If you live in the US, then you probably have a standard mixing valve
If you live elsewhere, it’s probably a thermostatic one
For US:
You want to turn your handle all the way hot to clear your hot water lines fast, it’s room temperature in the hot water lines. Once the water is hot, then you start mixing in cold water.
The first cold water is from the lines in your house. It is heated or cooled by your home, basically room temperature water.
So say I turn the valve on full hot. Pure hot water is pouring out. Now you add some of that “room temperature cold water” to get to your perfect temperature.
Now, once you run out of “room temperature cold water,” it will start pulling water from the street.
I’m guessing you live in a cooler climate area?
120°F + 70°F = perfect temperature
But if the outside water becomes, say 50°F after you use all your water stored in your cold water lines
120°F + 50°F = colder water
So you have to add less 50°F water, which means slowly creeping your valve up until you have steady temperature water going to the valve.
Things like the type of water heater matters. If you use a tank then as you use water it adds water. If you keep your tank at 120° and you’re adding 70° cold water or 50° water to the tank matters. You also have “room temperature water” in your cold lines going to your tank at first, then colder water. So that creates another “lag” in temperature
US standard mixing valves aren’t as nice as a thermostatic valve. They are just cheap and standard and work well enough in most places.
Thermostatic valves allow you to select, say 100°F water, and the knob just controls the water flow rate. No matter what, the water that comes out of your shower will be 100°F. As the water coming into your house gets colder it will automatically adjust. As the water from your tank gets colder, it will automatically adjust.
Sounds like your valve is working as intended though
It’s definitely a nice upgrade. Little pricey in the states because hardly anyone uses them, so they are “specially”. Not any more difficult to install really but plumber might charge a premium.
If you live in the US, then you probably have a standard mixing valve
If you live elsewhere, it’s probably a thermostatic one
For US:
You want to turn your handle all the way hot to clear your hot water lines fast, it’s room temperature in the hot water lines. Once the water is hot, then you start mixing in cold water.
The first cold water is from the lines in your house. It is heated or cooled by your home, basically room temperature water.
So say I turn the valve on full hot. Pure hot water is pouring out. Now you add some of that “room temperature cold water” to get to your perfect temperature.
Now, once you run out of “room temperature cold water,” it will start pulling water from the street.
I’m guessing you live in a cooler climate area?
120°F + 70°F = perfect temperature
But if the outside water becomes, say 50°F after you use all your water stored in your cold water lines
120°F + 50°F = colder water
So you have to add less 50°F water, which means slowly creeping your valve up until you have steady temperature water going to the valve.
Things like the type of water heater matters. If you use a tank then as you use water it adds water. If you keep your tank at 120° and you’re adding 70° cold water or 50° water to the tank matters. You also have “room temperature water” in your cold lines going to your tank at first, then colder water. So that creates another “lag” in temperature
US standard mixing valves aren’t as nice as a thermostatic valve. They are just cheap and standard and work well enough in most places.
Thermostatic valves allow you to select, say 100°F water, and the knob just controls the water flow rate. No matter what, the water that comes out of your shower will be 100°F. As the water coming into your house gets colder it will automatically adjust. As the water from your tank gets colder, it will automatically adjust.
Sounds like your valve is working as intended though
That’s fantastic info. Thank you! Though it sounds like I want to upgrade to thermostatic.
It’s definitely a nice upgrade. Little pricey in the states because hardly anyone uses them, so they are “specially”. Not any more difficult to install really but plumber might charge a premium.