Most people think that it’s only the filters that get dirty. That’s almost right. Almost. Your filters are going to be the first thing you notice being incredibly gross, but the entire HVAC system is exposed to the same types of dirt, pollen, and mold. These can sometimes get past the filter, but that’s not where the biggest problems lay.
The key parts to your HVAC system are often radiators of some sort (depending on the type of system). If you have hot water heat, you probably have baseboards, which are essentially radiators. Your air conditioner has two radiators, a condenser and an evaporator (these usually called Coils). The job of these devices is to move heat from one place to another. In some places we take heat from the air and put it into a refrigerant. in other cases we take it from the refrigerant and put it in the air.
When these things are designed, engineers use materials that are known to have incredible thermal conduction capabilities. We know that paper is an awful thermal conductor and that metals tend to be amazing conductors. Beyond that, we know that specific metals are better conductors than others, conduct into the air better, and we know the number of fins and distance between them necessary to get amazing performance.
Under ideal circumstances, especially when these products are fresh and new, they will work flawlessly. When the coils are all fresh and shiny, they have perfect contact with the air. Everything is at its very best. Nothing has had a chance yet to interfere with that air flow in any way. Time however, makes fools of us all, and eventually that perfect airflow isn’t so perfect.
Eventually, something will get between the air and the coil. This can be anything from leaves to dirt to bacteria and mold. This build up is not an ideal thermal transfer medium. The metals of your coil will readily give away heat. Coatings of mold? They’ll act more like an insulator. The heat will go from the coil to the gross stuff on it, and at half the speed, it’ll get out into the surrounding air.
There’s only one way to fight this issue: a good, thorough cleaning. There are numerous contractors that offer these types of cleaning services and in some cases, your own maintenance staff may even be able to do the work. There are two common approaches to this: chemical cleaners and steam cleaning.
Using chemical cleaners on your coils is a lot like cleaning any other surface in your facility. Typically a spray application is used here, as the coils are incredibly fragile and physically scrubbing them could damage them. The chemicals will kill bacteria and dissolve whatever is contaminating the coils. This does make them particularly harsh though, and will have a negative impact on the air quality of your facility until the vapors have dissipated.
The alternative approach is to use green cleaning techniques like Steam Cleaning. In this process, specialized equipment will blast steam over the coils at incredibly high temperatures. The heat will break down and loosen anything in your path. With dry steam, you can achieve similar results to using a high temperature torch, with none of the burning and equipment damage. This process requires pricier equipment, but it doesn’t stink up the facility or harm the environment.
Depending on the degree of obstruction, the performance increase after a cleaning will likely be significant. If your system has never been cleaned and it’s not new, this should improve its efficiency and reduce the amount of time it runs to do the same amount of work. With a dirty system, you’re basically driving with the parking brake on: destructive and harmful to your operation.