Lets Talk Hot Water Heaters - Tankless Versus Tanked (Mine just died)

Mine let go and we are in the closing stages of cleaning out the water. I had a 50 gal gas fired tank type unit. I can get a replacement for under $500 and have it installed in about an hour. They really are that simple. Literally two water lines and a gas line and the vent. Since I would replace like with like there should be very little modifications to the existing hookups as they are all in about the same location. Furthermore I have replaced these in the past at other houses of mine so I know exactly what I am getting in to.

BUT

My godfather's house is going to be torn down and he has a Reni (sp) tankless unit that is only about 6 years old. It cost him something like $2500??? Now I can take it for free. I want it BUT the install of it looks to be a serious bit of work. I will have to find a place to mount it on the wall as well as vent it (bore a 4 inch hole in my rim joist)and I probably will have to bore a hole for makeup air. Then there is the plumbing of the unit. I can do all of it but it is going to take time like at least a day and probably two when you add in trips the the plumbing supply store for fittings etc. And it is nothing close to a plug and play. I will have to get the electric, gas and water all sorted and routed to the unit. I have done projects like this in the past so I am not intimidate by this I have a pretty good idea as to what it is going to take to get this done.

SO what would you do. Spend $500 +/- on a new one that is a snap to install or are the newer tankless ones that much better and energy efficient that I should be considering going through the hassle of doing the install.

I have heard that the tankless units use a lot of gas. It may need a larger gas line to feed it. Most of the ones I have seen use concentric flues, so you just need one 6 inch hole for make up air and exhaust.

Hummm good point re the gas supply. I will have to look at that and see what is feeding that unit currently and compare it to what I have.

I have a tankless and I like it a lot, but don't buy one with the expectation that it's going to save enough money to pay for itself, not unless you use a LOT of hot water.

To start with, yes, it needs a bigger supply line, and that's a lot of labor. It also needs a bigger vent stack, which is more labor. You can avoid the vent stack concerns if you mount it on the outside wall (it just vents to the air), but that only works if it doesn't freeze all that often, and since you then need to run gas and water lines to that point it may not be any less work.

The big win for the tankless system is that you'll never run out of hot water because someone else took a long shower before you. The second win for me was that it reclaimed space in my garage.

The downside to the tankless system is that it takes even longer to get hot water at the tap now, because first the burner needs to heat up the heat exchanger, and then the hot water needs to heat the pipes between the heater and you. They also need annual flushing with a weak acid (5 gallons of white vinegar) to clean the mineral deposits out of the heat exchanger.

Put the plug and play in and install the thankless at your leisure, its free

TRoglodyte wrote: Put the plug and play in and install the thankless at your leisure, its free

Yes. This.

I've loved the tankless water heater my parents put in. They've replaced it twice in the last decade.

Don't know what the deal is with that, but research lufe expectancy.

I've had to make a similar decision a couple of times in the past few years (for myself and friends) and I've always ended up with the direct fit replacement. In my own home and two others the tankless lost just because it would be too much of a pain to install. I found that my new 40 gallon heater was a lot more efficient than the one it replaced, so I won on that end anyhow.

I'll probably make the switch when the time comes to put in a new furnace. I'm hoping to have replaced this heater a few times by then.

I probably wouldn't even bother with the free tankless as they too are evolving for the better every year. I had no idea about the need to acid flush them. That would suck.

My 40 gallon died and I replaced it with the same. Not enough to time to reconfigure plus wifey wanted the water back on.

Heating hot water seems redundant...

Why not just install a water heater?

Went with the plug and play system. I am still going to get the tankless one as well as the wall mount boiler and all the pumps and controls from my godfathers house. I may install it at my leisure and gave it up and ready for when my boiler craps out. It I a twenty plus year ok Burnham that should last another twenty years but who knows.

Or just sell them on craigs list.

New codes on all water heaters manufactured as of April 16. New codes mandate increased efficiency. Some of the old ones are still in the pipeline, but the new ones are about 25% more expensive. So here is what you need to know. Old school regular water heaters over 50 gallons...gone. They can't make them efficient enough to meet the new standards. Electrics are going to hybrids for the larger sizes. 50 and under are similar to the old ones, except they are physically bigger because there is way more insulation between the tank and the jacket. Basically the same thing is going on with gas water heaters. Small ones that can vent in to a chimney will still be available, but most gas units in the future will be on demand or direct vent fan assist units. If you are in the chimney business, start looking for a new job, because they are going to be as rare as a pay phone in 10 years. FWIW, the new mandates extends to all gas fired heating appliances, but I haven't figured out how that effects furnaces and boilers yet. If you opt to go with an on demand unit you will need to do some gas piping. Old school water heaters fired at around 40,000btus. Rennai and other on demand units are anywhere from 130,000 up. Most residential units are in the 200,000 btu range. If you are swapping a 40,000 for a 40,000, then no problem. If you go up in size, you need permission from the gas company. Believe it or not, there is a shortage of gas in some neighborhoods, and they don't automatically give you permission. If they do grant your request, you will need to run at least a 3/4" line to the unit. Larger if it is a longish run. Next you will need to resize the main running thru the house. You will most likely need a larger gas meter, and you may even need a new feed from the gas company to your house. These things are a real pain to install in an existing house. Nothing is where it needs to be. Most home owners won't switch when they find out what is involved to retro install one of these, so the federal govt passed these mandates to basically force you to do it. On a new construction house, I get $2500 to $3000 to install a Rennai, On a retro, it is always at least $4K. By the time you buy the unit, the special vent pipe, the piping and tempering valve, you are at $2K in parts. I had to replace 2 electric WH last week. One was a 30 and one was a 50. Called around and could not find an old 30, and the new one was $436, so I bought an old 40 for $289. Scored the last 50 at my supply house for $359. They haven't even ordered any of the new 50s yet because the cost is close enough to the hybrids that most people are just going electric hybrid now. Hybrids are $1000 but there is a $750 incentive from the electric company. The kick in the balls about this whole thing is that the govt wants everybody to go to high efficiency units to save on natural gas, but you need to be able to deliver way more gas over a given time than the gas network can deliver. Picture 6:00 in the morning when a whole town is up taking showers and these on demand units are firing away at 200,000 btus in every house. All ready starting to see issues on new developments where these units lock out because there isn't enough gas pressure at certain times of the day.

Oh by the way, a tankless is the type that uses a coil within your heating boiler. A stand alone water heater without a storage tank is called an on demand water heater.

The new heater I got is a Rheem. It is a 50 gal 40K BTU unit. My old one was the same 50gal but was a 50K BTU so I am hoping that I will see some savings however you can not get around the fact that it takes the same amount of energy to heat 50 gallons of water to a given temperature no matter what so if you are blasting it with 40k BTU's versus 50K BTUs I don't think it is going to realize any savings.

I am hoping I see some savings with better insulated tank and I hope that they some how have got better heat transfer to the water in the new units. The new unit is about 3 inches bigger in diameter with about the same height. I am hoping that is due to increased insulation.

All I know is I need a shower. As soon as the burner shuts down telling me that the water is up to temp I am going to go boil my self.. .. . It is to the point that the dog will not sit with me.

In reply to tr8todd:

That is some GREAT information!!!!