Air Change Rate (ACH) Calculator
Calculate the air changes per hour (ACH) for a room or building. Determine ventilation rate from airflow volume and room size.
Setback Temperature Savings Calculator
Calculate how much you save by lowering your thermostat a specific number of degrees. Estimate savings per degree of temperature setback.
Heating Setback
deg F
deg F
$
Cooling Setback (Summer)
deg F
Raise temp to save on cooling
deg F
$
Temperature Reduction⧉
4 deg F
Noticeable but Comfortable
Heating Savings %⧉
4.0%
8 hrs/day setback
Annual Heating Savings⧉
$72.00
Estimated yearly savings
Monthly Heating Savings⧉
$6.00
Average per month
Cooling Savings⧉
$48.00
+4 deg F raise, 4%
Total Annual Savings⧉
$120.00
Heating + cooling combined
5-Year Savings⧉
$600.00
Cumulative projection
Per Degree Saved⧉
$18.00
Annual savings per 1 deg F setback
Savings vs Annual Heating Cost
4%
Savings by Setback Amount
| Degrees Lowered | New Setpoint | Savings % | Annual Savings |
|---|---|---|---|
| 1 deg F | 71 deg F | 1% | $18.00 |
| 2 deg F | 70 deg F | 2% | $36.00 |
| 3 deg F | 69 deg F | 3% | $54.00 |
| 4 deg F | 68 deg F | 4% | $72.00 |
| 5 deg F | 67 deg F | 5% | $90.00 |
| 6 deg F | 66 deg F | 6% | $108.00 |
| 7 deg F | 65 deg F | 7% | $126.00 |
| 8 deg F | 64 deg F | 8% | $144.00 |
| 9 deg F | 63 deg F | 9% | $162.00 |
| 10 deg F | 62 deg F | 10% | $180.00 |
Savings by Setback Duration
| Hours/Day | Savings % | Annual Savings |
|---|---|---|
| 4 hrs | 2% | $36.00 |
| 6 hrs | 3% | $54.00 |
| 8 hrs | 4% | $72.00 |
| 10 hrs | 5% | $90.00 |
| 12 hrs | 6% | $108.00 |
| 16 hrs | 8% | $144.00 |
| 20 hrs | 10% | $180.00 |
| 24 hrs | 12% | $216.00 |
Multi-Year Savings Projection
| Year | Cumulative Savings |
|---|---|
| Year 1 | $120.00 |
| Year 2 | $240.00 |
| Year 3 | $360.00 |
| Year 5 | $600.00 |
| Year 7 | $840.00 |
| Year 10 | $1,200.00 |
| Year 15 | $1,800.00 |
| Year 20 | $2,400.00 |
Planning notes, formulas, and examples
About the Setback Temperature Savings Calculator
The simplest energy-saving strategy is turning down your thermostat. Every degree Fahrenheit you lower your heating setpoint saves approximately 1–3% on your heating bill, depending on your climate and insulation. In a cold climate with high heating costs, each degree is worth $15–$30 per year.
This calculator shows precisely how much you save by lowering your thermostat by any amount. It factors in your climate (HDD), current setpoint, and heating costs to give a realistic savings estimate. It also shows the impact on heat loss rate and daily energy consumption.
Whether you're considering a permanent adjustment or evaluating setback temperatures for a programmable thermostat, This calculator gives you the hard numbers to make an informed decision.
Understanding this metric in precise terms allows energy managers to evaluate investment options, forecast savings, and build compelling business cases for efficiency upgrades and retrofits. Tracking this metric consistently enables energy professionals and facility managers to identify consumption trends and implement efficiency improvements before costs escalate unnecessarily.
When This Page Helps
Lowering your thermostat costs nothing and produces immediate savings. This calculator quantifies the savings per degree so you can decide how much comfort you're willing to trade for lower energy bills. Having accurate metrics readily available streamlines utility bill analysis, budget forecasting, and investment planning for energy efficiency projects and renewable energy installations.
How to Use the Inputs
- Enter your current thermostat setpoint.
- Enter the new reduced setpoint.
- Enter your annual heating cost.
- Enter your local heating degree days.
- Review savings per degree and total reduction.
Formula used
Savings % = ΔT / (Setpoint − Balance Point) × 100
Balance Point ≈ 65°F (standard)
Simplified: Savings % ≈ ΔT × 3% (for 70°F setpoint, cold climate)Example Calculation
Result: $216/year savings (12%)
Lowering from 72°F to 68°F (4°F reduction). At a balance point of 65°F, the effective temperature difference drops from 7°F to 3°F, but the HDD-based approach gives approximately 3% per degree: 4 × 3% = 12% of $1,800 = $216/year.
Tips & Best Practices
- The savings per degree increase in colder climates.
- Wear a sweater at 68°F instead of heating to 72°F — it's the cheapest energy upgrade.
- Each degree of cooling setpoint increase saves 3–5% on AC costs.
- Use setbacks for the hours you're sleeping or away, even if you keep it warm when home.
- Heat pumps should use smaller setbacks to avoid activating expensive auxiliary heat.
- Humidity affects comfort — at 45% RH, 68°F can feel as comfortable as 72°F at 30% RH.
The Science of Setback Savings
Heat loss follows Q = UA × ΔT, where Q is heat flow rate, UA is the building's heat loss coefficient, and ΔT is the indoor-outdoor temperature difference. By reducing indoor temperature, you reduce ΔT and therefore Q. The furnace runs less to maintain the lower temperature.
Savings Vary by Climate
In a 7,000 HDD climate (Minneapolis), the indoor-outdoor ΔT averages about 40°F during heating season. Lowering your thermostat 4°F reduces ΔT by 10%, saving 10% on heating. In a 3,000 HDD climate (Atlanta), the same 4°F represents a 20% reduction in average ΔT, but total heating costs are much lower.
The Comfort Factor
Most people adapt to 68°F within a few days. The key is consistent temperature rather than constant adjustments. Humidity management makes a big difference — maintaining 40–45% relative humidity makes 68°F feel comfortable. A humidifier running 8 hours/day costs about $5/month in electricity.
Sources & Methodology
Last updated:
Frequently Asked Questions
The DOE estimates about 1% savings per degree per 8-hour setback period, or about 3% per degree for a 24-hour reduction. In a 6,000 HDD climate with $1,500 heating costs, one degree ≈ $45/year for a 24-hour change.
68°F is the commonly recommended daytime setting for comfort and efficiency. Lower to 60–65°F while sleeping or away. Health agencies recommend not going below 64°F for elderly or ill occupants.
Yes. The myth that recovery costs more than the savings is false. During the setback period, heat loss is reduced because the indoor-outdoor temperature difference is smaller. The total energy saved always exceeds the recovery energy.
Savings are roughly proportional to both the number of degrees and the number of hours. A 5°F setback for 10 hours saves about the same as a 10°F setback for 5 hours. Choose whichever schedule matches your comfort needs.
Wear warm clothing (sweaters add 2–4°F equivalent), use warm blankets, keep humidity at 40–50% (dry air feels colder), use area rugs on cold floors, and close doors to unused rooms. Personal heating (heated blanket, space heater) uses less energy than whole-house heating.
Both. Lowering the thermostat provides immediate free savings. Insulation provides long-term savings. They multiply: a 4°F setback in an insulated home saves more total energy than in an uninsulated home because the baseline bill is higher in the uninsulated home.
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