On a similar vein....

We also have a microwave/ oven/ grill thing but the LCD screen stopped
working years ago - luckily we only use it to warm food/ baby bottle
so can operate it blindly!!!

We moved the microwave to another room the other week and all of a
sudden it seems to be more efficient. A few times a day we warm water
for my daughters bottle in the bottle itself. So each time it is the
same volume of water and same size bottle. Anyway for the past 6
months, 40 seconds was fine (sometime 50 in the winter because the tap
water is colder!!). A few weeks ago, this seems to have reduced to
around 20 seconds!!! Whilst on the surface this seemed a good thing.
Should I be worried????

thanks

Lee.