On Demand water heaters

We are building an addition onto our house that will have a laundry and a bathroom. I was thinking of going with a propane on-demand water heater. Looking for some feedback from some of you that may have one. Pro's and Con's?

Really no such thing as an on demand in applicable terms. It still has to pass through the piping. The better name is tankless. The better units have built in recirculating pump within. I like them

I have an LP version I put on my New Home! I love mine, can't remember the brand but i'll look today. I installed it myself. Wasn't to difficult. All I gotta do is get the flush and descale kit now.

Not sure if he is referring to a tankless system or not, but there are on demand hot water systems. A friend of mine has one...within a second or two after turning on the water it comes out hot.

My friend said the hot water is in a constant state of circulation throughout the pipes and heater. Not sure if he described it accurately but I can vouch that it does work.

Personally, it sounds like a lot of waste of energy to keep the water constantly circulating, but he lives in a $2 million dollar house in Sugarloaf and probably does not care about the cost.

I have an outside mounted Noritz NG tankless. It has been in operation for 8 years. Absolutely no problems. You have to delime it every 8 or 9 months, but it is a simple process using a sump pump.

It supplies our whole house. If I had to do over I would have have replumbed upstairs and kitchen on a separate unit. The WH is about 30' from the kitchen and takes about 30 seconds for hot water to get there.

Never running out of hot water is great but it also cut power bill as I eliminated a 60 gal Electric HWH. It has long since paid for the cost difference of Tankless vs Tank HWH.

i have the rinnai tankless for whole house and its awesome i have wife and 2 teenage daughters that love hot water.

The better one's come with a built in recirculating pump that also has a remote to mount to the wall that lets you control the time parameters you want it to circulate. Most people don't cycle during sleeping times. If your unit is mounted close to the main usage, like a Master in a one bedroom, retirement house, you may not need the recirculating. However, whole house, and you will need it to recirculate. It takes very little materials to create the loop to return for circulation

Thanks for the input. Sorry I wasn't clear. I'm looking at a tankless water heater such as a Rinnai.

Old Crusty said:

Thanks for the input. Sorry I wasn't clear. I'm looking at a tankless water heater such as a Rinnai.

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I have used many Rinnai's over the years. Recently I reluctantly let my plumber talk me into another brand that I can't recall, but so far so good

1gr8bldr said:

The better one's come with a built in recirculating pump that also has a remote to mount to the wall that lets you control the time parameters you want it to circulate. Most people don't cycle during sleeping times. If your unit is mounted close to the main usage, like a Master in a one bedroom, retirement house, you may not need the recirculating. However, whole house, and you will need it to recirculate. It takes very little materials to create the loop to return for circulation

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Make sure you get the recirculating pump. Instant hot water at faucet is awesome.

Only drawback IMO is that they have to be serviced(cleaned) once a year. Takes about one hour and a few gallons of vinegar, a pump, and hoses with standard fittings..... a task none the less.

Benefits outweigh the only con though

How much propane do these use? I know it would depend on actual use, just looking for estimates.

We only have a 100 gallon tank, only thing on LP is generator and gas logs which arent used often.

If you are satisfied with your current hot water heater...

Our kitchen is a long way from the hot water heater in the laundry room. We just added one of the recirculation pumps. Built in timer, mixing valve installed under farthest sink recirculates hot water through the cold line, effectively providing nearly instant hot water at all fixtures. Turn the cold side on, and in a few seconds, cold water overrides the system. No more wasting cold water down the drain waiting for hot. We set the timer for breakfast/dinner hours, and manual override as needed. Some smart folks (not me), put a wireless remote programmable timer on the pump plug and have switches here and there to turn the pump on as needed. Haven't noticed enough extra energy cost to offset the joy of almost instant hot water everywhere.

Recent hard freeze=me running the pump 24/7, basically heats all the water lines in the house. Hmmm...

https://www.amazon.com/Grundfos-595916-Horsepower-Comfort-Recirculator/dp/B000JG81AQ

https://us.grundfos.com/products/find-product/comfort-pumps-up-10.html

normaldave said:

If you are satisfied with your current hot water heater...

Our kitchen is a long way from the hot water heater in the laundry room. We just added one of the recirculation pumps. Built in timer, mixing valve installed under farthest sink recirculates hot water through the cold line, effectively providing nearly instant hot water at all fixtures. Turn the cold side on, and in a few seconds, cold water overrides the system. No more wasting cold water down the drain waiting for hot. We set the timer for breakfast/dinner hours, and manual override as needed. Some smart folks (not me), put a wireless remote programmable timer on the pump plug and have switches here and there to turn the pump on as needed. Haven't noticed enough extra energy cost to offset the joy of almost instant hot water everywhere.

Recent hard freeze=me running the pump 24/7, basically heats all the water lines in the house. Hmmm...

https://www.amazon.com/Grundfos-595916-Horsepower-Comfort-Recirculator/dp/B000JG81AQ

https://us.grundfos.com/products/find-product/comfort-pumps-up-10.html

Click to expand...

I have these at 2 locations in my home. They work great. You can barely hear the pump come on, which is good, to let me know they are working, however if the power goes out, you will need to reset your cycle times. Mine are set not to cycle during bed time but to come on just before we awake. But if the power goes out for say.... 6 hours, then your cycles are now off 6 hours. Mine need to be reset. Easy to do, it just requires moving stored stuff under the sink, out of the way. I mounted mine way back out of the way. That may be a mistake. Just inside the door, up high where you can adjust without removing stuff would be best. It works by pulling the hot water that has cooled in the pipe, pulling it until it senses hot again and stops. It dumps it into the cold side rather than waste it. It will make your cold water briefly luke warm. It can be done simply with the valve and no pump. You can buy that valve at a plumbing supply. It will open and shut by temperature just like a cars thermostat. However, your going to go through much more hot water since this does not ration it and you would then have to route that water down the drain rather than recycle