Installing a whole-home air purifier in Sunnyvale, Santa Clara or Cupertino means adding filtration or treatment to the furnace or air handler you already have, usually on the return side in a hall closet, garage or attic. Mounting the equipment is the easy part. The real work is choosing a device your blower can push air through, sealing it so air cannot slip around it, and confirming afterwards that airflow did not drop. Start with the problem: smoke, dust, allergies or odors each point to a different device.
Whole-home purifier types
| Type | What it does well | Limits |
|---|---|---|
| Media filter cabinet, 4 to 5 inches deep | Fine dust and smoke particles with low airflow resistance | Needs space at the return; periodic filter replacement |
| Bypass HEPA unit | Very fine filtration of part of the air, with its own fan | Takes floor or wall space and power; separate upkeep |
| Electronic air cleaner | Collects particles on charged plates that can be washed | Plates need regular cleaning; choose a model that makes no ozone |
| UV lamp at the coil | Keeps the coil and drain pan clean | Little effect on airborne particles; lamps need replacing |
| Carbon or odor filter | Some odors and gases | Saturates over time; weak on fine particles alone |
Portable, Sensi or whole-home?
A portable unit, whether a Sensi air purifier or any other brand, cleans the room it sits in, all day, with no effect on your ducts. A whole-home purifier cleans the air in every room the ducts reach, but only while the system fan runs. When comparing, look at room coverage, the yearly cost of replacement filters, noise at the speed you will really use, and whether the choice affects HVAC airflow.
A portable unit is the better fit for a home without ducts, such as an Eichler heated through the slab, for a single bedroom, or for a rental. Whole-home makes more sense in a ducted house where several people react to dust or smoke. Many homes end up with both: whole-home filtration plus a portable unit in the most sensitive bedroom.
What we check before installing
- Static pressure with the current filter, measured against the blower’s rating.
- Return size and filter location. One undersized return grille is common in older homes and limits what can be added.
- Return duct leaks between the filter and the blower, which let unfiltered air bypass the new equipment.
- Space and power. Room for a cabinet in the closet or attic, and an outlet or circuit for electronic, UV or bypass units.
- Your goal. Equipment chosen for allergies is not always right for smoke odor, and the reverse.
You get the findings, the options and the cost factors before installation starts.
How the installation goes
- The cabinet is set into the return plenum or at the air handler inlet, and every seam is sealed with mastic or foil tape so air passes through the filter, not around it.
- A UV lamp mounts near the indoor coil, where it can be reached for lamp changes.
- Electronic and bypass units are wired and their controls set.
- If it helps, the thermostat fan is set to circulate on a schedule.
- Static pressure is measured again to confirm the blower still moves enough air.
- You see how to change the filter or clean the plates, and get the exact filter size written down.
Before smoke season
Install new filtration before late summer, when smoke days usually start, and keep a spare filter on hand. During a smoky stretch, run the fan, keep windows closed and check the filter afterwards. See wildfire smoke filtration for the smoke-specific details and our indoor air quality page for humidity, ventilation and allergy options.
Local notes
Furnaces in 1950s–1970s homes around Sunnyvale, Santa Clara and Cupertino often sit in tight hall closets or attics, and the space around the return decides which cabinet fits. Condos with compact mechanical closets may only have room for a slimmer media filter or a portable unit. Related work: air filtration systems, UV light air treatment, humidifiers, dehumidifiers, ventilation and duct cleaning. City pages: Sunnyvale, Santa Clara and Cupertino.