Quick buying box — exact OEM parts and when to change them
Short answer: the Honeywell HPA300 uses Honeywell R HEPA filters (OEM part HRF‑R3) together with A‑type pre‑filters (pre‑cut A / HRF‑A300 in OEM kits). Replace the R (HEPA) element about once every 12 months under typical household use; replace the A pre‑filter every 2–3 months (sooner with pets, heavy cooking, or wildfire smoke).
Dimensions to confirm before buying: R HEPA ≈ 10.2 × 6.5 × 1.6 in; A pre‑filter ≈ 14.2 × 17.2 × 0.2 in (manufacturers list these sizes in their product pages).
Buy links (vetted pages on this site): Honeywell OEM value kit (3 R HEPA + 4 A pre‑cut) — $79.58 — https://airpurifierfaq.com/product/honeywell-hepa-air-purifier-filter-replacement-kit-for-hpa300-hpa3300-hpa5300-hpa8350-series-air-purifiers-value-combo-pack-includes-3-hepa-r-4-a-carbon-pre-cut-pre-filters/
Cheaper compatible packs we vet below: isinlive, APPLIANCEMATES, Funmit, Smilyan — see the “Recommended replacement packs” section for links and reasons to pick each.
OEM vs compatible filters — quick comparison
| Part / Brand | What’s in the pack | Fit / compatibility | Filter media | Replacement cadence (guidance) | Pros / cons |
|---|---|---|---|---|---|
| Honeywell (OEM) — HRF‑R3 + A pre‑cut | 3 R HEPA + 4 A pre‑cut | Designed for HPA300, HPA3300, HPA5300, HPA8350 | Honeywell R HEPA + activated carbon pre‑filters | HEPA ~12 months; A pre‑filter every 3 months | Best guaranteed fit and manufacturer support; higher price |
| isinlive | 3 HEPA R + 4 A carbon pre‑cut ($21.24) | Lists HPA300 series and replaces HRF‑R3/R2/R1 | HEPA + activated carbon + pre‑filter | HEPA 6–12 months; pre‑filter 2–3 months (vendor guidance) | Low cost; matches listed dimensions. Pros: value. Cons: vendor test data not Honeywell‑verified |
| APPLIANCEMATES | 3 True HEPA R + 6 A pre‑cut ($23.80) | HPA300 family; specifically lists HRF‑R3 | True HEPA + activated carbon pre‑filter | HEPA ~12 months; pre‑filter every 3 months | Good value if you change pre‑filters often; vendor claims True HEPA |
| Funmit | 3 R + 4 A pre‑cut ($27.06) | HPA300 series; lists HRF‑R3/R2/R1 | HEPA + activated carbon | HEPA 6–12 months; pre‑filter 2–3 months | Midrange price; vendor claims improved construction; no Honeywell testing shown |
| Smilyan | 6 HEPA R + 8 A pre‑cut ($37.98) | HPA300 series; replacement for HRF‑R3/R2/R1 | True HEPA + activated carbon pre‑filters | HEPA ~12 months; pre‑filter 2–3 months | Higher pack count, value if you prefer bulk; vendor efficiency claims should be verified on product page |
| Caveat: “Compatible does not mean comparable.” Honeywell warns that only genuine filters are guaranteed to offer the same performance or efficiency. | |||||
Recommended replacement packs (vetted picks)
Shortlist to buy now — each entry links to our product page with purchase options and pack contents.
- Honeywell OEM value kit — $79.58; includes 3 R HEPA + 4 A pre‑cut. Recommended when you want guaranteed fit and Honeywell’s stated replacement cadence.
- isinlive — $21.24; 3 HEPA R + 4 activated carbon pre‑cuts. Best budget pick when you want the lowest upfront cost and matching dimensions.
- APPLIANCEMATES — $23.80; 3 True HEPA R + 6 A pre‑cuts. Good value if you plan frequent pre‑filter replacements.
- Funmit — $27.06; midrange option claiming durable construction and low airflow resistance.
- Smilyan — $37.98 currently; larger pack counts (6 HEPA R + 8 pre‑filters) if you want to stock up.
How to replace the filters — photo‑led step sequence
Notes before you begin: power off and unplug the HPA300. Have new HRF‑R3 and A pre‑filter(s) ready. Use gloves if the old filters are very dusty. Follow local rules for disposing used filters.
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Step 1 — Position the unit so the rear panel is accessible
Rear of the HPA300: move the unit away from the wall so you can open the back cover fully. -
Step 2 — Remove rear cover
Unclip the rear panel by releasing the press‑fit tabs. No tools required on standard HPA300 models. -
Step 3 — Pull out the A pre‑filter
The pre‑filter sits in front of the HEPA R elements; pull straight out along the arrows on the frame. -
Step 4 — Remove the R HEPA element(s)
HPA300 uses R HEPA filters (stacked). Note orientation and any labels so you insert the new filters the same way. -
Step 5 — Insert new HRF‑R3 filters
Slide each HEPA R into the slots in the same orientation the originals occupied. Seat the filter fully to avoid gaps. -
Step 6 — Fit the new A pre‑filter
Place the pre‑cut A filter over the intake area so it lies flat and covers the full opening. -
Step 7 — Reattach the rear cover, test, and observe
Snap the rear cover back into place, plug in, and power on. If the unit has a filter indicator, check your owner’s manual for reset instructions.
Sizing & label checks — what to confirm before you buy or install
- Confirm R HEPA dimensions listed on the pack: 10.2 × 6.5 × 1.6 in.
- Confirm A pre‑filter (pre‑cut) dimensions: ~14.2 × 17.2 × 0.2 in.
- Look for explicit model compatibility (HPA300, HPA304, HPA3300, HPA5300, HPA5350, HPA8350) and references to HRF‑R3.
- Check whether the pack states “True HEPA” versus “HEPA‑type” and whether activated carbon is included if odor reduction matters to you.
- Remember Honeywell’s label: “Compatible does not mean comparable” — compatible filters may fit but aren’t guaranteed to match Honeywell’s tested performance.
Maintenance tips & replacement cadence for edge cases
- Heavy pet hair or lots of occupants: replace the A pre‑filter every 1–2 months; inspect the HEPA at 6 months and replace earlier if it looks discolored or airflow is reduced.
- Wildfire smoke exposure or frequent indoor smoke: replace pre‑filters every 1–2 months and consider HEPA replacement toward the lower end of the 6–12 month range if the unit runs continuously during smoky periods.
- Low‑use seasonal homes: pre‑filters still collect dust — check every 3 months and replace if visibly soiled; HEPA can often reach 12 months in light use.
- When in doubt follow these cues to replace earlier: visible darkening of the HEPA pleats, a measurable drop in airflow, or persistent odors that carbon pre‑filters no longer stop.
- Disposal: seal used filters in a bag and follow local waste/recycling rules for fibrous filters and activated carbon materials.
For a deeper look at the HPA300’s strengths, limits and CADR numbers, see our full review: Honeywell HPA300 Review: Specs, Strengths & Limitations. For general model replacement guidance, visit our Air Purifier Replacement Filter Guide by Model.
