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Calcimator

Whole-House Surge Protector Calculator

Size a whole-house surge protector for your electrical panel. Calculate kA rating, cost, and ROI based on your home and risk profile.

Inputs

A
$
$

Results

Recommended Rating

100 kA

Protection Level2
Device Cost$250.00
Installation Cost$200.00
Potential Savings$3,688.00
ROI Ratio8.2x
How to Use This Calculator
  1. Enter your Panel Amps (100–400 A) and Home Value to size the protection level for your electrical system.
  2. Estimate Sensitive Electronics Value (computers, TVs, appliances) — this determines how much coverage you need.
  3. Select your Lightning Risk level (low, medium, high) based on NOAA ground flash density for your region.
  4. Review Recommended kA — the minimum surge current rating your whole-house protector should have.
  5. Check Protection Level (1–3) and Device Cost to select a unit at or above the minimum recommended kA rating.
  6. Use Potential Savings and ROI to compare the device cost against the electronics at risk from a single surge event.

How the result changes with Main Panel Size

Main Panel SizeRecommended Rating
13080 kA
205120 kA
295150 kA
370150 kA

What each input means

Main Panel Size
Main electrical panel amperage. Most modern homes have 200A service.
Home Value
Estimated home value for risk assessment and potential savings calculation.
Electronics Value
Total value of sensitive electronics: computers, TVs, smart home devices, appliances.
Lightning Risk
0 = Low (dry/mild climate), 1 = Moderate (seasonal storms), 2 = High (frequent thunderstorms).

What each result means

Recommended Rating
Surge protector kiloamp rating needed for your panel and risk level.
Protection Level
1 = Basic, 2 = Standard, 3 = Premium protection tier.
Device Cost
Estimated cost for a whole-house surge protection device.
Installation Cost
Estimated electrician fee for panel-mount installation.
Potential Savings
Estimated cost avoided from surge damage to electronics and appliances.
ROI Ratio
Return on investment: potential savings divided by total cost.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Main Panel Size = 200, Home Value = 350000, Electronics Value = 8000, Lightning Risk = 1 = 4 input(s) provided
  2. Calculate Recommended Rating
    Recommended Rating
    100 = 100
  3. Calculate Protection Level
    2 = 2
  4. Calculate Device Cost
    Device Cost
    250 = $250

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