Find a HVAC contractor with experience in plumbing. Most HVAC contractors have some level of experience with plumbing, but you want someone with more experience than the average worker. You want to hire someone that will be able to handle every aspect of the hot water tank installation process. If you don't, then you may be stuck hiring extra hands to work on a project that could have been handled by one person. This isn't just inconvenient and time consuming. It is also much more expensive than just hiring one person to do the whole job.

Find out whether the contractor is insured. If the contractor is insured, then you should find out how much insurance he or she has. This is a very important component of hiring an HVAC contractor. Installing a hot water heater is a very routine thing that can create significant problems if it is done incorrectly. If your contractor has insurance, then you won't be held financially responsible if damage is incurred as a result of the work done by the contractor.

Get an estimate from the contractor you decide to work with. This estimate should include the cost of the water heater as well as the contractor's hourly wage. Some contractors only quote the hourly wage and conveniently forget to tell you what they expect the hot water heater to cost. This is usually used as a ploy to help the contractor look cheaper than his or her competitors.