How Much Will a New AC Save on Your Electric Bill? (Texas Calculator)

Updated 2026-03-27 · DFW Air Cost

How Much Will a New AC Save on Your Electric Bill? (Texas Calculator)

You're thinking about replacing your AC system. Before deciding, you want to know: How much will I actually save on my electric bill?

Let's calculate real savings based on your Texas home.

The Simple Math

Monthly cooling cost depends on three factors:

System size (tonnage): Larger systems use more electricity
System efficiency (SEER2): Higher efficiency uses less electricity
Usage: How many hours per day AC runs

Texas cooling costs (estimated, 2026 electricity rates):

|---------|----------|----------|----------|

| 3-ton | $150-180 | $125-150 | $100-130 |

| 4-ton | $200-240 | $165-200 | $135-170 |

| 5-ton | $240-290 | $200-240 | $160-200 |

These are monthly costs during heavy cooling months (June-August).

Note: Actual costs vary based on your specific electricity rate, thermostat setpoint, home insulation, and system runtime.

How to Calculate Your Specific Savings

You need three pieces of information:

1. Your Current Electric Rate

Check your most recent Oncor bill:

Look for "base rate" or "energy charge"
Typically $0.10-$0.15 per kWh (kilowatt-hour)
DFW average in 2026: ~$0.12/kWh

2. Your Current System's Efficiency (or Estimate)

If replacing an old system:

System built before 2010: Assume ~11 SEER (very inefficient)
System built 2010-2015: Assume ~13 SEER (moderate)
System built 2015-2020: Assume ~15 SEER (decent)

If replacing a recent system, look up the SEER2 rating online using the model number.

3. Your Current Monthly Cooling Cost

Look at your electric bills from June, July, August for last year (or last summer):

Find the average monthly bill during cooling season
This includes all electricity use (lights, appliances, etc.)
AC is typically 40-60% of total summer bill

Estimate: If June/July/August bills are $150/month and total house, AC is likely ~$80-$100/month of that.

Real Examples: Texas Homes

Example 1: Older Home, Plano

Current system: 3-ton, ~11 SEER (replaced 2005)

Current cooling cost: ~$180/month during June-August

Option A - Economy replacement (SEER2 ~13):

New monthly cost: ~$155
Annual savings (6-month season): ($180-$155) × 6 = $150/year

Option B - Midrange replacement (SEER2 ~15):

New monthly cost: ~$130
Annual savings: ($180-$130) × 6 = $300/year

Option C - Premium replacement (SEER2 ~17):

New monthly cost: ~$105
Annual savings: ($180-$105) × 6 = $450/year

System costs (from earlier in blog):

Economy: $10,060 → Payback: 67 years (not viable)
Midrange: $12,560 → Payback: 42 years (not viable)
Premium: $15,163 → Payback: 34 years (not viable)

Wait, why aren't paybacks viable?

Because this home's current system is already relatively efficient (replaced 2005). The jump from ~11 SEER to 15-17 SEER2 is good but not huge. Real payback happens when:

Example 2: Older Home, Dallas (More Realistic)

Current system: 3-ton, ~10 SEER (original 1998 installation, struggling)

Current cooling cost: ~$200/month during June-August

Option A - Economy replacement (SEER2 ~13):

New monthly cost: ~$155
Annual savings: ($200-$155) × 6 = $270/year

Option B - Midrange replacement (SEER2 ~15):

New monthly cost: ~$130
Annual savings: ($200-$130) × 6 = $420/year
System cost: $12,560
Payback: 30 years (not great, but acceptable if staying long-term)

Option C - Premium replacement (SEER2 ~17):

New monthly cost: ~$105
Annual savings: ($200-$105) × 6 = $570/year
System cost: $15,163
Payback: 27 years (okay for very long-term ownership)

Real talk: Electricity savings alone don't justify AC replacement. You replace because:

Old system is failing or failed
Repair costs are high
You want reliability and warranty

Electricity savings are bonus, not primary reason.

Example 3: Two-Story Home, McKinney (High Cooling Load)

Current system: 3-ton undersized (running constantly to keep up), ~13 SEER

Current cooling cost: ~$220/month during June-August

Option A - Properly sized 4-ton, SEER2 ~15:

New monthly cost: ~$160
Annual savings: ($220-$160) × 6 = $360/year
System cost: $13,905
Payback: 39 years

But wait—there's a benefit beyond electricity:

Old system struggles to cool upstairs (undersized)
New system cools properly (comfort improvement)
Dehumidification is better (humidity control)
System lasts 15-20 years vs. old system dying soon

Real value: Not just electricity savings, but reliability, comfort, and warranty.

Monthly Bill Breakdown

Your electric bill during cooling season includes:

Example June bill for Plano home:

Base charge: $15
Energy usage (AC + everything else): $135
Taxes and fees: $15
Total: $165

That $135 breaks down roughly as:

AC system: $70-$90 (50-65% of usage)
Lights, refrigerator, TV, water heating, etc.: $45-$65

When you replace AC and go from 3-ton 11-SEER to 4-ton 15-SEER:

New AC portion: ~$55
Everything else: ~$50 (unchanged)
New total: $120 (rough estimate)

Monthly savings: ~$45-$50 during cooling months

This is the real-world impact.

Seasonal Variation

AC costs vary month to month:

June-August peak: $120-$200/month (peak cooling demand)

May & September: $80-$120/month (moderate cooling)

April & October: $40-$80/month (light cooling)

November-March: $20-$50/month (minimal cooling, heating might factor in)

Total yearly savings from AC replacement:

Add up 6 months × monthly savings
Expected range: $200-$600/year depending on system and home

Payback Period Reality

Truth: Most AC replacements have 15-25 year payback on electricity savings alone.

Why replace then?

Old system is failing: You have no choice
Repair is expensive: $1,000+ repair vs. $12,500 new system, new system makes sense
Warranty protection: New system comes with 10-year warranty (old system is out of warranty)
Reliability: New system runs 15-20 years; old system might fail next summer
Comfort: New system cools better, dehumidifies better, runs quieter

Electricity savings are bonus, not primary reason for replacement.

Comparative Electricity Usage

If comparing two options:

3-ton SEER2 ~13 vs. 3-ton SEER2 ~17:

Different equipment
Same size (same cooling capacity)
Efficiency difference: ~25% electricity reduction
Cost difference: ~$4,000-$5,000
Electricity payback: ~8-10 years

For large difference in efficiency with same tonnage, payback is more reasonable.

How to Use This Information

Know your current bill: Check June/July/August bills
Estimate AC portion: Likely 50-65% of total summer bill
Estimate new AC cost: Using our efficiency calculator
Calculate annual savings: (Current AC bill - New AC bill) × 6 months
Evaluate payback: Electricity savings ÷ system cost = years to payback

Example calculation:

Current AC cost: $80/month
New AC cost: $60/month
Monthly savings: $20
Annual savings: $120 (6-month season)
System cost: $12,560
Payback: 105 years (not good)

BUT: If you were going to replace anyway (old system failing), payback doesn't matter. You're choosing which tier (economy vs. midrange vs. premium).

Use the DFW Air Cost Calculator

dfwaircost.com provides estimates for your specific home and location, including:

Proper system sizing for your home
Estimated electricity costs for each efficiency level
Monthly payment calculations
Estimated payback on efficiency upgrades

Plug in your home details and current electricity rate to get personalized savings estimates.

Key Takeaway

Electricity savings alone usually don't justify AC replacement. You replace because:

Old system is failing
Repair costs justify replacement
You want warranty and reliability
You want better comfort and dehumidification

Electricity savings are a benefit, but not the primary reason.

When you do replace, choosing 17 SEER vs. 13 SEER has real payback (typically 20-30 years), so most homeowners choose midrange (15 SEER2) as the sweet spot.

Ready to calculate your specific savings? Head to dfwaircost.com now.

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