Whole House Electrical Load Calculator

Calculator Inputs

Finished floor area

Lighting VA per square foot

Small appliance circuits

VA per small appliance circuit

Laundry circuits

VA per laundry circuit

Fixed appliance total watts

Fixed appliance count

Fixed appliance demand percent

Range or cooktop watts

Range demand percent

Dryer nameplate watts

Dryer minimum watts

Water heater watts

Cooling equipment watts

Heating equipment watts

Shared blower watts

EV charger watts

Workshop or welder watts

Largest motor watts

Motor multiplier

Continuous load watts

Continuous load multiplier

Service voltage

Power factor

Safety margin percent

Proposed panel amps

Formula Used

This tool uses a planning method for early construction estimates. Always confirm final service sizing with local rules and a qualified professional.

General load = floor area × lighting VA per square foot + small appliance allowance + laundry allowance.
General demand = first 10,000 VA + 40% of remaining general load.
Fixed appliance demand = fixed appliance total × fixed appliance demand percent.
Range demand = range watts × selected range demand percent.
Dryer demand = greater of dryer nameplate watts and selected dryer minimum.
HVAC demand = greater of cooling path or heating path, with blower included.
Final demand = base demand + selected safety margin.
Service amps = final demand ÷ service voltage ÷ power factor.

How to Use This Calculator

Enter finished floor area and the general lighting allowance.
Add small appliance and laundry circuit allowances.
Enter all fixed appliance, range, dryer, and water heater loads.
Add heating, cooling, blower, EV, shop, motor, and continuous loads.
Set voltage, power factor, safety margin, and proposed panel size.
Press Calculate Load to view the result above the form.
Use CSV or PDF buttons to save the report.

Example Data Table

Input	Example Value	Purpose
Finished floor area	2,200 sq ft	General lighting load
Small appliance circuits	2 × 1,500 VA	Kitchen and dining allowance
Laundry circuit	1 × 1,500 VA	Laundry allowance
Fixed appliance total	6,500 W	Dishwasher, disposal, microwave, and similar loads
Range	12,000 W at 66.67%	Cooking equipment demand
HVAC	Heating path 8,600 VA	Larger heating or cooling path
EV charger	9,600 W	Vehicle charging demand
Proposed panel	200 A	Reserve comparison

Whole House Load Planning

A whole house electrical load review helps estimate service size before a panel change, addition, remodel, workshop build, or large appliance upgrade. It combines general lighting load, required branch circuit allowances, fixed appliances, climate equipment, vehicle charging, motors, and reserve margin. The goal is not to replace a licensed design. It gives a structured planning number before drawings, permits, and contractor review.

Why Load Matters

A home can have many connected watts, yet not every device runs at full output together. Demand factors reduce selected loads to a practical planning demand. This calculator separates the general household base from large dedicated loads. That makes the result easier to review. You can see which equipment drives the final service amperage.

For construction planning, the most important items are usually heating and cooling equipment, electric range, dryer, water heater, EV charger, workshop tools, and continuous loads. The larger heating or cooling load is normally used, because both are rarely at peak at the same time. Continuous loads are raised by the chosen multiplier, often 125 percent, because they may operate for long periods.

Good Inputs Improve Accuracy

Use nameplate watts when possible. For volts and amps, multiply them to get volt-amperes. For motors, include the largest expected running load and use the motor adjustment field. For appliances, enter realistic totals and counts. The fixed appliance demand field lets you test a full connected value or a reduced planning value.

Reviewing the Result

The calculator reports connected load, demand load, safety margin, final volt-ampere estimate, service amperes, and panel reserve. A negative reserve means the selected panel size is probably too small for the entered assumptions. A high used percentage may still need professional review, especially when future equipment may be added.

Use the CSV button to save tabular numbers. Use the PDF button for a simple report. Keep both with bid notes, electrical schedules, and contractor questions. Local rules differ, so final sizing should be checked by a qualified electrician or designer before purchase or installation.

The method also helps compare design choices. Changing a charger size, range rating, or spare margin shows how quickly reserve capacity changes during early construction decisions and final budget review discussions later.

FAQs

What is a whole house electrical load calculator?

It estimates the demand load for a house. It combines area load, branch circuit allowances, appliances, HVAC, motors, EV charging, and margin. The result helps compare the estimated service amps with a proposed panel size.

Is this calculator a permit-ready electrical design?

No. It is a planning tool. Local codes, utility rules, equipment ratings, and inspection requirements can change the final answer. A licensed electrician or qualified designer should verify the final service calculation.

Why does the calculator use demand factors?

Demand factors recognize that many household loads do not run at full output at the same time. They help create a practical planning estimate instead of simply adding every connected watt at full value.

What value should I enter for appliances?

Use nameplate watts when available. If an appliance lists volts and amps, multiply volts by amps. For grouped fixed appliances, enter the total and use the demand percent field to test different planning assumptions.

How is heating and cooling handled?

The calculator compares the cooling path and heating path. It uses the larger value because both systems usually do not peak together. The blower field is added to each path for a simple planning comparison.

Why include a safety margin?

A margin helps account for future loads, estimate uncertainty, and design changes. It does not replace code review. It only gives a more conservative planning number for early construction decisions.

Can I include EV charging?

Yes. Enter the EV charger watts as a separate load. For example, a 240 volt charger at 40 amps is 9,600 watts. Confirm continuous loading rules and circuit sizing with a professional.

What does negative panel reserve mean?

Negative reserve means the estimated service amps exceed the selected panel size. That may indicate a larger service, load management, different equipment, or professional review is needed before construction decisions.