Does the in-line water heater warm up my bath? No. The in-line water heater on Ella hydro massage tubs is designed to maintain your bath temperature, not to raise it. You fill the tub with comfortably hot water from the faucet, and then, whenever the hydro massage pump is running, the in-line heater keeps that water at a consistent, comfortable temperature so you stay warm through your whole soak. It will not warm up a bath that was filled with cool water, and it only operates while the hydro pump is on.

How It Works

As the video explains: when you fill your Ella walk-in tub with the five piece or two piece fast-fill faucet set, you set the temperature at the level that suits you best. When you engage the hydro massage, the in-line water heater works together with the water pump to maintain a consistent warm temperature so you stay warm and comfortable. In practice that means:

1. Fill the tub from the faucet at your preferred temperature. Your home water heater does the heating.
2. Once the water is 2 inches above the highest jets, turn on the hydro massage. Our water level article explains why that level matters.
3. The in-line heater switches on and off automatically with the hydro pump. There is no separate heater button and no thermostat to set.
4. While the hydro massage runs, the heater offsets the natural cooling of the bath and holds the temperature steady.

On tubs equipped with the independent foot massage, the in-line heater is attached to the foot massage pump, so running the foot jets is what keeps the water warm on those configurations. For safety, bath water should be kept at or below 100.4 F.

What the In-Line Heater Is Not

• It is not a water heater for filling. Your household water heater supplies the hot water for the bath. We recommend the largest capacity unit available for your home, and anything under 75 gallons is not recommended. For tankless systems, choose a flow rate of 11 GPM or higher. See what size water heater you need.
• It is not a heater for the air massage. The air system does not have its own heater. Only the hydro loop is heated.
• It is not the heated seat and backrest. That optional system warms the seat surfaces with its own button and has nothing to do with the water.
• It does not run during a still soak. If all pumps are off, the heater is off too. Keeping the hydro massage running is what keeps the heater working.

Which Packages Include It

The in-line heater is included with every hydro massage package. Soaking tubs have no pumps and no heater, and air-only configurations have no heater either, because the air blower simply moves air. Our therapy package inclusions cheat sheet lists what comes with each package.

In-Line Heater Ratings by Model

Every rating below is exactly as printed on the current spec sheets:

If Your Bath Still Cools Off Quickly

The most common reason a bath does not stay warm is that it did not start warm enough, usually because the home's water heater ran low while filling. Checking your hot water supply is the best first step. This video walks through how to size your hot water capacity:

As it recommends, check the water capacity of your tub on the Compare Specs page, shown in gallons occupied and unoccupied, and make sure your hot water system can cover the tub plus the other demands in your home. Three quarter inch supply lines with easily accessible shut off valves are recommended, and a dedicated hot water system just for the tub is worth considering for larger models. Your plumber or installer can confirm the right setup for your home.

If the tub was filled hot and the water still cools quickly with the hydro jets running, or the jets blow noticeably cold water, the heater circuit deserves a look. Open a ticket with your model and serial number so the team can check it; the heater is a replaceable part, and our pump and massage system troubleshooting guide covers the power and connection checks that come first.

In this testimonial, a dealer interviews a 93 year old owner who mentions that the in-line heater keeps the water temperature constant during her hydro massage, which is exactly the job it is built for.

Common Questions

Still need help? Open a ticket at ellasbubbles.com/support or call (800) 480-6850 and our team will be glad to walk through it with you.