I just remodeled two 18-year-old bathrooms. In one I replaced a cracking fiberglass tub with an American Standard Princeton “Americast” tub. I considered cast iron, but Americast is a durable porcelain-coated composite offering much better insulation against temperature and noise — not to mention being significantly lighter than cast iron.
The bigger project was our master bathroom, and when it came to finding a new bathtub I had several goals. I wanted something big enough for my 5’9″ wife to stretch out in, but not so big that it would never get used. I wanted a massage feature that didn’t use waterjets because of all the cleaning and hygiene problems associated with running bathwater through an enclosed pump system.
Kohler’s BubbleMassage line sounded like a good solution: These are acrylic tubs with 120 little holes around the base perimeter through which a motor blows heated air. After the bath is drained the motor blows any residual moisture out of the system to prevent mold growth.
A 6’x3′ drop-in looked like it would be the right size so I bought and installed a Kohler Mariposa BubbleMassage tub (just over $2000 from Home Depot). At 72 gallons to the overflow I thought that would be ample capacity for a luxurious bath.
It turns out things aren’t so simple.
The problem with blowing large volumes of air through hot water is that it cools off very quickly. BubbleMassage blowers are supposed to preheat the air with a 300W element. I measured the temperature of air coming directly out of the blower and found it fluctuating wildly between 90F and 110F. In practice I found that running the BubbleMassage cooled a full bath at 1 degree every 1-2 minutes. Start your bath at a relaxing 102F and within ten minutes it’s below your body temperature.
There may be a workaround for this if you plan ahead. As I will explain shortly, the Mariposa needs to be filled to the overflow. You could probably adjust a steady stream of hot water to keep the temperature up, but only if you put the fill faucet near the opposite end of the tub from the overflow. Otherwise additional hotwater just shoots right down the drain. However, further complicating temperature problems is the fact that with a bather in place the BubbleMassage doesn’t mix the water very well. It doesn’t take long before the water at the head of the tub (being significantly shallower) is noticeably cooler than the water at the feet.
One more quirk of BubbleMassage: Skin pressed up to or almost touching bubble vents often gets a “pins-and-needles” sort of sensation. My wife swore that it was blowing ice-cold air out of some of the vents even though objective measurements showed neither the air nor water were below body temperature. It wasn’t until I tried it myself that I realized this is a real physiological illusion. Moving an affected area slightly away from the bubble jets removes the sensation of being pinged with icy bubbles. But it’s a weird effect that I imagine most people will find irritating.
Mariposa: Not as big as it looks
BubbleMassage is offered on a number of tub designs. I chose the Mariposa not only for what seemed like an ideal size, but also because it has the profile of a good soaking tub. It takes an actual bath to discover that its proportions are far from ideal. It advertises a water depth of 14″, but that depth is achieved only at the drain. The upper end of the tub is raked so sharply that with your head and arms resting on the appropriate contours your navel is right at the waterline, even with the tub filled to the overflow. I thought 72 gallons would provide an enveloping bath, but for a full-sized adult sitting comfortably this tub offers little more than half a bath!
I called Kohler Customer Service and after briefly explaining that we found the BubbleMassage uncomfortable, but that we were past Home Depot’s return period, the agent said they would send me a voucher authorizing Home Depot to take my used tub and credit my full purchase price towards a new one. So obviously Kohler gets an A+ for customer service!
I replaced this tub with Kohler’s Archer Whirlpool. Yes, we have to deal with regular cleaning of the waterjet system, but the Archer is an excellent tub. Even though its nominal capacity is the same as the Mariposa’s it manages a greater soaking depth and, at least for our proportions, is more ergonomic all around. For the same price as the BubbleMassage I replaced I was able to get the Archer model with a 1500W inline heater which is able to maintain the water temperature even with all eight jets running at full volume.