Dwelling Load Schedule Calculator

A dwelling load schedule calculator totals the major load groups entered for a residence and applies a user-selected planning demand factor. It produces three planning values:

• Connected schedule load
• Entered-demand schedule load
• Entered capacity margin

These results help organize an early load review when comparing proposed dwelling loads against an assumed service, feeder, generator, inverter, or distribution capacity expressed in kW. The schedule is useful when evaluating additions such as EV charging, heat-pump HVAC equipment, electric appliances, or accessory loads before completing a formal electrical load calculation.

The calculation does not select an AWG or kcmil conductor, determine feeder ampacity, establish service size, calculate voltage drop, or apply an NEC dwelling-demand method. Those decisions require the actual system voltage, phase configuration, power factor where applicable, equipment nameplate data, continuous-load treatment, terminal ratings, conductor insulation temperature rating, and the governing code requirements accepted by the AHJ.

Entered Load Groups

The worksheet combines five entered load categories:

Input field	Electrical planning use
General load (kW)	General dwelling load entered for the planning screen
Fixed appliance load (kW)	Fixed appliance load entered for the planning screen
HVAC load (kW)	Heating, cooling, or other HVAC-related load entered for the planning screen
EV load (kW)	Electric-vehicle charging load entered for the planning screen
Other load (kW)	Other identified load not included in the preceding categories
Entered demand factor (%)	User-entered percentage applied to the connected schedule load
Entered comparison capacity (kW)	User-entered planning capacity used to calculate available or deficient margin

Each load group is entered in kW, not amperes. The entered values should be consistent with the planning basis being used. For example, mixing one appliance’s nameplate kW with another appliance’s estimated diversified kW can make the resulting schedule difficult to interpret.

For an actual service or feeder review, verify whether each load represents input power, output power, heating nameplate load, motor branch-circuit load, EVSE rating, or another electrical basis. A load schedule may support conductor and feeder planning, but it does not replace the equipment-specific calculations needed for branch circuits, overcurrent protection, ampacity adjustment, correction factors, or raceway fill.

Connected and Demand Schedule Load

The calculator first adds the entered groups to establish the total connected schedule load:

\(\displaystyle \text{connected schedule load} = \text{general} + \text{fixed appliance} + \text{HVAC} + \text{EV} + \text{other loads}\)

It then applies the entered demand percentage:

\(\displaystyle \text{demand schedule load} = \text{connected schedule load} \times \frac{\text{entered demand percent}}{100}\)

Finally, it compares the demand schedule load with the entered comparison capacity:

\(\displaystyle \text{entered capacity margin} = \text{entered capacity} - \text{demand schedule load}\)

A positive capacity margin indicates that the entered comparison capacity exceeds the calculated entered-demand schedule load. A negative margin indicates that the entered-demand schedule load is greater than the entered comparison capacity.

The demand factor in this worksheet is an input selected by the user. It is not a hidden demand table and does not determine whether a particular demand factor is permitted under the NEC or by the AHJ.

Calculation Example

Assume the following dwelling planning inputs:

Input field	Entered value
General load (kW)	4.0 kW
Fixed appliance load (kW)	6.0 kW
HVAC load (kW)	5.0 kW
EV load (kW)	7.2 kW
Other load (kW)	1.0 kW
Entered demand factor (%)	75%
Entered comparison capacity (kW)	24.0 kW

The connected schedule load is:

\(\displaystyle 4.0 + 6.0 + 5.0 + 7.2 + 1.0 = \text{23.2 kW}\)

The entered-demand schedule load is:

\(\displaystyle 23.2 \times \frac{75}{100} = \text{17.4 kW}\)

The entered capacity margin is:

\(\displaystyle 24.0 - 17.4 = \text{6.6 kW}\)

Result	Value
Connected schedule load	23.2 kW
Entered-demand schedule load	17.4 kW
Entered capacity margin	6.6 kW

In this example, the entered 24.0 kW comparison capacity exceeds the entered-demand schedule load by 6.6 kW. That margin can be used to flag whether the preliminary schedule appears to have room for the listed loads, especially the 7.2 kW EV load, before detailed service and feeder design begins.

Feeder and Service Review Limits

A kW result cannot by itself establish conductor size or overcurrent protection. Conductor ampacity is based on current, while the relationship between kW and current depends on the electrical system.

For a simple single-phase planning conversion where the load basis is appropriate:

\(\displaystyle I \approx \frac{P}{V}\)

For a three-phase load, power factor and system voltage affect the conversion:

\(\displaystyle I = \frac{P}{\sqrt{3} \times V \times \text{power factor}}\)

Actual feeder and service design must separately evaluate the applicable load-calculation method, continuous loads, EV charging requirements, noncoincident heating and cooling treatment, motor loads, conductor ampacity, terminal temperature limitations, ambient-temperature correction factors, adjustment factors for current-carrying conductors, and voltage-drop design criteria.

The calculator’s stated boundary is specific: it is a planning worksheet only. It makes no NEC dwelling load calculation, service-size determination, or code-compliance approval. Use the resulting schedule as a documented load-totaling and capacity-comparison step, then complete the governing electrical calculation and installation review for the project.