Verdict: The Dyson Purifier Hot+Cool Formaldehyde HP09 is an impressively versatile appliance that combines a purifier, fan, heater, formaldehyde sensor, app control, and voice control. However, its high price is difficult to justify for particle purification alone. The reasons to buy it are its all-in-one design and formaldehyde-focused hardware—not class-leading clean-air delivery.
Independent testing measured a PM1.0 clean-air delivery rate of 87 m³/hr (51 CFM), with a recommended maximum-speed room size of only 7.4 m² (80 sq. ft.). At a quieter setting, the estimated room size fell to 3.5 m² (38 sq. ft.). These results matter more than the HP09’s H13-grade filter description when deciding whether it suits a bedroom, renovation project, or living space.
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Quick verdict
| Category | Assessment |
|---|---|
| Particle purification | Good filter technology, modest independently measured airflow |
| Formaldehyde | Distinctive sensor and catalytic system, but real-world residential removal performance is not independently established by the available evidence |
| Heating | Useful localized electric room heating |
| Cooling | Fan airflow only; it is not an air conditioner |
| Noise | Comfortable at low speed, substantially louder at maximum speed and with heat enabled |
| Running cost | Expect a replacement filter approximately every 12 months, plus electricity |
| Value | Weak for purification alone; more defensible as a premium multi-function appliance |
Best for: someone who wants one premium appliance for a small room, occasional heating, air circulation, app monitoring, and formaldehyde awareness after furnishing or renovation.
The Tool Desk
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#1 Best Overall
- Multifunctional. Intelligently purifies, cools and heats you.
- Automatically senses, captures and traps pollutants for cleaner air. Even detects and destroys formaldehyde.¹
In the United States, Dyson’s listing showed a price of $849.99 and an out-of-stock status when checked in August 2026. Availability, prices, warranty terms, and electrical specifications vary by market, so treat those figures as dated US signals rather than universal current prices. See Dyson’s HP09 listing.
What is the Dyson HP09?
The HP09 combines five practical functions in one tall, bladeless appliance:
- Particle filtration through a glass-fiber HEPA filter.
- Some odor and gas adsorption through activated carbon.
- Formaldehyde detection through an onboard sensor.
- A catalytic filter that Dyson says permanently breaks formaldehyde down into carbon dioxide and water.
- Fan circulation and electric resistance heating.
It can be controlled with the supplied remote, the MyDyson app, and compatible services including Amazon Alexa, Google Assistant, and Siri Shortcuts, subject to regional and account requirements. Dyson’s HP09 support page contains the applicable setup and maintenance information.
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1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesThe design is attractive for a renovation or construction-related household because one appliance can monitor and treat air while also providing heat and circulation. The compromise is that an all-in-one device may deliver less purification performance per dollar than a dedicated purifier.
Particle purification: the important numbers
Dyson describes the replacement filter as HEPA H13-grade, capturing 99.97% of particles as small as 0.3 microns under specified test conditions. That is a filter-efficiency claim: it describes how effectively air is filtered when it passes through the filter. It does not say how quickly the machine cleans an entire room.
For room cleaning, airflow and CADR—clean-air delivery rate—are more useful. CADR combines filtration efficiency with the volume of air the appliance processes. A highly efficient filter cannot clean a large room quickly if the machine moves only a modest amount of air.
Independent RTINGS testing measured the following:
| Test | Result |
|---|---|
| PM1.0 CADR | 87 m³/hr (51 CFM) |
| Recommended room size at maximum speed | 7.4 m² (80 sq. ft.) |
| Low-noise CADR | 41 m³/hr (24 CFM) |
| Recommended room size at low noise | 3.5 m² (38 sq. ft.) |
Those figures make the HP09 much more convincing for a small bedroom, office, nursery, or enclosed renovation area than for a large bedroom, living room, or open-plan floor. A dedicated high-CADR purifier will generally be the better purchase if your only goal is to reduce airborne particles quickly.
Rank #2
- The fully sealed filter system combines an Activated carbon filter to remove gases with a HEPA filter that captures 99.97% of microscopic allergens² and pollutants as small as 0.3 microns.¹
- The whole purifier, not just the filtration system, is fully sealed to HEPA H13 grade – so what goes inside, stays inside.³
- Dyson Air Multiplier technology projects over 76 gallons per second of smooth, yet powerful airflow⁷ to cool you in summer.⁶
- Captures 97% of odors such as cooking odors, pet odors and smoke.⁸
- Control and monitor air quality from anywhere using the MyDyson app, or hands-free with compatible voice services.⁵
For construction dust, sanding residue, smoke, and other heavy particle loads, source control remains essential. Use appropriate extraction, ventilation, containment, and respiratory protection. A household purifier is not a substitute for controlling dust at the work area.
Read RTINGS’ HP09 test results.
What the formaldehyde system does—and does not prove
Formaldehyde can be emitted by some pressed-wood products, cabinetry, flooring, furniture, adhesives, paints, textiles, and building materials. That makes the feature potentially relevant after installing new joinery, flooring, furniture, or other interior finishes.
Dyson’s system is designed to detect formaldehyde and use a catalytic filter to break it down. This is the HP09’s main distinction from the cheaper HP07. The catalytic filter is described as permanent, while the combined HEPA and carbon filter is replaceable.
There are important limits:
- The purifier cannot remove the source of formaldehyde. New cabinetry, flooring, adhesives, or furniture may continue emitting it.
- Ventilation, temperature and humidity control, source isolation, and material selection may be more important than filtration.
- A displayed reading is useful for observing trends, but it is not a laboratory-grade indoor-air assessment.
- The available evidence verifies Dyson’s design and claims, but does not independently establish the HP09’s formaldehyde removal rate in an ordinary home.
If readings remain elevated, investigate the source. Possible explanations include a continuing emission source, inadequate ventilation, an undersized purifier, low fan speed, a source in another room, or sensor limitations. A suspected exposure problem may require professional indoor-air testing rather than simply running the purifier harder.
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Heating
The HP09 can provide localized electric room heating, which is useful when you want warmth near a desk, bed, or seating area without installing or operating a whole-home system. It is not a heat pump, central-heating replacement, or efficient way to heat an entire large home.
Electricity costs depend on the local tariff and how long the heater operates. The exact electrical specification and safety requirements also vary by region, so consult the manual for the country where the unit will be used rather than relying on a specification from another market.
Heating also increases measured noise. RTINGS recorded 41.8 dBA at the lowest setting with the heater operating and 55 dBA at maximum speed with heat, compared with 34.1 dBA and 54.1 dBA without heat.
Rank #3
- Automatically senses, captures, and traps pollutants for cleaner air.
- Multifunctional. Intelligently purifies, heats, and cools you.²
- Fully sealed to HEPA H13 standard. It's not just the filter that's fully sealed, it's the whole machine. So what goes inside stays inside.⁴
- Air Multiplier technology generates the circulation power to draw distant pollutants into the machine, projecting purified air throughout the whole room.¹
- Automatically senses and reacts to changes in air quality, then reports pollution in real time on LCD screen and on the MyDyson app.³
Cooling
“Hot+Cool” can be misleading. The HP09 is a fan, not an air conditioner. Its airflow can make occupants feel cooler, but it does not remove heat from the room or lower the actual room temperature like a compressor-based or evaporative air conditioner.
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Noise and bedroom use
The HP09’s noise depends heavily on fan speed and whether heating is active:
| Operating condition | RTINGS measurement |
|---|---|
| Lowest fan speed, no heat | 34.1 dBA |
| Maximum fan speed, no heat | 54.1 dBA |
| Lowest speed with heat | 41.8 dBA |
| Maximum speed with heat | 55 dBA |
That makes it potentially comfortable for a small bedroom at a low setting, especially with night mode, scheduling, and remote control. But “quiet” does not mean “quiet while delivering maximum cleaning.” At the low-noise setting, the independently estimated room size was only 3.5 m² (38 sq. ft.). A larger room may require higher airflow and therefore more audible operation.
App, remote, and smart-home controls
The MyDyson app can make the HP09 easier to live with. Depending on the current app version and region, it can be used to monitor air-quality trends, schedule operation, change fan speed and temperature, check filter life, and control the unit remotely. Compatible voice services can provide hands-free control.
The app is not essential. Setup requires a compatible phone, account, and network, and app labels or features can change. Some buyers may also prefer an appliance that works entirely offline. Keep the physical remote available: it remains the most dependable fallback if Wi-Fi, account setup, or voice control fails.
If connection fails, confirm that the purifier is powered on, update the MyDyson app, check network compatibility, try pairing again, and use the remote while troubleshooting. For regional connection problems, consult Dyson support.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Filters, maintenance, and ownership cost
The main recurring maintenance item is the combined 360° Glass HEPA + Carbon filter. Dyson recommends replacement every 12 months or when the machine indicates replacement is needed. Dyson’s US listing showed the compatible filter, part 965432-01, at $79.99 when checked. That is approximately $79.99 per year at the nominal interval, before electricity and regional price changes.
Rank #4
- 【Perfect Fit】A seamlessly crafted 360° Glass HEPA and Activated Carbon Filter Replacement designed for Dyson PC1, HP1, HP2, PH04, PH03, PH02, PH01, HP10, HP09, TP09, HP07, TP07, HP06, TP06, TP10, and PC2 Series Air Purifiers. Fully compatible with Dyson Pure Cool, Pure Hot + Cool Cryptomic, and Humidify + Cool series—delivering a precise fit and effortless performance upgrade.
- 【Incompatible】This TP10 filter is not compatible with TP03, TP02, TP01, AM11, BP01, HP02, HP01, DP02, or DP01 models. Please check the model number located on the bottom or side of your device before purchasing to ensure the perfect match.
- 【Upgrade 2-in-1 Filter】This 360° combination glass filter integrates HEPA filter and Activated carbon filter into into one streamlined component—making installation and maintenance effortless. (Replacement part number #970341-01)
- 【High-Quality Materials】Crafted with premium HEPA media, these replacement filters for PH04, PH03, PH02, PH01, HP09, TP09, HP07, TP07, HP06, and TP06 deliver reliable, high performance. The Activated carbon layer is made from FSC-certified charcoal materials, offering a cleaner, more sustainable choice for your purifier.
- 【Installation Tips】Before installing the filter, please disconnect the power and ensure the side with the pull strap is facing upward. After replacement, remember to reset your device so it can properly recognize the new filter. If your previous setup included a separate filter mesh and Activated carbon layer, be sure to remove both before installing the upgraded 2-in-1 filter.
The actual interval can be shorter with wildfire smoke, tobacco smoke, construction dust, pets, continuous high-speed operation, or other heavy pollution. Follow the machine’s filter-life notification rather than treating 12 months as a guarantee.
Basic replacement procedure:
- Switch off and unplug the purifier.
- Press the release buttons on both sides and remove the outer covers.
- Remove the old combined HEPA and carbon filter.
- Fit the replacement filter until the tabs click securely into place.
- Refit the covers, reconnect power, and switch on the machine.
- Reset the filter-life indicator using the remote’s specified filter-reset/Night mode control for approximately five seconds.
Button layouts and electrical details can vary by region. The cited HP09 owner manual is a UK document, so use the manual for your country before servicing the unit.
The catalytic formaldehyde filter is described as permanent and normally does not require replacement. Verify the exact model and regional part number before buying a replacement filter, particularly for a used or imported machine. Check Dyson’s filter listing.
HP09 versus the alternatives
| Alternative | When it makes more sense | What you give up |
|---|---|---|
| Dedicated high-CADR purifier | You mainly need fast particle removal and strong performance per dollar | No integrated heater, fan design, or Dyson smart-home ecosystem |
| Dyson TP09 | You want Dyson’s formaldehyde-focused purification but already have heating | No HP09 heating function |
| Dyson HP07 | You want a Dyson heater, fan, and purifier without a specific formaldehyde concern | No HP09 formaldehyde-specific catalytic system and sensing |
| Separate purifier plus heater or fan | You want better specialization, redundancy, or room-by-room flexibility | More equipment, controls, floor space, and potentially higher combined purchase cost |
The Dyson TP09 is the more logical Dyson option if heating is unnecessary. The HP07 may suit buyers who want the hot-and-cool platform but do not have a particular formaldehyde concern. Prices and availability for both vary by country.
Who should buy the HP09?
- You need one appliance that purifies, circulates air, and provides occasional room heating.
- You have a small room rather than a large open-plan area.
- You are furnishing or renovating and specifically value formaldehyde monitoring.
- You want a bladeless design, remote, app, scheduling, and compatible voice control.
- You accept annual filter costs and the electricity cost of heating.
- You can obtain a credible warranty and genuine replacement filters.
Who should skip it?
- You need the highest particle-cleaning performance per dollar.
- You want to clean a large bedroom, living room, or open-plan space.
- You expect air conditioning rather than fan airflow.
- You need a whole-home heating solution.
- You are on a tight budget or dislike proprietary replacement-filter costs.
- You are buying only because the phrase “HEPA H13” sounds like proof of high whole-room performance.
If buying a refurbished or used HP09 because of availability, verify the exact model number, remote, filter condition, warranty transferability, return policy, voltage compatibility, and local availability of genuine filters. The US Dyson listing was out of stock when checked in August 2026, but that does not establish that the model is discontinued or unavailable in every market.
Final verdict
The Dyson HP09 is a polished, technically interesting all-in-one appliance, but it is not the obvious choice for air purification alone. Its independently measured CADR is modest relative to its premium price, and its effective room size is limited—especially at a comfortable low-noise setting.
The purchase becomes more rational when the formaldehyde system, localized heating, fan circulation, app control, and compact all-in-one design all matter to you. For a small room after renovation or furnishing, it can be a convenient premium solution. For a large room, serious particle-cleaning needs, air conditioning, or the best performance per dollar, buy a dedicated purifier and separate the other functions.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
