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StopWatt

How to measure results

StopWatt before and after: measuring it properly

'Before and after' photos and bill screenshots are common in ads for energy gadgets, but they are easy to stage or take out of context, and we won't publish any we can't verify. Instead, this page walks through exactly how to build your own credible before-and-after comparison at home.

By the StopWatt official store teamUpdated

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Quick answer

We don't publish customer bill screenshots because we can't verify the conditions behind them (weather, occupancy, rate changes). We'd rather help you run your own controlled comparison.

Why we don't publish before/after bill screenshots

A screenshot of a bill total dropping between two months could be caused by weather, occupancy changes, rate changes, or a shorter billing cycle — not necessarily anything you installed. Without controlling for those variables, a screenshot proves very little, so we'd rather show you how to do a controlled comparison yourself.

The variable to isolate: kWh, not dollars

Your bill total in dollars moves with utility rate changes, time-of-use pricing, and seasonal demand charges — none of which have anything to do with StopWatt. Kilowatt-hours (kWh) consumed is the number that reflects actual usage, so that's what a fair before-and-after should compare. Our electricity cost calculator can help you translate kWh changes into dollar terms once you have real numbers.

A simple before-and-after protocol

PhaseDurationWhat to record
Before1-2 full billing cyclesTotal kWh, major appliance run patterns, thermostat settings
InstallDay 1Placement location(s), date, outlet used
After1 full billing cycle minimumTotal kWh under the same routine and similar weather
CompareAfter cycle endskWh vs. before, and vs. same month last year

Controls that make your comparison meaningful

  • Compare against the same calendar month a year earlier when possible, to reduce weather bias.
  • Keep thermostat setpoints and major appliance habits roughly consistent across the two periods.
  • Note any changes in occupancy (guests, vacations) that could skew usage independent of the device.
  • If you have a smart meter or utility app with daily/hourly data, use it — daily-resolution data isolates changes faster than a single monthly total.

Following the installation guide matters

Placement affects what you're even measuring. Install units near your largest inductive loads as described in the installation guide — a unit plugged into an outlet far from any motor load isn't positioned to show a meaningful before-and-after difference.

What a realistic result looks like

Plausible outcomes

  • A modest kWh reduction in homes with meaningful motor-driven load
  • Essentially no change in homes with mostly resistive loads
  • A result that's consistent when you re-check the following cycle

Not a fair test

  • A single-month dollar total compared against a different season
  • A comparison during a rate change or new tiered pricing plan
  • A comparison where occupancy or routine changed significantly

If your before-and-after doesn't show what you hoped

That's exactly the situation the guarantee is for. You can return the units within 60 days of delivery for a refund of the purchase price, no elaborate justification required. Every order from this official store includes free worldwide shipping, delivery in 1-2 business days to processing, and a 60-day money-back guarantee on the purchase price.

Ready to run your own test

Start your before period now, then buy StopWatt from the official store or check StopWatt bundle pricing for multi-unit discounts if you plan to place devices near more than one load.

60DAYS

60-Day Money-Back Guarantee

Test StopWatt for a full billing cycle. Return it within 60 days of delivery for a refund of the purchase price.

Issued by the official StopWatt store · Refund of the purchase price

Frequently asked questions

Can you show me real before-and-after bills from customers?
We don't publish customer bill screenshots because we can't verify the conditions behind them (weather, occupancy, rate changes). We'd rather help you run your own controlled comparison.
How long should I test before deciding?
At least one full billing cycle under your normal routine, ideally compared against the same month a year prior to reduce weather-driven noise.
What number should I actually compare — dollars or kWh?
Compare kWh. Your dollar total is also affected by rate changes and time-of-use pricing that have nothing to do with the device.
What if my before-and-after shows no change?
That is a possible, legitimate outcome depending on your home's wiring and appliance mix. Return the units within 60 days for a refund of the purchase price.
Does placement affect my before-and-after result?
Yes. Units placed near your largest motors, pumps, or compressors are positioned to show the most meaningful difference; see the [installation guide](/installation-guide) for placement tips.
Should I test with one unit or several?
If you have multiple heavy motor loads on different circuits, testing with more than one unit (see [StopWatt bundle pricing](/price)) gives a more complete picture than a single unit on one circuit.

Keep reading on the official StopWatt site

Ready to order? Buy StopWatt direct or compare StopWatt bundle pricing.

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Pick the bundle that matches your home size, then complete your order securely on this page — no redirects, no account required.

Sizing rule of thumb: one device per 800–1,200 sq ft, so most homes over 1,500 sq ft use the 3-device bundle.

Checkout — 3 Devices

$105.84

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Prices in USD. The bundle price shown is the full discount — there is no code to hunt for. Add-ons available only here: add 1 extra stopwatt and 3-year replacement protection.