Moen Flo vs Phyn Plus: Which Smart Water Shutoff Finds Leaks Best?

In the Moen Flo vs Phyn Plus comparison by No More Leaks, a YouTube channel focused on water leak prevention, the two shutoffs handled large leaks about equally, while Phyn learned the home over a longer period and logged more detail on small drips.

The Hook Up, a smart home YouTube channel known for side-by-side measurements, also measured the Flo against his city water meter and picked it as his overall choice. Here is how the two compare on learning, small leaks, sensors and price, as of October 21, 2026.

Moen Flo vs Phyn Plus: prices and specs

Prices checked on Amazon Oct 21, 2026. I may earn a commission from links, at no cost to you.

Moen Flo vs Phyn Plus: learning period

Both valves learn your water habits before they act on unusual flow. No More Leaks says the Flo uses a fixed one-week learning period and does not shut off automatically during it. Phyn adapts over about 1,000 water events, which took roughly a month in his home. The Hook Up saw the Flo’s learning mode in practice: during its first seven to ten days it did not flag his simulated large leak.

Large leaks

For medium and large leaks, No More Leaks found results similar on both. Each sends an alert first and then closes the valve if the flow continues, and he says both makers keep refining their detection over time.

Small leaks and plumbing checks

Both run micro-leak checks by closing the valve and watching pressure. No More Leaks says the Flo’s health check takes as little as 30 seconds and up to four minutes, while Phyn’s automatic check runs from three to ten minutes. In his drip tests, he narrowed Phyn’s sensitivity to a drip just over every four seconds; the Flo caught a drip every 6.5 seconds but not one every 52 seconds. In separate tests, each detected a drip every four minutes.

His tip for Phyn owners: open the plumbing check history once a week. A baseline pressure drop in his home was about 0.14 psi over three minutes, and he watches for readings around 0.3 psi as a sign to investigate.

Sensors

The Moen Flo Smart Water Monitor and Shutoff (3/4″) measures flow with a turbine, or impeller. The Phyn Plus Gen 2 Smart Water Shutoff (1″) uses an ultrasonic sensor with no moving parts and recognizes the pressure signature of each fixture; No More Leaks says it spotted a newly added fixture after about 19 gallons. The Hook Up notes impellers are generally very accurate but can wear, and No More Leaks says some long-term Flo owners in his desert area reported mineral buildup on the turbine magnets affecting flow readings.

Accuracy and app

The Hook Up measured the Flo within about 1.5 percent of his city meter across a day and 2.5 percent in a bucket test, with flow detected down to 0.2 gallons per minute. He called its app the best in his group for speed and analytics. He did not test Phyn’s inline valve; the Phyn product in his video was its under-sink Smart Water Assistant, so his Phyn numbers do not apply here.

Smart home

The Hook Up says Home Assistant can use the Flo through an API the community reverse-engineered, which Moen has not documented, so it could change. Check Phyn’s current integrations before buying if Home Assistant matters to you.

Installation

Both valves go into the main line just after your main shutoff and before the line branches, and both need a nearby outlet. The Hook Up used female-threaded fittings for his Flo and finished the job in a little under an hour with a plumber friend supervising. Buy the size that matches your main; the Amazon Flo listing here is 3/4-inch and the Phyn listing is 1-inch.

Price

Amazon lists the Moen Flo 3/4-inch at $559 as of October 21, 2026. Amazon listed the Phyn Plus Gen 2 at $466.28. Both makers recommend a licensed plumber, so add installation to the cost.

Which should you buy?

• Moen Flo for a quicker start, short health checks, a strong app and no required subscription, per The Hook Up.
• Phyn Plus for a sensor with no moving parts, fixture recognition and detailed pressure history, per No More Leaks.

Video: No More Leaks: “Flo by Moen VS Phyn Plus: Which Detects Leaks BEST?!?”. Embedded with credit; the findings are the creator’s own.

Video: The Hook Up: “Prevent THOUSANDS in damages with these smart water monitors.”. Embedded with credit; the findings are the creator’s own.

Frequently Asked Questions

Moen Flo vs Phyn Plus: which detects small leaks better?

In No More Leaks’ drip tests, Phyn was narrowed to a drip just over every four seconds and the Flo caught a 6.5-second drip; both caught a drip every four minutes in separate tests.

How long does the Moen Flo take to learn?

About one week, during which it does not shut off automatically.

Does the Phyn Plus have moving parts?

No. It uses an ultrasonic flow sensor, while the Flo uses a turbine.

Do I need a subscription for the Moen Flo?

The Hook Up said Moen no longer requires one for app features; the optional plan adds warranty and deductible benefits.

Sources

• Amazon product listings for the products linked above, checked October 21, 2026
• Phyn Plus Gen 2 listing, homedepot.com, checked October 21, 2026
• No More Leaks: “Flo by Moen VS Phyn Plus: Which Detects Leaks BEST?!?”
• The Hook Up: “Prevent THOUSANDS in damages with these smart water monitors.”

Related: Best Smart Water Shutoff Valve | How to Choose a Whole Home Water Monitor | Best Smart Home Hub