Hey guys I am Roger Wakefield, LEED AP, The Expert Plumber.
Coming to you this morning to talk to you about tankless water heaters.
Now, tankless water heaters.
One big question is will I have to change my gas system for a tankless water heater?
Chances are, probably yes.
Unless you go a very low BTU tankless water heater, you're probably going to have to upsize
or increase the volume of your gas system.
One thing that a plumber should do before he ever even starts installing a tankless
for you, or a tankless water heater for you is to do a gas load calculation.
Now what a gas load calculation is the plumber will need to come into your house, get up
in your attic or whatever it is you've got where your gas lines are ran, measure every
linear foot of gas pipe that you have, draw this out, put the BTU ratings for every appliance
or fixture that you have on there, and make sure it's going to be big enough.
He's also got to look at your meter to determine how big is your meter, how many BTUs will
your meter, your gas meter allow through.
A lot of the meters around here, most of - probably the average meter around here, allows 275,000
BTUs or 275 cubic feet an hour.
So, what you've got to look at is you're taking out a tank type water heater, possibly, probably
that calls for 40,000 BTUs, you're putting in a tankless water heater that calls for
199,000 BTUs.
So you're looking at a big delta there.
Now if you've got, say a 40 or 50 gallon water heater you draw 40 to 50,000 BTUs right now,
if you go a tankless water heater and you increase that demand, even if it's a temporary
demand because, you know, we call tankless water heaters on-demand water heaters.
But if you increase that demand, even for a little bit - here's worst case scenario
and here's why you wanna upgrade that.
And I tell this to people not to scare them but to be honest, say you come home in the
middle of the winter, you turn on your log lighter to light a fire in the fireplace,
your wife jumps in the shower to take a hot shower and turns on the hot water, if your
gas system is undersized and your water heater or your new tankless water heater draws, you
know, 199,000 BTUs and it draws so much of your gas that your fire goes out at your log
lighter and you don't realize it, and then she turns off that water so now the water
heater stops, now it starts supplying gas back to your log lighter because you left
it on, now you're filling your house with natural gas.
Is that possible?
Absolutely.
Every plumber should know to do a gas load calculation chart.
Every plumber should know to test it once he hooks it up, hook up a monometer to it,
call for it at a tub, someplace that's going to create that big demand and see how far
does that pressure drop.
Because you still want to make sure you've got enough pressure and volume for every other
appliance in the rest of the house.
You know, the last thing you want to do guys, is turn your house into a bomb and the way
to do that is by installing a tankless water heater with your current gas line, it is really
going to try to suck gas in in order to give you the hot water that you're calling for.
You don't want it to starve something else.
Now, I used a fireplace because that's the one that doesn't have pilot light, it's not
going to shut off.
You know luckily most appliances that we have are fail safe, you know, they've got a fail
safe built in to where, you know, your water heater for example, if you lose your flame
your pilot light goes out, it will not let gas into the chamber.
So there's a lot of reasons that you want to look at this.
I used a fireplace because a log lighter just has a manual valve, you open it up, gas flows
to it, you close it, you cut the gas line off.
So what you have to do is one of two things.
You check it out, you decide that you need to increase to size of the pipe, your meter
is big enough, you got enough linear footage, or your linear footage is actually short enough
that your meter can handle it the way it is, you may just need to increase the size of
the line to that water heater.
Everything goes back to manufacturers recommendations and even cities that say look, you know, we
don't require a gas load calculation chart, they want you to do it because you need to
know, do I have enough gas getting to this water heater.
So tankless water heaters are a big deal guys, the popularity of them is going to grow more
and more.
A good thing is, and I point this out on people and their ROI is look, if you invest the money
now, to upgrade your system where this tankless water heater works for you, you're not going
to have to do that again.
Meaning, 20 years from now when you go to change your tankless water heater out, your
gas lines is already upsized, your vent piping is already done.
Everything is already ready for you to come out just like a regular water heater, take
out the old one, put in the new one, it's not going to cost you a lot extra then.
Does that still mean it's worth it for everybody?
No.
Does that still mean the ROI is worth it?
If it's going to take you forty years to pay it off, or recoup your investment, maybe not.
Is it worth it to have a tankless water heater on there so you're using less gas every month?
Absolutely.
Guys, upgrading your gas is something that is very important to think about and to consider
and if your plumber is coming in and putting in tankless water heater and not even talking
to you about your gas line, your gas system.
If he's not checking it out guys I'd be afraid.
Make sure you deal with reputable plumber, make sure you're pulling permits, getting
it inspected because that's going to be a big deal for you.
It's going to have the city inspector who knows all about these come out, look at your
system and say hey this'll work or hey this won't work.
And then that puts the burden back on the plumber.
So make sure you cover yourself because all plumbers may not be looking out for your best
interest.
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My name is Roger Wakefield with Texas Green Plumbing.
Saving you money one drop at a time.