"how heavy is" is a correct and usable phrase in written English.
It is commonly used in questions to inquire about the weight of an object. Example: "How heavy is the package I need to lift?".
How heavy is the person's workload?
How heavy is your frying pan?
How heavy is the asylum-seeker burden Audio and Video content on Economist.com requires a browser that can handle iFrames.
In asking about size, one asks How big is it?; about weight, How heavy is it?; and about evaluation, How good is it?
Whether one wants to be reminded of this with her morning coffee is, of course, a personal decision — how dark is your humor, how heavy is your pathos.
How heavy are the drums on those songs?
It would be hard to describe, or, in later years, believe, how heavy was the weight of every single word in those days.
"Come far?" "How heavy's all that gear?" But nobody said anything; they just looked at me as if I were some sad freak, and I couldn't help wondering whether money sucks all the romance out of your soul.
