My family and I just spent the holiday weekend in a very nice cabin in the mountains. Everything about it was great. But I was reminded about how nice it is to have a pressure-balancing mixing valve in the shower. This cabin did not have one, so when I was taking a shower and my wife turned on the cold water elsewhere in the house, I was treated to I painful blast of scalding water through the showerhead. I knew right then that this beautiful cabin did not have pressure-balancing mixing valves in the showers.

hotshowerYou may not know what a pressure-balancing mixing valve is. But you have certainly experience a shower where one is NOT installed. We all have had the unpleasant experience of getting scalded when taking a shower and someone in another room flushes a toilet or turns on the cold water in a sink. All of a sudden your shower loses its cold water and all that comes out of the showerhead is scalding hot water, as happened to me in the cabin. You jump to the side to avoid getting burned and frantically adjust the temperature of the water. Of course, as soon as the other plumbing fixture that stole your cold water is no longer running, your cold water returns with a vengeance and you are treated to a blast of icy cold water that reminds you of a frigid mountain stream. This is both uncomfortable and potentially dangerous if the hot water heater is set at a high temperature, skin burns can result.

You don’t have to suffer like this. You simply need a pressure-balancing shower valve. Most manufacturers of plumbing fixtures offer these. A mixing valve is the hot and cold water adjustment apparatus on your shower. By turning the handle one way or another, you adjust the temperature of the water coming out of the showerhead by allowing more or less hot and cold water to mix together to get the temperature you want. In standard mixing valves, once you have found the setting you want, the amount of hot and cold water is set and does not change.

In a pressure-balancing mixing valve, the amount of hot and cold water can change automatically. When a toilet is flushed elsewhere in the house, it calls for cold water to refill the tank. That causes the water pressure on the cold side in your shower to go down. And that means all you get is hot water, thus the scalding effect. But a pressure-balancing mixing valve immediately detects the lower pressure on the cold side and equally reduces the pressure on the hot side to keep the same ratio of hot and cold water coming through the showerhead. You will experience a slight drop in water pressure through the showerhead and the stream of water will diminish temporarily, but the temperature of the water will not change. Once the cold water pressure returns to normal, the valve readjusts and the stream of water goes back where you originally set it. No scalding!

Pressure-balancing shower valves cost a bit more than standard valves. But the small added cost is well worth the comfort and safety you will gain. You can take the comfort and convenience of your shower valve up another notch by choosing a thermostatic mixing valve the keeps a preset temperature whenever you turn on the shower. But we’ll talk about those in another blog post.

Please read my other posts for more useful information about house design and construction.