March 27, 2026
March 27, 2026
For decades, residential load calculations under the National Electrical Code have relied on 3 volt-amperes (VA) per square foot for general lighting and general-use receptacles in dwelling units. Generations of electricians, inspectors, and engineers have applied that figure without much question.
But with the 2026 NEC, that long-standing assumption officially changes.
The general lighting unit load has been reduced from 3 VA per square foot to 2 VA per square foot in Section 120.41 (formerly found in 220.41). This represents a big philosophical shift in how the Code reflects modern electrical usage.
Now, not to make this more confusing, but the unit load to determine the number of required branch circuits for general lighting and general use receptacles remains 3 VA. So to lay it out there clearly, when you’re sizing a service or feeder we will use 2 VA. If we are determining how many 15 or 20 amp breakers will be required for these branch-circuits we will still use 3 VA.
Let’s break down what changed, why it changed, and what it means in the real world.
The original 3 VA per square foot value dates back to a time when:
• Homes were lit primarily with incandescent bulbs
• Lighting loads were significantly higher
• Plug loads were less energy efficient
• Air conditioning, electronics, and modern appliances weren’t as widespread
Back then, a living room with several 60- or 100-watt incandescent lamps could easily consume hundreds of watts just for lighting alone. The NEC built in a conservative safety margin to ensure services were large enough to handle typical demand — even during peak usage.
And to be fair, it worked well for decades.
But the world changed.
One of the biggest factors behid this NEC update is simple:
Lighting today uses a fraction of the power it once did.
A quick comparison:
That’s roughly an 80–90% reduction in lighting energy for the same brightness.
A study was done by Lawrence Berkely National Lab that showed dwelling units who use 100% LED lighting had an actual unit load of around 1.5VA/square foot. That is half of the traditional unit load used for general lighting and general use receptacles. 2 VA/square foot was the number settled on which assumes 80% high-efficiency lighting (LED). Our load calculations were stuck in the 20th century and it was certainly time for change.
Under the 2026 NEC:
👉 General lighting and general-use receptacles in dwelling units are now calculated at 2 VA per square foot instead of 3 VA.
That’s a 33% reduction in calculated load.
2,000 sq ft home
2,000 × 3 VA = 6,000 VA
2,000 sq ft home
2,000 × 2 VA = 4,000 VA
That’s a 2,000 VA difference — the equivalent of over 16 amps at 120 volts.
That is a significant difference.
This change doesn’t mean electricians should start undersizing services or ignoring good design practices. But it does mean the NEC is now:
Here are some real-world impacts.
In borderline load calculations, this reduction could be enough to:
• Keep a dwelling at a 150-amp service instead of bumping to 200 amps
• Avoid unnecessary service upgrades
• Reduce material and labor costs
Not every home will see a change — large homes with electric heat, ranges, dryers, and EV chargers will still push service sizes up — but many average dwellings may now fall comfortably within lower service ratings. Now something to keep in mind… In 2023 garages were removed from exclusions to dwelling unit square footage calculations. In other words, we have to include (attached, 2026 change) when calculating general lighting load for a dwelling unit. That could be a significant increase for houses with large garages. Lowering the unit load will help offset this increase in square footage.
And this is where the change really shines.
By lowering the general lighting load, the NEC effectively creates headroom in residential calculations.
That extra capacity can help account for:
Instead of artificially inflating lighting loads that no longer exist, we now have room to accommodate the things people actually use today.
This update is part of a broader trend in the NEC toward realistic diversity and modern usage patterns
Rather than assuming everything runs full blast all the time, the Code is slowly evolving to reflect how loads truly behave.
It’s still conservative (and it should be), but it’s no longer ignoring decades of efficiency improvements.
Short answer: No — safety remains intact.
The NEC didn’t pull this number out of thin air.
The change is based on:
• real-world energy data
• residential load studies
• efficiency standards
• modern appliance behavior
Even with 2 VA per square foot, services are still designed with ample margin for peak loads and diversity.
You’re not getting weaker electrical systems — you’re getting more accurate calculations.
Expect more updates like this in future Code cycles.
As homes continue to evolve with:
• smart systems (energy management systems)
• renewable energy
• higher efficiency appliances
• electric transportation
Load calculations will keep adjusting to reflect reality.
The 3 VA number survived for decades — but efficiency finally caught up to it.
The shift from 3 VA per square foot to 2 VA per square foot in the 2026 NEC may seem minor, but it’s a meaningful modernization of residential load calculations.
It recognizes:
✔ The dominance of LED lighting
✔ Improved energy efficiency across homes
✔ The need to accommodate new technologies
✔ Realistic electrical demand patterns
And perhaps most importantly, it keeps the NEC what it’s always intended to be:
A practical document grounded in real-world conditions — not outdated assumptions.
After decades of applying 3 VA per square foot to calculate the general lighting load for dwelling units, the unit load has officially decreased to 2 VA per square foot.
This reflects modern power consumption (let’s just say it… LEDs), opens the door for today’s electrical demands, and brings residential calculations into the present.
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