Calculator Inputs
Formula Used
Electrical input from watts: PkW = watts ÷ 1000
Electrical input from amps: PkW = volts × amps × power factor ÷ 1000
If rating is heat output: Pelectric = Pheat ÷ COP
Period energy: kWh = Pelectric × hours × days × duty cycle
Monthly estimate: total = Σ(kWh × rate) + fixed charge + fees + tax − credit
How to Use This Calculator
- Select a SMUD-style preset or choose custom rates.
- Enter the heater rating from the label or manual.
- Use amps and volts when wattage is not shown.
- Add daily heating hours by off-peak, mid-peak, and peak periods.
- Enter duty cycle, billing days, fees, taxes, and credits.
- Press calculate to view the result above the form.
- Download the CSV or print the result as a PDF.
Example Heating Scenarios
| Scenario | Power | Daily schedule | Duty cycle | Use case |
|---|---|---|---|---|
| Small room heater | 1,500 W | 4 off-peak, 1 peak | 55% | Bedroom evening use |
| Baseboard zone | 3.5 kW | 5 off-peak, 2 mid-peak | 45% | Single living area |
| Heat pump output | 12,000 BTU/h | 6 off-peak, 2 peak | 70% | Efficient whole-room heat |
Understanding SMUD Electric Heating Cost
Electric heating is simple to use. It can still create surprise bills. The main reason is timing. A heater that runs during peak hours costs more than the same heater at off peak hours. SMUD residential pricing uses time periods. Summer prices are higher during hot afternoon and evening demand. Non summer prices are lower, but the evening peak still matters. This calculator helps you test those periods before the bill arrives.
Why heater rating matters
Every heater has a power rating. A small space heater often uses 1,500 watts. A baseboard circuit can use much more. Power becomes cost only when time is added. One kilowatt used for one hour equals one kilowatt hour. A 1.5 kilowatt heater running four hours uses six kilowatt hours. The calculator converts watts, kilowatts, amp loads, and BTU per hour ratings.
Duty cycle changes the answer
Most heaters do not run every minute. A thermostat cycles them on and off. Duty cycle estimates that behavior. A sixty percent duty cycle means the heater runs sixty percent of the selected hours. Better insulation lowers the duty cycle. Air leaks raise it. Large temperature setbacks can also change it. Use a realistic value for the room or whole home.
Season and time periods
SMUD pricing depends on season and time. Summer has off peak, mid peak, and peak periods. Non summer has peak and off peak periods. Weekends and holidays are usually cheaper than weekday peak periods. This page keeps rates editable. That is important because utility prices can change. It also lets renters, homeowners, and solar customers model special cases.
Fees, taxes, and credits
Energy cost is not always the full bill impact. Monthly fixed charges, local charges, and credits can change the final number. The calculator adds these lines after energy cost. It also shows an annual heating projection. This helps compare electric resistance heat, portable heaters, and heat pumps. A heat pump may use less electricity for the same heat.
Planning useful changes
The best use is comparison. Try the current schedule first. Then move one heating hour away from peak time. Try a lower duty cycle after air sealing. Try a heat pump performance factor. Review the difference in monthly and seasonal cost. Small changes can matter when a heater runs many cold evenings.
Advanced checks
Use the safety margin for colder weeks. It raises the modeled electric load. Use other fees for line items not listed separately. Use the discount field for credits or rebates. The average rate shows what each kilowatt hour costs after timing is considered. The useful heat value helps compare equipment with different performance.
Interpreting the result
The result is an estimate. Real bills depend on weather, thermostat settings, building leakage, and exact tariff rules. Review your latest bill for final values. Save copies of each scenario for later comparison.
Frequently Asked Questions
What does this calculator estimate?
It estimates electricity cost for heaters using SMUD-style time periods. It includes power, runtime, duty cycle, rates, fees, taxes, and credits.
Can I use it for a portable space heater?
Yes. Enter the wattage from the heater label. Many portable heaters use 1,500 watts on high, but always check your exact device.
Why are there off-peak, mid-peak, and peak inputs?
Time-based pricing can charge different rates during the day. Splitting hours shows how timing changes the same heater cost.
What duty cycle should I enter?
Use 100 percent if the heater runs constantly. Use a lower value when a thermostat cycles it on and off during selected hours.
How do I model a heat pump?
Select delivered heat output when the rating is heat capacity. Then enter the estimated COP. The tool divides heat output by COP.
Are the SMUD preset rates final bill values?
No. They are editable planning values. Your bill can include tariff details, taxes, credits, and adjustments not known to this page.
Why include a monthly fixed charge?
A fixed charge can affect the monthly estimate. Include it when comparing bill impact. Set it to zero for energy-only comparisons.
Can I compare summer and non-summer heating?
Yes. Change the rate preset, review the entered rates, and calculate again. Save both results for a direct seasonal comparison.
Does this handle taxes and discounts?
Yes. Enter a surcharge percentage, other fees, and any monthly credit. The final total updates after energy cost is calculated.
What does one-hour shift savings mean?
It estimates savings from moving one daily peak heating hour to off-peak time. It only appears when peak pricing is higher.
Can I save the result?
Yes. Use the CSV button for spreadsheet records. Use the print button and choose save as PDF in your browser.