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Keeping a large humidor stable can become a daily chore when passive humidity packs cannot keep up with dry air, frequent door openings, or a leaky cabinet. The Cigar Oasis Plus 4.0 Electronic Humidifier is built for larger enclosures that hold about 300 to 1,000 cigars, with active fan-driven humidification and an adjustable digital setpoint. Its strongest advantages are fast air circulation, a compact 6-inch body, and optional remote monitoring. Its main tradeoffs are the paid SmartHumidor service for app features and the manufacturer’s warning that this model is not intended for climate-controlled wineadors.
Quick Verdict
Rating: 8.5/10, recommended with caveats
Best For: End-table, chest, and small-to-medium cabinet humidors with 4 to 10 cubic feet of interior space
Bottom Line: The Plus 4.0 gives you automatic humidity control, strong circulation, and a clear temperature and humidity display in a compact unit. It is a better fit for a traditional wooden humidor than a wineador, and remote app control requires a subscription after the trial period.
| Specification | Detail |
|---|---|
| Brand | Cigar Oasis |
| Model | Plus 4.0, SKU FA2-2000 |
| Product type | Active electronic humidor humidifier |
| Recommended capacity | About 300 to 1,000 cigars |
| Humidor volume | 4 to 10 cubic feet |
| Dimensions | 6 x 2 x 3.5 inches |
| Weight | About 16 ounces |
| Humidity range | Factory preset to 70% RH, adjustable from 40% to 80% RH |
| Display | Backlit humidity and temperature display |
| Controls | Soft-touch setpoint buttons and sensor-controlled fan |
| Connectivity | Built-in WiFi for the SmartHumidor iOS and Android apps |
| App requirement | Subscription required for remote data, alerts, history, and setpoint control after the trial |
| Power | AC power through a thin ribbon cable that passes through the humidor seal |
| Water cartridge | Pre-treated refillable cartridge, distilled water only |
| Typical refill interval | About every 2 to 4 months, depending on conditions |
| Replacement interval | Replace the cartridge about once per year |
| Warranty | One year on the electronics module against qualifying defects |
| Important limitation | Not suggested by the manufacturer for climate-controlled or wineador humidors |
Key Takeaways
- The Plus 4.0 is sized for traditional humidors holding roughly 300 to 1,000 cigars or 4 to 10 cubic feet.
- Its sensor-controlled fan adds moisture only when needed and circulates air through a larger enclosure.
- The unit shows live humidity and temperature, but it controls humidity only.
- WiFi is built in, while remote alerts, charts, readings, and setpoint changes require the SmartHumidor service.
- The refillable cartridge uses distilled water and normally needs an annual replacement.
- You should choose a different model for a climate-controlled wineador.
What Is the Cigar Oasis Plus 4.0?
The Cigar Oasis Plus 4.0 is a compact electronic humidifier for end-table humidors, chests, and small-to-medium cigar cabinets. Unlike a passive pack or bead system, it uses a humidity sensor and fan to respond when the measured level drops below your chosen setpoint.
The unit is only 6 inches long, yet its open-vent design is intended to move more humidified air than the smaller models in the Cigar Oasis line. You can read humidity and temperature on the backlit display, adjust the setpoint with the soft-touch controls, and use the built-in WiFi when you want remote monitoring.
Who Should Buy It?
Best For
- Traditional wooden humidors with 4 to 10 cubic feet of interior space
- Collectors who want active humidity control instead of replacing several passive packs
- Owners who value a local display and optional remote alerts
Skip If
- Your humidor is under 4 cubic feet or holds far fewer than 300 cigars
- You use a climate-controlled wineador or refrigerated cabinet
- You want free remote monitoring with no subscription
Before You Buy: Measure the usable interior volume, not the outside of the cabinet. The Plus 4.0 is designed for 4 to 10 cubic feet and is not the maker’s recommended choice for a wineador.
Why Choose the Oasis Plus 4.0?
Active Humidity Control
The sensor monitors relative humidity and activates the fan when moisture is needed. Once the setpoint is restored, the fan stops. This active cycle can be more dependable than passive systems in a large humidor, especially in a dry room or a cabinet that is opened often.
The factory setpoint is 70% RH, and you can adjust it between 40% and 80% RH. That range gives you control, but you should choose a setting that suits your cigars, humidor construction, and independent hygrometer readings.
Improved Air Circulation
The Plus model uses extra air openings and an open-vent design to move more air than the smaller Excel model. Better circulation helps reduce humid and dry pockets across shelves, and it can limit the stale or musty smell that develops when air sits in a tightly sealed cabinet.
Circulation still depends on cabinet layout. Closely packed boxes, solid shelves, and blocked vents can prevent even distribution, so the device needs open space around it.
Display and Local Controls
The backlit screen shows humidity and temperature at the unit. The temperature reading is useful for checking storage conditions, but the Plus 4.0 does not cool or heat the humidor. Soft-touch buttons let you change the humidity setpoint without using the app.
How the Plus 4.0 Supports Cigar Storage
The main benefit is consistency. A sensor-controlled system can add moisture in short cycles instead of releasing humidity at a fixed passive rate. For a large collection, that response can reduce the amount of manual checking needed and help prevent prolonged low-humidity periods.
The fan also moves air across more of the cabinet, which is useful when cigars are stored on several trays or shelves. It cannot correct a poor seal, blocked airflow, or an oversized cabinet, so you should treat the stated 4-to-10-cubic-foot range as a real sizing limit.
How to Set Up the Plus 4.0
- Confirm the humidor size: Make sure the interior is within the 4-to-10-cubic-foot range.
- Fill the cartridge: Use distilled water only. Current units ship with an empty cartridge, so prepare it before first use according to the product instructions.
- Choose the location: Place the unit at the lowest practical point and leave at least 1 inch of clearance around the air openings.
- Route the cable: Pass the thin ribbon cable through the humidor seal so you do not have to drill the cabinet.
- Set the humidity: Start with the factory 70% RH setting or choose your preferred setpoint.
- Allow it to stabilize: Give the cabinet time to settle before judging performance, especially after adding dry boxes or opening the door for a long period.
- Verify the reading: Compare the display with a calibrated independent hygrometer placed away from the unit.
Pro Tip: Leave airflow gaps between shelves and cigar boxes. The fan can only balance the cabinet when humidified air has a clear path to move upward and across the collection.
What Can the SmartHumidor App Do?
The built-in WiFi works with the Cigar Oasis SmartHumidor apps for iOS and Android. With an active service plan, you can view humidity and temperature, adjust the humidity setpoint, create threshold alerts, and review historical charts remotely.
Rapid Response Technology sends changes of 3 percentage points or more to the app quickly. When conditions remain stable, the unit checks in about every eight hours. The sensor itself continues to manage humidity locally, so the eight-hour interval describes app communication during stable periods, not how often the humidifier measures the cabinet.
The subscription is the key limitation. The humidifier still operates through its screen and buttons without remote service, but app data, notifications, history, and remote control require a paid plan after the introductory trial.
Maintenance and Cartridge Care
The pre-treated cartridge uses distilled water only. The manufacturer estimates a refill about every 2 to 4 months, though a dry climate, frequent door openings, a new humidor, or a weak seal can shorten that interval.
For best performance, replace the cartridge about once per year. The maker also recommends replacing it after roughly five or six refills because the cartridge treatment becomes less effective over time.
- Use distilled water, not tap water or flavored additives.
- Drain loose water and dry the outside of the cartridge before reinstalling it.
- Keep the fan openings clear of cigar boxes, liners, and shelves.
- Check the seal if the unit runs often or uses water much faster than expected.
How It Performs in Real Use
In an End-Table Humidor
This is the Plus 4.0’s strongest use case. Its compact body does not take much shelf space, while the higher-airflow design can serve several trays in a cabinet that falls within the rated volume.
In a Dry Home
Active humidification can recover from low ambient humidity more quickly than a small passive device. You may still see longer fan cycles and more frequent refills during winter heating or in an arid climate.
After Frequent Door Openings
The sensor reacts when humidity drops, and the fan helps restore the setpoint after you browse or reorganize the collection. Rapid recovery depends on a sound seal and enough space for air to circulate.
For Long-Term Aging
The display, adjustable setpoint, and optional history charts make it easier to spot trends across weeks or months. You should still keep an independent calibrated hygrometer in the cabinet as a cross-check.
Compatibility and Safe Use
The Plus 4.0 is a humidor accessory, not a household room humidifier or temperature-control device. Use it only inside an appropriately sized cigar humidor and follow the manufacturer’s filling, placement, and electrical instructions.
Do not use tap water, and do not reinstall a cartridge with loose water dripping from it. Keep the powered top section dry. The manufacturer does not recommend the Plus 4.0 for climate-controlled wineadors, where condensation, cooling cycles, and limited airflow can create different operating conditions.
Pros and Cons
Pros
- Rated for larger 4-to-10-cubic-foot humidors
- Sensor-controlled fan provides active humidity response
- Compact 6 x 2 x 3.5-inch body
- Backlit display shows humidity and temperature
- Optional WiFi alerts, charts, and remote setpoint control
Cons
- Remote app features require a subscription after the trial
- Not recommended for wineadors or climate-controlled cabinets
- Needs distilled-water refills and yearly cartridge replacement
Is It Worth the Price?
The Plus 4.0 sits in the premium range compared with passive packs and basic bead systems. The extra cost makes the most sense when your collection is large enough to benefit from active circulation, digital controls, and automatic recovery after humidity drops.
It offers stronger value for a traditional cabinet owner who would otherwise maintain several passive devices. It is not the best value for a small desktop humidor, a wineador, or a buyer who mainly wants free remote monitoring.
How It Compares to Alternatives
For a smaller desktop or small cabinet humidor, the Cigar Oasis Excel line is sized for about 100 to 300 cigars and 1.5 to 4 cubic feet. The Ultra 4.0 is slimmer and intended for roughly 50 to 150 cigars. For a much larger cabinet, the Magna 3.0 supports about 10 to 55 cubic feet.
The Plus 4.0 makes the most sense between those models, especially when you need more airflow than the Excel but do not need the size and capacity of the Magna.
Frequently Asked Questions
What size humidor is the Plus 4.0 designed for?
It is designed for about 300 to 1,000 cigars and 4 to 10 cubic feet of interior space. Measure the inside of the cabinet and account for shelves, drawers, and boxes that can restrict airflow.
Does the Plus 4.0 work without WiFi?
Yes. You can read humidity and temperature and adjust the setpoint on the unit itself. WiFi is optional and adds remote features through the SmartHumidor service.
Does the SmartHumidor app require a subscription?
Remote readings, notifications, history charts, and setpoint control require an active plan after the introductory trial. Check the current service terms before buying because subscription details can change.
How often does the cartridge need water?
The manufacturer estimates about every 2 to 4 months. Your interval can be shorter in a dry climate, during seasoning, or when the humidor is opened often.
When should the water cartridge be replaced?
Plan on replacing it about once per year or after roughly five or six refills. Annual replacement helps maintain the cartridge treatment and moisture output.
Where should the Plus 4.0 be placed?
Place it at the lowest practical point in the humidor and leave at least 1 inch of open space around the vents. Avoid blocking the fan with boxes or a solid shelf.
Can the Plus 4.0 be used in a wineador?
The manufacturer does not suggest this model for climate-controlled or wineador humidors. Compare the Excel line or ask Cigar Oasis support which model matches your cooled cabinet.
Does it control temperature?
No. The display reads temperature in addition to humidity, but the unit only regulates humidity. You need a separate cooling or heating solution when temperature control is required.
What warranty comes with the Plus 4.0?
Cigar Oasis lists a one-year warranty on the electronics module against qualifying defects in materials or workmanship. The water cartridge has more limited coverage for initial defects that cause leakage.
The Bottom Line
The Cigar Oasis Plus 4.0 is a strong choice for a 4-to-10-cubic-foot traditional humidor when you want automatic humidity response, active air circulation, and a clear local display. Skip it for a small desktop box, a wineador, or a setup where a recurring app subscription would reduce the value.
