Is the JXi 400 worth it over the 260K model?

If you heat a large pool or want faster warm-up, the 400K output is the reason to pay more. Smaller pools and spas do fine with the 260K.

Will it replace my Pentair MasterTemp without plumbing changes?

Jandy lists the JXi as a direct retrofit for MasterTemp and Max-E-Therm heaters, so the plumbing connections should line up. Gas supply and venting still need to meet local code.

Does it work with my existing automation?

It has an RS485 interface for Jandy AquaLink and iAqualink systems. Other brands' automation may need extra parts or may not control it fully.

What comes in the box?

The heater plus a Versa Plumb sweep elbow, two 2-inch universal union tailpieces, one union cap, three union O-rings and three union nuts. Gas piping, venting and a pad are not included.

How much space does it need?

It fits on a 2' x 2' pad and is 22.1 inches deep, 22.9 wide and 26.5 tall. Keep the clearances in the manual for venting and service access.

When is the price lowest?

Pool heater prices tend to dip in fall and winter, outside swim season. The current best is $3,949 at PoolSuppy4Less as of November 7, 2026; check the price history before buying.

Where can I buy the Jandy JXi 400,000 BTU Natural Gas Pool Heater?

4 stores we checked sell it, including PoolSuppy4Less, SOS Pool & Spa Supplies, Pool Supply Depot, Amazon.

Jandy JXi 400 Pool Heater Price History: Lowest $3,949.00

Q: Where is the Jandy JXi 400,000 BTU Natural Gas Pool Heater cheapest?

At PoolSuppy4Less, for $3,949.00, as of our latest check.

What reviewers say

Owner feedback on the JXi line centers on fast heat-up and the easy swap from older heaters. Complaints tend to involve service and part failures over time rather than day-to-day heating.

What people mention

Heat outputPraisedOwners say the 400K model warms a large pool fast.
FootprintPraisedThe 2' x 2' size and low weight make installation and replacement easier.
RetrofitPraisedBuyers replacing MasterTemp or Max-E-Therm heaters report the plumbing lines up without changes.
AutomationPraisedAquaLink and iAqualink users like controlling heat from the app.
ReliabilityMixedSome owners report years of trouble-free use, others need repairs within a few seasons.
Repair costCriticisedOut-of-warranty parts and service visits are expensive.

From PoolSuppy4Less

Ultra-compact 2' x 2' footprint for small spaces and flexible installation
Lightweight design for easy maneuverability and transport
Best retrofit option for quick Mastertemp and Max-E-Therm replacement with no plumbing adjustments
RS485 digital interface compatible with Aqualink/iAqualink pool and spa automation
High-efficiency, low-NOx design
Available in 200K, 260K and 399K BTU sizes, natural gas and propane models

Materials: Plastic cabinet; copper heat exchanger and tubing; stainless steel header
Fit: Indoor or outdoor; pool or spa; 2" water connections; 0.75" NPT gas connection; 8" flue diameter
Guarantee: 1 year warranty
Returns: 30-Day Returns Easy return policy
Shipping: Free Shipping On orders over
In the box: Versa Plumb Sweep Elbow (1), 2" Universal Union Tailpiece (2), 2" Universal Union Cap (1), 2" Universal Union O-ring (3), 2" Universal Union Nut (3)

About the Jandy JXi 400,000 BTU Natural Gas Pool Heater

The Jandy JXI400N Natural Gas Heater Total Package. The JXi heater sets a new standard in pool and spa heating technology with its ultra-compact size, lightweight design, and installation flexibility, making it a top choice for pool professionals and pool owners everywhere. The high-efficiency, low-NOx JXi is available in four BTU sizes, 200K, 260K, 399K, and offered in both natural and propane gas models. Pro-driven features for the fastest, most customer-friendly installation include: Ultra-Compact - 2' x 2' footprint for small space requirements and maximum installation flexibility. Lightweight Design - Weighs less than 126 pounds unpackaged for easy maneuverability and transport. Best Retrofit Option - Plumbing flexibility for quick Mastertemp® and Max-E-Therm® replacement that requires no plumbing adjustments.* Easy to Control - RS485 digital interface is Aqualink®/iAqualink™-compatible for pool and spa automation.