Tankless Water Heater - Question
 

So neighbor puts in a new propane tankless water heater.
To save money over a regular tank water heater - gas or electric.

The neighbor though wants instant hot water at all faucets. So some sort of circulator is put in.

So to get instant hot water at all faucets with this tankless water heater - is the tankless propane water heater running all of the time?

Not seeking any information on other types of water heaters. Just the question above concerning my neighbors tankless water heater set up.

Does the tankless propane water heater have to run all of the time to get instant hot water at all faucets?

If so, is the neighbor saving any money?

He is probably installing a recirculation pump on his tankless on demand system. No it does not run all the time and is actually a “greener” way of delivering hot water as your not letting water run down the drain until your hot water shows up.

If your neighbor is only using his place on weekends or seasonally he is most likely saving some money using a tankless system. If he is living there full time not sure tankless is the best way to go unless space is an issue.

Google Chilipepper recirculating pump for an explanation on how they work as I am not a plumber but am a little familiar with them.

Sounds like your neighbor has a good responsible plumber.

Dan

I have that at the far distant bathroom. push button, pump runs for a couple minutes then instant hot water. The pump pulls hot and pushes it back on the cold side making a loop, so no water wasted/

By what measurement? If he replaced a perfectly good gas water heater with a tankless one, he probably spent $1500+ on parts and install, and he may not ever save enough to break even on that.

If he replaced a dead electric water heater with an LP or NG tankless model, he spent more than just getting a new electric unit, but his operating costs will be much lower, so savings over time is likely.

One issue with tank-based heaters, particularly in cold climates, is that they can lose a lot of heat to the ambient environment over time. This is particularly bad when you have periods of time with no hot water usage (eg: overnight), where the unit may be re-heating the same static water multiple times over.

There are closed-loop recirc systems, and also options where you have a small (10 gal) tank-based heater close to the point of use for your instant or short-burst hot water usage, and then a tankless model for extended use needs (showers, laundry, etc.).

Many energy-saving/cost reduction things like solar, tankless heaters, etc. are more like "one big upfront payment". You pay up front, but then have reduced operating costs over time. If your net goal is the absolute lowest total cost of ownership over time, then these systems rarely pay back, particularly if you consider earning potential of the money used for their up-front purchases.

I presume from the description that your neighbor replaced a central tank type heater with a central tankless heater. If that is the case, having a circulator on the system is not typical. It wouldn’t surprise me if the tank system had a circulator, and they discovered that it took a long time to get hot water, after they installed the tankless system.

Assuming the same fuel source, the amount of energy lost through water usage is identical in either system. (The amount of hot water that goes down the drain)

With a tank system, there is further energy loss through the walls of the tank. (The energy needed to keep the water in the tank warm 24/7)

Without a circulator system, you also lose energy from the the hot water that got left in the pipe, after the water is turned off. With a circulator, there is continual energy loss through the walls of the pipe, plus the energy loss attributable to running the circulator.

The savings from a tankless system are largely attributable to avoiding the energy loss through the walls of the tank. If you add a circulator to the tankless system, the tankless system needs to operate often enough to offset the energy loss through the walls of the pipe, which is the same energy loss that would be lost through the pipes of a tank system with a circulator. The tankless sytem would not operate continuously, but would turn on each time that the water in the circulation system fell below the temperature setpoint.

Long story short, your neighbor might be saving “some” energy, but the savings would be nearly impossible to calculate, given the number of variables. My gut instinct is that the savings are probably negligible.

The chili pepper system described above is different, in that it only serves a fixture or two. It is electrically operated, and only produces a small amount of hot water. It would not be intended to replace a whole house tank hot water heater.

I'm a big fan of tankless but one other consideration for tankless is the incoming water temp. They are mostly rated by how many degrees they can heat the water from the incoming temperature at a given flow rate.

these are not real numbers, just the concept.

tankless can raise it 75 degrees at 5 gpm so if the incoming water is 45 the max temp would be 120.

I have a tankless in my rv and love it but when the temp gets close to winter and the water is just above freezing it does not get very hot unless the flow is really low.

Chili Pepper
 

The way I have seen this system used is in conjunction with a tankless system so instant hot water is available. Never used as a replacement to a tank or tankless system...

Thanks for the info!

Dan

The discussion about solar energy has been moved to its own thread. This thread is about tankless water heaters.

Tankless in a seasonal home?
 

Anyone have a tankless hot water heater in their seasonal home? It seems like it would be great; I understand they are easy to drain, our hot water usage is not great, takes up less space, and you're not heating water when not at the house (or turning it off to avoid heating water when away).

I have one in my camp on Welch Island and love it! Very easy to drain and only heats up when I need it. I have had it for 12 years now with zero issues.

Dan

My Rinnai is also 12 years old....flawless.

Is quantity of hot water an issue?
 

We are debating replacing our water heater with a tankless when it dies, But my neighbor mentioned that they run out of hot water, and there are only two of them in the house. We are a family of five, including a teenage girl who uses lots of hot water, so I am wondering if it just can’t heat it quickly enough to keep up or how does supply become an issue with a tankless heater?

Rinnai
 

Rinnai never runs out of hot water. Think infinity.:D

Totally not true...endless hot water.

Dan

see my comment above in #6. You can get low flow if the incoming water is exceptionally cold

My incoming water was 38 degrees at my camp this year at the end of March. No issue whatsoever of getting 120 degrees at the faucet without adjusting anything. I have never touched my system in 12 years. Been using it right at or before ice out Every year. No issues.

Dan

Dan, is that propane? Is there a difference between fuels? I'm pretty sure I've read that electric on-demands blow.

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Mine is LP. I would never own an electric one.

Dan

Electric is really only practical for very low flow applications.

LP > NG >>> Electric in terms of how many degrees of heat rise you are going to get for a given flow rate.

The only issue I have with propane is it is expensive on the islands at $155.00 per 100 lb tank. Luckily I only use it for my hot water!

Dan

I know, I know...
 

Fuel prices have been discussed here forever.

Just my .02-
My last non-island/non-waterfront propane delivery was on 4/17/20. I don't use much- generally, a once-a year delivery = about 50 gallons.

Price on this date was $3.539 per gallon.

What got me was the "hazard impact" fee- $6.35.

What is that about?

Just checked my last bill
 

Just checked my last bill from Eastern and the important stuff was date of delivery, gallons, price, total, and a 10% prompt pay discount, and the net total.

I would be contacting my propane supplier if I saw hazard impact charge. Am I the hazard or are you by delivering. :eek:

Dave

So...
If you paid $155.00, and a 100lb. tank holds 24 gallons, was your rate about $6.40/gallon?

Yes...that is correct!

I guess I use about 60-75 gallons over the season, from ice out till mid November Living there every day...

The extra charge includes delivering tanks by barge, muscling them up to back of my home and connecting, then removing empty tanks. 100 lb tanks are no bargain to haul around...

Dan

That actually seems cheap for all that!

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Gone, But Not Forgotten
 

Our place on East Bear Island used propane gas for a stove and an oven when we purchased it in 1967. We would get our propane tanks sold at Fay's Boat Yard, when it was allowed, and brought them in our boat to the island. Later, we had the tanks delivered to our dock. We would roll them over 100' uphill to the back of our cottage and install them. When our old kitchen was replaced, an electric stove, oven, and microwave were installed. Yippee!!! 🐻

Yes it is...it’s a lot of work!

Dan

True or not...?
 

I've recently had some plumbing work done. This thread inspired me to ask a few questions of the plumber.

1. I have tank-less hot water- what kind of system would he call it?
Answer- heat coil. On a system like this, he told, your boiler (oil) will come on,occasionally (all four seasons), to keep the coil ready to produce hot water immediately.- It was the occasional (warm weather) running of the boiler that was the real basis of my question.
I get (almost) instant hot water at all faucets (from a well).

2. So, what/is there a difference between what I have and what I've heard is called (tank-less) on demand?
Answer- The heating element in "on demand" only comes in to play when hot water is called for- therefore, it takes longer to get hot water.

I'm not a "handy man", and I understand that certain knowledge and terminology can alter perspectives, but does any of this hold water? ;)