You're first selecting a trim kits. "Trim kits" contain all the bright and shiny chrome controls, shower head, body sprays, etc, that hang on your shower walls.

The second selection process then has you buying the brass valve body or valve bodies that do the actual temperature control, or do the actual diverting of the water to the shower heads.

Both trim kits are expensive. They usually are when you get into multiple shower heads, wall bars, and valve controls.

The shower valve itself that goes inside the wall, which is what you are purchasing in the second step on that website? The Hansgrohe set has a SINGLE valve inside the wall, whereas the Moen setup needs THREE valve bodies.

Valve bodies and trim sets need to be matched to one another. But once you choose that valve body and trim kit that fits that valve body, you can use pretty much any shower head or heads with that valve. Sure you'd want to make sure the styles and finishes coordinate. But you can shop freely. You pick a valve body that will do what you want it to do:
-control water temperature
-act as a volume control
-act as a diverter to send water to just the shower head, OR to just the handheld, OR to both at the same time

Some companies make a single valve that can do all that. Other companies, you need several valve to do all that.

Fewer parts usually means less money.

As an example, a SINGLE valve that can do everything you want would be the Hansgrohe Thermobalance III valve. It's affordable too.

If you were to buy that Hansgrohe TBIII valve, then you'd need a Hansgrohe trim kit that fits that specific valve. But then you can use a Hansgrohe rainshower head or any other manufacturer's rainshower head. And you can use a Hansgrohe handheld on a bar or any other manufacturer's handheld on a bar.

If that's confusing, you may find clarity or even more confusion here.

Good luck with your search!

Oh, thank you so much! That link was super helpful!

So if I like the look of the Hansgrohe trim kit, is the iBox 3/4" valve a good one or should I look for one that takes the Thermobalance III valve? Or do all Hansgrohe shower trim kits take all the Hansgrohe valves? And in that case what's the difference between the iBox and the Thermobalance III?

And for my son's bathroom and the guest bathroom, is there a quality difference between the different brands of valves? I will probably go with pressure balanced for these locations, and I don't want to spend a lot. But I assume I don't want to skimp on the valve if it's going to be buried in the wall and difficult to replace down the line, unlike the shower head, right?

Yes, if you like the Hansgrohe that you originally chose, you can use that valve and that trim kit, but you'll have to modify the valve a bit when you install it.

"Out of the box" the iBox valve is only an A OR B diverter. It can't send water to BOTH heads simultaneously. When you install the valve, you'll need to remove a small rotation limiting clip (I don't recall the exact name of the clip) on the valve that limits the rotation of the diverter valve. With that clip removed you can fully rotate the diverter valve to an AB position and water will flow out of both heads simultaneously. They probably have instructions for that in the installation manual.

So to make things easy, yes, you can stick with the 3/4" iBox, just remove that diverter limiting clip when the valve is installed.

For your other baths, if you want to stick with Hansgrohe, their pressure balanced valves are around $75 and the trim kits for those valves are another $125-$500 for a valve trim kit and a coordinating shower head and tub spigot.

If you're looking for economy, I usually recommend the Symmons Temptrol pressure-balanced valve. They aren't the prettiest ones out there, but you can buy a complete setup (the rough valve body PLUS trim kit PLUS a shower head and tub spigot) for about $90-$100 total. The valves are excellent, they have been around forever, and they are well supported. The few times I've needed a replacement part Symmons sends them out for free.

A lot of folk will install the Symmons set, then later maybe spend a few dollars and replace the shower head that came with the Symmons kit with one they like better.

With Hansgrohe, you can buy several pieces that act as one. You can buy one component of a set that will be your rain shower, with the other set utilized as the handheld. It seems that this forum has gone over the topic several times, but the prices Mongoct is pointing out is right in line. Best to pick it up, install is usually a 4 on a 1-10 difficulty scale, yet more than scalable.

i think i understand. if i get a shower system from symmons that will give me the trim kit ( shower head + hand shower + tub faucet) + the valve, which i guess controls both water pressure and temperature.
OR I could just get this: http://www.symmons.com/Bathroom-Products/Temptrol-II/Symmons-Temptrol-II-BP-Series-Shower-and-Tub-Shower-Systems-BP-56-2.aspx
and then replace the shower head and hand shower alone if i wanted to. but the temperature control knob thingy would always be like the one shown?
i dont understand why this thing above costs $100, and the system with just a hand shower added costs $500 (http://www.symmons.com/Bathroom-Products/Temptrol-II/Symmons-Temptrol-II-BP-Series-Shower-System-BP-56-500-B30-V.aspx)
What I am reading and hearing is that the Symmons insides are amazing, buy those and I can go get the Moen Voss shower head if that's what appeals to me. is this correct?
thx!

Here is a link that might be useful: shower system from symmons

The set with the handshower has a diverter - that is the handle abovet the shower handle/valve. It also has the handshower and the wide shower head. The tub/shower set has the diverter in the tub spout.

You can piece together a system or you can buy a set. You can put together a Symmons valve and trim and a Symonns diverter and trim. Add a Moen shower arm and head and a Grohe or Hansgrohe handhshower on a slider bar. The only parts that must come from the same brand are the valves and diverters and their corresponding trim covers. People typically use the same brand of valve and diverter so that the handles match.

Competitively shop the internet. Sites can really vary in their prices. You can find some good prices from reputable sellers on Ebay too.

This post was edited by Anna_in_TX on Tue, Feb 18, 14 at 10:10

thank you! after reading everything, it looked like i was able to find things that for pretty much all the bathrooms from symmons. until the plumber said they're commercial i don't like them. he only recommends moen or grohe. i don't want to go back to the start, should i ignore him?

Ignore the plumber on this one. Most plumbers recommend products that they are familiar with and have easy and fast access to for parts. Symmons shower cartridge is not going to need to be replaced as frequently as Delta or Moen, but if it does, you may need to order the part which could take mail time. If I were to have any problems, I would call Symmons first and then go from there. If you don't want to deal with any plumbing issues and want to just call the plumber and not get involved in the details, then install what he likes to fix. But most of the folks who frequent this forum are usually more hands on and maintenance savy.

I currently have builder installed Delta in my baths. I have hard water. Yes, the cartridges are available at Home depot 5 minutes away, but I have had to replace them twice in 16 years. The Delta cartridges are like Moen, plastic. I am looking at upgrading with my 2 remodels.

This post was edited by Anna_in_TX on Thu, Feb 20, 14 at 6:52

Also, for the DIY folks, exploring beyond Home Depot, Menard's, Lowe's and the like might reveal resources for immediate supply of hard-to-find parts, especially if one lives in or near a larger city.

For example, in the Chicago area, a plumber-neighbor recommended The Faucet Shoppe to me 30 years ago when I was looking for a replacement faucet part I couldn't find at my hardware store (there were no Home Depots back then). While it has the fancy "Shoppe" spelling, the place is a dumpy hole in the wall. Yet they carry faucet and toilet parts going back 100 years. They've been in business at the same location for 50 years.

Here is a link that might be useful: The Faucet Shoppe

This post was edited by DreamingoftheUP on Thu, Feb 20, 14 at 9:17

It wouldn't hurt to go ahead and find a plumbing supply in your area that carries Symmons parts. You may even be able to get specific information and a good price from them. If they have the items in stock, or similar items, you may be able to actually touch and feel the products. Also, it helps to keep your fixture paperwork to look up model and part numbers. Most manufacturers make fixture diagrams available on the internet.

This post was edited by Anna_in_TX on Thu, Feb 20, 14 at 13:35

When I did my research in selecting shower fixtures I couldn't tell the difference between pressure balance and thermostatic valve and after much reading I came to this conclusion.

I'm only talking about the Pfister line since that's what I purchased.

Pressure balance valves

Normally work at a maximum of 2.5 gallons per minute which is what a standard shower head needs.

They normally operate at full pressure when turned on and the single handle valves only adjust the temperature, not the volume, unless you purchase a higher end fixture.

The temperature is controlled by way of adjusting the water pressure and attempts to maintain it with within +- 3-5 degrees and you will notice a drop in water pressure when a toilet if flushed etc., since it's attempting to balance the pressure to maintain temperature.

There will not be a temperature setting on the trim kit as since the pressure balance valve has no idea what temperature the water is, it only knows where you adjusted the handle. Summer and winter the temperature to the valve will be different so you adjust accordingly.

Based on the 2.5 gpm flow rate you can normally operate one item at a time unless you don't mind a reduction in water pressure.

Thermostatic Valve;

Pfister has a 7.0 gpm and a 12 gpm flow rate at 70 psi, to accommodate multiple shower heads, rain cans body spray to operate at once.

They generally come with at least one volume control and you can add onto it as well as add diverter valves.

The temperature is monitored by way of a wax ring and when it senses a change in temperature, not water pressure it adjusts up to 1-3 degrees without changing the pressure.

Regardless of the water temperature coming into the valve, you adjust the temperature on the indicated ring and it remains that way any time of year. In other words, it has a temperature setting on the trim kit.

Since shower heads are normally 2.5 gpm, body sprays 1.6 gpm, you can add up what you want to operate at one time as long as you don't go over the either 7.0 or 12.0 gpm.

Again this is based on the Pfister pressure balance custom line.

wouldn't you know it, he backtracked. said they're real good quality, was only saying no because replacement parts are hard to find. onward to tub faucets, which are all $1000 and up.
thanks for your help!

Symmons has nice looking roman tub faucets. Check ebay.

This post was edited by Anna_in_TX on Thu, Feb 20, 14 at 23:16

Pegasus 8 inch solid chrome plated brass "power shower"

if you have to ask.....................................