WattShed Measure
See what the bills say changed after the work.
Export a home's monthly usage to CSV, choose that file here, and tell this tool which columns are the billing month and the kWh. It matches each month after a retrofit to the same calendar month before it, raw billed kWh against raw billed kWh. It is deliberately not weather-normalized: a hotter or colder year moves these figures. Every number it produces is an estimate from your bills, not a guarantee and not utility-grade M&V.
Everything runs in this browser tab: the CSV is read, matched, and compared on your device. Nothing is uploaded, sent to a server, or stored. Close the tab and it's gone.
A retrofit is easy to blur. Moved occupants, an added load, or a year that ran hot or cold can move these numbers as much as the work itself. Read the signals below before trusting the headline figure, and treat this as a first read, not a verdict.
1. Load usage
Choose a CSV file
Export a home's monthly billed usage to CSV, then choose it here. Or load a small example first to see how the check works.
Computed entirely in this browser. Your usage never leaves this device, and nothing is uploaded or stored.
Load usage and map its columns to see a savings estimate here.
No file handy? Load the example data to see the full report first.
Related tools
How it measures
Three rules worth knowing before you trust a number.
The pairing rule
Each month after the retrofit is matched to the same calendar month before it, up to twelve months on either side. The retrofit month itself is excluded, since it is neither fully before nor fully after the work.
What breaks the comparison
Moved occupants, an addition or a new major appliance, a home office added mid-year, or a year that ran unusually hot or cold can move these numbers as much as the retrofit did. None of that is visible from a column of monthly kWh alone.
Not weather-normalized
This reads raw billed kWh only. It does not adjust for degree days or a hotter or colder year, so it will not match a proper M&V read exactly. Weather-normalized measurement tied to a live program is the arranged tier, done with WattShed directly.
At least six paired months are needed before this tool will annualize a savings figure. Fewer than that, and the paired-month total is shown on its own, with no yearly projection attached.