The following tests were done to ensure temperature sensor accuracy.
These tests were done with an extremely accurate commercial sensor plugged into a Heat Guardian base unit. Temperature readings were taken for both sensors every 30 seconds.
To get a range of temperatures, we cause a slow temperature ramp. The commercial sensor takes longer to react to temperature change so it lags the Heat Guardian in the early stages where the large temperature differential causes faster temperature shifts.
The Heat Guardian is extremely accurate. In our tests it was within 1/2 degree of the reference at almost all times between the tested temperatures of 40°F and 120°F.
In this test, we placed the Heat Guardian + sensor in a cooler in a refrigerator. After they got cold we removed the cooler (containing the two) from the refrigerator and placed it in a small box so the heating process would be very slow.
As noted on the chart, the unit and sensor start out the same. As the systems warm the Heat Guardian reacts more quickly but soon the two are almost exactly in sync.
In this test, we placed a Heat Guardian + sensor outdoors in the sun in a cooler. After it heated up the cooler was brought indoors and the temperature monitored as the system cooled off inside a second container - to slow the heat loss and let both sensors settle more.