Pro HVAC company Southern Comfort Mechanical says on its blog, “If there’s mold growth inside the handler due to excess moisture, algae in the condenser drain line or a dirty evaporator coil, it can negatively impact your AC unit’s efficiency. The filters inside may also build up excess dirt and become clogged, which will also make your AC [or heat pump] waste energy trying to sustain the cool climate inside your home.” These issues are easy to solve. They don’t require replacing the air handler.
Whether or not central air adds value to your home depends on your location. You probably won't recoup the entire cost for the installation, as it is an expensive project that isn't as flashy as something like a new deck. But this invisible upgrade can help you sell your home if you live in a hot climate. And many buyers are willing to pay a bit more for a working AC.
PickHVAC Tips: Installing the right size central air conditioner is extremely important. Have a load calculation done to ensure proper sizing. ACs that are too big aren’t as energy-efficient as they should be, and they cycle on and off too much. This creates over-cooling and temperature imbalance. Units that are too small run constantly in very hot weather and can’t keep your home cool. When an air conditioner is properly sized, it runs at optimal efficiency and indoor comfort.
Installation: The old furnace is disconnected from the ductwork plenum, exhaust flue, gas and electrical hookups. In most cases, a new plenum must be made onsite or ordered from a local sheet metal fabricator. A new vent might be required too. The furnace is set and reconnected. Adjustments to the blower fan speed and burner are made to optimize furnace performance for your home and climate.
An important component of natural ventilation is air change rate or air changes per hour: the hourly rate of ventilation divided by the volume of the space. For example, six air changes per hour means an amount of new air, equal to the volume of the space, is added every ten minutes. For human comfort, a minimum of four air changes per hour is typical, though warehouses might have only two. Too high of an air change rate may be uncomfortable, akin to a wind tunnel which have thousands of changes per hour. The highest air change rates are for crowded spaces, bars, night clubs, commercial kitchens at around 30 to 50 air changes per hour.
Be careful of dishonest HVAC contractors. There’s no magical formula to see if an HVAC contractor is scamming you, unfortunately, but remember that they typically do this in one of two ways: first, they are charging grossly low prices (far below everyone else), or second, they aren’t including what everyone else is. In the first situation, they will charge you change fees, other hidden fees, or they stole the equipment and are passing themselves off as legitimate contractors (very common in California these days). In the second situation, they are charging you a very fair price, but aren’t including what the other contractors are (i.e. charging $10,500 for the installation which is fair, but not including the ductwork which is a scam unless there is some other, complex stuff going on there).
HVAC professionals in the US can receive training through formal training institutions, where most earn associate degrees. Training for HVAC technicians includes classroom lectures and hands-on tasks, and can be followed by an apprenticeship wherein the recent graduate works alongside a professional HVAC technician for a temporary period. HVAC techs who have been trained can also be certified in areas such as air conditioning, heat pumps, gas heating, and commercial refrigeration.
Fuses -- Anyone who has worked with electrical systems knows all about fuses and how they fail. They can burn out over time, may just be loose, or can blow out during an electrical storm or due to overload from another failed component. Of course, that's what they're supposed to do; they stop surges from going through and damaging the rest of the system. When a fuse fails, whatever system it was protecting will stop working.