Short answer: The standard method adds a house’s loads in a fixed order: general lighting at 2 VA per square foot plus small-appliance and laundry circuits, with demand factors; fixed appliances (75% if four or more); the dryer; the range; and the larger of heating or cooling. For a 120/240 V single-phase service, divide the total by 240 for amps.
Dwelling load calculations come up on both parts of the Texas Journeyman exam. The PSI outline lists Load Knowledge in NEC Knowledge and Load Calculations in the Calculations part. The Texas Journeyman Practice Pack adds more calculation practice with worked solutions, so you can see exactly where a demand factor or table value went wrong. US$39 once.
Tsai Electro is an independent learning site. Not affiliated with TDLR, PSI or NFPA. We explain the method in our own words and do not reproduce NEC text. Use this guide to learn the calculation sequence, and use the 2026 NEC to confirm the requirements and table values.
Article 220 is now Article 120
In the 2026 NEC, these load calculations moved from Article 220 to Article 120; older study material and the 2023 NEC still use 220. Most training material still calls this “NEC 220.” The 2026 NEC load calculation rules are in a new Article 120, according to the City of Denison’s summary of 2026 changes (Denison 2026 NEC summary) and IAEI’s 2026 change overview (IAEI Magazine). Texas adopted the 2026 NEC effective September 1, 2026, and the TDLR exams use it from the same date (TDLR rule adoption notice). The overall standard-method workflow is familiar, but use the 2026 NEC for current section references, demand tables and revised values. One revised value matters in every example below: general lighting for service and feeder calculations is now 2 VA per square foot (120.41). The 2023 NEC used 3 VA, so older study material gives different answers. The 3 VA figure now applies only when you count branch circuits (120.13).
Want to check the arithmetic for a single load? Our circuit breaker size calculator can help estimate current from watts and voltage. It does not replace the NEC checks required to select an actual breaker, conductor or service size, and the full house calculation below is something you do by hand.
The standard method in order
| Step | Load | How it is counted | Where to look |
|---|---|---|---|
| 1 | General lighting | 2 VA per square foot of floor area, including an attached garage | 120.41 |
| 2 | Small-appliance circuits | 1,500 VA each, at least two | 120.52(A) |
| 3 | Laundry circuit | 1,500 VA | 120.52(B) |
| 4 | Demand on steps 1 to 3 | First 3,000 VA at 100%, next 117,000 VA at 35%, the rest at 25% | Table 120.45 |
| 5 | Fixed appliances | Nameplate; 75% if four or more (not counting range, dryer, heating and cooling) | 120.53 |
| 6 | Dryer | Nameplate or 5,000 VA, whichever is larger | 120.54 |
| 7 | Range | Demand from the range table | Table 120.55 |
| 8 | Heating or cooling | The larger of the two when they will not run at the same time (noncoincident loads) | 120.6 |
Worked example: a 2,000 square-foot house
A single-family house at 120/240 V: 2,000 square feet of floor area counted under 2026 NEC 120.5(C), including any attached garage, two small-appliance circuits, one laundry circuit, a 1,200 VA dishwasher, a 900 VA disposal, a 4,500 W water heater, a 1,500 VA built-in microwave, a 5,500 W dryer, a 12 kW range, 5,000 VA of air conditioning and 10 kW of electric heat.
- General lighting: 2,000 × 2 = 4,000 VA.
- Small-appliance circuits: 2 × 1,500 = 3,000 VA.
- Laundry: 1,500 VA.
- Subtotal for steps 1 to 3: 4,000 + 3,000 + 1,500 = 8,500 VA.
- Demand: the first 3,000 VA at 100% is 3,000 VA. The remaining 5,500 VA at 35% is 1,925 VA. Lighting demand: 4,925 VA.
- Fixed appliances: dishwasher, disposal, water heater and microwave are four, so 75% applies: (1,200 + 900 + 4,500 + 1,500) × 0.75 = 8,100 × 0.75 = 6,075 VA.
- Dryer: 5,500 VA, because it is more than 5,000.
- Range: one range not over 12 kW takes 8,000 VA from the range table.
- Heating or cooling: heat 10,000 VA is larger than air conditioning 5,000 VA, so 10,000 VA.
- Total: 4,925 + 6,075 + 5,500 + 8,000 + 10,000 = 34,500 VA.
- Amps: 34,500 ÷ 240 = 143.75 A. The next standard rating above that is 150 A in this example. The final service equipment, conductors and overcurrent protection must each still meet their own NEC requirements.
Check: add in a different order. 10,000 + 8,000 = 18,000, plus 6,075 = 24,075, plus 4,925 = 29,000, plus 5,500 = 34,500. Same total.
The range rule, one more time
For one household range rated 8¾ kW up to 12 kW, the range table gives 8 kW. For a larger range, a note to the table increases the 8 kW by 5% for each kW over 12. A 14 kW range is 2 kW over, so 8 × (1 + 2 × 0.05) = 8.8 kW. This is a common exam trap: candidates use 14 kW, or forget the increase and use 8 kW.
Mistakes that wreck a dwelling calculation
- Counting the range or dryer as a fixed appliance. They have their own steps.
- Taking 75% of three appliances. The 75% applies only with four or more.
- Adding heat and air conditioning together. Use only the larger.
- Applying 35% to all the lighting. The first 3,000 VA stays at 100%.
- Using the wrong floor area. Under 2026 NEC 120.5(C), an attached garage counts in the dwelling floor area. Detached garages, open porches and unfinished areas not adaptable for future use are left out. Do not count only finished living space.
Check yourself
Our own practice questions. Answers below each.
- A 1,600 square-foot house. General lighting, two small-appliance circuits and laundry, after demand? Answer: 3,200 + 3,000 + 1,500 = 7,700 VA. Demand: 3,000 + (4,700 × 0.35) = 3,000 + 1,645 = 4,645 VA.
- Three fixed appliances of 1,000, 1,200 and 4,000 VA. Demand? Answer: Fewer than four, so 100%: 6,200 VA.
- A 4,200 W dryer. What value goes in? Answer: 5,000 VA, the minimum.
- Total load 28,800 VA at 240 V. Amps? Answer: 28,800 ÷ 240 = 120 A.
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A printed workbook for the two-part exam
Texas Journeyman Electrician Exam Prep 2026 NEC (Tsai Electro, paperback): 486 practice questions and 2 full two-part mock exams for the Texas Journeyman exam on the 2026 NEC. Use it alongside your own code book. Not affiliated with TDLR or PSI.
FAQ
How do you do a residential load calculation?
With the standard method: first find the floor area under 120.5(C), including any attached garage. Then add general lighting at 2 VA per square foot (3 VA in the 2023 NEC) plus small-appliance and laundry circuits, with demand factors; fixed appliances, at 75% when there are four or more; the dryer at nameplate or 5,000 VA; the range from its table; and the larger of heating or cooling. Divide the total by 240.
What are the lighting demand factors for a dwelling?
The first 3,000 VA at 100%, the next 117,000 VA at 35% and anything above 120,000 VA at 25%. They apply to general lighting plus the small-appliance and laundry circuit loads.
Is NEC Article 220 still used for load calculations?
Not in the 2026 NEC. Load calculations moved to Article 120. The overall workflow is familiar, but the article and section numbers changed and some values changed too, such as general lighting at 2 VA per square foot, so check your 2026 code book.
How much VA is a small-appliance circuit in a load calculation?
1,500 VA for each small-appliance branch circuit, with at least two required in a dwelling, and 1,500 VA for the laundry circuit.
Sources checked October 2026
- City of Denison, 2026 NEC significant changes (Article 120): https://denisontx.gov/DocumentCenter/View/4131/2026-National-Electrical-Code-Significant-Changes
- IAEI Magazine, NEC 2026 significant code changes: https://iaeimagazine.org/standards/nec-2026-significant-code-changes/
- TDLR rule adoption notice, 2026 NEC: https://www.tdlr.texas.gov/news/rulemaking/2026/09/01/commission-adopts-rules-12/
- PSI Candidate Information Bulletin for TDLR (updated 9/15/2026): https://test-takers.psiexams.com/api/content/bulletin/1682
- NFPA 70 (NEC), 2026 edition, Article 120, read in your own copy: https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70
