How to Keep Your Energy Cost Low During the Texas Summer

In a typical San Antonio home the air conditioner accounts for half or more of the summer electric bill. That makes it the single biggest lever you have. The good news is that most of what drives the bill up is fixable without buying a new system. Here is what actually moves the number, in rough order of impact.

Stop the heat before it gets in

Attic insulation and radiant barrier are the biggest structural wins in this climate. A San Antonio attic hits 140 degrees in July, and an under-insulated ceiling pours that heat straight into the living space. Bringing attic insulation up to R-38 or better and adding a radiant barrier can cut cooling load 15 to 25 percent. Solar screens on west-facing windows and blackout shades in bedrooms are cheaper and still meaningful.

Fix the ducts

Leaky ductwork in a hot attic is the most common efficiency problem we find. Twenty percent leakage means one in five dollars of cooling goes into the attic. Sealing with mastic, insulating exposed runs, and adding a return in a starved house often does more than a higher SEER rating and costs a fraction of a new system.

Keep the system clean and charged

A dirty evaporator coil, a clogged condenser, and a refrigerant charge one pound low can together cost 20 to 30 percent of efficiency. A spring tune-up with coil cleaning brings the system back to its rated performance. Replace the filter every 30 to 60 days in summer.

Use the thermostat correctly

Seventy-eight when home, 80 to 82 when away, fan on auto, and no constant adjusting. Each degree is 3 to 5 percent of the cooling cost. Pre-cool before the hottest part of the day if you are on a time-of-use rate, and let the house coast through peak pricing.

Take the load off

Ceiling fans let you raise the set point two or three degrees with no loss in comfort, and they cost about a penny an hour. Run the dishwasher, dryer, and oven in the evening. Switch remaining incandescent bulbs to LED; they run cool. Seal the gap under exterior doors and around the attic hatch. Keep the garage door closed if the air handler is in the garage.

Check the CPS Energy programs

CPS Energy has offered rebates for high-efficiency equipment, smart thermostats, attic insulation, and duct sealing, plus demand response programs that pay for allowing brief thermostat adjustments during peak events. Programs change, so check the current list before starting a project. Ask us which ones apply to the work you are planning.

When replacement is the answer

If the system is over 12 years old, uses R-22, and needs repairs every summer, a properly sized high-efficiency replacement will cut cooling costs 30 to 40 percent and stop the repair bills. Read our post on the efficiency of modern HVAC units for the numbers, and use our system builder to see what a replacement would cost for your home.

Where to start

A spring inspection with a duct evaluation tells you which of these will pay off fastest in your particular house. Our inspection service includes a written list of recommendations in priority order. Call 210.549.4839 and we will help you get the summer bill under control.