Why Texas Heat Waves Spike Business Electric Bills

The week of July 20, 2026 was one for the record books. While Tropical Storm Bertha fizzled out over the Gulf before reaching the Texas coast, the real story was on land: Houston logged its first 100°F day in nearly a year, hit 104°F under an Extreme Heat Warning with heat index values near 115°F, and on July 22 the ERCOT grid blew past 91 gigawatts of demand for the first time in its history — shattering the previous all-time record of roughly 85.5 GW set in August 2023.

The grid held. There were no conservation calls, and wholesale prices stayed well below the cap. But for Texas businesses, the bill that arrives after a week like this is another matter. If you're asking why your business electric bill is so high in summer, the answer isn't simply "the AC ran more." Extreme heat raises commercial electricity costs through three separate mechanisms — and each one calls for a different response.

Mechanism 1: Cooling Load — You Simply Use More kWh

The most visible driver is volume. HVAC is the largest single load in most commercial buildings, and consumption in June through September typically runs 30% to 50% above the spring and fall shoulder months. Every degree of outdoor heat above your system's design temperature forces compressors to run longer and less efficiently, so a 104°F afternoon doesn't just add a little load — it compounds it.

Some businesses can trim around the edges. Many can't. Restaurants fighting kitchen heat, hotels with occupied rooms, medical offices with equipment and patient-comfort requirements, and gyms full of members absorb the extra kilowatt-hours almost entirely. For these operations, the question isn't whether summer usage rises — it's what rate structure that usage lands on.

Mechanism 2: 4CP and Demand Charges — Your Worst 15 Minutes Cost You All Year

The second mechanism is less visible and often more expensive. In ERCOT, annual transmission costs are allocated through the Four Coincident Peak (4CP) program: your facility's demand during the single highest 15-minute grid-wide interval in each of June, July, August, and September determines a large share of your transmission charges for the following year.

Here's the catch: those four intervals land on exactly the kind of days a heat wave produces — hot weekday afternoons, roughly 2 to 7 p.m. A record week like July 2026 is precisely when your 4CP exposure gets set. For large commercial accounts, 4CP-driven charges can represent 15% to 30% of the total bill, and demand-related charges broadly can run 30% to 70%. A single un-curtailed peak during one of those windows can cost tens of thousands of dollars over the following year.

If demand charges are new territory, start with our full explainer on what a demand charge is and how it's calculated, then look at load factor — the ratio of your average to peak demand that determines how hard these charges hit you.

Mechanism 3: Wholesale Price Volatility — What Heat Does to the Market

The third mechanism plays out in the wholesale market. When triple-digit heat pushes demand toward the grid's limits, real-time prices become volatile — especially in the 6 to 9 p.m. window, when solar output falls off while air-conditioning load stays high. The July 2026 record week was actually a calm version of this story: reserves held and prices stayed low. But that's the exception heat-wave buyers should not count on, as anyone who remembers past scarcity events knows.

Who eats this volatility depends entirely on contract structure. Businesses on an index rate or variable plan pay spot-market prices directly — a scorching week flows straight into their bill. Businesses on a fixed rate are insulated on the supply side, though not from demand and delivery charges. Our guides to how ERCOT wholesale pricing works and fixed vs. variable rates cover the mechanics.

What a Heat Wave Adds Up to on a Real Bill

Consider a facility that normally peaks at 500 kW and uses 150,000 kWh in a shoulder month. In a heat-wave month, the three mechanisms stack:

• More kWh: usage rises ~35% to roughly 202,500 kWh. At a fixed $0.08/kWh, the energy charge alone climbs from $12,000 to about $16,200.
• A higher peak: cooling load pushes the facility's peak from 500 kW toward 575+ kW — and if that new peak lands in a 4CP interval, it raises transmission-related charges for the next year, not just this month.
• Market exposure: if the facility is on an index rate, the kWh consumed during peak-priced evening hours cost several multiples of the off-peak price.

To be clear: there is no universal percentage. The exact impact depends on your rate structure, load factor, and TDU territory. But the pattern is consistent — the businesses hit hardest are the ones exposed on all three fronts at once, usually without knowing it. If you can't tell which charges on your bill are usage, demand, or delivery, our guide to reading your commercial electricity bill is the place to start.

Five Ways Texas Businesses Blunt the Summer Spike

1. Know Your Contract Type Before the Next Heat Wave

Pull your contract and confirm whether you're on a fixed, index, or hybrid structure — and when it expires. If you're on an index rate and didn't choose it deliberately as part of a risk strategy, a heat wave is the market telling you to revisit that decision. A fixed-rate contract converts summer price risk into a known number.

2. Watch 4CP Days and Curtail From 2 to 7 p.m.

ERCOT's likely coincident-peak days are forecastable — they're the hottest weekday afternoons of each summer month. On those days, pre-cool the building in the morning, stagger equipment, and shed non-critical load in the 2–7 p.m. window. Businesses that curtail successfully during the four 15-minute intervals can cut a major line item for the entire following year.

3. Improve Your Load Factor

Flattening your load profile — spreading usage instead of spiking it — reduces every demand-based charge on the bill, not just 4CP. Staggered startups and pre-cooling alone can cut peak demand 15–25% with no operational impact.

4. Don't Let a Contract Expire Into an August Market

Holdover and default rates are at their worst when the market is hot. If your contract ends mid-summer, you'll be shopping — or worse, defaulting — at seasonal price highs. Our guide on when to renew your commercial electricity contract covers why renewal timing is a bigger lever than most operators realize.

5. Shop the Structure, Not Just the Rate

The cheapest per-kWh headline rate can still produce the most expensive summer if the contract handles demand, swing, and peak pricing badly. An energy broker compares how each contract treats the charges heat actually inflates. Elite shops 25+ REPs on your behalf — and is paid by the REP, not by you.

Frequently Asked Questions

How much more electricity does a business use during a Texas heat wave?

Commercial consumption typically runs 30% to 50% higher in June through September than in shoulder months, and a sustained 100°F-plus week pushes HVAC-dominant buildings toward the top of that range. Restaurants, hotels, medical offices, and gyms — businesses that can't simply turn the cooling down — absorb the increase almost entirely.

What is a 4CP charge and why does it hit in summer?

4CP stands for Four Coincident Peaks. ERCOT allocates annual transmission costs based on your demand during the single highest 15-minute grid-wide interval in each of June, July, August, and September — intervals that land on hot weekday afternoons, roughly 2 to 7 p.m. Your demand in those four windows sets a large share of your transmission charges for the following year. See our full demand charge explainer for the mechanics.

Do fixed-rate business contracts protect against heat waves?

Partially. A fixed rate locks your per-kWh energy price, so wholesale spikes don't touch your supply rate. But it doesn't cap how many kilowatt-hours you use, and it doesn't shield you from demand-based TDU delivery charges or 4CP allocations — those are set by your peak load, not your contract.

Did the 2026 Texas heat wave set an ERCOT record?

Yes. On July 22, 2026, air-conditioning demand pushed ERCOT past 91 GW for the first time — preliminary figures showed roughly 91.3 GW near 5 p.m. — surpassing the previous record of about 85.5 GW from August 2023. ERCOT's summer 2026 forecast had already projected peaks between 90.5 and 98 GW, driven by population growth, data centers, and industrial expansion. The grid held under normal conditions with no conservation calls.

When are ERCOT peak hours during a heat wave?

Grid demand peaks on hot weekday afternoons, roughly 2 to 7 p.m. — which is when 4CP intervals are set. Wholesale price volatility often stretches later, into the 6 to 9 p.m. window, as solar output falls while air-conditioning load remains high.

The Bottom Line

You can't control a 104°F week, and Texas summers are trending hotter, not cooler — ERCOT's own forecasts assume demand records will keep falling. What you can control is the structure that heat lands on: your rate type, your renewal timing, and your peak behavior during the handful of 15-minute intervals that set next year's charges. Businesses that get those three right treat a record heat wave as a line item. Businesses that don't find out about all three mechanisms at once, on one bill.