This first thing you need to think about with concern with any kind of HVAC system is that price does matter. Not only should you shop around for the best price, but you also need to look into customer reviews and ask some experts about their opinion on those units that are within your price range. Knowing your price range first is very important. Instead of being swayed into buying something extremely expensive because the installer claims it is the best, you can present to them only what is doable for you and get a much more honest answer.
Whatever kind of HVAC you may have it is imperative you make sure it is installed by a trustworthy professional. Even if you purchase a low-end system, the lifetime of that system can be greatly extended by getting expert installation. Look for a company that is associated with the Better Business Bureau, in a positive way of course, and see how long the company has been around. Five years or less means they are barely keeping their head above water. A decade or two means they have a large customer base. A couple generations means they know what they are doing better than anyone else in their area.
Regular maintenance should be the constant mantra of any HVAC owner who wants to keep down heavy repair costs. You may be thinking that your HVAC in St. Louse is working just fine so why pay the small maintenance fee now if you can avoid it. However, that would be the kind of thinking that causes large fees in the future. Regular maintenanceensures you keep your heating and air conditioning in prime condition so you never get stranded without it on the coldest or hottest days of the year. Replace a small part today or pay to replace the entire unit tomorrow; it is your choice.