Slow Hot Water – Why Does It Take So Long?
Do you have to stand naked and shivering waiting for the slow hot water to reach the shower? Why does it take so darned long to get hot
water from the water heater to the fixture?
Plagued by slow hot water? – Why does it take so long to get hot water to the fixture?
There are a number of variables involved in getting
the hot water from your water heater to your fixtures. Obviously the
distance from the water heater to the fixtures is a major factor in how
long it takes to get hot water. Another important factor is what kind of
pipe is used in your plumbing system? Is it galvanized iron pipe,
copper pipe, copper tubing, plastic pipe or maybe some kind of plastic
Since the material that the pipe is made out of can
absorb heat from the water it is important as well. Other factors
include whether or not the pipes are insulated, the ambient temperature
around the piping, and the speed of the water through the pipe.
Tankless water heaters contribute to slow
One last thing to consider is what type of water
heater you have. If you have a storage type water heater where there is
a big tank full of hot water just waiting to fill the pipes, you will
get it much faster than if you have a tankless water heater. The
tankless heater has to first heat the water, before it can send it to
you, increasing how long it takes.
Pipe diameter makes a difference
A gallon of water will fill 63 feet of ½ inch
galvanized iron pipe, 36 feet of ¾ inch galvanized pipe, or 20 feet of
1 inch galvanized pipe. In the case of type K copper pipe, a gallon of
water will fill 88 feet of ½ inch pipe, and 44 feet of ¾ inch pipe.
This means that if you run your faucet at 2 gallons
per minute, and you have 1 inch galvanized pipe, the water will travel
41 feet per minute. However, if you have ½ inch type K copper pipe, the
water will travel 176 feet per minute, quite a difference. So the smaller the diameter of the pipe, the faster
the hot water will reach the fixture, given the same flow rate.
The piping material contributes to slow
hot water delivery
galvanized pipe has a much thicker wall than the copper pipe and is much
heavier, it will absorb more heat energy from the hot water as the water
flows through it. So if you have galvanized pipe it will take longer for
you to get hot water than if you had copper pipe of the same length.
Seasonal variations - ambient air
temperature plays a role
In the winter it will take longer than in the
summer, since the ambient temperature will be lower. The colder the
ambient temperature the more heat the pipe will suck out of the water
and so the longer it will take. Insulating the pipes does help a
Fixture flow rate is a big factor in the
speed of the water through the pipes
In the old days you could get shower heads that
would permit flows of over 7 gallons per minute…but now days everything
is low flow. Most showers now are limited to 2 gallons per minute and
many faucets are below 1 gallon per minute. This adds significantly to
the time it takes to get hot water.
Instant hot water systems use a pump to
speed up the water
There are ways to speed up the delivery of hot
water to your fixtures. Use a pump. A number of manufacturers offer
various types of hot water pumping systems designed to provide speedy
hot water to your fixtures.
The oldest style system just uses a pump to
circulate hot water in a loop, through the hot water piping and back to
the water heater. With that type of system you have nearly instant hot
water. However, the circulating hot water loses a lot of heat energy so
it’s expensive to run. Another problem is that usually running a pipe
from the last fixture back to the water heater is very expensive.
Hot water demand system
Another option is a demand type hot water system.
With a demand type system the cold water piping is used as the return
line back to the water heater. When you want hot water you “demand” it
by pressing a button. The pump turns on and circulates the water
through the piping until hot water reaches the pump. When the hot water
reaches the pump it shuts off to prevent filling the cold water lines
with hot water. Now you have instant hot water when you turn on the tap
or shower, and you did not wastefully run water down the drain while you
waited. With the right pump, the hot water can get to the fixture twice
as fast as normal too.
If you have to wait for lengthy periods to get your
hot water, then by using a hot water pumping system you will save time,
water and energy. Some such systems claim water saving of up to 10,000
gallons a year for a family of four.
Chilipepper Sales 1380 Greg St., # 221 Sparks Nevada, 89431