A 'WordPress theme' is a way to roll out a structure / look on a WordPress site very quickly. ProHaus is one option for HVAC companies ($79), originally meant for plumbers and builders, Airtech is made for HVAC companies ($59), FreshAir ($49), and HeaCool ($59), are others. There is a lot of work to rolling out HVAC WordPress templates & themes – so use a little caution when you see the demonstrations, as they are hard to match. Always deploy 'sample content' whenever you use a WordPress theme as soon as possible after purchasing and before adding any content yourself.