sous vide in the oven?

I placed 3 qts of water and a thermocouple datalogger in the oven over the past couple days to see if an oven could hold a stable temperature.  The water's heat capacity certainly helps to smooth out the fluctuations, but I didn't realize how much.  This is just an excerpt of many hours of evaluation, but wow, it's pretty darn stable.  I was also surprised how much lower the temp of the water was compared to the atmosphere inside, must be the inefficiency in heat transfer?  Whatever, looks good enough to plan a big slab o steak!

In all 3 temp ranges, I didn't wait long enough for complete equilibration, but it looks promising.  Click on image to make it more readable.

Given the length of time required to equilibrate this system, it's lame compared to any circulator, but still a fun observation and good for intermittent use.