Tankless - What to know before you buy 

Production quality and depth of information continues to get even better! You're doing a really nice job with this channel.

Thanks for posting this! It's so hard to find unbiased info on water heaters where I live!

I have three electric tankless units located next to each point of use. One under the kitchen sink for sink/dishwasher/washing machine, one in each bathroom for the sink/shower. Not everyone can install smaller units like that, I planned for it during a remodel. When you install one large unit for the whole house there are two issues. By installing smaller units you have several advantages. 1. Smaller units are usually electric. Electric tankless don't need to be vented. Venting cost money to install and maintain, not only that but every molecule of air which is vented out of the house negatively pressurizes the house. Which increases HVAC costs. Electricity cost more than gas, but doesn't require venting, which offsets that difference somewhat. 1a. Smaller units can be installed close the point of use, inside cabinets, under counters, in nearby closets. 1b. Because the unit is installed close to the point of use there is instant hot water. In larger whole house systems, whether gas or electric, tank or tankless, when you turn on the water you have to wait for the cold water to cycle through before you get hot. Smaller systems are installed at the point of use, so the hot water is nearly instant. 2. By having the unit so close to the point of use there is very little energy waste. In many hot water systems, both gas and electric, the water has to be piped 20-50 feet on average. Those pipes need to be installed, insulated and maintained. The longest run from heater to tap is around 8 feet in my house. That's only because I have a shower head in the ceiling, not the wall. 3. Smaller units don't require significant rewiring of the breaker box. They can be connected with a 220V outlet (Some are even 110, but that won't run a shower) 4. If you have multiple smaller units, if one unit fails the entire house doesn't lose hot water. So for instance I have two bathrooms. If one unit has a maintenance issue it is shut down, while the other is still operable. We can get by with hot water in one bathroom until a service can be scheduled. No more costly emergency service calls.

Matt - Your videos have always saved me hours of product research online. I now send your video links directly to my clients. They also love your videos. Thank you and please keep them coming!

Matt happy new year! I love all your videos! I gutted/remolded my 870 sq ft condo in Florida & ALL your videos helped. I made my handyman look at your pocket door videos before he installed mine. Also your sooo HANDSOME!

Matt, perfect timing, I’m educating myself now for an upgrade this year. Great stuff!

Great video for "newbie" in tankless water heaters. Very clear explanation, in simple, plain English. Thanks! 👍 👍 👍

Hi Matt. I'm loving your videos. I watched one yesterday and subscribed. I've worked in the building industry all of my adult life. I'm 65 now and want to build a small masonry/framing solar home for myself and your videos have a lot of valuable information that I hope to learn much more from. Thank You

Dude you are in my mind....... last few videos have been on subject that I am working thru as we speak.... Keep up the great work!!!

My ole water heater is going out after 22yrs.. I am considering installing tankless and watched this video to gain more knowledge. Thanks for the high quality video and simple to understand overview!..

Thanks Matt for a great, and easy to understand, breakdown of these units. I'm currently prepping to install the one in the middle.

Right around 5:30, I’m in New York and temps have been colder than normal past couple of weeks. My unit is inside however still getting colder water. I’m sure you already know this but it helped a bunch being able to move the burner temp up a couple degrees to satisfy my needs of hot water. Currently 24*f and I maintain 112 @ the heater and adjust accordingly. Great video, very informative!

When I was in Japan, the house we lived in had a tankless unit made by Rinnai. About half the size of the smallest one in your video. It worked beautifully! There was a remote control box installed in the kitchen. It allowed you to turn the unit on and off and control the temperature from inside the house. The water was brought to temperature almost immediately. For me tankless is an easy choice.

Your point on size and regional temperature is spot on. I have a tankless. I live in NY and I totally notice the temp difference between a hot summer day and a very cold winter night.

Just got the largest Navion dual , domistic and water heating boiler installed. Such great technology in the new heaters. To be free of Oil AND 24 /7 240 electric hot wayer , im very happy

Matt, thanks for another informative video. I really appreciate you clarifying the issue of how long for payback on the energy savings of tankless, explaining that the biggest selling point is the unlimited hot water, not saving energy. Ever since I upgraded from a 20 to a 40 gallon water heater I’ve never run out of hot water, so I’m glad to know that there is little reason for me to change to tankless.

Congrats Matt! You made it over 100K subscribers (like over night?) I swear the count was at 99K just yesterday. Great way to ring in the new year! We love our endless water (Noritz unit, 94 % efficient.) Great comments. Another bonus for the 90+ models in new construction is being able to plan ahead on the gas line needing to be sized to be able to supply the 199K BTU. The only thing I don't like on ours (because I have not installed a circ pump) is the sandwich effect. When turned on, the hot water is warm (from previous water in the line), then goes cold (from the water that has slipped by the heater) then finally gets hot from the unit producing hot water. At least I can plan on that at the beginning of a shower, and not run out of hot water before I'm done!! The more of your videos I see, the more I appreciate the building science approach! Thanks again! - Wally

I wasn't expecting to learn much but I did! Thanks Matt

thanks, I am planning on building in the deep south, that was a really solid tip.

Really great, fully integrated video.

You have a well speaking voice for RU-vid I'm also converting my oil tank at oil burner system to a Natural Gas tankless system

Matt Thanks for the GREAT Videos. You do a fantastic job informing us.

Hey Matt, I have owned/installed 3 Bosch tankless and 2 Rheem hybrids, in houses I have owned, with much satisfaction. However!!! Last winter (sometime in April we had a severe freeze. During that freeze, due to a power outage, my most recent RTGH95xlp developed a leak. I called warranty and PG&E. Both told me that I was out $1200 bucks. The small leak is in the area of the top intake tube going into the stainless pre-warmer compartment. I took the heater guts apart from the enclosure (enough to slide the guts toward the top to expose that plastic elbow, p2). I couldn't determine where the leak is (no split or broken on fittings or copper tube). They tell me at Rheem that there are no repair parts available. The woman I spoke with was very cold and unconcerned about my plight. So, I do not recommend Rheem.

My tank’s lifespan is just about up and it’s in the attic( don’t ask why a builder thought this was a good idea.). This video has really helped on which unit to use.

Such a good video, I don’t know how someone could give it a thumbs down

Thanks Matt. That was very comprehensive.

Great explaination. my tank WH is close to replacement so this helps.

Great info and great video. After watching your video on tankless vs. tank, I ended up replacing our water heater in our current house with another tank. However, we're getting ready to build a new house and this video helped me get a batter understanding of how the condensing tankless operates. A well deserved like and subscribe from me. :)

In a retrofit situation, I often still install the condensing models. I use a condensate neutralizer to correct the acidity of the condensate water, a condensate pump, and the old pressure relief piping to get it to the outside.

wonderful explanation and good insights into whcih type of model to go for when doing a retrofit vs brand new building.........thanks for the video

I have used a Takagi for 13 years without an issue. Next to the furnace so venting was not an issue. The natural gas input line had to be resized so it could supply both the furnace and the hot water heater. Pumps between the hot and cold water at the end points give almost instant hot water. Gas line and pumps were the major expense not the hot water heater with installation. Also put one in my mother’s house for both hotwater and radiant heat. It works very well doing both functions.

This was SO helpful, thanks from California!! 🥰

Tank Water Heater is very conveniently , I truly recommend !!!

We've got a cold stretch here in Boston. You here of any units freezing from the intake? May happen if not used much... I have a hybrid unit so it's always warm. You didn't discuss the hybrid. AO Smith. I have an Eternal

Hey Matt... I'm not sure for up north, but here in South Florida, and as an electrical contractor, for an electric tankless water heater, I have had amazing results with EcoSmart tankless water heaters. The brand you showed today I have had nothing but complaints here especially with not heating water that well. I personally havr an ecosmart eco27 in my home and I will NEVER go back. Ecosmarts are also a LOT smaller and slimmer than most others and most of the time less expensive! But I know everyone's got their own preferences :)

Hey, thanks for making the video. I learned a lot. Take care

Matt...Awesome teacher! Thanks!

Thanks! My chimney is rusted through. Thinking about getting the one that can use pvc out the side of the house.

Great speaker,great info.Well done.

awesome review, helped me make a decision between the two form factors.

Hi Matt, could you include a total cost of ownership comparison in these videos? A true cost comparison for me is starting from an existing tank heater and would include every expense from acquisition cost, replacement cost (plumbing charge to remove old unit and install new), operating costs over lifetime, and maint costs over lifetime. Thanks! great videos

Great video Matt.How about one with the tankless with recirculator pump theres two types manifold ,recirculator line very interested in which ones best Thanks keep up the good work

You should include the fact that if installing a non-condensating tankless model, but have a vertical (through the roof) exhaust vent then it will create condensate. In fact, if the exhaust must raise more than 2 feet above the unit it will create condensate. I didn't know this and am now having to buy extra parts to install my unit.

Great information. Make sure that the condensate water drains into PVC and not cast iron. The acidity of the condensate will erode the cast iron.

Good summary Matt. I found going w/ a condensing model for my retrofit was the best option. It was right above a laundry drain, so no issues with condensate. The additional cost of the condensing unit was offset by the savings on installing the more expensive concentric, stainless venting needed by the non-condensing unit. And it was easy to run the new PVC exhaust vent up in place of the old tank heater venting. A couple of 22.5* elbows allowed for the needed offset to line up with the roof penetration. Unit has been running great for 3 years now and is using about 1 therm of gas/mo. compare to 6+ for the old tank heater. Payback time should be under 10 years in gas savings.

Great info, looking to build in a couple years so it helps!

Just bought a 8.4 gallon rheem outdoor. Cant wait!!

Good summary, thanks! Can you describe how you size these based on the number of hot water fixtures you will have in a home? What assumptions do you make about maximum demand? Also, hope to see a similar set of videos on hydronic radiant heat sources!

Thanks Matt thanks for your thorough and excellent explanation. Appreciate it! 😀

I like the sealed combustion idea that way your not chucking air you paid to heat or cool outside. I would love for someone to figure out how much that costs to operate a non sealed system. Great video

I really like the Takagi T-H3M units because they use a 1/2” gas line which makes them much easier for an in place swap out.

For the acidity issues it depends on the plants around whether they will die or not. Pines and Firs like acidic soil it helps so they don't have to share nutrients and Hydrangeas change color depending on whether the soil is basic or acidic.

Hi, I live in Michigan and I'm always buying a water heater I'm thinking about going tankless because of my flooding problem. I want thank you for your unbiased opinion

Matt is the man. Smooth talker and nice looking : )

Thanks. Very informative.

Any thoughts on the latest generation of tankless electric models? My builder was impressed with the latest one he installed. I've spec'd a heat pump unit as I wanted the cool air produced (hot AZ garages couldn't be more perfect for HP water heaters). Tankless electric (if actually functional) would be nice for all electric, net zero/ off the grid homes.

I've heard of issues with reverse air flow in freezing temps. When the non-condensing units are not running, cold air enters possibly freezing the exchanger due to other appliances creating a vacuum on the building envelope.

great video, very well presented

I live in RI and have a possible carbon monoxide venting issue with our 3 yr old Kenmore gas hot water heater. I thought a tankless heater didn't need to be vented, and your video just totally bummed me out big time. Now I gotta call in the hvac guy to replumb the vent tube, which is a tough and costly job in my old house.

Great vid, I'm curious if you have ever used tank-less with a radiant floor hydronic system. If so I'd be curious about performance. We are finishing up a house in the High Rockies and it has tubing for radiant heat. I also need to heat water and don't know if I should go with 2 tank less units, a combi boiler, or just an old fashioned boiler. Any feedback will be appreciated.

Thanks great video with choices, Learned A Lot :)

Thanks! I'm right in the middle of deciding which way to go on our vacation home.

Great over view thank you. Considering a unit for a cottage on my property using propane. Water softeners that discharge into a septic system can cause deterioration to concrete tanks. Wondering if the acidic nature of the condensate will alter the bacteria and possibly the concrete septic tank??

Thanks for this, Matt. Have you heard about LG washing machines not being compatible with tankless because the LG washers pulse water, and the tankless needs a steady flow of water demand to fire up the burner.

Thanks for all the great info Matt! I like your videos, but this one really helped me. I haven’t built a house since before tankless water heaters were common (2007-8) and I’m building new again and have no knowledge of tankless, until now. This was one of the areas I knew nothing about. BTW If you ever want to do an interesting video for Californians you should come to Cali and do one on the Title 24 crap here. After 2020 the energy requirements are going to be insane.

Excellent presentation.

Thank you , I truly appreciate the information

Matt hits all the good points

Thanks for the great explanation.

Great Video Matt

Best investment we ever made. Replaced 2x50 gal electric with one Ranai natural gas. Saving about $45/ month on electric.

@Matt Risinger I think you should mention the duct on the middle unit has high heat in the middle, but it's a two way vent, meaning the intake is surrounding the exhaust. There won't be heat to worry about on the vent pipe. Also, another factor on going with the condensing units is they are rated Energy Star and can give you a tax credit on your income taxes, up to $600.

I just installed a Rheem gas tankless condensing unit - because our old Bosch W.H. failed without notice so we bought what was readily available - we needed hot water. Installing the unit itself was quite simple but our model was very heavy to lift into place. My vents are not final yet - AND - we have not had any condensate produced from the unit's condensate drain :-)

Outstanding presentation, review, comparison, information for on-demand as water heaters. Question: My current 50 gallon water heater, natural gas (40,000 BTU input) - will my current gas line be sufficient to supply/provide enough gas to achieve adequate hot water? Thanks.

Matt, I have a new build starting in a week or so and have been contemplating using a high efficiency tankless unit. My issue is with the home being on a 1000 gallon propane tank. I don’t want the tankless to eat up the limited resource of propane....We are looking at two bedrooms, three baths, and stacked washer and dryers in each of the bedroom walk-in closets. My wife and I will be the only two living in the house. I’d like to hear your thoughts on this...Thanks for all of your videos!!

May be new Tech but there are some condensing models I have found that have build in PH Neutralizers for the condensate so you can just let it drip outside or into a sink P-Trap

I upgraded from old tank water heater to an ao Smith 96% efficiency model. Installed it myself. Was a bit of a pain but no regrets. I did it primarily for efficiency but the endless hot water is nice too. I would recommend the condensating model even if you have to drill a hole in the side of your house for the intake/exhaust.

Great video thanks for everything you do.

Hello, great video...can you do one on electrical ones?

Most important point missed- some instant systems today come as a combi unit- where you can run hot water to heat your house and domestic HW. That’s when the real savings kick in. Get rid of your big old boiler and one tiny machine can do it all!!! Savings are big, currently lots of utilities and cities offer nice rebates or other form of incentives.... do your research on your local incentives..... I have units that run up to 250k BTUs to do heat and HW.... work great!!! Keeps monthly bills down!!

Nice follow up on the other video! Really helpful. What do you think of electric water heaters?

Great video, thanks. Our house does not have gas to it, electric only. What are your views on Electric on demand heaters? Cheers.

Matt, Love your videos. Can you also make a video comparing electric tankless heaters?

Found your video very informative. What about electric tankless water heaters? I bought one for a garage I recently built and for $400 think it's great. Planning on building a new home this year and figure I need 3 tankless heaters and would like to use the electric ones?

I have a Noritz Unit and in Philadelphia/New Jersey area winter water is 38* F in Feb. Thats what you have to know before installing a Tankless Unit.

I use two electric tankless running in parallel (180 Amps total) with a 120gal tank on a circ pump. The tank provides a buffer for peak usage (six bathrooms plus three dw & two washers) yet still allows me to have continuous hot water to meet typical usage. The alternative would have been to add a third tankless.

I have a 20+ year old Seisco electric on demand hot water heater. It still works perfectly and support has been great. The only downside is this year my electric utility instituted peak demand charges onto residential electric customers bills! So the 28KW peak draw costs me a few extra dollars every month. On the plus side I have never run out of hot water in over 20 years and can take as long a shower as I want or fill my 48 x 72 inch tub any time.

How does a condensing version compare in pricing? I don' think I heard that? Would like to have heard about the mechanics of how a condensing works vs a non-condensing. On cold days in SWFL like now water flow really degrades! Lastly whats code say about distance to venting for a window that can open? Thanks!

Do you have a video on weather stripping for doors? Can't decide what kind to buy and I need to replace mine for sure, can feel cool are coming in around the gaps!

Great! Now I know what to buy. Thanks

Excellent info regarding the condensing tankless - but why is the condensation acidic?

We got the condensing. Great unit! Everything about these are great! Just ask our kids...It condensed shower time to ENDLESS!!!

Matt, Great job on reaching 100K ! Easy to understand how that happened. On my recently completed new build in central Texas, they installed a gas tankless non-consendating unit in the attic crawl space. Is the location a problem?

Good videos. Very clear. Couple points to toss out there, for what it's worth. Not sure if they were discussed: 1) Another possible benefit of going non-condensing if installing in a basement is the unit would be consuming some basement air for combustion. Although it is air you paid to condition, that additional bit of air movement and consumption on a daily basis may help reduce the humid basement effect, and prevent or mitigate possible basement mold issues. 2) PVC venting works and is easy. But on long-ish runs especially with condensing HWH's and boilers where condensing element runs back down the exh vent pipe, there is research out there that indicates chlorides can leach out of PVC and cause pitting to common stainless heat exchangers over time. It does not occur with Polypropylene or stainless venting. Like I say, depending on the installation it may be worthy of consideration. Thanks for your straight-forward information...

Good Overview!

Very helpful! Thank you.

Was recently at a relatives house which has a tankless. I was loading the dish washer and I like to rinse the dishes with warm/hot at a low flow. If cut the hot water back too much the water turned cold. I assume there is a minimum flow that the heater needs to fire.

Any updates to these recommendations for 2020?

Great videos with great information. How about some information for us Northerners? What would be your recommendation for a house with a large soaking bathtub up North? Previously we had two 50 gallon heaters. I replaced them with a traditional water heater and a condensing water heater. It's a good set up, but when the traditional dies, should I buy another condensing? Would I send one into the other? Should I plumb them parallel? Should I buy a holding tank? Should I put the holding tank in front of the water heater to temper the incoming water, or should I put in after the water heater to hold the temp? Thanks for any info.

The other thing too consider is that at full flame condensing will lose some of that efficiency. There are many technical reasons but let me try to put it in simple terms. Think of driving a car and your running at red line to get maximum power which means maximum gas flowing to the injectors. Generally to heat water that fast one is running at the red line. The main efficiency one gets with an on demand heater is that only runs when the tap is open which is why I like mine.