You can get hot water too fast.
How to get hot water to second floor faster.
Since you know hot water is making it to the 2nd floor there are pretty much two possibilties.
The lower the flow rate gpm of the showerhead the longer it takes for the water coming out of the shower to heat up.
For between 180 to 500 depending on how fancy a unit you want to buy some have motion sensors built in simple ones use just a timer you can attach this unit to your water heating system and have hot water up to 80 faster that means within seconds in the summer than you get today from your standard water heating system.
The other is that the shower is on a separate hot water feed line from the sinks and that this.
Solution for low flow showerhead.
Divide the house into two zones one for each floor.
If hot water has to travel through dozens of yards of winding pipework before it reaches your fixture cold water will flow while the hot water is making its way there.
For 1 the furnace fan running all day with the a c on might solve some milder heat trap problems for your second floor.
Saves water but wastes a lot of energy gas propane or electricity to keep the pipes hot.
Common terms referring to hot water pumps used to circulate hot water.
You might also want to try adding a ceiling fan in.
Flow rate too low on shower head.
Add a small return vent duct to each room on the second floor.
One as tpe suggested is that you have a thermostatic shower valve that s not working or even a mixer valve that isn t opening on the hot water side.
Here s the best part.
Make the second floor return vent duct bigger.
If you have a showerhead that has a low flow rate such as under 2 5 gpm gallons per minute it may be time to upgrade to a higher flow shower head higher water flow will allow the water to flow out of.
Another way to get hot water faster especially in newer homes is structured plumbing.
In a structured plumbing scenario your water heater is situated at the center of the house rather than in your garage or basement.
Whenever you need hot water you simply switch on the hot water pump.
The farther pipes are from the main water line the less water pressure there is for fixtures such as sinks and showers.
A one inch main hot water line runs through the home.
For example if your water heater is located in the basement it can take a relatively long time for hot water to get to the sink in your second floor bathroom.