Most fixture manufacturers make thermostatic valves that do just one thing -- control the mix of hot and cold water at a temperature that you select. Turning the handle on a thermostatic valve doesn't turn the water off and on, it simply selects the temperature setting. In addition to the thermostatic valve, you need a volume control valve for each emitter (shower head/body sprays/tub filler/handheld/etc.) that you want supplied with temperature controlled water passing through the thermostatic valve. The volume control valve allows you to turn each emitter off and on, and to control the volume of water flowing to each. You can have as many emitters (and volume control valves) as you want, although the number of emitters you'll be able to have running at any one time will depend on your water pressure, and the size of the water line supplying the thermostatic valve. Generally, if you intend to have more than one emitter on at any given time, you should probably have a 3/4" supply feeding the thermostatic valve. If you plan to have only one emitter on at any one time, you can get by with 1/2" supply line. The cost of a thermostatically controlled system will vary based on the brand and quality of the fixtures you select, and the number of emitters. Almost all thermostatic systems will cost more than a pressure balanced system with a two or three-way diverter valve. The labour cost to plumb a thermostatic system will be greater, too. Hope this helps. James

I am thinking that you simply are reacting negatively to the newly implemented 2.5 gpm restriction. As you point out in your other thread, going from 8 gpm to what you have now is a huge adjustment. Will your plumber (or contractor) tell you if 3/4" pipe was ripped out? Or was it also 1/2"? You are right that either are in the code, but does the valve and shower head combo prevent any difference in what gets to you in the shower, anyhow? Does your apartment building now require 1/2" and that is why you got it? However, if the supply valve is supplying a satisfying pressure at a "warm" setting, where both hot and cold are mixed, I understand your question about why you can't get the same pressure and volume of water when you turn to only hot water. Barnes Custom Builder does not address that in their first answer. It sounds like you are willing to replace your valve if that will get you the shower you want, you just want someone with more understanding of the way these valves work to give you word that it will be worth it. I can understand your reasoning about the valve you have, because the handle controls both volume and temperature, you should have max volume at the highest temperature, yet you are getting less pressure with just hot water being called to the shower. What is going on? Does pressure coming from the hot water tank naturally differ from the pressure of the cold water delivered directly from the city? These are all questions that a plumbing professional with an understanding of the dynamics of this type of apartment building situation needs to address with you.

But it’s pressure balancing rather than thermostatic. You won't get as much pressure from it as a thermostatic from the beginning. Your real issue is pressure, not volume. Think of a 5 gallon bucket of gatorade dumped over your head. No pressure. All volume. Now think of a pressure washer that uses 1 gallon of water at 1200 psi pressure to clean the mold off of the sidewalk. You need an air entrained pressure head if you want more force. and your building’s pressure tank isn't supplying it. 2.5 gallons is more than enough volume to give a good shower.

I would advise your clients to do a feature wall with the dimensional tile that DOES NOT have the plumbing on it, and then get matching or coordinating flat field tile for the remaining walls. I'm in the midst of doing something very similar for a current bath project: textured tile on the long wall that faces the door as you walk in the bathroom, with flat matching field tile everywhere else. Here's an example: Regarding the window, you could also trim it out with the same solid surface material you're using for the counters. Schluter works too.