All About Water Heaters | Ask This Old House

In this video, Ask This Old House plumbing and heating expert Richard Trethewey walks through all the various options available to homeowners for purchasing or renting a water heater

Richard Trethewey teaches Kevin O’Connor all about water heaters. Since 90% of water heater purchases are emergencies, Richard thought a bit of homework on the topic would help avoid purchasing what’s available over the best water heater for the scenario. It’s not just discussion, either; Richard shows Kevin the gruesome interior of the shop’s water heater, comparing it to the other models available.

Types of Water Heaters:

* Gas burner is underneath the tank. Cold water enters the glass-lined tank by the dip tube and goes to the bottom of the tank. Through the process of convention, hot water rises to the top of the tank.
* A flue runs through the tank and up out of the house to take away exhaust gases.
* Most popular in the USA

* The process is very similar to the gas water heater. A dip tube brings cold water to the bottom of the tank, where it is heated.
* There is no direct burner but there are electric elements to heat the water, just like the elements found in a coffee machine.
* There is no gas, so there is no need for a flue.
* Usually more expensive to run than a gas water heater.

* The water in the tank is heated by a heat pump. It works like an air conditioner does - it moves heat from one location to another. It pulls heat from the surrounding air and, through fans and coils, heats that air even more, then dumps it into a tank to heat water.
* Can be two to three times more energy efficient than conventional electric resistance water heaters.
* They work best in a warmer climate.

* Also known as “instantaneous” or “on demand” because they make hot water only when you need it.
* When the hot water tap is turned on, cold water travels through a pipe into the tankless heater, and a heating element (usually a gas burner, or sometimes an electric element) heats the water as it travels through the tank.
* Popular in Asia and most of Europe. They are starting to gain popularity in the USA.

* Has no direct flame. It relies on a boiler or furnace to produce its heat. It is typically a stainless steel-lined tank that holds a coiled heat exchanger. Boiler water is pumped into the coil through a pipe that connects the units. The coil transfers the heat into the water in the tank. The water from the boiler never mixes with the water in the tank.
* You’ll need to have a boiler in your home for this type of water heater.

Where to find it?
Richard explains different types of hot water heaters you can install in your home: gas storage tank water heater, electric storage tank water heater, hybrid tank water heater, tankless water heater and indirect water heater. Water heaters can be purchased at home centers or sourced through a local HVAC technician or sales representative.

About Ask This Old House TV:
From the makers of This Old House, America’s first and most trusted home improvement show, Ask This Old House answers the steady stream of home improvement questions asked by viewers across the United States. Covering topics from landscaping to electrical to HVAC and plumbing to painting and more. Ask This Old House features the experts from This Old House, including general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor Jenn Nawada, master carpenter Norm Abram, and host Kevin O’Connor. Ask This Old House helps you protect and preserve your greatest investment—your home.

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All About Water Heaters | Ask This Old House

[michaeljohnson]

I’m a master plumber and own a plumbing business in Wisconsin. Tankless heaters still have lots of issues. I deal with Rinnai and while I certainly like the product it has plenty of expensive issues.

[curtismiesner]

the one electronic water heater they forget about is the plastic heater from marathon, it may cost more then a metal glass lined but it out lives all of them just a simple replacement of the element every 10-30yrs, depending on your water condition. but thanks for all you guys do on this old house I enjoy watching and learning new stuff

[twistingterrain]

I have a tankless water heater and it really dropped our propane bill (by 40%) and the peace of mind that we can all shower and never run out is so worth it. $2300 installed. Love it and recommend it.

[nottad]

After a month of 1 minute hot showers from my existing 20 year old electric hot water heater I said forget it and went and purchased another standard electric how water heater. I have researched out the wazoo of what type to get. The tankless is more than I want to spend right now and I don't want to do the required maintenance each year. The other option was the Hybrid but it seems the current Rheem model has a fan issue that has this annoying buzz that would drive me nuts. Their support has been utterly, utterly useless so I replaced like for like to be done with it. Maybe in another 10 years the issue will be addressed.

[laurie]

Have had an indirect for 7 years running off my Lochinvar high efficiency boiler. Can't be beat.

[Jimbobo]

I love my A.O. Smith tankless electric water heater.

[larryholland]

Perfect explanation! I'm a home inspector and have learned so much from Richards style of explaining. Thank you!

[frankthefixer]

Indirect water heater in my home since January 1993. It’s over 29 years old. One of my better purchases when I switched from all electric heat back to oil furnace fixed hot water. It wasn’t cheap at the time, but still in service.

[bikeny]

I've got the indirect model. Stainless steel with insulation wrapped around it on the outside. Kock wood, it lasts another 20 years (yes, right now it's 20 years old). I love it.

[dirtyhairy]

Great and very important information, it's good to know what's available out there. Thank you gents!👊

[landservicesandmore]

many places in the world use water heaters at the point of use. In Brazil, my wife's house there has individual heaters placed on the lines where the water is actually used. Each unit then only runs when the water is actually used from that faucet/shower/etc. Seemed strange to me, and most of them are based on a 210/240 volt electric service, but they do add a level of efficiency where electricity is not as "cheap" as it is in the USA (yes, compared to many places, it is still cheap here)... I brought one back to install an outside shower near my pool so we could rinse in relative comfort instead of always getting a blast of COLD water. Like many places that widely use MINI-SPLIT air conditioners, there are other ways of heating water that are in use in other places other than a systemic system of a tankless water heater or a water heater tank, both of which distribute heated water over a longer system. This point of service system reduces delay in being able to access hot water, and if one goes bad, you can replace it for a lot less than a tank or whole home tankless heater.

[demagab]

Some tankless water heater actually have a very small tank built in, so some water can always be efficiently kept hot and there's no delay when demanding hot water

[lsatenstein]

Here in Canada, our winters are too cold to leave a hotwater tank in the near outdoors. In Montreal, our garages are part of the building Our homes have basements, part of which is reserved for furnance and A/C,
One trick I learned to do to save money is to have the hot water connection to the house follow the S trap idea. What is the S trap idea? It is an S shaped connection to the hot output of the tank. .

When no water is flowing from the basement area into the upper floors of the house (days and overnight), hot water, by convection wants to go up the pipes from the tank in the basement, and in those same pipes, cold water cooled from the connections on the above floors, flows back into the hot water tank. In effect, we have a hot-water heat-loss. A S trap using the flexible shielded hose connection, has the hot water having to flow down before it goes up into the upper floors. The top of that S trap is hot, as it connects to the tank, but the other end of that S trap is at room temperature UNTIL taps are turned on. Yes, hot water does not flow up when the taps are off. Law of physics --cold water is more dense than warm water.

Our home, and many around Montreal, are "all electric" homes. Our standard hot water tank is an insulated Canadian norm, a 60 gallon tank with three heater elements. The sequencing is top heater (3800 wh, middle is at 3000wh along with the 800watt lower element and then only the lower 800wh, under thermostat control.

The Canadian tanks are sized to 61 gallons Canadian, corresponding to 74 gallons American.
When the upper element turns off, the two lower elements are turned on concurrently. When the middle element turns off, the lower element, also thermostatically controlled heats on and off at 800 watts recovery.

It is important to have that S trap to prevent undesired convection currents.
The S trap idea generally pays for itself within a year.

Here is an additional information. If your hotwater tank is inside the house proper, check with your insurance company about coverage for tank water leakage. My insurer, and other insurers, demand a tank replacement after ten years of use or to have a tray under the hot water tank to capture a water leak. The tray must have a leak detector (similar in appearance to a fire/smoke detector). Our water supply has low calcium, and from experience, our tanks last about 15-20 years before a leak occurs. Re elements, we expect one replacement during the life of the tank.

[javiergalvan]

Great illustration guys, that is why I love the show and subscribed to not miss any content. :)

[Sc]

Just installed a tankless water heater at my dads house, thing is awesome

[joejr]

To say the tank heaters are on 24/7/365 is a little misleading. They heat the tank to it's set temperature then standby. The tanks heater isn't constantly heating the water like the 24/7/365 comment insinuates. Once the tank is heated the heater doesn't kick on again until the temperature in tank falls below a certain point. If not in use water heaters hold their heat for quite awhile.

[AndrewBurgess]

I have one of those hybrid water heaters. The heat pump only setting is very efficient and provides plenty of hot water for normal use. The newer ones that are smart enabled have geofencing and schedule learning technologies in them so it’s not heating when no one is home or at times hot water is not needed. Whenever possible, heat pumps are best.

[nultari]

I just replaced my water heater from ‘83…. Was interested in a tankless but my old house needed the breaker upgraded in amps first which was too much of an investment

[VideosbySteve]

My water heater leaked last year for about an hour. I was home and had no idea. Had about 3 inches of water in a 20x30 area. I freaked out. Luckily my neighbor is a plumber and put in a tankless. Theres just something about a 50 gallon tank of water in my house just sitting there, one day will fail. Luckily my tank flooded onto concrete floor so no big loss. But if yours is located on regular wooden flooring I would highly recommend switching it out for a tankless. Yes, its more expensive upfront, but just knowing that its not a ticking time bomb waiting to explode and the fact it will use less energy and save money every month really makes it worth it. Be sure to check your tank when it was manufactured because most only are rated for just 6 years, some are 9 or 12. And if your water heater is past its due date get it replaced as soon as possible to avoid a further headache in the future because unlike me your water heater may start leaking if youre at work or in bed.

[dalefrolander]

So if the hybrid water heater is pulling heat out of the space you heat, meaning the furnace has to resupply that heat to the room, does it really save anything. Maybe in the garage is ok, but something to think about if the water heater is inside the house.