hot water on Demand
 

Been looking at hot water on demand water heater(ex. Rinnai). Has anybody have any experience with them on a seasonal camp. My understanding is they put a couple of valves to drain water from heater.
Also do you have to use your gas supplier for the heater/install/inspection.

Thanks Dave M

I have one at my island camp and love it! Nothing to really winterize except blow out the lines with the rest of the camp then simply open two drain valves. (remember to shut valves before turning on water in spring!;)

Any good plumber with gas line experience can install, does not have to be your propane supplier...

Go for it, you will not regret!

Dan

Diito......i have a Rinnai and it works great. Easy install and a snap to drain. Get the valve cluster made for it. Easy easy

Actually, I just had a 25 year old tankless replaced with a new Rinnai by Gary Auger of Christian Repair out of Tilton. Highly recommend him! And you will love the tankless.

Question - ventless?
 

My camp is built into a side of a hill. I can walk under back half of camp. I also have a deck to entrance of camp which runs along the back side of the camp. Would like to install water heater under my stairs in the house. The back half of house and deck block any vertical piping for exhaust. Do they make a ventless version.

Dave M

Last time I installed my direct vent 15 years ago it had to be no closer than 4 ft from any opening(window,door,etc) and there is a minimum height off the ground so snow doesnt cover it.

Doesn't someone make an electric on demand unit?


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I have looked into the electric units in the past and even in the last6 months as I have been doing my place over. every plumber and electrician I speak to say the electric units have a very long way to go to match the propane or gas units, and if have to stay electric, like I do, then to stay with a water heater, and trust me I wanted to go tankless on demand in a big way, need all the space I can get

Rinnai - ventless
 

Went to Rinnai website and dug deeper. They make a ventless version. I'm looking at RUS65E(130,00 BTU) in the Ultra Series. It mounts on the outside. It has slots on the front panel. Don't know if one set of slots is air intake and the other exhaust. Since I'm seasonal its no issue for draining but I'm leery of leaving heater since it may get taken. Also if one side is exhaust I may still have the issue of the back of the house and deck. Guess I'll have to have somebody come out and take a look.
Does any body have a rough idea how much these cost. I'm up the Lake from May until October. Trying to justify cost.

Dave M

I'd guess about $1,336.73 without expert installation. ;)

That's actually the amount for the 75, not the 65. Just started to consider these myself.

https://www.amazon.com/Rinnai-RUS75E.../dp/B010Q1XCNY

I got a cheap (propane) wall-hanger type for my camper/guest house. It works reasonably well. If I'd spent another $100 bucks for the next-up model it would probably be impressive.

One designed for house should make you very happy.

You can get cheaper ones at Sportsman's Guide but you may be better off removing them to inside storage.

Good luck!

Not Happy with On-Demand
 

We have an on-demand Rennai heater in our year-round home. I am not too happy with it and would not buy another.

It is installed in our basement, which is about 50 degrees. The water sitting in the unit cools down quickly. When you turn the faucet on, you get 50 degree water for quite a while. It takes the unit a few seconds to decide to start up, then quite a while to produce real hot water. Even for faucets close to the heater, it takes a long time to get hot water. Once you turn it off, 5 minutes later it's back to cold water. We waste a lot of water waiting for it to get hot.

I asked the plumber if it could be adjusted somehow; he said no.

Given the high cost of an on-demand unit, I think a basic electric hot water heater could be better for a seasonal camp. You can get one for less than $350 and install it yourself, using fittings that do not require sweating pipe. Winterizing is very simple.

They do make recirculating systems. You push a button and a pump runs the water in a circle through your heater.

Doesn't sound right to me....mine is pretty instant. The only water that may not be hot at first is water in the line between on demand unit and faucet but this is the same with any hot water heater...

Dan

I agree with Dan. I have a Rinnai condensing boiler combo with on demand heating. After replacing a 60 gal hot water tank, I see no difference in the delivery of the hot water. In fact if 2 people take a shower at the same time, the third person have cold water with the tank system. On demand is constant regardless of use.

After talking to a number of on-demand users, problems are because of faulty installations, not all plumbers have the knowledge to install.

I think you are onto something here. The system should be close to where the demand is, otherwise the hot water has to displace the cold water in the pipes, with these new low flow faucets that can take forever, you would have the same issue with a traditional system.

I have recirc system in my mass house because the HW heater is 30 to 50 feet from the faucets. It is on a thermostat, so no button to push, but the setup you describe above would be more energy efficient.

The other thing is the tank needs to be appropriately sized for the number of bathrooms. Having a unit sized for one bathroom would definitely be an issue for a house with 3 or 4 bathrooms, it's tough to blame issues like that on the unit.

If I were to put a recirculating system in, I would put it on an automatic timer so that it kicked on only when I expected to use it regularly, for example for a morning shower, time it to go on about 30 minutes before you normally get up and shut off an hour later. It wouldn't be perfect but if it met your need 80%+ of the time, that would be pretty good.

At worst you could run it during the day and off at night. Or off while you are at work as well. Keeping it running all the time could be expensive.

I have a Jacuzzi brand tankless heater that I believe is actually a Rennai. It is located at the far end of the house. In the furthest bathroom I have a circulator pump that runs with a button push. Hit it and the pump stops in a minute or two and I have instant hot water.

The kitchen faucet is literally about 10 feet from the water heater but it seems to take forever to get hot water because of the low flow faucet. As mentioned above, no matter the type of heater the existing cold water must be pushed thru the pipe if it has not been used for a while

He talked of a recirc system with a button. You want hot water, you push the button for a few seconds, then open the spigot. I'm sure the circulator pushes the hot water through much quicker than it coming out of a 1.25 gpm faucet. It sounds like a great idea, especially for an instant heater where you don't want the thing firing until you want water.

net search term "water recirculator" many more responses than I am showing here



https://www.energystar.gov/products/...ulating_system


https://www.amazon.com/Watts-500800-.../dp/B000E78XHG

An instant heater doesn't fire until you start drawing water anyway. A recirc system keeps the water in the delivery pipes hot so you don't have to wait for it to get from the heater to where you are using it. However, pumping hot water around the pipes full time is going to waste heat to keep the pipe water hot, even while you are sleeping and not using water.

As to a push button recirc system, if it hasn't been running, it is still going to take some time to heat the water in the pipes, probably just about as long as if you just turned on the faucet. The only advantage would be that you wouldn't be wasting water down the drain while it heated up. You could push the button, do something else for a minute or so, then turn the water on.

Hmmmm... low flow, mentioned earlier. I have an EPA "approved" low flow faucet in the bathroom sink, takes 5 mins to fill up a gallon jug. I'm really thinking this low flow "feature" is what is causing the heater to ....decide...to turn on later, as opposed to the recirc pump, which will certainly trip the flow switch instantly, when you push the button.

We should make every EPA official have a low flow faucet on an instant system :)

Maybe, in a few months, we can have a realistic EPA.

Go to a Home Depot type store in SE Asia - and most on display are electric on demand water heaters.

Sort of off topic. BUT, there is nothing more stupid than a low flow faucet on a kitchen sink. If I need to fill a pot I'm not going to fill it less, it just takes longer.

If you really need a recirc loop you'll need a holding tank. Why not just go with a tank from the beginning and save yourself some money! I wouldn't put in an instantaneous water heater in my home... but what do I know, except I do get tired of pissed off customers complaining about theirs!

Also beware that buying from a non certified dealer may void your warranty!

No. You don't.

That's the point of an 'on-demand' system. You aren't wasting energy keeping a tank of water hot.

The point of adding a recirculating system is that you don't waste water. The 'loop' runs back from near the faucet to just before the heater.

I don't know a lot about these heaters but I thought the selling point was tankless instant hot water, maybe not. A circulator would get hot water through the pipe much quicker than a low flow faucet.

I just checked out the Rinnai site and they have a heater with a built in recirc pipe, to keep the water in the pipe hot.

Doesn't the heater need to turn on and off to keep the loop hot? Wouldn't that defeat the purpose of saving energy? We are still talking on demand systems right?

I went with an on demand system for one reason, convenience. If your thinking about an on demand system for savings, I would think twice. The energy savings of an on demand system does not justify the upfront cost. You will never make your money back in the energy savings.

For us it was a simple decision. We initially had a small electric hot water tank under our camp. Didn't have room for anything larger. We were constantly running out of hot water and it was extremely inefficient in an outdoors environment. Our plumber recommended the on demand system and he was spot on! It's a small wall mounted unit that we installed inside in our bathroom. We never run out of hot water now, it's efficient, and takes seconds to winterize. It has worked flawlessly for eight years now and we are thrilled with it!

Dan

Our Masonic Lodge had an oil fired hot water heater coupled with a large insulated tank that was installed back in the 70's, which was fine back when fuel oil was as cheap as a bottle of soda. The problem was in the last several years, we were spending a lot of money, $675 - $800+ per summer just keeping the hot water hot. Oil fired furnace was turned off during the summer months.
We opted to go with an on demand propane fired hot water heater. It was just under $2,000. One of our members is a licensed installer, so we had no additional cost other than a small amount of supplies for the hookup.
We only use our kitchen 30-35 times per year, so the increase in propane use was negligible. We do have a commercial dishwasher, but it is a low water use model.
Even with the fluctuation in fuel prices, we felt we did recoup our costs in only a little over 3 years. I do realize our case is quite unique, but depending on use, cost recovery is possible. I also agree that convenience is often the driving force to using on demand system. It was for us as well.
Dave

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You definitely recouped your costs and you have given a great example of a perfect use and reason for on demand! No doubt you saved a ton especially where you had no install costs!

I should of been more clear in my post, it was geared more towards average homeowner daily use...

Dan

With the push-button system the water only circulates when you want it to. The on-demand saves energy and the circulator saves water.

So you have to push a button on the circulator?
Where is the button?

If the shower is at the other end of house, there is cold water in the pipe. Pushing a button some place still has to heat up that cold water in pipe.
So apparently one is still using fuel to heat up the cold water in pipe.
6 or one and a half dozen of the other.

But let the engineers here explain all.

With a recirc pump on a traditional hot water tank/boiler/reserve (you can just repurpose an old circulator pump), and a check valve that taps in close to the end of your run, recirculates it back to the input side of your hot water source.

That way you save water (and some power) because now you can prewarm up your pipes at a push of a button, and cycle water from the heater to just before your shower/back room sink back to the water heater getting it up to temp BEFORE you turn the shower on and 'let it warm up' for 10 mins.

Electric on demand
 

I also had the dilemma last year of what to do for hot water. My space was limited under the house and the existing hot water tank was 18 gallons 120 volt. I decided to take a chance on an electric on demand system leaving the existing 18 gallon tank in place. My plan was the on demand system could boost the temp from the 18 gallon tank as it was slowly hetting colder. Well one year later the system made it through the winter. When its just me i dont turn on the 18 gallon tank and rely solely on the on demand. Last week it was set at 138 degrees and i noticed the shower going warm and cold so i turned it to 120 and now its perfect. I do have a low flow shower head. The only scenario where it couldnt keep up was a shower and two sinks all needing hot water. I heard lots of skepticism on these initially but for a camp they may not be a bad idea if you have the necessary power. I draw water from the lake, so if you have a well the entering water temp would be colder. I also didn"t want to have propane cylinders on my dock as im on an island. The unit is also warrantied for life for whatever thatvis worth. If the 18 gallon tank goes i may consider just going with the on demand electric entirely after another year of use.