Heating & AC Repair

Guide to HVAC System Options and Accessories

Use this article to get a feel for the types of options and accessories you may want to consider. For more detail on each of these, ask your trusted HVAC company or one of our more detailed guides on each of these areas.

Many companies offer premium accessories along with the replacement or repair of your HVAC system. While the accessories in this section have a purpose, don’t assume that you are at risk if you don’t have all of them installed. Some companies use fear tactics related to your health—For instance, they might show you what the inside of a few feet of your duct work looks like to scare you into additional purchases. In some cases there may be a valid reason to purchase these options. If you decide to purchase one, just be sure you understand what they can – and cannot – be expected to do. It could be that poor installation or configuration of the core system is the underlying issue and the recommended accessory is just a band-aid.

UV Lights

We see lots of units that have UV lights installed in the ductwork especially around the coil. The idea is that pathogens, mold, mildew, etc are growing inside your ductwork. The reality is that in most cases the UV lights have burned out or stopped working long ago. In certain situations a UV light might have a real benefit, but most often it’s used as an unnecessary add-on to increase the overall cost of the installation. 

Air Purification & Filtration

Every central air system comes installed with some method of filtering out particulates. It typically involves air filters that need to be changed or cleaned regularly as part of proper maintenance of your system. This type of filtration is sufficient for most households, but there are some situations where additional filtration is advantageous. Central air systems distribute air through your house through ducts in each room, and the air is recirculated through one or more air returns located inside the house. These air returns typically hold filters that remove dust and other contaminants from the air. Replacement choices for the most common sizes of disposable filters advertise various amounts of filtration, but this normal type of filtration system can only remove so much—It is only designed to allow one air filter and thus one level of filtration, and it cannot be used to catch the smallest particles without overly restricting the airflow of the entire system. When homeowners want additional improvements in air quality, supplemental air filtration and purification systems are available. These supplemental systems generally use their own fans in order to push the air through multiple layers of filters so they can catch much smaller particles and return significantly cleaner air. The type of supplemental system to be purchased will depend on the particular areas of concern for the homeowner, which may include pet dander, dust mites, outdoor allergens, or smoke of various kinds. Indoor air quality can also be affected by chemicals from cleaning products, offgassing of furniture or carpets, air fresheners, pesticide sprays and the like. A supplemental system integrated with your HVAC system provides benefits to your whole house, but some people choose to purchase freestanding units for individual rooms. Again this choice will depend on your particular situation.

Air Quality Monitoring

If you don’t know whether you should be concerned about your indoor air quality or not, your contractor might be able to recommend a good monitoring system. In these systems, sensors detect and record indoor air quality including temperature, humidity, and contaminants in the air

such as VOC’s, carbon monoxide, and increased particulates. These contaminants make up indoor air pollution that can be unhealthy for your family to breathe. Today’s airtight houses can continue to recirculate much the same air for long periods of time, so the peace of mind that comes from having this information can be worth the cost.


In the summer, central air conditioners remove humidity in the air of your home as it cools it down. If the air conditioner runs a sufficient portion of the time, it will generally be unnecessary to separately dehumidify the air. But depending on the design of your house and the preferences of your household, the air conditioner may not be enough — You don’t want to choose between an uncomfortably cold home and the problems caused by excessive moisture, such as mold and mildew. If only a particular area is problematic, such as a

basement, you might consider installing a separate unit for that room. In other situations, a whole house dehumidifier might make sense. 


In winter, the cold outdoor air naturally holds much less moisture. In general this means your indoor air, while warmer, will also be very dry. To make matters worse as your air is heated by your furnace or heat-pump additional moisture is lost. When this occurs, you will notice excessively dry air when you wake up in the morning — Your throat may be scratchy or simply feel dry. You may also notice that you get cracked lips or need skin moisturizer even if you don’t spend much time outside. Central humidifiers are available from most major equipment manufacturers. The humidifier needs to be sized appropriately to your system and set up properly to avoid introducing excessive moisture in your ductwork, which can cause unintended air quality problems. You should also plan to have regular maintenance on your humidifier. They will not run for years on end without regular maintenance and in extreme cases can become leaky and lead to other problems. 


A standard residential HVAC system has a single thermostat and a single area or “zone”. In other words, if all the heated or conditioned air is evenly distributed (as it should be), the entire house will be within a degree or two of the set temperature. A zoned system provides one or more additional zones with their own thermostats, providing greater temperature control throughout the house. A zoned system isn’t the same as having a unique system for each area of the house, but zone systems, in most cases are the most cost effective way to provided an added level of temperature control throughout a residence.  For more information about zoning, see our zoning guide.


There are a dizzying array of thermostats available. From basic digital, to WiFi smart thermostats, to “learning” thermostats like the Nest(r) it can be very difficult to choose one that meets your needs. We have a guide specifically for choosing a new thermostat so there is not point in going into more detail than necessary here. The best advice would be to figure out in advance which features you want and are likely to use. Many customers find they don’t use many of the features that are available on their expensive thermostats. An app to control it and some basic daily programming are the features most consumers would say they use the most. We do have a guide on installing your new thermostat that might be helpful.