The bill shows Tier 1, Tier 2, baseline, block rate, over baseline, or different prices for different kWh amounts.
A small kWh increase can become expensive if it moves usage into a higher tier. The marginal kWh may cost more than the average kWh shown by the full bill.
Check first
Find tier, block, baseline, or allowance lines on the bill.
Compare usage against the threshold for the higher tier.
Check whether weather, EV charging, heating, cooling, or pool equipment pushed usage over the line.
Separate tiered energy rates from fixed delivery and customer charges.
Practical savings moves
Target the usage that falls into the highest tier first.
Use appliance estimates for the load that pushed the bill over the threshold.
Compare daily kWh so a longer bill does not look like a tier problem.
Use savings math based on the marginal tier rate, not only the average rate.
Avoid these mistakes
Do not use the average bill rate to value the final high-tier kWh.
Do not ignore billing days when comparing tier thresholds.
Do not assume tiered charges are a billing error without checking the rate table.