A question from DT in New York, NY:
I’ve been told that I am required to use a thermostatic or a pressure-balanced shower valve in my bathroom renovation. Why is this “required” and what’s the difference between the two?
If you’ve ever been blasted by hot water in the shower, after someone in your house either flushes a toilet or runs the water in another room, then you will bless the day that thermostatic and pressure balanced valves came on the market.
Both valves prevent scalding water from entering the shower and are now required by plumbing safety code, but each one works differently.
Thermostatic valves prevent scalding water via … you guessed it … a thermostat!
These devices sense the temperature of the water entering the valve.
Your plumber will calibrate the thermostat during installation using a thermometer, in order to keep the temperature reading on the control accurate.
An additional safety feature is a heat limit , which can be set (or not) by your plumber to prevent the hottest temperature on the valve from exceeding 120° F.
(Alternatively, you can reduce the temperature on your water heater to achieve this same result.)
Another nice feature of the thermo valve is that you can pre-set your favorite water temperature so that when you’re ready for a shower, all you have to do is to turn it on –
no more fiddling with the valve to get the temperature just right.
This valve tends to be higher in cost for both the product and the labor required for installation, but for a high-end renovation, it’s well worth it.
Pressure balanced valves also limit scalding water via … did you guess right?
Water pressure! By sensing the pressure of water as it enters the valve, a pressure balanced valve also prevents scalding hot water from reaching the bather.
This valve typically has an on-off feature which is also the cold to hot control
whereas with a thermostatic valve, you can control the water temperature and the
the pressure independently. With a pressure balanced valve, you have one pressure,
all the time and you cannot pre-set a “known temperature” like on the aforementioned thermostatic valve.
Hope this helps and happy renovating!