Borderline 100A Panel?
Get a Clear Electrical Path Before You Assume 200A.

Send us 2 panel photos + the heat pump specs. We’ll tell you within 24 hours if you can pass inspection without a panel upgrade.

Text a panel photo 
24-hour response • NEC compliant documentation
Boston-based team

For heat pump installers without an in-house electrical team:

When panels look tight and load calcs are borderline

You’re forced to:

  • Pull in your electrician partner

  • Assume a 200A upgrade

  • Or price conservatively and hope it passes

You need clarity during the estimate and confidence to pass inspection

On borderline 100A services, upgrades are often assumed but not always required.

Stepwise verifies the panel’s actual capacity so you don’t rely solely on conservative load calcs.

Why Stepwise?

Stepwise is the creator of the Stepwise Tap load management system, installed on 100A service panels across hundreds of homes — all inspection-approved.

The data from these real installations is what allows us to review panels with confidence.

We’re not guessing at load behavior.
We’ve seen it across hundreds of panels.

How this fits a real job

Step 1: Take 2 photos during the estimate
– Breakers + panel cover
– Text them to 508-684-2402

Step 2: You receive a conservative electrical quote (<24 hours)
~ $1,000 most jobs
~ $2,000 when space is tight
~ $5,000 upgrade only when truly required
Note: Stepwise can work directly with your electrician partner

Step 3: Monitor when the job is borderline
– Installed by your team or ours
– Runs in parallel, no delay to design or scheduling

Step 4: Receive inspector-ready data report
– Use with permits/inspections
– Reduces guesswork and late changes

  • No. You take 2 photos during the estimate and text them to us.
    We return a conservative electrical path within 24 hours and often same day.

    If monitoring is needed, it runs in parallel with design and scheduling.
    No waiting on an electrician just to finalize the quote.

  • Inspectors look at two things: 1) safety and 2) available ampacity.

    We assess safety from the panel photos. If the panel is compromised, we recommend an upgrade.

    For ampacity, we provide documented usage data and inspector-ready reports so the decision isn’t based solely on conservative assumptions.

    Inspectors make the final call. Our role is to reduce guesswork and late surprises.

  • Data gives you clarity. There are two possible outcomes.

    • If the panel is already overloaded, monitoring provides documented evidence to justify an upgrade. That protects you at inspection and reduces homeowner pushback.

    • If the panel is near capacity but not unsafe, the data lets you choose: upgrade now or apply load management to control peak demand.

    Monitoring gives you data and credibility to recommend the right option.

  • Whichever works for your workflow.

    • Your service tech can install it during the walkthrough

    • Or a Stepwise electrician can handle it

    We coordinate directly so it doesn’t slow down your schedule.

  • No. If an upgrade is required, an electrician still performs the work.

    We can coordinate with your existing electrical partner or provide a certified Stepwise electrician if you don’t have one.

    Our role is to clarify the electrical path early so you can quote confidently.

  • Most residential heat pump installs rely on NEC Article 220 — typically the Optional Method under 220.82 — which applies demand factors to nameplate loads. That method is intentionally conservative.

    For existing dwellings, NEC 220.87 allows service sizing based on recorded maximum demand data (typically 30 days of load measurements). Stepwise uses monitored demand data to determine actual peak load rather than relying solely on theoretical assumptions. When panels are borderline, this gives you documented ampacity based on real usage.

    If load management is applied, it operates under NEC Article 750 to ensure the panel never exceeds safe limits.

    We still respect code calculations. Monitoring strengthens them when the panel is close to the threshold.

    • Borderline panels.

    • 100A services.

    • Homes where load calcs are close to the limit.

    • Situations where you’re unsure whether to assume an upgrade.

    If the panel is obviously undersized or unsafe, we’ll tell you upfront

  • Monitoring is only used when the panel is on the fence.

    It gives you data to justify avoiding a costly upgrade or confirms that one is truly required.

    Most homeowners prefer data over a blanket $5,000–$8,000 upgrade.

Frequently Asked Questions

Text us 2 panel photos to get started.

Text a panel photo

Or email us at sales@getstepwise.com