DayWatcher can save you thousands of dollars each year!

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What is DayWatcher?

The DayWatcher is a fully automated Degree Day System that logs Heating and Hot Water Degree Days for Fuel Delivery suppliers. It also has the ability to calculate Cooling & Growing Degree Days for Energy and Agricultural industries.

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Works with your PC

Export your degree-day information to your PC-the DayWatcher connects quickly and easily to your computer’s USB or serial port.

Easy-to-read screens

The DayWatcher's easy-to-read face lets you get weekly and monthly degree-day totals, the time, and other information with a quick glance.

Space-saving size

Johnson Degree Day has distilled decades of experience with degree-day meters into the DayWatcher's compact, space-saving size.

Includes everything

The DayWatcher comes with all the pieces and parts you need to get your degree-day logging system up and running quickly.

What's Included

The DayWatcher Degree Day logging System comes
with everything you need to get started.

The DayWatcher Inside Unit
AC Adapter
Three AA Batteries
Radiation Shield with Electronics Module


With over 50 years of fuel management expertise, we know how to use accurate degree day logging to save you money.

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Eliminates Daily Posting
Increased Profits
No More Guessing
Pays for Itself in Weeks

High-Low Method vs. Our Method

The High-Low Method

The High-Low is an average of the daily high-low temperatures. Most web-based calculators use this method and has large amounts of error. Here is a math example to prove it:
(80.1° + 52°) / 2 = 66.05°
65° – 66.05° = -1.05
Heating Degree Days – 0.00

But is this really an accurate way to measure degree days?

Johnson Degree Day’s Method

Our method collects thousands of data points each day to graph the temperature and calculate the exact degree day in your area.  The DayWatcher is a local weather station unlike the NWS which could be miles away in different weather patterns than your customers.

Using the same information as the example above, we have expanded the data to show the temperature hour-by-hour (as indicated by the blue line). The grey line indicates the baseline of 65° (as was also used in the High-Low method).

The shaded area is used to calculate the actual degree days. As you can see, it’s quite different than what the High-Low method calculated:

Heating Degree Days – 3.89

How the High-Low method costs you money

Even though the difference between the High-Low and Johnson Degree Day methods is only a few degree days in a 24-hour period, think about how that small error can build up over time.

A small difference can build to a very large one in a matter of a week, a month, a season and especially a year.
Without an accurate picture of what’s really happening, you could be throwing away thousands of dollars in a year. The potential savings from using the DayWatcher could pay for its cost in a matter of weeks.