Once a month is a pretty good rule of thumb for most people. Depending on where you live and how much dirt, pet dander, and other contaminants are present, the answer could be more or less. Check your filter frequently to determine if it’s dirty. If it is, change it.

There’s no easy answer for this one. A lot of factors will go into what size heating and cooling unit you’ll need. The type of house you own, its walls, insulation, attic space, and more can go into determining what size unit is required. A system that is too large could result in a home that’s too humid, causing problems with moisture and mold. A system that is too small will run constantly, running up your energy bill. Only a qualified heating and cooling technician can determine what size unit is best for your home.

In most cases, the answer is yes. There are a variety of reasons why you should replace both the outdoor and indoor units simultaneously. For starters, air conditioner and heat pump outdoor units are manufactured to work with a matched indoor unit. When you mix and match units, it can result in reduced efficiency and performance.

Also, if you bought your indoor and outdoor units at the same time, your indoor unit will probably be approaching the end of its useful life at about the same time as the outdoor unit. By not replacing the indoor unit too, all you’re doing is delaying the inevitable and likely paying higher energy bills at the same time.

By purchasing indoor and outdoor units simultaneously, you’ll get a warranty covering the whole system, meaning that you won’t have to cover the full cost of any needed repairs to your unit during the warranty period.

While covering your unit can prevent unwanted debris from accumulating on the unit, it can also cause problems if you try to operate it with the covering in place. If you’re going on a long trip and plan to turn the unit off while you’re gone, feel free to cover it up. Just make sure you disconnect the power source before leaving.

There are a lot of reasons why your air conditioning system might freeze up, and all of them require help from a professional technician to resolve, as only they have the training and correct tools to fix the problem.

Ironically, low refrigerant can cause your system to freeze up. Over time, wear and tear to your system can result in leaks that cause the system to lose refrigerant. When your unit loses refrigerant, it causes the system to freeze up because of low pressure inside the system.

When freon levels are low, the refrigerant still is forced to expand to the same amount. The more that expansion occurs, the cooler the temperature is produced. The colder temperature will cause moisture in the air around your unit’s evaporator coil to freeze, eventually icing up the coil and impeding its function.

Dirty evaporator coils can cause units to lose airflow and, eventually, cause the system to freeze up. Defective blower motors can also cause freezing.

Indoor air quality is a major concern, as many studies show that air pollution is much worse indoors than outdoors. You can improve your indoor air quality with frequent dusting and vacuuming, and you can also have a qualified technician install devices such as UV light units, special air filters, and electronic air cleaners to improve indoor air quality. Poor indoor air quality has been linked to many illnesses, so improving your home’s air quality is an investment worth making.