The average DFW household electric bill in August runs $250–$400, and in larger homes or older systems it can exceed $500. For most households, the HVAC system accounts for 50–65% of total electricity use in summer. That means if your bill is unusually high, your air conditioner is almost certainly the primary culprit. Here are the most common HVAC-related causes of high August bills — and what you can do about each.
1. Dirty Condenser Coil
Your outdoor condenser unit works by dumping the heat from inside your home into the outdoor air. If the coil fins are caked with cottonwood fluff, grass clippings, dust, or debris from months of summer operation, heat cannot escape the system efficiently. The compressor has to run longer and harder to reach the same cooling effect — meaning more electricity for the same result. A single coil cleaning can reduce cooling energy consumption by 10–15%.
2. Low Refrigerant Charge
A system running with a slow refrigerant leak is less efficient than a properly-charged system. Low refrigerant means reduced heat transfer capacity, so the system runs longer to cool the same space. On a per-degree-of-cooling basis, a system at 80% refrigerant charge consumes significantly more electricity than a fully-charged system. If your bill has spiked from last August without a change in usage habits, a refrigerant check is worth having.
3. Clogged Evaporator Coil
Over time, dust and biological growth accumulate on the indoor evaporator coil — even with regular filter changes. A dirty evaporator coil insulates the refrigerant from the air passing over it, reducing heat absorption. The system runs longer and pulls more electricity to compensate. Evaporator coil cleaning requires a technician and access to the air handler cabinet, but it can meaningfully reduce runtime and electricity consumption.
4. Duct Leakage Into the Attic
In August, your attic is 140–150°F for most of the afternoon. Every cubic foot of cooled air that leaks out of your supply ducts into that attic environment is energy wasted — and the leaked heat radiates down through the attic floor and into your living space, adding to the cooling load. The Department of Energy estimates that duct leakage in typical homes wastes 20–30% of cooling energy. Sealing and insulating your ductwork is one of the highest-ROI HVAC improvements available in a DFW home.
5. An Aging System Running Beyond Its Rated Efficiency
A 15-year-old system rated at 14 SEER may be operating at effectively 9–10 SEER after years of degradation, dirty coils, and minor refrigerant losses. A new 18 SEER2 system would use roughly 40% less electricity for the same cooling load. If your system is more than 12–15 years old and your summer bills have been climbing year-over-year, the math on replacement may favor action sooner rather than later — particularly with the federal tax credits available on qualifying systems under the Inflation Reduction Act.
6. Thermostat Setting and Schedule
Every degree lower you set your thermostat adds roughly 3% to your cooling cost. Raising the setpoint from 72°F to 76°F during peak afternoon hours (2–7pm) can reduce cooling costs by 10–12%. A smart thermostat makes this effortless with automated scheduling — pre-cooling your home in the morning when electricity is cheaper and letting the temperature drift up slightly during the hottest part of the day.
Get a Free Efficiency Assessment
If your August electric bill is higher than it should be, a NewRise technician can evaluate your system's efficiency, check refrigerant levels, inspect coils, and give you a written summary of what is driving the cost and what the fixes are. Schedule a diagnostic call today. Comfort Club members receive a 15% discount on any service.