Energy Savings
How to Reduce Cooling Costs in the Rio Grande Valley
Fourteen ways to cut summer electric bills in South Texas, ranked from free to expensive, with an honest assessment of what each one is actually worth.
By A&A HVAC LLC Editorial Team, Licensed HVAC Technicians serving the Rio Grande Valley
Cooling accounts for more than half of a typical Rio Grande Valley summer electric bill. That means almost every worthwhile saving comes from one of two places: reducing how much heat gets into your house, or improving how efficiently your system removes it.
Here are fourteen things that work, ordered from free to expensive, with an honest note on what each is actually worth.
Free
1. Set the fan switch to AUTO, not ON
Check this first. It takes five seconds and it is one of the most common silent costs we find.
With the fan set to ON, the blower runs continuously. After the compressor cycles off, the evaporator coil is still wet with condensate, and continuous airflow evaporates that moisture straight back into your house. You pay to remove humidity and then pay again to remove it a second time.
Set it to AUTO.
2. Close blinds on the south and west sides in the afternoon
Solar gain through glass is one of the largest loads on a Valley home. Unshaded west facing windows on a July afternoon can add the equivalent of a significant fraction of a ton of cooling.
Closing blinds or curtains costs nothing and produces a noticeable difference in rooms on the sunny side.
3. Use ceiling fans, but only in occupied rooms
A fan does not cool a room. It makes people feel roughly three to four degrees cooler by moving air across skin. That is enough that many households can sit comfortably a degree or two higher on the thermostat.
Running fans in empty rooms is pure waste, because the motor adds a small amount of heat and cools nobody.
4. Raise the thermostat one degree
Every degree matters more here than in a mild climate, because the system runs so many more hours. Combined with fans, going from 75 to 76 or 77 is often unnoticeable in comfort and clearly visible on the bill.
5. Use a moderate setback while away
Four to six degrees, not off. Turning the system off entirely in this humidity lets the structure soak up heat and lets indoor humidity climb, and recovering both usually costs more than the setback saved.
6. Keep interior doors open
A bedroom with a supply register, a closed door, and no return path pressurizes and stops accepting air. The rest of the house then gets overcooled while that room stays warm.
If doors must stay closed, undercut them or add a transfer grille.
7. Shift heat producing activities to the evening
Ovens, stovetops, dryers, and dishwashers all add heat and moisture. Running them at 3pm on a July afternoon adds load exactly when your system is already at its limit. Running them at 9pm is cheaper.
Use the range hood and bathroom exhaust fans so that moisture leaves rather than becoming your air conditioner's problem.
Cheap
8. Change the filter on schedule
A restricted filter makes the blower work harder and cuts airflow across the coil, which reduces capacity and, in bad cases, freezes the coil entirely.
Check a one inch filter monthly. In the Valley, expect to replace it every 30 to 60 days, sooner during dusty stretches or with pets.
9. Rinse the condenser coil
The outdoor coil rejects your house's heat into the air. Packed with dust, grass clippings, and lint, it cannot, so head pressure climbs and efficiency drops.
With the breaker off, rinse gently with a garden hose from the inside out. Never use a pressure washer, which flattens the fins and makes the problem permanent. Twice a year is enough in most of the Valley.
10. Clear two feet around the outdoor unit
Vegetation, stored items, and fences too close to the unit restrict the airflow it needs to reject heat. This one is free if you already own hedge trimmers.
11. Get a spring tune up
A proper cooling tune up restores efficiency lost to a low refrigerant charge, a dirty coil, weak capacitors, and restricted airflow. In a climate where the system runs eight months a year, returning it toward its rated efficiency shows up on the bill.
Schedule it February through early April, before the rush.
Worth the money
12. Seal the ductwork
This is the highest return improvement available to most Valley homes.
Typical residential duct systems lose 20 to 30 percent of their air to leaks. Here that is worse than the percentage implies, because attic temperatures regularly exceed 130 degrees. Supply leaks dump cooled air into that oven, and return leaks pull the superheated attic air into your system. Both losses compound.
Sealing is done with mastic, not cloth duct tape, which dries out and releases within a few years in attic heat. Ask for static pressure to be measured before and after so the improvement is demonstrated rather than claimed.
13. Add attic insulation and solar screens
Attic insulation is one of the more reliable improvements in this climate. If you can see the tops of the ceiling joists, you do not have enough.
Exterior solar screens on west facing windows are also strong value here, because they stop solar heat before it passes through the glass rather than after.
14. Upgrade equipment, with realistic expectations
Replacing a 12 to 15 year old system with modern equipment usually produces a substantial improvement, both because efficiency standards have risen and because an aging system has drifted well below its original rating.
Two honest caveats.
First, installation quality and correct sizing affect your real world bill more than the last few points of efficiency rating do. A carefully installed mid efficiency system beats a carelessly installed high efficiency one.
Second, a new system on leaking, undersized ducts cannot deliver what it promises. Fix the distribution system first, or at the same time.
What to do in what order
If you are starting from scratch, this sequence gets the most for the least:
- Set the fan to AUTO and close afternoon blinds today
- Change the filter, rinse the coil, clear around the outdoor unit this weekend
- Adjust the thermostat schedule and start using fans in occupied rooms
- Book a spring tune up
- Have static pressure measured and the ducts inspected
- Seal ducts and add attic insulation
- Consider equipment replacement when the current system reaches end of life
Most households find that steps one through five change the bill more than they expected, and that step seven becomes a planned decision rather than an emergency one.
The short version
Free changes to how you run the system, plus a clean filter and coil, plus sealed ductwork, will do more for a Valley electric bill than most people expect. Equipment efficiency matters, but it is the last step, not the first.
- energy savings
- electric bill
- efficiency
- summer
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A&A HVAC LLC covers McAllen and the Rio Grande Valley, 24 hours a day.
Reviewed by the A&A HVAC LLC service team, licensed HVAC technicians serving McAllen and the Rio Grande Valley.
Last reviewed for accuracy on . Guidance here is general. Diagnosis of your specific system requires an on site inspection.