# Hot water taking 5 minutes to get hot



## artmonk80 (Dec 11, 2009)

I have a rental home where the tenant is complaining it takes 5-7 minutes for the water in the shower to get hot. Is there any DIY remedy for this? Is it a bad unit? Should I call a technician? Any input is appreciated. Thanks to all who contribute here.


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## Yoyizit (Jul 11, 2008)

98' of 1/2" ID pipe holds one gallon. 5 min to get hot water would need a flow rate of 0.2 GPM, depending on the length of the pipe. 

Maybe the pipe is restricted, or maybe the heater's t'stat is taking longer than usual to kick on.

If NG WH, measure the voltage to the gas valve.


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## Alan (Apr 12, 2006)

What you need to do is go there and time it. People ALWAYS exaggerate the length of time it takes to get hot water. They never actually time it. It seems longer when you stand there waiting for it.

Reasons for the problem are long distance from the water heater, or oversized hot water lines. If the line is oversized, and it cools off, you have to clear an oversized line through a 3/8" opening, which will take much longer than clearing just a 1/2" line through a 3/8" opening in the faucet supply.

You could solve both of these by putting a recirculating pump on the hot water piping. They make aftermarket ones that you can put under the sink, but they dump a little hot water into the cold side, so you will get warm water out of the cold for a second, instead of cold water out of the warm. I'm not sure how much these cost. You could have a plumber come and replumb the hot water piping to where a standard pump could be put on the hot water lines.

If your renters are good renters and this is going to cause them to move out, it might be worth installing the under-sink unit. If not, i'd tell them to deal with it or move out. :whistling2: It will probably cost you a couple grand to get a plumber to replumb the hot system.


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## Thurman (Feb 9, 2009)

Good advice from Alan! I work on rental houses for customers and this issue seems to begin with the coming of colder weather in my area. The first thing I do is to measure the amount of time it takes for warm, then hot water, to come out of _the faucet_ of the bath tub, not the shower. IF the time interval seems to be within decent limits to me, I then check the shower head for the amount of water coming out of it. IF this seems limited, I then remove the shower head and check the strainer in the rear of the unit, if it has one. One problem in my area is with older homes that have galvanized piping run underneath the houses and no insulation. This lead to what Alan and Yoyizit were talking about, these pipes will get cold/cool and then when the warmer water starts through them the pipes will pull a lot of the heat from the water. The re-circulating pump is a good idea, I've seen them in homes and they work. Check the flow rate at the faucet of the tub and see what you get first. Keep us posted, Thanks, David


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## AllanJ (Nov 24, 2007)

A tank type water heater thermostat does not kick on until a good amount of the hot water in the tank has been consumed. In turn the water at the faucet should have finally gotten hot and run hot for a reasonable length of time before the thermostat kicks on.

The first person to use hot water after a few hours will have to wait until not only the colder water occupying the pipe has come through the faucet/shower but also until the pipe itself has heated up and therefore stopped sapping heat from the next batch of water passing through.

FYI if the contents of the tank was not that hot to begin with, namely you turn on the water and it never gets hot enough, then it will really never get hot if you still keep running the water even after the thermostat on the heater kicks on. The flow through your shower and replenishment of the tank contents from the cold supply line will be faster than the heater can heat it.

If you install one of those recirculating units that uses the cold water line instead of requiring a new, third, pipe installed, then you will be waiting for the cold water to get cold.


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## Livewire78 (Dec 6, 2009)

Yoyizit said:


> 98' of 1/2" ID pipe holds one gallon. 5 min to get hot water would need a flow rate of 0.2 GPM, depending on the length of the pipe.
> 
> Maybe the pipe is restricted, or maybe the heater's t'stat is taking longer than usual to kick on.
> 
> If NG WH, measure the voltage to the gas valve.


 Took me a min. to figure this out but, got part of it. 231 in cu. divided by pie R squared times 12 inches . Or 231/2.35619449 = 98'., How do you get formula for flow rate, I know they said 5 min.. But how do you get 0.2 GPM? just curious i've been trying to figure it out


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## Yoyizit (Jul 11, 2008)

Livewire78 said:


> I know they said 5 min.. But how do you get 0.2 GPM? just curious i've been trying to figure it out


1 gal takes 5 min, so when you divide you get 1/5, which equals 0.2 gals in each minute.


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## artmonk80 (Dec 11, 2009)

*Thanks!*

Thanks to everyone who responded. I appreciate your help.


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## 130 plumber (Oct 24, 2009)

better yet,how is the pressure in the house and how far away is the WH from the fixtures?also do you have copper or galvanize pipe?


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## beenthere (Oct 11, 2008)

Also check to see if the pipe is ran through an unconditioned area.
If it is, it will cool the water down a lot before it reaches the faucet. Which make sit take longer to get hot water out of the faucet.

May need to insulate some of the pipe.


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## 130 plumber (Oct 24, 2009)

Laing autocirc recirculation pump would be the cheapes way to solve your problem without replacing your water lines or opening up walls.This can be install under a sink or next to your water heater if you already have a return line for the wh:thumbsup:


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## Yoyizit (Jul 11, 2008)

From another post, an uninsulated pipe is half way to the ambient temp in 30 min., insulated may take 90 min.


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