Need recommendations for a tankless gas water heater...

[ctrcbob]

I have no idea how modern tankless hot water heaters work, HOWEVER,
64 years ago (1960-1961) when I lived in a suburb of Nicosia Cyprus,
My rental house had a tankless water heater that heated kitchen sink, shower and bath tub. Water entered from bottom, in copper coil. When water turned on, natural gas flame lighted in center of coil. Faster the water flowed, higher the gas flam. Worked great the entire two years I lived in Nicosia.

Again, don’t know how modern units work.

 

[Rand]

air intake, exhaust, BIG ENOUGH GAS LINE - need 3/4", power.
room to put in all the valves so you can flush it yearly(or more) easily.

 

[alarmguy]

You cant get "limitless hot water" with a tank, you can only get what the tank can provide at one time.

What does it matter? The op has one bathroom and even in a home with two bathrooms with showers and and a washer going at the same time you are not going to run out of hot water with a 50 gallon water tank, even a 40. For 16 years we had a 50, with two teenagers and ourselves, never even close to a cold shower. Tank temp of 130 to 140 would take what, 80 gallons of water to be quickly emptied? Most shower heads use 2.5 gallons of water.

You WILL run out of hot water with a tankless as the heat exchanger gets coated with public water supply chemicals or well water minerals. This can start happening within the first year and certainly by the 3rd and will need to be flushed out with a cleaner. Which most people (except maybe in here) will have a plumber come and do.

Granted in another post, someone who wants to fill a hot tub as full speed may benefit with an instant with of course the short comings of maintenance and reliability. All good, just discussing, I had both and current have a tankless. But would never switch form a tank to tankless.

 

[KrisZ]

Not worth to convert in my opinion. Tankless would probably make sense if you had an electric tank and there is no good way to route the exhaust and the gas lines.
Otherwise a natural gas tank unit is the best overall choice in general.

 

[Donald]

my tank heater is starting to leak from the bottom. I'm considering going tankless. What are some decent ones? It's for 1 bathroom, single family home.

My plumber said a Rinnai condensing. You need to figure out how many GPM you need.

The local propane company only wants to vent out the wall. Not the roof. You need to block off the roof vent if you go with a wall vent. And need a condensate pump.

A heat pump water heater will save you money and there is a tax credit. And less plumbing work.

 

[UncleDave]

What does it matter? The op has one bathroom and even in a home with two bathrooms with showers and and a washer going at the same time you are not going to run out of hot water with a 50 gallon water tank, even a 40. For 16 years we had a 50, with two teenagers and ourselves, never even close to a cold shower. Tank temp of 130 to 140 would take what, 80 gallons of water to be quickly emptied? Most shower heads use 2.5 gallons of water.

You WILL run out of hot water with a tankless as the heat exchanger gets coated with public water supply chemicals or well water minerals. This can start happening within the first year and certainly by the 3rd and will need to be flushed out with a cleaner. Which most people (except maybe in here) will have a plumber come and do.

Granted in another post, someone who wants to fill a hot tub as full speed may benefit with an instant with of course the short comings of maintenance and reliability. All good, just discussing, I had both and current have a tankless. But would never switch form a tank to tankless.

It matters because the OP is interested in it. Does it make sense to do, depends. Likely not.

Like you mentioned the prior post with the guy filling a jacuzzi/ hot tub, or even a large bathtub while showering multiple people will bottom out a tank. Bunch of teenager staying with you, or a large family at a holiday can hot cold pretty quick - standard house with ma pa and 2 kids, prob not.

I have a tankless in my current house and a tank in my rental, I agree you arent saving anything going tankless.

It took me about 5 minutes to hose up for a 20 minute vinegar run through mine to clean it , but any heater can and will clog over time at least you can clean a tankless unit.

I know you dont particularly like your unit, and I understand your position.

 

[Donald]

The tankless is probably an extra $1000 to have a plumber install one over swapping in a new tank.

People often don't end up washing their hands in warm water. A tankless is quick but not instant. Most people don't feel like waiting for warm water for just a basic hand washing.

 

[UncleDave]

A heat pump water heater will save you money and there is a tax credit. And less plumbing work.

Have these been around long enough to determine what the average lifespan would be?

 

[BurrWinder]

My plumber said a Rinnai condensing. You need to figure out how many GPM you need.

The local propane company only wants to vent out the wall. Not the roof. You need to block off the roof vent if you go with a wall vent. And need a condensate pump.

A heat pump water heater will save you money and there is a tax credit. And less plumbing work.

I am a ( + 1 ) on the hybrid as well. I have had mine for 4 years and it works very well for very little operating cost. Plus the benefit of the dehumidification. It runs cheaper than my old gas water heater did. You can even get ones that are 120V and can plug in to a shared or dedicated circuit for easier conversion from gas. Best way to heat water now days for most standard households. The efficient operation and rebates make them cost less over the life cost of any standard electric, gas or tankless options.

 

[Egg_Head]

Not true with my Renai - no power I get cold water.

I like it, but I have two daughters, so it runs pretty much constant. Our water here is pretty soft. I have never flushed it. Been meaning to but never have.

@SC Maintenance is correct. My experience involved power loss with temps being 10 F, water likely froze in outside tankless unit. Experience was so distressing it clouded my mind and objectivity for these devices. I previously has a 50 gallon quick-fire NG unit and could take hot showers for days w/o power.

 

[Donald]

Have these been around long enough to determine what the average lifespan would be?

Well the warranty is 10 years parts and 1 year labor. I had the same basic design in 1980 as a unit you installed next to the water heater and it heated the water in the heat pump and circulated it. Now it's integrated with the compressor bolted to the top of the tank. And the condenser inside the tank in contact with the water. Probably at the bottom of the tank.

But it's a tank water heater with electric coil backup if desired. Drain & flush the tank and change the anode. Obviously the question of how long it will last somewhat depends on your water.

 

[Donald]

I am a ( + 1 ) on the hybrid as well. I have had mine for 4 years and it works very well for very little operating cost. Plus the benefit of the dehumidification. It runs cheaper than my old gas water heater did. You can even get ones that are 120V and can plug in to a shared or dedicated circuit for easier conversion from gas. Best way to heat water now days for most standard households. The efficient operation and rebates make them cost less over the life cost of any standard electric, gas or tankless options.

I liked the idea of a 120V one but they cost a few hundred more than a 220V one. And slight less energy efficient according to the efficiency spec. And have no or a tiny coil. You can control the unit from your phone over WIFI and can run as heat pump only, coil only or both. Seems like the 220v one is a smarter buy. I can keep it on heat pump only unless the kids & grandkids are down for a week. And having a coil could be handy if the compressor breaks and waiting for repair guy.

 

[Donald]

@SC Maintenance is correct. My experience involved power loss with temps being 10 F, water likely froze in outside tankless unit. Experience was so distressing it clouded my mind and objectivity for these devices. I previously has a 50 gallon quick-fire NG unit and could take hot showers for days w/o power.

With a well, no power = no water. So whether a hot water heater runs without power is not that big a deal.

 

[4WD]

With a well, no power = no water. So whether a hot water heater runs without power is not that big a deal.

Huh ? I can put the gen on a well - bcs NG is far more reliable than electricity … I’ll never own anything that’s not on NG unless it’s my choice …

 

[benjy]

my 10 YO german made steibel eltron i installed on 220 about 10 years is ago is still good, its fed off my oil furnace hot line to preheat but oil is OFF when coal stove is ON-one chimney! only me + its mounted CLOSE to all water users, works for me!! no heat given off in summer when oil + coal is OFF another PLUS!!