No one has addressed mfg homes and doesn't seem any of the comments are from people in So CA which of course does make a difference as my dust comes from the outside not from the vents. My windows are open pretty much 365 days a year. Secondly mfg homes don't have basements or attics I keep mine clean with my vacuum as they are only about 2 ft deep. I purchased my home 10 yrs ago and it is a high end home but have never had a problem. I clean my furnace filter about twice a month as I have cats and most everything in there is cat fur. I am not saying they don't ever need to be cleaned but I am questioning mfg homes, I also clean my own filters in my AC unit outside as the HVAC guy told me too he QUATITY they would sell. I use this same company every year now for my tune up and inspection which takes them about 10 minutes. Not a bad return for them and I don't mind the $79 fee. If anyone has more info than this on mfg homes please let me know!
Filtration systems -- A second-stage filter is sometimes inserted & used to remove particulates such as pets, smoking or cooking, as well as other odors, gases, and VOCs (volatile organic compounds). A HEPA filter is also available to remove spores, pollens, bacteria and lung-damaging particles. There are also systems that use ultraviolet (UV) light to protect against bacteria and germs.

The performance of vapor compression refrigeration cycles[26] is limited by thermodynamics. These air conditioning and heat pump devices move heat rather than convert it from one form to another, so thermal efficiencies do not appropriately describe the performance of these devices. The Coefficient-of-Performance (COP) measures performance, but this dimensionless measure has not been adopted. Instead, the Energy Efficiency Ratio (EER) has traditionally been used to characterize the performance of many HVAC systems. EER is the Energy Efficiency Ratio based on a 35 °C (95 °F) outdoor temperature. To more accurately describe the performance of air conditioning equipment over a typical cooling season a modified version of the EER, the Seasonal Energy Efficiency Ratio (SEER), or in Europe the ESEER, is used. SEER ratings are based on seasonal temperature averages instead of a constant 35 °C (95 °F) outdoor temperature. The current industry minimum SEER rating is 14 SEER.[27][dead link]
Is there a such thing as a PQ-15 valve? No…but how do we know? And oh, by the way, there are only two types of line-sets: 3/4 inch, and 7/8 inch. All modern equipment runs on a 7/8 inch line-set, so the only time they’ll have to change something is if you have antiquated 3/4 inch line-set from the 60’s or 70’s. I’m digressing though…the point is that they can easily prey on uninformed consumers…like you, baby bird! Don’t worry though…you’ll be flying by the end of this article.
Cost Factors: The size of the unit, its efficiency and it’s single-stage, two-stage or variable-capacity are the top cost factors. Features like communicating technology and improved dehumidification performance also affect the price. Learn more about communicating technology here including the pros and cons, before being agreeing to a communicating system.
Clean air delivery rate is the amount of clean air an air cleaner provides to a room or space. When determining CADR, the amount of airflow in a space is taken into account. For example, an air cleaner with a flow rate of 100 cfm (cubic feet per minute) and an efficiency of 50% has a CADR of 50 cfm. Along with CADR, filtration performance is very important when it comes to the air in our indoor environment. Filter performance depends on the size of the particle or fiber, the filter packing density and depth and also the air flow rate.[30]
Central home air conditioner service systems consist of two major components: a condensing unit that sits outside your house, and the evaporator coil (often referred to as an A-coil) that sits in the plenum of your furnace or air handler. The refrigerant in the A-coil picks up the heat from your home and moves it to the outdoor condensing unit. The condensing unit fan blows outside air through the condensing coil to remove the heat. The condensing unit houses the three parts replaceable by a DIYer: the AC contactor, the start/run capacitor(s) and the condenser fan motor. The condensing unit also houses the compressor, but only a pro can replace that. The A-coil has no parts that can be serviced by a DIYer.