Cyclette is way much better when outside is really cold. 30 minutes everyday would be' fine?
Yeah, that is what I was thinking for the cyclette, atleast you can do it inside when all the snow is outside.
As far as the time on it, that really depends on what you are wanting to accomplish. You were asking about best cardio, so that is why I said to get your heart rate to the level of 60-80% which is what is really needed to improve your cardio output. But many endurance athletes have found they get their best results from just going at these intense level for 1 workout a week, possibly 2x/wk, which has worked well for me as well. You could do intervals at 2-3 minutes at that heart rate, take 1 to 2 minutes to recover(depending on your fitness) then go at intense higher heart rate interval again, getting atleast 15 minutes of time at the higher heart rate. But if you can do 30 minutes of interval time, that would be good too.(so the 1-2 minute recovery time does not count towards the 15 minutes)
If you are wanting to lose weight as well, then on your other workout days you may want to go up to an hour on the cyclette, but at a slower pace and lower heart rate.
To find your max heart rate, take 220 and minus your age. Then do 60-80% of that max number during your intense intervals. So for example, if you are 20 yrs old, your max heart rate would be 200(220-20) and 60-80% of that would be 120-160 heart beats per minute.