I'm in a new house, and the cook is getting frustrated with our new cooktop. Water takes a long time to boil and when it finally does, there is no way to simmer as it is now too hot. Is this normal behavior? How can I test the stove for normal operation?
I had the exact same experience after my wife bought a glass top stove for our kitchen. I had many pots boil over and burn the first year and I hated the beast. It took some experience and practice to get a feel for how the glass stove performs. I eventually learned how to anticipate something coming to a boil and turning down the heat early enough to avoid a problem, though it still happens at times. Simmering a covered pot takes a far lower setting than you would naturally think if you have are used to a gas stove.
It is not like a gas stove where you can turn down the heat and immediately see a change. The glass stove tops take a little longer to get up to temperature and then retains heat for some time after you turn down the setting. I think this is normal behavior.
I agree with woodchips' advice about checking the bottom of your cookware for flatness. The more surface area in direct contact with the glass the better it will work.
A reason for this may be your pots and pans. A glass cooktop works best with flat bottomed pans. This gives better heat transfer into the pan from the cooktop.
Take a straightedge, and place it against the bottom of your pans. If they are deeply dished or they are warped, then you may need a new set of pans.