What about electric stoves? Do they have BTUs too?
The heating power of electric stoves tends to be measured in watts, instead of BTUs. You can directly convert a heat measurement in watts to BTUs (per hour).
More BTUs are automatically better than less, right?
Not necessarily! The macho stoves with enormous amounts of BTUs and crazy high flames are very fun to play with, and great for restaurants that are constantly putting out high-heat seared food. But in a home kitchen, the premium you will pay for a lot of extra BTUs is not necessarily better. Professional ranges can scorch your cookware and be hard to handle on a normal schedule of cooking.
How many BTUs should my stove have?
This is the key question, right? A home stove has, on average, about 7000 BTUs per burner. Some burners are lower, designed for simmering and low-heat cooking, and may put out 3000 to 5000 BTUs. And there may be one monster burner on a range that goes up to 12,000. (That's the one you always put your pasta pot on!)
Ultimately, you want to make sure your stove has enough BTUs to quickly boil a large pot of water, but that there is a large and effective dynamic range between all the burners. You need to be able to simmer on low, fry on medium, and sear on high. If your stove jumps quickly from low to high heat or doesn't ever do low heat at all, that's not very helpful. A responsive dynamic range and easy control is more important than sheer BTU numbers.
The one other place that BTU numbers come into play is choosing a range vent hood. Hoods are calibrated to handle certain amounts of BTUs, so when you are picking out a new hood, make sure you know how many BTUs your stove puts out.
Do you have a high BTU range?