You should enjoy every shower without worrying about sudden changes in temperature. A thermostatic shower faucet provides separate temperature and pressure controls.
Showers available on the market fall into one of two definitions; pressure balanced or thermostatic. The primary difference is in how the shower valve controls unexpected dips in temperature if someone else in your house (rudely) starts a load of laundry, flushes the toilet or runs the dishwasher while you're in the shower. Both work great to avoid unnecessary flashes of scalding hot or icy cold water, but a thermostatic valve gives you independent control over both temperature and water volume. Here's how Delta and Kohler stack up against each other.
Pressure or Thermostatic: What's the Difference?
A pressure balance valve typically involves a single handle and responds to pressure to keep your water mix at the right temperature; if the cold water is in use elsewhere, it will shut down the amount of hot water running to the faucet, thereby reducing your water pressure. Thermostatic valves have independent controls for temperature and volume and respond to temperature changes without any change to water volume, which means you can reduce water flow without affecting temperature for tasks like shaving, shampooing and washing your face.
Delta Thermostatic Shower
Thermostatic showers from Delta typically come with two controls; one for temperature and another for volume, and both are most often contained on a smaller, single piece of trim. Operating a Delta thermostatic trim is relatively intuitive: You set the temperature you like best and then turn the water on with the other handle until you reach the right volume/water pressure.
Delta Thermostatic Shower-1
Once you set your preferred temperature, you can leave that lever in place and just use the volume control to turn the water off and on and to the right pressure.
Another benefit of choosing a Delta thermostatic shower is that you pair it with a universal valve. If you change your trim in the future to a single-handle control, you only need to remove the existing trim, replace the cartridge, and install your new trim.
Kohler Thermostatic Shower
Thermostatic showers from Kohler are configured with separate handles for temperature and volume control as well but with a larger profile. Like its Delta counterpart, you set your desired temperature with one handle and operate your shower with the other handle.
Kohler Thermostatic Shower TrimAs with Delta, you do not have reset the water temperature every time you finish showering. Instead, the temperature handle can be set and then left alone while you control the strength of the spray with the other handle.
You are at a disadvantage with the Kohler valve, however, should you change your mind about your shower trim. Instead of just changing out the cartridge should you replace your two-handle thermostatic with a single handle trim, you will need a new valve installed behind the wall.
There are distinct advantages to choosing either the Delta or the Kohler thermostatic shower, but you decision will most likely come down to how much flexibility you want with your ability to change your trim. Both Delta and Kohler allow you to set your temperature control and leave it in place.
If you like the ease with which you can change your mind a few years down the road, then Delta's thermostatic faucet will work great. But, if you don't plan another bathroom remodel for quite a few years, and you enjoy having your controls completely separate, the Kohler faucet will appeal to you more.
Price will almost certainly come into play as well; Delta thermostatic trims have a price range of $380 to $800 while Kohler prices range from $400 to $1,250.