Tankless Hot Water Heaters (specifically gas)

[beelzerob]

Ya, we're fortunate that the kitchen, master bath, and laundry room are almost all directly above the water heater area. The powder room and family bath are across the house, but they certainly won't have the demand the other rooms will have.

Hehe...and David has a good point...I've lived this long not expecting hot water to be there when I turn the handle. I also have the rituals I go through while the hot water is coming up to adequate. heck, I'd probably hurt myself if there was instant hot water when I turned it on.

 

[gcimmino]

FWIW, regardless of the technology, the amount of time for the hot water to get from the heating source to the tap will be the same, right? That includes the heat lost warming up the pipes and "draining" the cold water in the line. To avoid wasting water during this inevitable process, that's where the recirculating pumps with remote switches come in.

In the tankless, the flow sensor is there to turn the unit on. That's why very low flow rates on the hot water will sometimes not turn on the tankless heater.

We just installed an electric tankless in an "outbuilding", really the house next door, converted into office space. Being office space, we don't expect much hot water use. So for us it is more the savings of not keeping water hot when it is infrequently needed.

When you do crank on the hot, it goes from cold to "move the hand" within a minute.

 

[ginigma]

I've just started looking into tankless hot water. I currently have two 40 gal "normal" water heaters in the basement. This was the setup when I bought the house a couple years ago. Water comes in to tank 1, out to tank 2, then distributed. Basically they are in series. Anyway, they're about 12 years old, so I need to think about replacing them, as I already lived through one tank failure in a previous house.

I really like the tankless idea, because you're not spending money keeping the water hot when it's not needed. It's only me and the wife, but we do enjoy long showers. I'm assuming it will take approx the same amount of time to get hot water from the basement upstairs to the master bath. I'm looking to get a gas unit, as gas is cheaper than electric here in NJ.

One of my concerns is that when washing dishes, I usually don't open the faucet all the way when rinsing them. Will the low flow cause problems (meaning not enough flow rate to kick the burner on)? I like that they have a longer service life than tank water heaters.

I got one estimate via email, at $3400 installed, which seems ridiculous to me. I'm going to get some plumbers in to give me a better estimate. Any thoughts? Am I a good candidate for a tankless water heater?

 

[Digger]

I went tankless 25 months ago. I wanted to replace my old 40 gal gas water heater before it went. I bought the unit for $500 and spent another $150 for misc parts as I relocated it right below the plumbing chase in the basement (very short runs to everything except a half bath). Total expense was $650 and I got $300 rebate on taxes that year.

My gas bill dropped $40 a month on balanced billing from $145 to $105. Just 3 months ago it went up to $108 a month on balanced billing and that includes my heat and a gas dryer (and gas prices have gone up).

A tankless is not equivalent to a tank water heater in performance in my opinion. Each has its strong points. The only real drawback to me is that any faucet without an aireator has to high of a flow to allow the heater to get to the set temperture on my model. I got a low end model with no real electronics for control. Had I known I would have bought a better unit.

I have to adjust it twice a year. In the winter I turn it up a little and in the spring I turn it down. I try and have it run between 120 to 130 F.

I am satisfied with the tankless and would do it again but would buy a higher end unit. At this point I got my money back long ago (in the first 8 months) so maybe some day I will upgradeut these things last a longgggggggggggg time I was told.

Edit:

I forgot to mention that the gas company replaced my gas meter saying that they thought there was a problem since my consumption dropped about 30%. I tried showing the guy the tankless but he said he had a workorder and needed to bring the old meter back.

 

[beelzerob]

Well, this topic certainly doesn't seem cut and dried to me yet. There seem to be 3 competing factors:

1) Initial cost
2) Operating cost
3) Amount of hot water available
4) Quality of hot water

These all seem to point in different directions. I'm kinda concerned about living up here in PA. I'm going to test my well water temp today just to see where I'm at, but I found a national graph that showed I'd probably be at 50 or below. With most of the Rinnai heaters claiming a raise of 50 deg at the lowest output level, that wouldn't get me very far....I'd like hotter water than 100 deg.

Then I toyed with the idea of having a small electric water heater feeding the tankless, probably with a mixing valve. A lot of the complaints I've read about online describe a "cold water sandwich", where the water will instantaneously alternate a few times between hot and cold. It seems most of those complaints come from northern areas, where maybe the cold groundwater is too much for the unit to overcome. So if I pre-heated the water enough to bring it up to tepid, that might mitigate that issue...but then I've killed any considerable operating cost savings.

I dunno at this point. I'm close to just sliding back down to a 50 gal electric, which resolves 1 and 4 above, but not 2 and 3.

 

[Ranger Digital]

tank water heaters should just be outlawed. I cant imagine even wanting to install one. Tankless is the only way to go, IMO>

You dont have to install gas to save energy. the electric tankless saves money as well.

Tankless is just NOT expensive. I dont get the complaints on the cost.

 

[Digger]

Well, this topic certainly doesn't seem cut and dried to me yet. There seem to be 3 competing factors:

1) Initial cost
2) Operating cost
3) Amount of hot water available
4) Quality of hot water

These all seem to point in different directions. I'm kinda concerned about living up here in PA. I'm going to test my well water temp today just to see where I'm at, but I found a national graph that showed I'd probably be at 50 or below. With most of the Rinnai heaters claiming a raise of 50 deg at the lowest output level, that wouldn't get me very far....I'd like hotter water than 100 deg.

Then I toyed with the idea of having a small electric water heater feeding the tankless, probably with a mixing valve. A lot of the complaints I've read about online describe a "cold water sandwich", where the water will instantaneously alternate a few times between hot and cold. It seems most of those complaints come from northern areas, where maybe the cold groundwater is too much for the unit to overcome. So if I pre-heated the water enough to bring it up to tepid, that might mitigate that issue...but then I've killed any considerable operating cost savings.

I dunno at this point. I'm close to just sliding back down to a 50 gal electric, which resolves 1 and 4 above, but not 2 and 3.

I am on Long Island and probably within 5 degrees of your temperatures. The settings on my heater are actually pretty low on the scale (I can crank it a lot higher but I would hit the over temperature limit and the safety would kick in). I just aim for 120 to 130 degree range and its PLENTY hot for showers etc.

If you want to fill a bath tub you need a larger unit because of the flow rate. I can take a shower while the washing machine or dishwasher is running with mine. Its a cheap unit but it works. I think the company name is Omega2000 or something like that. I have their largest unit I think. It was $475 last I looked.

Again I would buy a better one if I was doing it again but mine does work fine for what my needs are and I am saving a fortune.

 

[123]

Speaking of ROI, a storage-tank water heater has near-zero maintenance. I say near-zero because you *should* drain it once a year to remove deposits and change the sacrificial anode when needed. Few people do this yet the tanks last for 10+ years.

A tankless gas water-heater is a small furnace. One out-of-warranty service-call can nullify any savings in operating cost.

I think it is important to examine energy costs in your region and the cost difference between a tankless and storage-tank heater. Do the math and then choose the best solution for your needs.


FWIW, electricity rates in Quebec are low and most homes use electric power exclusively (heating the home and water, cooking, drying, etc). It'd take a long time to recoup the purchase price difference between a tankless and storage-tank unit. Many people opt for a 60 gallon tank and never look back. My friend (and wife and 5 kids) has two 60 gallon tanks. Clearly, this solution works well here but not something that makes economic sense elsewhere.

 

[beelzerob]

Well, comparing the costs directly is an exercise in magic math.....

I can get the kwHour costs for electricity, and I can get the per gallon cost for propane....but then how do you compare tanked vs. tankless for the amount of energy to do the same thing?

All I do know is that by all references I have, electricity is expensive here...and appearantly about to head higher with an oncoming deregulation.

 

[Digger]

Well, comparing the costs directly is an exercise in magic math.....

I can get the kwHour costs for electricity, and I can get the per gallon cost for propane....but then how do you compare tanked vs. tankless for the amount of energy to do the same thing?

All I do know is that by all references I have, electricity is expensive here...and appearantly about to head higher with an oncoming deregulation.

To be honest I thought I would save $10 a month so I went for the cheaper unit figuring a 5 year payback. After it was in I realized there was the tax write-off and then a few months later my gas bill balanced billing dropped dramtically (like I said they came and replaced the meter thinking it was broken). I got lucky and saved a lot more than expected. Its a tough call to make. I also installed it myself (I dont reccomend that to everyone).

Gas and electric prices will continue to increase so technically savings will increase. Its like my Hybrid car. Four years ago gas was $1.56 when I bought the car (I wrote it down). I calculated 5 to 6 years to break even on the cost of a hybrid over a regular car. At this point I think I am even at 4 years since the price of gas is now double. I am now saving money.

 

[Steve]

tank water heaters should just be outlawed. I cant imagine even wanting to install one. Tankless is the only way to go, IMO>

You dont have to install gas to save energy. the electric tankless saves money as well.

Tankless is just NOT expensive. I dont get the complaints on the cost.

That sounds like a very emotional reply from a happy customer who either has a financial stake in tankless sales, or doesn't really know all the facts . I should be a better candidate being in Fla as my temp rise is not as great as the great white North. But... we don't have gas, so either I would need to bury a really big tank or use electric. Going the gas route is not practical to depend on for something like hot water because what if the tank runs out early - you have to call the gas company and hope they can send out a truck between normal trips to refill - not too practical. So that really only leaves electric. Depending on flow rate, temp rise, etc I would need a rather large unit to cover the house. The large electric heaters are an absolute beast, taking up to 150A. Considering the whole house is only a 200A service, that means putting in a whole secondary main panel. That would run in excess of $3000 (probably closer to $5000). The unit itself is probably around $800 and then installation. So, I am looking at least at $5k just to install it. Now look at how much electricity is gonna cost me to run it. I think it would be like a 20-30 year payback last time I did calculations. Bottom line is they do have their place and work well in many circumstances, but nowhere near all. Looks like I'll be replacing my 60Gal tank with a new efficient 80 and call it good.

Now Ranger, if you want to pay for the up front costs, then maybe the tankless would be worth a try

 

[Photon]

Going the gas route is not practical to depend on for something like hot water because what if the tank runs out early - you have to call the gas company and hope they can send out a truck between normal trips to refill - not too practical.

Don't write off LPG unless you have had that experience. My in-laws in Northern Wisconsin have used LPG for heat and hot water for years without such a problem. The gas company, always anxious to sell every drop they can, always gets there on time.

 

[DavidL]

Going the gas route is not practical to depend on for something like hot water because what if the tank runs out early - you have to call the gas company and hope they can send out a truck between normal trips to refill - not too practical.

Don't write off LPG unless you have had that experience. My in-laws in Northern Wisconsin have used LPG for heat and hot water for years without such a problem. The gas company, always anxious to sell every drop they can, always gets there on time.

Unfortunately, I have that experience most every year, but probably because I have been too "stupid" to be on Keep full contract and reliant on me to call. The issue is I am on geothermal heat so don't use all that much propane. My barn is heated with propane and has it's own tank, and that is typically the one that requires more than one fill per winter. I just purchased a wireless propane sensor, hoping to integrate into MainLobby, but I took it apart and no easy means to suck out the data (on quick electrical look). I looked for a wired unit with RS232 (they do exist) but found it difficult to just purchase it (requires retailer, etc just to get pricing). A bit off topic, but interesting from an HA perspective is that they have a hall effect sensor that snaps ontop of the existing gauge, which is magnetic. So, no physical contact with propane. Just need to get that hall sensor value into RS232 and we have a neat propane monitor solution.

I know that this issue has cost me on average $100 per season because I am not doing a good job of proactively monitoring. Keep Full contracts are also "Keep you buying our high priced propane" contracts. Ideally monitored propane with adaquete alert allows you to shop when you need it to ensure best current pricing (which they play games with all the time, is my experience). Each purchase can save $100 in my case so is close to worth the effort (if I did it religiously).

 

[Sacedog]

There is no circulating loop and it takes only about 3 minutes to get hot water to the master shower (heater about 35' away) - about the same as a tanked unit.

And that is acceptable? So you have to wait in the shower with water running for 3 minutes before the water gets hot? Mine currently takes like 45 seconds and that is too long. During the bathroom remodel either going to put in a small 6 gal tank or a recirc system because even that 45 sec is too long.

We have two gas heated tanks with a recirc pump. One tank feeds the other, so we have never run out of hot water (family of 6). When the recirc is on (which is most of the day), we only have to wait a few seconds for scalding hot water.

It may not be that energy efficient, but it works great.

 

[Waynedb]

That sounds like a very emotional reply from a happy customer who either has a financial stake in tankless sales, or doesn't really know all the facts . I should be a better candidate being in Fla as my temp rise is not as great as the great white North. But... we don't have gas, so either I would need to bury a really big tank or use electric. Going the gas route is not practical to depend on for something like hot water because what if the tank runs out early - you have to call the gas company and hope they can send out a truck between normal trips to refill - not too practical. So that really only leaves electric. Depending on flow rate, temp rise, etc I would need a rather large unit to cover the house. The large electric heaters are an absolute beast, taking up to 150A. Considering the whole house is only a 200A service, that means putting in a whole secondary main panel. That would run in excess of $3000 (probably closer to $5000). The unit itself is probably around $800 and then installation. So, I am looking at least at $5k just to install it. Now look at how much electricity is gonna cost me to run it. I think it would be like a 20-30 year payback last time I did calculations. Bottom line is they do have their place and work well in many circumstances, but nowhere near all. Looks like I'll be replacing my 60Gal tank with a new efficient 80 and call it good.

Now Ranger, if you want to pay for the up front costs, then maybe the tankless would be worth a try

I would think in Florida a Solar water heater should work really well for you. I have been trying to decide between a tankless propane water heater and solar, I have been quoted around $5000 for a solar water heating system and $3000 for a tankless propane system. I live in So. California but at a higher altitude so I can see single digit temps here. I like the idea of free hot water and hate the idea of propane deliveries so I will probably end up with solar myself.