Effective Rate vs Advertised Rate for Electricity Plans

The difference between advertised and effective rates

When an electricity supplier advertises “8.99¢/kWh,” that number is designed to attract your attention. It's a marketing number. Whether it represents what you'll actually pay depends on the fine print.

The advertised rate is the headline number — the lowest, most attractive figure the supplier can legally claim. It might apply only during an introductory period, only up to a certain usage level, or only before monthly fees are added.

The effective rateis what you actually pay per kWh over the full contract term, accounting for all costs and conditions. It's the single number that lets you accurately compare any two plans regardless of their underlying structure.

This guide teaches you to calculate the effective rate. Once you internalize this math, no teaser rate will fool you again.

Common ways advertised rates mislead

Four common pricing structures create gaps between the advertised rate and what you actually pay.

1. Introductory periods (teaser rates)

The most significant gap. An introductory rate — 7.59¢/kWh — applies only for the first month or first few months. After that, the rate resets to a higher standard rate — perhaps 14.99¢/kWh. The supplier advertises 7.59¢, but you'll pay 7.59¢ for one month and 14.99¢ for eleven months.

2. Tiered pricing

Tiered plans charge different rates at different usage levels. You might pay 8.99¢ for the first 500 kWh and 12.99¢ for everything above that. If you use 850 kWh/month, your effective rate is higher than 8.99¢ — you're paying 12.99¢ for 350 of those kilowatt-hours.

3. Monthly fees

Some plans charge a flat monthly fee — $5.95, $9.95, $14.95 — in addition to the per-kWh rate. This fee doesn't appear in the advertised rate per kWh, but it adds significantly to your effective cost. At average usage, a $10/month fee adds more than 1¢ to your effective rate.

4. Bill credits with usage requirements

Some plans offer credits — $50 bill credit, $25 rebate — that require meeting certain conditions. You might need to stay enrolled for 6 months, use more than a minimum kWh threshold, or sign up through a specific channel. If you don't meet the conditions, the credit disappears — but you're still locked into the contract.

Worked examples: seeing through the numbers

Let's calculate effective rates for several plans to see how this works in practice. We'll assume average Pennsylvania residential usage of 850 kWh/month.

Example 1: Teaser rate vs. fixed rate

Plan A: 7.59¢/kWh for month 1, then 14.99¢/kWh for months 2-12. 12-month term.

Plan B: 9.09¢/kWh fixed for 12 months. No monthly fee.

At first glance, Plan A looks better — 7.59¢ is much lower than 9.09¢. But let's calculate the effective rates.

Plan A calculation:

• Month 1: 850 kWh × 7.59¢ = $64.52
• Months 2-12: 850 kWh × 14.99¢ × 11 months = $1,401.57
• 12-month total: $64.52 + $1,401.57 = $1,466.09
• Total kWh: 850 × 12 = 10,200 kWh
• Effective rate: $1,466.09 ÷ 10,200 = 14.37¢/kWh

Plan B calculation:

• 12-month total: 850 kWh × 9.09¢ × 12 = $927.18
• Effective rate: 9.09¢/kWh

Result:Plan B saves $538.91 over 12 months despite the “higher” advertised rate. Plan A's teaser rate is marketing; Plan B's rate is real.

Example 2: Tiered pricing

Plan C: 8.99¢/kWh for first 500 kWh, 12.99¢/kWh above 500 kWh. No monthly fee.

At 850 kWh usage:

• First 500 kWh: 500 × 8.99¢ = $44.95
• Next 350 kWh: 350 × 12.99¢ = $45.47
• Monthly total: $44.95 + $45.47 = $90.42
• Effective rate: $90.42 ÷ 850 = 10.64¢/kWh

The advertised rate is 8.99¢. The effective rate at typical usage is 10.64¢. That's 1.65¢/kWh higher — $168 per year on 850 kWh monthly usage.

Example 3: Monthly fee impact

Plan D: 9.09¢/kWh + $9.95/month fee. 12-month term.

At 850 kWh usage:

• Monthly supply cost: 850 × 9.09¢ = $77.27
• Monthly fee: $9.95
• Monthly total: $77.27 + $9.95 = $87.22
• Effective rate: $87.22 ÷ 850 = 10.26¢/kWh

The $9.95 fee adds 1.17¢/kWh to the effective rate. A plan advertising 9.09¢ with that fee costs more than a simple 10¢ plan with no fee.

The fee impact varies with usage. At 1,500 kWh/month, the $9.95 fee adds only 0.66¢/kWh. At 500 kWh/month, it adds 1.99¢/kWh. Low-usage households are hit hardest by monthly fees.

Example 4: Conditional bill credit

Plan E: 10.99¢/kWh, 12-month term, $100 bill credit applied after 6 months of enrollment.

At 850 kWh usage:

• 12-month supply cost: 850 × 10.99¢ × 12 = $1,121.22
• Bill credit: −$100.00
• Net cost: $1,121.22 − $100.00 = $1,021.22
• Total kWh: 10,200
• Effective rate: $1,021.22 ÷ 10,200 = 10.01¢/kWh

The credit brings the effective rate to 10.01¢ — competitive, but only if you collect the credit. If you cancel before month 6 or fail to meet any other conditions, you pay the full 10.99¢ effective rate.

A simple framework for comparing any plan

Use this four-step process to calculate the effective rate for any electricity plan:

Step 1: Identify ALL costs

Read the Plan Information Document. List every cost component:

• Per-kWh rate (check for tiers or introductory periods)
• Monthly fees
• Any usage-based adjustments
• Credits (and their conditions)

Step 2: Calculate total cost over the full term

Using your expected monthly usage (check your bills for historical average), calculate what you'll pay each month of the contract. Sum all months to get total contract cost.

Step 3: Calculate total kWh over the term

Multiply your monthly usage by the number of months. This is your denominator.

Step 4: Divide total cost by total kWh

This gives you cents per kWh — your effective rate. Compare this single number across all plans you're considering.

The lowest effective rate is the best deal, assuming similar contract terms (length, ETF, renewal conditions). If two plans have similar effective rates, prefer the simpler pricing structure — fewer things can go wrong.

Quick reference formulas

Converting monthly fee to per-kWh equivalent:

Fee per kWh = Monthly fee ÷ Monthly kWh usage

Example: $9.95 fee ÷ 850 kWh = 1.17¢/kWh

Weighted average for introductory rates:

Effective rate = [(Intro rate × Intro months) + (Standard rate × Remaining months)] ÷ Total months

Example: [(7.59¢ × 1) + (14.99¢ × 11)] ÷ 12 = 14.37¢/kWh

Tiered pricing at specific usage:

Effective rate = [(Tier 1 rate × Tier 1 kWh) + (Tier 2 rate × Tier 2 kWh)] ÷ Total kWh

Example: [(8.99¢ × 500) + (12.99¢ × 350)] ÷ 850 = 10.64¢/kWh

Pennsylvania-specific notes

In Pennsylvania, PA Power Switch lists rates as advertised by suppliers. The site shows the headline rate, but may not prominently display monthly fees, tiers, or introductory period details. Always click through to the full Plan Information Document before enrolling.

Your utility's Price to Compare is a true per-kWh rate with no monthly fees or tiers — it's apples-to-apples comparable to any effective rate you calculate. If a supplier's effective rate is higher than the PTC, the plan doesn't save you money.

Frequently asked questions

Why does my actual bill differ from the advertised rate?

The advertised rate covers only the per-kWh supply charge. Your total bill includes delivery charges from your utility, various fees and taxes, and potentially monthly supplier fees that aren't in the per-kWh rate. Additionally, if you're on a tiered or introductory plan, your average rate may differ from the headline number. The effective rate calculation accounts for supply-side costs; delivery charges remain separate.

How do I calculate the effective rate of a tiered plan?

Multiply each tier's rate by the kWh you expect to use in that tier, sum the results, then divide by your total usage. Example: Plan charges 8.99¢ for first 500 kWh and 12.99¢ above that. At 850 kWh usage: (500 × 8.99¢) + (350 × 12.99¢) = $44.95 + $45.47 = $90.42. Effective rate: $90.42 ÷ 850 = 10.64¢/kWh. The headline 8.99¢ understates the true cost.

Are monthly fees considered part of the electricity rate?

Monthly fees should be converted to a per-kWh equivalent to make fair comparisons. A $9.95/month fee at 850 kWh average usage adds 1.17¢/kWh to your effective rate. A plan at 9.09¢ with a $9.95 fee has an effective rate of 10.26¢/kWh — higher than a simple 10¢ plan with no fee. Always factor monthly fees into your comparison.

What's the difference between a teaser rate and an introductory rate?

They're the same thing with different connotations. “Introductory rate” is the industry term for a promotional rate that applies only during an initial period. “Teaser rate” is the consumer-advocacy term for the same practice, emphasizing that the rate is designed to attract sign-ups rather than represent ongoing cost. Both describe a low initial rate that resets to a higher standard rate after a promotional period.

How do I compare plans with different rate structures?

Convert every plan to a single effective rate using your expected monthly usage and the full contract term. Include all costs: per-kWh rates (with tiers and intro periods), monthly fees, and any credits with conditions. The resulting cents-per-kWh number is directly comparable across plans regardless of their underlying structure. The lowest effective rate wins.