The oven works well,  however the preheat takes a very long time.   First times using it kept burning all my baked goods so I got it calibrated.  Found out it hold the tempura tire at the set level,  however on preheat it will add 40-50 degrees to the set temperature.  So I’ve been putting my biscuits into a 450 degree oven instead of a 400 degree oven.  Now I wait for preheat to end.  Open the door for a full minute so the heat will go to set, then put my product in.  Very wastfull and annoying.