As part of the requirements set by Nevada for Home Inspectors I'm required to check built-in appliances. This includes Ovens and Ranges. What that actually means is up for interpretation by the inspector. Many turn on the oven and see if it gets warm. If it's warm it must be working, right? Not exactly.
Checking an ovens ability to cook properly is beyond the score of a Home Inspection but with a simple laser thermometer an Inspector like myself can get enough information to give the customer an educated report to it's operating condition. Ovens can get warm and not get hot. The recommended test temperature for an oven is 350 degrees. When an oven is turned on it will often run up to something like 400 and then shut off and then when it goes down to 325 it turns on again till it reached 375. This happens about three times then the oven will beep or signal that it's at the right temperature.
Most of the time we take for granted that the parts that control the temperature in the oven are working properly. While the oven may cook it might not be doing so at the right temperature. That's where my thermometer comes in during the home inspection process. I set the oven at the 350 degrees and wait for it to beep. I then open the door and take the temperature. With that reading in hand I'm looking to find something no higher or lower than 25 degrees from the set point. Anything beyond that I'm going to recommend that the appliance be checked out by a appliance repair person. The buyers now know that there maybe an issue with the appliance. I've found ovens as far off as 60 degrees below. Most of the time they are within the 25 degrees.
If the reading is just slightly outside the accepted limits then the repair may just be as simple as an adjustment. Most thermostats have a way to be adjusted. Even digital appliances can be adjusted. If you feel comfortable with doing a little DIY repair the link below will help guide you through the adjustment process that will work a majority of brands.