Indoor air quality · Air cleaners
An air cleaner in the duct system treats the air every time the blower runs. Whether it's worth adding depends on what you want gone, and on what the product can show about how it was tested.
Whole-home air cleaners mount in the return duct or at the air handler, so all the air the blower moves passes through them on its way back to the coil. That's the advantage over a portable unit in one room. When the system runs, the whole house is being treated.
The category is broad, and the products in it work in very different ways. Some are simply bigger, better filters. Some use an electrical charge to collect particles. Some use ultraviolet light, catalysts or charged ions to treat the air and the surfaces it touches. Carbon media go after odors and gases rather than particles. A comparison only makes sense type by type.
In home HVAC, "air scrubber" usually means a unit installed in the supply or return duct that shines a UV lamp on a surface coated with a catalyst, sometimes paired with an ionizer. As air passes through, the unit is designed to break down odor-causing gases and treat surfaces the air reaches. It isn't a filter. It does little for dust, and it does nothing for humidity, so it works alongside a good filter rather than in place of one.
An air scrubber makes the most sense when there is a specific target, such as lingering cooking or pet odors, in a house where moisture and the coil have already been checked. Before choosing one, ask for independent test data, confirm it is validated for zero ozone, and know when the lamp and catalyst cell need replacing. A lamp and cell past their service life keep running without doing much.
For particles like dust, pollen, pet dander and smoke, the most dependable upgrade is usually better filtration: a deep media cabinet that holds a high-rated filter without choking airflow. It's simple, the evidence behind it is strong, and the upkeep is a filter change.
For odors, carbon is the plain option. It adsorbs gases until it fills up, and then it gets replaced.
Products that claim to treat germs or chemicals in the air deserve more questions. Ask what was tested, by whom and at what airflow, and whether the device produces ozone. EPA advises against adding ozone to indoor air, and some ionizers and older electronic designs create it.
A lot of "air quality" complaints have causes an air cleaner won't touch. Dust that comes back days after cleaning can point to leaking return ducts pulling in attic air. A musty smell usually traces back to moisture: a dirty coil, a drain pan that doesn't empty, or a house that stays too humid. We check those first. Then, if an air cleaner or air scrubber would add something, we'll say which type and why.
| Type | How it works | Good at | Watch for |
|---|---|---|---|
| Media air cleaner | A deep pleated filter in a cabinet at the air handler or return | Dust, pollen, pet dander and, at higher ratings, much of the fine particle load | Has to be sized for the system's airflow, and the media is replaced on schedule |
| Electronic air cleaner | Charges particles and collects them on metal plates | Fine particles, with little resistance to airflow | Collector cells need regular washing, and some designs produce ozone |
| In-duct air scrubber | A UV lamp shining on a catalyst-coated surface inside the duct, sometimes with an ionizer | Designed to treat odors and gases in the air stream and on surfaces the air reaches | Results vary by product and by house. Ask for independent test data and zero-ozone validation |
| Ionizing devices | Release charged ions into the air stream so particles clump and settle | Varies widely by product | Claims often run ahead of independent evidence, and some produce ozone |
| Activated carbon | Adsorbs odor and gas molecules onto the carbon's surface | Cooking, pet and stale odors | Fills up over time and does little for particles on its own |
General characteristics of each technology. Specific products differ, so ask for their test data.
What it does
What it doesn’t do
What does it remove, and where's the independent test data?
A product sheet should say which pollutants it was tested against, by whom, and at what airflow. A test in a sealed chamber is not the same as a duct system at full blower speed.
Does it produce ozone?
EPA advises against devices that generate ozone indoors. Look for validation of zero ozone emissions, such as UL 2998.
What does it do to airflow?
Anything in the air path adds resistance. A static pressure reading before and after shows whether the system can handle it.
What's the upkeep?
Media, cells, lamps and carbon all need replacing or cleaning on a schedule. Know the interval and the cost of the parts before you commit.
Does the problem actually call for it?
Dust everywhere can mean leaky return ducts. A musty smell usually means moisture. Fixing the cause often matters more than adding a device.
Usually not on its own. Musty smells in South Florida homes mostly come from moisture: a dirty coil, a backed-up drain pan, or humidity that stays too high. Fixing the moisture is the real cure, and carbon media can help with odors once that's done.
EPA advises against adding ozone to indoor air, and some ionizers and older electronic air cleaners produce it. If you're considering a device, ask for validation that it emits no ozone, such as UL 2998, and for independent test data on what it removes.
Start with what you're noticing, whether that's dust, odors or a stuffy feel, and we'll look at the system before we talk about equipment.
Florida license CAC1821225
