$10-$3x range. All depending on years of experience, certifications, what your speciality is in the hvac field, and company you work for.
If you have knees issues now, it will only get worse unless you land a gravy job. Honestly the hvac has its ups and downs. I have been doing it for 12+ years and am wanting to get out of this field but that is for my own reasons. It is a seasonal trade. If the weather is blistering hot or a frigid cold there will be work. But usually the winter/spring time area it slows down. One last thing, tools, consider it an investment. Dont buy crap as you will purchase same tool multiple times.
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