The math of tankless water heaters

x-posted with TTips

I am living on borrowed time on my water heater, it's 21+ years old, and I'm thinking I should replace it before it demands replacement in a catastrophic incident. So here's the math.

Replacement water heater: $900-1000, lasts ~10 yrs
Tankless water heater: $2850, lasts 20 yrs.

So, in the short term it hurts. But it will last twice as long, "saving" me another water heater at 1000 (and they could be lots more that far in the future? or less?), and it looks like my savings per year will be around $100 (based on my summer gas usage, but this is a question mark admittedly). Sounds like I will "break even" at ~10yrs, when the water heater needs replacing again.

Does that math seem correct?

I'd love to have an unlimited shower, so if the thing works as advertised it will be an improvement. The only other issue is the possibility that I will rent the house out and a tenant will get the benefits, not me.

One small factor to consider is that the tankless will be more expensive after Jan 1, by a few hundred, so if I am going to do that, I need to do it asap.

Any thoughts, ideas, commiserations?

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Originally Posted by Danno

Does that math seem correct?

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No, I bought mine for about $600, granted it is small since I currently live in a small house, but even a bigger model could be purchased for a grand.

Why are they going up after Jan 1?

There is a big thread on it here somewhere.

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Originally Posted by Rideski

No, I bought mine for about $600, granted it is small since I currently live in a small house, but even a bigger model could be purchased for a grand.

Why are they going up after Jan 1?

There is a big thread on it here somewhere.

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Not sure if I understand your post. What did you buy for $600, tank or tankless? I have had 3 quotes now on tankless and 2 on tanks (haven't gotten the last guy's exact quote yet, but he gave me the ballpark). In any case, prices used here are including install for a 40g tank or the Rinnai 75 tankless.

Prices going up because the cheapest guy is running a $200 off special that ends Dec 31st.

I replaced my regular tank water heater about 4 years ago, nothing fancy (standard off-the-shelf at Home Depot, mid-line warranty), for around $500. I did the install myself.

Have prices gone up that much on regular heaters?

Tankless would be nice, but is it worth it? (do you need endless hot water? or plan on staying in that house forever?)

I bought a tankless (gas model) for about $600, and then yeah I paid another $100-$200 for some help putting it in.

isn't there a tax incentive of some sort for buying a tankless?
And if you decide on old-school, definitely get a buddy to help you with the carrying and do the install yourself.

I replaced my 55 gal tank heater about 2 months ago. I put in a ao smith 55 gal as a replacement. I put it in myself and paid $600 to $700 for the heater. I just don't see where it would be worth it to go tankless. Maybe see how many years in energy savings it would take to pay off the difference if you went tankless?

Don't forget about the possibility of tax credits that go into effect in 2009.
I haven't done all the homework but I saw this awhile ago.
http://finehomebuilding.taunton.com/...and-homeowners

Also, I question your assumption that the tankless will last twice as long. Not saying it is wrong just questioning it.

I have a tankless in a rental property and it was a huge pain in the ass to vent properly.

I have no handyman skills and it's a gas heater, so doing the install isn't something I'm interested in doing myself. And given that it is a gas line, I'm wary of just having a buddy do it. As for the prices, like I said, these are plumbers giving me estimates. I don't know why they are higher than what some of y'all are saying, but these are reputable plumbers in my area. :shrug:

Looking at that tax-credit info, maybe the price won't go up, because the tax credit will offset the higher price of the unit?

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Originally Posted by mcsquared

Also, I question your assumption that the tankless will last twice as long. Not saying it is wrong just questioning it.

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I don't know, that is just what the literature says. Unfortunately, they don't have the long track record in the U.S. to have local evidence, but they've been in other countries for ages.

We replaced our water heater in January (after a catastrophic event while away skiing - glad it was in the garage) for a bit less than $500 installed. $1000 sounds like way too much.

Edit to add - like El Chupacabra, ours was standard off-the-shelf at Home Depot, mid-line warranty

I replaced my HWT this fall for $300. Your math seems whacked.

Not trying to give you a hard time, but good info here:

here

here


And yeah, if your plumbers are quoting thousands of dollars, shop around more.

I have had 2 reputable plumbers give me estimates, and another gave me a similar price on the phone. Do I tell them that people on the net say that is too expensive? I'm not doubting the numbers y'all are putting out there, but what am I supposed to do when the professionals are giving me a different number?

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Originally Posted by Danno

I have had 2 reputable plumbers give me estimates, and another gave me a similar price on the phone. Do I tell them that people on the net say that is too expensive? I'm not doubting the numbers y'all are putting out there, but what am I supposed to do when the professionals are giving me a different number?

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Move to the Bay Area. As you can see, everything's cheaper here.

I got full boat emergency install for $780 on a tank one, so the prices are def. wack. Also, on the tankless be ready for a longer period of time for water to heat up initially, as that's the primary issue with tankless.

Not the beat all end all, but a resource I have used a few times:
www.ServiceMagic.com



ps, I bought a conventional gas 40 gal tank heater 8 years ago for $500 installed.

Danno, Get a water heater tank and I will be happy to help you install it. I have done many gas and electric ones and it's a breeze to do. No need to pay a plumber to do such a simple job.

Get a flex-gas-hose and a heater "tub" (the tank sits in it and will hold water in case of a leak.) New dialectric unions are nice to have and flex connectors, too, help the job go faster.
Call Johnstone in Denver for great prices on tanks.

As you calculate the costs of a tankless versus tank - don't forget to include fuel costs savings.

A tankless generally activates the burners only when it senses water flow unlike a tanked heater that cycles all day and night whether there is actually use demand or not.

When I converted my cabin to tankless - I saw a 15% reduction in propane usage compared to tank. At $3.85 a gallon - it adds up.

However, one little "glitch" in most tankless heaters is they will only fire up when they sense enough water flow to activate. The flow rate varies with manufacturer - but from experience - be prepared to remove each and every "flow-restrictor" from your faucets and shower heads.

Finally - despite what the manufacturer says about tankless - they do "surge" - meaning you will get hot - to semi-hot water pulses - especially in the shower. Also - the further away from the tankless your appliances are located - the greater the surge effect.

You did not mention where the heater is going to be installed. This may be the reason for large price discrepancies. To install a gas hot water heater in a crawl space takes a specific model, this is more expensive. I have an on demand direct vent. At minimum you will be putting a new hole in the side of your house, also altering your gas line to fit a new location. These tasks require some carpentry skills as well as plumbing. It maybe worth it to you to pay a little more to insure a good job. Or maybe you could be happy with a peice of sheet rock left for you to patch.

Fuel cost savings are in my calculations. The heater is being installed in the laundry room, on an outside wall.

Bondo, I may be giving you a holler. The buffalo man may help me out, and he's closer.

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Originally Posted by Parvo Pup

When I converted my cabin to tankless - I saw a 15% reduction in propane usage compared to tank. At $3.85 a gallon - it adds up.

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I just paid $2.299 last week. It's a good time to top off.

Have you thought about going to an electric tankless unit? All things considered, this is the easiest (and by FAR) cheapest way if your existing breaker box can handle the load. Most of the decent units require a dedicated 240v 80A+ circuit. So if you can do that without necessitating a service upgrade from the power co. (or by having a piggyback/standalone box installed for the heater,) you'll save a ton. Yes that's a big demand, but remember it's only a few seconds/minutes a day all said and done.

A decent gas tankless unit runs $1000, a decent electrical unit is about half that, takes 1/5 the amount of time to install, and requires none of the astronomically overpriced (and UL required) double walled stainless venting. You can do the whole job for around $500 with one of those Titan 160 units from ebay, which are actually very good units, and also eliminate the need for LP/NG at the tank altogether.

I assume the electric ones suffer from the similar drawbacks of the gas ones in terms of the surging discussed above?

I think that's generally B.S. I have showered in dozens of places with tankless I never noticed it. Certainly not any more than when someone flushes the toilet or turns on the faucet somewhere else in the house with a standard tank.