When to Re-Evaluate Your Solar System Size

A solar system is designed around a snapshot in time.

It reflects how much energy your home used historically, what your roof could support, and how utility rules apply at the moment it was built. Over time, though, homes—and lifestyles—change.

Re-evaluating system size doesn’t mean something went wrong. It usually means something changed.

Here’s how to know when it’s worth taking another look.

Solar Systems Are Sized to Past Usage

When a solar system is designed, it’s typically based on:

• 12 months of historical electric usage

• Seasonal production patterns

• Roof layout, orientation, and shading

• Utility net metering rules
  
  

That design assumes your future energy use will look roughly like your past. When that assumption no longer holds, the system may still work—but it may no longer feel as effective.

Signs It Might Be Time to Re-Evaluate

Re-evaluating doesn’t mean replacing your system. It means checking alignment.

Common signals include:

Your Energy Use Has Increased

This is the most common reason.

Examples:

• Adding an electric vehicle

• Switching from gas to electric heating

• Working from home full-time

• Adding a hot tub, pool, or major appliance
  
  
  

If usage grows, solar may still be producing the same amount—but offsetting a smaller percentage of a larger load.

Your Bills No Longer Match Expectations

Occasional higher bills are normal. Consistently higher bills across multiple seasons deserve context.

Before assuming a system issue, it’s worth asking:

• Has household usage changed?

• Are credits being applied as expected?

• Are seasonal patterns lining up year over year?
  
  

Often, the answer points back to consumption—not production.

You’ve Lived With Solar for a Full Year (or More)

The best time to evaluate performance is after you’ve seen a full cycle:

• One summer

• One winter

• One full net metering year
  
  

That data gives a clearer picture than early impressions or first-year bills.

What Re-Evaluating Doesn’t Mean

Re-evaluating your system size does not automatically mean:

• Your system was designed incorrectly

• Solar “isn’t working”

• You need to start over
  
  

Most of the time, it simply means your home no longer looks the way it did on paper when the system was planned.

That’s normal.

How Utilities Factor Into the Equation

Utility rules shape how much impact resizing can have.

In Virginia, utilities like Dominion Energy and Appalachian Power Company typically:

• Cap system size based on historical usage

• Apply net metering credits within defined limits

• Review changes differently depending on scope
  
  

That’s why any re-evaluation needs to consider utility guidelines—not just roof space or desire for more production.

When Re-Evaluation Is Probably Not Necessary

It’s usually not time to resize if:

• You’re still within your first few months of operation

• The system was activated in winter

• Bills fluctuate seasonally but align annually

• Monitoring data matches expectations
  
  

Short-term variation is part of how solar works. Resizing decisions should be based on trends, not moments.

Re-Evaluation Is About Alignment, Not Perfection

Solar isn’t meant to perfectly offset every possible future scenario.

It’s designed to:

• Reduce reliance on the grid

• Stabilize energy costs

• Perform predictably over time
  
  

When life changes, revisiting assumptions is smart—not reactive.

The Takeaway

Re-evaluating your solar system size is about checking whether your system still matches your home—not whether it ever worked in the first place.

Most of the time, solar is doing exactly what it was designed to do. The question is whether your household still fits the design.

Clarity comes from looking at the right data, over the right timeframe, with the right expectations.

VirginiaSolar.org was created to give Virginia homeowners clear, unbiased information about solar—so decisions are made with confidence, not pressure.

Our Help Desk and resource library are here whenever you want to go deeper or ask questions.