Some companies may require a 10% deposit, some may not require any. For larger projects, you'll almost always need to give a deposit, and it's good to ask how much the deposit will be before going forward with a project. The Evansville contractor will know how much they need for a deposit when they've given you the estimate, so ask early.
Does the HVAC job require permits? If so, will you be pulling them yourself?
Many jobs in Indiana will require municipal permits in order to be approved by the town's inspector. It's always good to ask who will be responsible for pulling those permits, and if you'll be expected to do it. You'll almost never be told to pull your own, but knowing that Evansville HVAC permits are required makes you appear to be a well informed customer.
What is your projected timeline for the HVAC project in Evansville?
Though a standard question, it's important to ask. Most contractors will tell you how long they expect the job to take without you asking. If they don't volunteer that information, be sure to ask. It's also helpful to ask if that's a hard finish date, meaning that it's the definite finish date. If it's a soft finish date, it may be extended for any number of reasons.
Do you work with subcontractors?
The question is great for some industries and non-applicable for others. A general contractor, for example, will by definition employ subcontractors. Most Evansville HVAC companies do not, but there are exceptions. You should always ask this question to your service providers. If they do use subcontractors, ask if they're all licensed and insured independently.
Are you union or non-union?
This really only matters if you have preference, but it is good to ask. If you have a strong ideological belief about unions or nonunions, it's perfectly acceptable to make a decision based on the preference.