Don’t tell Ed Begley Jr. but I didn’t buy the A. O. Smith Vertex 100 hot water heater to be green. I didn’t even pick it to save money! Truthfully, we decided to buy this high-tech, 96% efficient water heater so we would have plenty of hot water. But of course the energy savings are nice, too!
(for six times the money…)
The Sad Truth About Water Heaters
Water heaters are giant tea kettles. Nearly all of them feature a gas burner or electric coil at the bottom of a large 40-50 gallon tank of water. When you turn on your tap, water is pushed off the top, through the pipe. The water stays hot all the time because the tank is insulated and the burner/element comes on when needed.
The sad truth is that all this is pretty awful in terms of efficiency and convenience. You have to heat 50 gallons of water at once, and that takes a ton of energy. Electric elements are fairly efficient locally, but generating and transmitting electricity is pretty lossy. Natural gas doesn’t waste energy outside your home, but 20-30% of the heat ends up blowing out the vent.
This is pretty awful. Since water heaters account for about 1/4 of the energy used in the home, this has a major impact. Over 5% of your energy bill is wasted by this single appliance!
But the worst thing for average users (read: everyone in your home) is the slow rebound time of conventional tank water heaters. Take a nice long shower and everyone else is stuck with lukewarm water for hours after. Fill the tub and you had better wait before doing dishes!
Alternative Water Heaters
Outside the USA, and in many newly-constructed homes here, a popular alternative is the inline water heater. These devices take in the cold utility or well water and heat it on demand. They allow the user to run hot water all day long, but they can only handle moderate flow. In other words, inline heaters are great for a single shower or sink, but they can’t handle a whole house of hot water users. For that, you need two or three units, or even “point of use” heaters all over the house.
A growing alternative is the hybrid water heater, which uses a small tank along with an inline heater system. These have a higher flow rate short-term but still can’t keep up with active whole-house use. But both inline and hybrid heaters are much more efficient, since there’s less energy used keeping water hot when no one is around. But they still waste about 20% of the energy used.
Then there are “green” alternatives. Since electricity generation and transmission is inefficient, it makes sense to reduce usage. That’s what heat-pump water heaters do: Rather than heat the water using electricity, they move ambient heat from the room into the water. Like an air conditioner in reverse, a heat pump water heater uses electricity to move heat rather than create it. This is much better for electric homes, but still not on par with gas.
The A. O. Smith Vertex: A Gas Vortex!
Not everyone wants an inline or point-of-use water heater, and many homes in the USA have cheap, plentiful natural gas. So plumbing companies have created another kind of water heater maximizing efficiency and water delivery.
The Vertex series are incredibly efficient. By passing the exhaust through a condensing pipe spiraling through the tank, the Vertex GPHE is 90% efficient. But the top-of-the-line Vertex 100 GDHE is even better: With a top-mounted burner, it blows the gasses down through the spiral, resulting in an amazing 96% efficiency for the Vertex 100. The Vertex leaves so much heat in the tank that the cool exhaust can pass through a simple PVC pipe.
Efficiency is nice, but the Vertex is incredibly expensive. At $2400 or $3800 list price (Vertex GPHE and Vertex 100 GDHE, respectively), it’ll take a long time to recover that investment. It is possible to buy a Vertex cheaper. Amazon sells the Vertex 100 for under $3k shipped, and the Vertex GPHE for under $2k, but your best bet is a local plumbing contractor or supply house. I got my Vertex 100 for just $2500 through my general contractor, for example. But even A. O. Smith’s own calculator says I’ll save just $110 per year with the Vertex 100.
Here’s another review of the A. O. Smith Vertex 100 water heater!
Not Buying It For Efficiency
Although I love having maximum-efficiency appliances, I’m really buying the Vertex 100 for one thing: Hot water. We recently remodeled our bathroom, adding a large tub and fancy shower. And I have three pre-teens in the house. So I’m going to need all the hot water I can get!
When I moved in, my home had two 50 gallon water heaters set up in parallel. After one died, I became concerned that I would soon have to buy two new water heaters, since a single one barely kept up with our showers, let alone our tub!
A typical gas tank water heater pushes about 40,000 BTU of heat per hour into about 50 gallons of water. If you need more hot water than this, you’re waiting or you’re buying a second water heater. This is the typical solution: Add more (inefficient) heaters.
The Vertex 100 changes that. Although it is “just” a 50 gallon heater, it is able to push 100,000 BTU per hour into the tank. This means it is able to rebound faster even than two standard water heaters! Although it’s only able to push half the BTUs of a tankless water heater, the Vertex easily beats the two units I found when I moved in.
Suddenly the savings doesn’t look so bad. Rather than spending about $800 on two 50-gallon tanks, I’m buying a single Vertex for $2500. It’s still about a 15-year payoff. But it’s conceivable that the Vertex will actually last 15 years or more. After all, the builder-grade water heaters in my house today lasted 14 years!
Stephen’s Stance
I justify spending six times more on the Vertex 100 for a simple reason: It’ll keep up with the heavy water use in my house. I’m hoping I’ll never have to worry about hot water as long as I live here. The fact that it saves over $100 per year due to energy-efficient design is just icing on the cake. I’ll post again once the Vertex is installed and running!
One more thing: “How It’s Made” visited the A. O. Smith factory and produced this video:
My wife and I are considering purchasing this very expensive water heater as we would like the super high output and rapid recovery without the drawbacks of an inline tankless heater. Would love to see a follow-up on how it’s been working for you. From what I can see the number 1 complaint people have about this unit is that it is noisy.
Also, does it handle your new tub OK without getting cold?
Caution about buying an AO Smith Vertex hot water heater. Two years I bought a Vertex hot water heater (GPHE 50 100) based on a strong recommendation from a friend who also installed a Vertex in his home. On 24Aug14, this unit began to leak. The plumber who originally installed the unit determined it was leaking inside the chassis. Since the unit was under a 6-year warranty, AO Smith replaced it. Unfortunately, I had to pay for the labor (over $500) even though this was no fault of mine. In essence, I paid for AO Smith’s faulty product. I requested reimbursement of that cost, but AO Smith denied it. BTW, the unit my friend installed had to be replaced just after 8 months.
Wonderful product, but quite expensive. I still have to save up for this water heater.