiarity means you're uniquely qualified to notice subtle changes. When a sound doesn’t feel quite right, it’s worth paying attention, especially at the start of cooling season.

Here are some AC sounds that could indicate there’s a problem:

• Buzzing or zapping – A steady buzz may point to electrical problems, like a failing contactor or capacitor. If it sounds more like a zap or pop, it could be a short or arcing wire inside the unit—something that should be addressed immediately before it worsens.
  
  
• Screeching or squealing – These high-pitched sounds can come from a worn-out fan belt or motor bearings in older systems. Even in beltless units, a squeal might mean the motor is struggling and needs lubrication or replacement.
  
  
• Rattling or clanking – Loose hardware, disconnected panels or even a misaligned fan blade can cause a rattling sound that may start small but worsen with every cycle. If left alone, it can lead to serious internal damage.
  
  
• Clicking – A single click at startup is normal, but repeated clicking without the system fully engaging could point to a faulty relay or control board.
  
  
• Hissing – This might indicate a refrigerant leak, particularly when it’s accompanied by weak airflow or uneven cooling. It could also come from high-pressure air escaping a gap in the ductwork near the unit.

When you hear something unusual, don’t try to self-diagnose. Jot down what it sounded like, when it happened and how long it lasted, then call Tom’s Mechanical. The more details you can give our techs, the faster we can pinpoint the issue and get it fixed.

Thermostat Troubles: More Than Just a Bad Setting

A thermostat that seems fine could be part of the problem, especially if you feel like your home is warmer than it should be. Some of the more common thermostat issues include:

• Faulty temperature readings – A miscalibrated thermostat can be off by several degrees, causing your AC to turn on too late or shut off too early. That leads to poor comfort and higher bills.
  
  
• Wiring issues – Loose or corroded wires can interrupt communication between the thermostat and your HVAC system. You might notice short cycling (turning on and off more frequently), total failure to turn on or a fan that runs constantly.
  
  
• Battery failure or display issues – If your battery-powered thermostat screen is blank or unresponsive, it might just need new batteries. If your thermostat is hard wired, there may be a deeper electrical issue. In many cases, thermostat replacement is the easiest and most affordable fix.
  
  
• Outdated or poorly placed thermostats – Older mercury-style thermostats or non-programmable digital models often lack precision and efficiency. They may also be placed in the wrong location, like near a window, exterior door or air vent, making them inaccurate. This is more of a persistent problem rather than a seasonal issue, but it might first become noticeable in the spring or summer after home modifications or thermostat relocation during the fall or winter.
  
  
• Smart thermostat glitches – Internet-connected units like Nest or Ecobee can experience connectivity loss, firmware bugs or integration issues with your system. These issues are more common when they’re not installed properly.
  
  

In some cases, the thermostat is the last thing a homeowner suspects, but there’s a reason it’s the first thing an HVAC technician checks during a maintenance visit. If your home has hot and cold spots, inconsistent cooling or a unit that seems to ignore your settings, your thermostat could be the weak link.

Get Your Dallas–Fort Worth Air Conditioner Ready for Summer

If you live in the DFW area and you haven’t had your air conditioner or heat pump checked yet, now is the ideal time to schedule a maintenance visit. At Tom’s Mechanical, we know how annoying it can be to spend your entire day waiting for a technician to show up. We use text messages to keep you updated and put a premium on great, timely customer service.

Get your air conditioner prepared for summer by calling us at 817-277-4493.