A bill that jumps by a third with no obvious change in how you live the house is unsettling, and the usual first instinct is to suspect a billing error. Occasionally that is the answer. Far more often the cause is sitting in the attic, the closet, or the yard, drawing more power than it did last year.
Working out which requires comparing the right things and then narrowing systematically. Here is how.
Compare Against the Right Month
Comparing this month to last month tells you almost nothing in a climate like this one. May and August are different seasons as far as your equipment is concerned.
Compare against the same month last year. That holds the weather roughly constant and isolates changes in the house rather than changes in the calendar.
Then check two things on the bill itself. The number of days in the billing period varies, and a 34 day cycle costs noticeably more than a 28 day cycle at the same daily usage. And check the rate. Utilities adjust rates and fuel adjustment charges periodically, so a higher bill at identical usage means the price changed, not your consumption.
Most bills show kilowatt hours used alongside the dollar figure. That number is what matters for diagnosis, because it is the one your equipment controls.
Cooling Is Most of Your Bill Here
In South Louisiana, air conditioning typically accounts for the largest share of household electricity use, and the season runs long enough that it dominates most of the year.
That has a useful consequence for troubleshooting. A large unexplained increase is far more likely to originate in the cooling system than anywhere else, simply because that is where most of the power goes. A refrigerator that becomes 20 percent less efficient barely registers. An air conditioner that becomes 20 percent less efficient is obvious on the bill.
It also means small degradations matter. A system running at reduced efficiency for 3,000 hours a year accumulates a cost that the same fault would never produce in a climate with a three month cooling season.
Signs the AC Is the Cause
Several faults raise consumption without stopping the system, which is why they go unnoticed until the bill arrives.
- Longer run times. If the system runs nearly continuously on days it used to cycle, capacity has fallen.
- Low refrigerant. A system with a leak still cools, just less per hour of operation, so it runs longer for the same result.
- A dirty condenser coil. When the outdoor coil cannot reject heat, head pressure rises and the compressor draws more current for the same output.
- A restricted filter or duct. Reduced airflow means less heat moved per hour.
- A failing capacitor. Motors that struggle to start draw heavily during each attempt.
- Short cycling. Frequent starts consume far more than steady running, because inrush current at startup is several times the running current.
A system that used to hold the house comfortably and now cannot quite get there is telling you the same thing the bill is. Annual AC maintenance exists largely to catch these before they run for a full season.
Electric Heat Strips
This is the single most common cause of a shocking winter bill, and it catches people out because the house feels fine.
Heat pumps move heat rather than generating it, which is efficient. When outdoor temperatures drop far enough, or when the compressor cannot keep up, auxiliary electric resistance heat strips engage. Those strips are essentially large toasters, and they consume several times what the compressor does.
Two situations run them more than necessary. Emergency heat left engaged after a cold snap bypasses the compressor entirely and runs on strips alone. And a thermostat set back sharply overnight, then raised in the morning, triggers strips because the compressor alone cannot recover that many degrees quickly.
If your winter bills are disproportionate to a mild winter, check whether emergency heat is on, and consider smaller setbacks. Our heat pump service includes checking that auxiliary heat is staged correctly rather than engaging whenever the thermostat feels behind.
The Water Heater
An electric water heater is usually the second largest consumer in the house.
The failure that raises bills without any obvious symptom is a failed upper or lower element combined with a stuck thermostat, which leaves one element running far longer than it should. Sediment accumulation has the same effect, because the burner or element has to heat through a layer of scale before reaching the water.
A leaking hot water fixture is an underrated cause. A tap dripping hot water runs the heater continuously in the background, and a leak inside a wall can do this invisibly for months.
If the tank is warm to the touch along its sides, insulation has degraded and it is losing heat continuously.
Phantom Loads and Standby Draw
Devices that are off but plugged in still draw power. Individually the amounts are trivial. Collectively, in a house with a lot of electronics, standby draw can account for a meaningful slice of the bill.
The larger offenders are set top boxes, gaming consoles left in instant-on mode, older desktop computers, and anything with a permanently illuminated display. Chargers left plugged in with nothing attached draw very little, despite their reputation.
This is rarely the explanation for a sudden jump, though. Standby draw is constant, so it raises the baseline rather than causing a spike.
Pumps, Outbuildings and Forgotten Circuits
Look for the things that run unattended.
A well pump cycling because of a small leak somewhere in the plumbing runs many times a day with nobody noticing. A pool pump left on a longer schedule than necessary is a substantial continuous load. A freezer in a hot garage works far harder than the same freezer indoors, and an old one with degraded door seals runs almost constantly.
Outbuildings deserve a look too. A shop light left on, a heater in a pump house, or a dehumidifier running in a crawlspace all add up and none of them are visible from inside the house.
Insulation and Duct Losses
Sometimes the equipment is fine and the house is the problem.
Ductwork running through an attic loses cooled air through leaks and through inadequate insulation. Attic temperatures here exceed 130 degrees on summer afternoons, so every foot of poorly insulated duct is a heat exchanger working against you.
A duct that has separated at a joint dumps conditioned air into the attic outright. A return that has come loose pulls superheated attic air into the system, which the equipment then has to cool.
Attic insulation that has settled, been disturbed by work, or been compressed by storage performs well below its rating. Gaps around recessed lights, attic hatches and plumbing penetrations let conditioned air escape continuously.
A Failing Motor
Any motor drawing more current than designed raises consumption while continuing to work.
Bearings that have worn, a blower wheel packed with dust, a fan motor running hot, or a compressor with degraded windings all fall into this category. The symptom is often a noise that developed gradually enough that nobody registered it as new.
If a motor anywhere in the house has become louder over the past year, that is worth investigating, and it usually points at a repair that is cheaper than the failure it precedes.
Narrowing It Down
A systematic approach beats guessing.
- Pull 12 to 24 months of kilowatt hour history from your utility account and look at the shape rather than the dollars.
- Establish whether the increase is seasonal, which points at heating or cooling, or constant, which points at a base load.
- Turn the HVAC off for a day when weather permits and compare daily usage if your utility reports it.
- Check the water heater for warmth at the tank and any dripping hot fixture.
- Walk the property looking for anything running that should not be.
- Have an electrical and HVAC check done if the increase has no obvious source.
When a High Bill Is a Warning
Some causes are safety issues rather than cost issues, and they deserve faster attention.
A circuit that draws heavily because of a fault generates heat at the fault point. Loose connections, damaged conductors, and failing equipment all consume power as heat, and heat inside a wall or a panel is how electrical fires start.
If a higher bill comes alongside warm outlets, flickering lights, a buzzing panel, or a burning smell, treat those symptoms as the priority and the bill as secondary.
Final Thoughts
A large jump in a Louisiana electric bill usually traces back to cooling, heating strips, or a water heater, in roughly that order. Comparing kilowatt hours against the same month last year, rather than against last month, is what makes the pattern visible.
What makes this worth chasing rather than absorbing is that most causes are faults rather than lifestyle changes, and faults get worse. A system running longer this year will run longer still next year.
One Way AC & Heating provides air conditioning and electrical service across South Louisiana, including Houma, Thibodaux, and Metairie. Estimates are free and the price is agreed before work begins.