Plainly, because this is the page most sites in this trade refuse to write:

Charm City Air Care is a marketing and referral service operated by ZT Direct LLC. It is not a heating and air conditioning contractor. When a homeowner calls Call for same-day help, writes to [email protected], or submits the estimate form, the request may be shared with an independent local HVAC contractor who performs the work, and ZT Direct LLC may be paid by that contractor for the referral or the completed job.

The household's agreement, price, scheduling, and any warranty on the work are between the household and the contractor who performs it. The contractor confirms the price before work begins. This site publishes typical planning ranges for household planning only; they are not the contractor's prices.

A homeowner is free to hire any contractor, referred or not, and owes this service nothing for the estimate, which is free, hassle-free, and without obligation whether or not any work follows from it.