Whole House Load Calculator

Enter area, appliances, motors, HVAC, and spare capacity. Get demand load, current, panel size, notes. Build smarter service plans for safer new homes today.

Calculator Inputs

Square feet.
VA per square foot.
Each circuit adds 1500 VA.
Each circuit adds 1500 VA.
Used for appliance demand factor.
Dishwasher, disposal, microwave, pumps, and similar loads.
Nameplate kW.
Percent of range nameplate load.
Uses entered kW or 5 kW minimum.
Nameplate kW.
Electric heat or heat pump backup kW.
Compressor and air handler kW.
Base VA before largest motor adder.
Percent added to motor load.
Nameplate kW.
Workshop, exterior, pool, or special equipment VA.
Loads expected to run for long periods.
Common planning value is 25%.
Future expansion margin.
Common dwelling value is 240.
Use 1 for purely resistive planning.
Most houses use single phase.
Optional notes for export records.

Formula Used

Lighting load: Floor area × VA per square foot.

Small appliance load: Number of small appliance circuits × 1500 VA.

Laundry load: Number of laundry circuits × 1500 VA.

General demand: First 3000 VA at full value, plus 35% of the remainder.

Fixed appliance demand: Fixed appliance VA × 75% when four or more fixed appliances are entered.

Range demand: Range kW × 1000 × demand percentage.

Dryer demand: Greater of entered dryer load or 5000 VA.

Climate load: Greater of heating load or cooling load.

Final load: Demand loads + continuous adjusted load + spare capacity.

Single phase current: Final VA ÷ voltage ÷ power factor.

Three phase current: Final VA ÷ 1.732 ÷ voltage ÷ power factor.

How to Use This Calculator

  1. Enter the finished floor area of the house.
  2. Add the general load allowance used for your planning method.
  3. Enter kitchen, laundry, appliance, HVAC, motor, and special loads.
  4. Use nameplate values whenever they are available.
  5. Choose voltage, phase, power factor, and spare capacity.
  6. Press the calculate button.
  7. Review demand load, current, panel size, and circuit estimate.
  8. Export the result as CSV or PDF for project records.

Example Data Table

Input Example Value Meaning
Floor area 2200 sq ft Used for general lighting and receptacle planning.
Small appliance circuits 2 Kitchen and dining receptacle allowance.
Range load 12 kW Cooking equipment nameplate value.
Heating load 10 kW Compared with cooling load.
Spare capacity 20% Future growth allowance.

Whole House Load Planning

A house load calculation estimates the electrical demand of a home. It supports service sizing, panel planning, and early construction budgeting. The result is not a final permit document. It is a structured guide for design discussion.

Why Load Matters

Every dwelling has general lighting, receptacles, kitchen circuits, laundry circuits, fixed appliances, and climate equipment. These loads do not always run together. Demand factors help reduce unrealistic totals. They also keep the estimate practical for normal use. A careful load review can prevent undersized services, overheated equipment, and costly changes after rough-in.

What This Tool Includes

The calculator starts with floor area and a lighting allowance. It adds small appliance and laundry circuit allowances. It then includes range, dryer, water heating, kitchen equipment, pumps, motors, and other fixed appliances. Heating and cooling are compared. The larger climate load is used, because both usually do not peak together.

Advanced Planning Notes

Power factor, voltage, service phase, continuous load margin, and spare capacity can change the final current. A spare margin is useful when future equipment may be added. Examples include workshop tools, outdoor kitchens, car charging, or larger air systems. The recommended panel size rounds upward to a common service rating.

Using Results Safely

Use the demand load as a planning number. Compare it with local rules, utility requirements, and equipment labels. Nameplate data should replace estimates whenever possible. Motors may need starting allowances. Electric heat, tankless heaters, saunas, and chargers can dominate the service size. Always confirm final sizing with a licensed electrician or code professional.

Better Construction Decisions

A load calculation helps teams make choices before walls are closed. It can reveal when a 100 amp service is too small. It can also show when a larger service adds future flexibility. Builders can coordinate panel location, feeder size, generator planning, and subpanel needs. Owners can see which appliances drive demand. Good planning keeps changes clear, measured, and easier to price.

Documentation Value

Saved results are useful for meetings. The CSV supports quick spreadsheet checks. The PDF can be shared with estimators. Keep the inputs with drawings, fixture schedules, and appliance cutsheets. Updates stay easier when assumptions are visible. This reduces confusion during final service approvals.

FAQs

What is a whole house load calculation?

It estimates the total electrical demand of a dwelling. It combines lighting, receptacles, appliances, climate equipment, motors, and spare capacity to support service and panel planning.

Is this calculator a permit-ready report?

No. It is a planning calculator. Final electrical design should follow local codes, utility rules, equipment ratings, and the judgment of a licensed professional.

Why is heating or cooling selected, not both?

Many homes do not run full heating and full cooling at the same time. The calculator uses the larger climate load for practical service demand planning.

Why does the dryer use a minimum value?

Dryer planning often uses a minimum demand value when the entered nameplate is lower. This keeps the estimate conservative for common residential designs.

What does spare capacity mean?

Spare capacity is an added margin for future loads. It can help plan for workshops, chargers, outdoor equipment, additions, or larger appliances.

Should I use actual appliance labels?

Yes. Nameplate values are better than estimates. Use actual labels for ranges, dryers, heaters, pumps, HVAC units, chargers, and fixed appliances.

What panel size should I choose?

The calculator rounds calculated current upward to a common panel size. Final panel selection must also consider conductors, breakers, service equipment, and local requirements.

Can this handle future EV charging?

Yes. Enter planned EV charger kW in the charger field. The load is added before spare capacity, giving a clearer picture of future service demand.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.