We've made a few major decisions over the last couple of days, not the least of which is that neither of us really enjoys showering with a bucket of lukewarm water.

Since we were thrust into the potentially life impacting decision making process surrounding the replacement of our fractured water heater, we've had a bit of a crash course on the subject of 21st century water heating.

It seems the whole industry has progressed rather significantly since our doomed gas fed 40 gallon hot water tank was installed in 1995. It's amazing what nearly 19 years will do to technology of nearly any kind.

To be totally honest, I've actually been brainstorming and generally researching water heating solutions for our home for many years. Well, I should correct that statement. I've actually been daydreaming about the day we'd eventually replace our outdated and inefficient tank heater, and I often daydream via Internet research and mock shopping. I know, I have a set of ridiculously exciting daydreams.

When our original tank was installed, it was considered a moderately efficient unit for its time. But at about 80% efficient, today it's an embarrassingly inefficient dinosaur. An example of A bygone era of home appliances when lower technology, lower fuel prices, and lower consideration for the environment reigned supreme.

The old tank used an atmospheric vent by way of our second chimney flue, and it was positioned in an awkward location in our basement behind a terribly built temporary wall. To complicate matters, it was positioned beneath HVAC duct work, we were unable to service it or to even gain access to the anodized rod that should be periodically changed. How this thing lasted 19 years...I haven't a clue.

While I've long dreamed of replacing our existing configuration of forced air furnace and independent hot water heater with a high efficiency condensing boiler and indirect water heater setup, I've recently begun thinking this may not be the optimal setup for us in our home. Now, this unexpected tank rupture has us in a position where we need to make a decision once and for all on our approach.

The first thing we did was to take to the Internet and begin researching basic unit pricing. Knowing we wanted to replace our existing tank with a high efficiency natural gas unit that changes over to direct venting, we had a good starting point for pricing. Here's what we found.

  • 50 gallon tank - $1,100
  • Tankless - $1,500
  • Boiler + Indirect Tank - $5,000

Now, this obviously isn't comparing apples to apples, but it gives a good idea of general unit pricing. Install obviously varies wildly based on gas line requirements, difficultly, individual rates, and complexity of the job, but it at least shows a rough comparison. It's also worth noting that the boiler option is far more geared to future benefit of using radiant heat in our home.

In weighing our options we started a pro and con list for each of the options, and that helped us to eliminate different pieces and prioritize our choice.

The biggest cons on the boiler option helped us to immediately eliminate that from contention. They were, cost and time to full implementation. We'd likely be looking at close to $15,000 on install of the boiler and indirect heater, and who knows how long it will take to realize the true benefit of radiant heat with out implementation timelines, so it was simply too large of an investment at this time. It also wasn't getting us anything more in the short term than a high efficiency tank would get us.

With the boiler option eliminated, we looked at our two remaining options, tank or tankless.

Tank Pros:

  • Lower cost for new unit/install
  • Proven to work in our house
  • Higher GPM flow rate (determined by city pressure)
  • Easier install
  • Smaller gas line
  • High efficiency units available

Tank Cons:

  • Takes more space
  • Runs out of hot water
  • 7-10 year life expectancy

Tankless Pros:

  • Never run out of hot water
  • Smaller footprint
  • Lower operating costs
  • Longer life (20 years plus)

Tankless Cons:

  • Lower GPM flow rate
  • More expensive
  • More complex install (larger gas line)
  • Cold water sandwich (depends on unit installed)

While price is often a driving factor for many people, I feel that's often a knee jerk reaction based on immediate impact on the wallet, rather than looking at the long term effect operating costs have on price. It's obvious that a lower initial price is more attractive, but what does that get you?

In the case of tank vs tankless, a tankless water heater will cost less to operate since it only heats the water that's needed, rather than the way a tank keeps the whole volume of the water warm to you have hot water whenever you need it. However, the amount of time you'll need to realize this efficiency benefit vs cost of install may take you as much as 10 years, so should you really care?

The other consideration with cost is in regards to useful life. Since a tankless will last as much as two or three times longer than a tank heater, you might need to install two tanks in the amount of time you have with one tankless. But if you're not going to be in your house for more than five years, does it really matter. Since we'll be carried dead from our house, this is a factor for us.

So as important as price is, from this whole list of pros and cons, there are two items that really stand out to us that we're going to focus on, and they do not directly involve price.

The first is install footprint, which puts the tankless in the lead. Our house is small, and we eventually want to finish the basement, so the smaller our utility appliances the better. Hanging a tankless on the wall is a great way to free up space in our basement now, and a great way to allow for more space in a finished basement of our future.

The second item is flow rate, measured in gallons per minute. Tankless heaters must heat water to an agreed upon temperature before delivering that water, and it takes time and energy to heat that water. So a tankless heater will not have a consistent GPM flow every day because it will reduce its flow rate to ensure water is being delivered at temperate, rather than delivering cooler water (like a tank heater does).

This means that a tankless rated at 9 GPM will only deliver that true 9 GPM at 120 degrees when the input water temperature is 70 degrees in the summer. When that water temp drops to 50 in the winter, the tankless drops to maybe 6 GPM rather than 9 GPM.

I know even 6 GPM sounds like plenty, and it probably is, but we have one major consideration. We have those two massive 12" rain shower heads for our master bathroom shower. And these things expect as much as 5 GPM each. If both are on at the same time, we're talking 10 GPM.

Concerned about the capability to deliver the water we need, I did a little test experiment in the backyard with our garden hose and a five gallon bucket to ensure they can still run at a lower flow rate.

First I tested by filling the bucket and verified a 5 gallon per minute flow by adjusting the hose bib and how far open it was.

Next I hooked the rain shower head to the hose and was able to see the performance at 5 GPM, which was very nice.

Then I got distracted and watered the plants and herbs with this giant shower head for a bit.

Finally, I reduced flow at the hose bib to about 2.5-3 GPM, which is the lowest flow rate I can imagine with both shower heads on. While the flow wasn't ideal, it was still very acceptable. This told me that 6 GPM in the dead of winter mixed with some cold water split between two large rain shower heads will be more than sufficient.

So based on all of this information, we've decided to go the tankless route. We're working with Tankless Concepts, a local company with a great reputation (including recommendations from several of our readers), and I can't wait to fill you all in on the process next week. I told them that we run a blog and hope they don't mind that I'll be hovering over their installers the whole time to watch, learn, take photos, and possibly annoy.

We'll give you a whole recap next week and hopefully report back that we're enjoying our new tankless water heater. We'll be sure to cover everything from estimate to brand selection to install, and we'll hopefully answer any questions you might have.

Comments 16


9/26/2014 at 1:40 PM

Oil or gas? I assume gas since you live in the city.

Tankless (albeit old) was a nightmare at our old house and I could run it out of water just because it couldn't go fast enough. My father in law was a boiler installer for our oil company so he did an indirect system with the boiler. However, we have to have a boiler for our forced hot water so it is using the hot water from the heating pipes to also warm our water. He was hoping we would get gas before he did the conversion but no luck in this rural area! So far, I've only run out of water once!


Gas. We shouldn't have the run out of water issues with the way these new units run, just reduced flow issues. I do wish we had high pressure gas in our area, but not luck.

Natalie Frith Smith
9/26/2014 at 2:30 PM
Thanks for sharing. I'm just waiting (maybe a little to anxiously) for the day when our tank hot water will bite the dust. I plan to get a tankless and your post is a great justification to show my husband :)

We all get excited about different things, sometimes it's the least expected. Good luck using this as ammunition. Nothing would make me happier.

9/26/2014 at 2:36 PM

yeah, tankless! does that mean you could convert your chimney flue into a laundry chute? 'cause those are fun.
FWIW hybrid water heaters have a small tank so you don't get the cold water sandwich.


I'm actually hoping we'll eventually convert the chimney flue into a 2nd working fireplace. The unit we chose has one of those little buffer tanks to prevent the sandwich, which is working well so far.

9/26/2014 at 4:39 PM

Can the tankless go where the tank was, or does it need to be someplace special?


Pretty much the same place, but on the wall. It will actually take up far less space, which is nice.

This will be interesting.

The main reason I have heard being the drawback to tankless heaters besides GPM is if you have a large family than it may not be enough, and hybrids as mentioned above may help circumvent that to some extent with the tank serving to perhaps augment the flow rate somewhat, as well as eliminate the hot/cold sandwich.


We should be okay since it's just the two of us, but a small tank to augment, and using a unit with a circulating pump to keep the tank warm would work well with a large family. Then again, you can also hook up multiple tankless heaters together to act as one larger unit.

9/27/2014 at 10:31 AM

We have a tankless hot water system and I absolutely love it. The only warning I will give you is to make sure that you have reasonably soft water. If you don't have soft water, the mineral deposits will clog up your system, making it less efficient. This is very important.


We should be good on water softness, but thanks for the tip, that's good info.

Jordan Wood
9/29/2014 at 10:24 AM

The tankless concept sounds particularly interesting

John Smith
9/30/2014 at 2:30 PM

thats a good topic to bring up, i have never lived without a water heater before, not sure if I could do without!

thanks great read,
- john

10/2/2014 at 9:42 AM

My recommendation if you go tankless is to look into hooking the system up to a motion sensor, rather than solely on a pressure switch. That way, when you walk towards the bathrooms, it kicks on and gets the water pre-warmed. Personally, I'm going with a tank model, since the one in our reno project is brand new. To get the instant hot though, I'm going with a circulation pump at the furthest point using a 1" return. To make it more efficient, I'll be using a controller that runs the pump on a timer and motion sensor. Kicks the pump on in the morning, before we wake up, and then whenever we walk in the bathrooms.

10/2/2014 at 2:12 PM

I installed my tankless 10yrs ago by myself and I'm a registered nurse by profession, not a plumber.I was slow but the install passed inspection 1st time, I was pretty happy.The system works well, the gpm hasn't ever been a problem.I'd suggest you make sure that there is adequate support in your area though.The one time I had to get service I found out that Home Depot sold a bunch of these Bosch units but the local plumbing community has gravitated to Renai and I only found one guy locally who would tackle my Bosch and he's a New England transplant.He says he installed lots of them up there but nothing but Renai since moving to N.C. A curious thing....

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