Tank OR Tankless Water Heaters

22 Replies

I've been having a problem with a water heater on the second floor unit of our apartment. This is unit already has a 30 gallon electric hot water heater. But the hot water in the shower is going out in 5-7 minutes. Tried turning the tempature up but only gave it about two more minutes.

I was also told to change the shower head that uses less water. Or to switch to a tankless hot water heater.

Has anyone here have experience in switching hot water heaters from tank to tankless?? If so was it worth it, and how did it go?

Before switching the hot water heater, test the current one to confirm that both elements are working ... sounds like your tank recovery is lacking.

That said, I would definitely recommend moving to a 1.5usg shower head.   We use a couple of models that folks never realise are low-flow until we tell them about it.

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

If you have natural gas - it can be done.  I have natural gas fired tankless units in my houses and have found them to supply endless trouble free hot water.

If you only have electric please be aware that many which are sufficient for a house require TWO 100 amp circuit breakers to supply the power to them.

That being said;  I do have a Florida rental which had a big delay to get hot water to the farthest bathroom.  So I added a 15KW electric tankless unit right at the far bathroom and . . . so far - so good.  Although it hasn't been long and Florida water is all hard as far as I can find.  

Also;  unless you have perfect soft water in your area tankless water heaters require a fair amount of maintenance - annual acid flushing and so forth.

Roy,

Can you share those shower head make and model numbers with me?  Because every one that I've ever tried have been Noticed Immediately. <g>

stephen
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 Originally posted by @Roy N. :

Before switching the hot water heater, test the current one to confirm that both elements are working ... sounds like your tank recovery is lacking.

That said, I would definitely recommend moving to a 1.5usg shower head.   We use a couple of models that folks never realise are low-flow until we tell them about it.

Tankless places high peak demands on the energy source, whether electric or gas; gas seems to be preferred. When I converted a property from oil heat and hot water to gas, I asked the gas company about whether tankless would be a possibility. Turns out the gas main was insufficient to supply the demands of a tankless unit. 

Low flow shower heads are not that bad, so try them. 

Originally posted by @Stephen S. :
Roy,

Can you share those shower head make and model numbers with me?  Because every one that I've ever tried have been Noticed Immediately. <g>

stephen
------------

Stephen:

We were using the Delta Classic Monitor 14-Series (144913) in all our bathroom renovations, but Delta recently changed the showerhead from 1.5gpm to 2.0gpm {Note: I was told it was always 2.0 gpm in the U.S.A. and that the "Canadian" version is no longer}.  We did find half-a-dozen of the pre-change packages at a local supplier and have put them aside for use in upcoming renovations.

When it comes to replacement shower heads we have used the Delta 1.5gpm H2O Kinetic heads (here and here) and find them to work well (use them in student rentals).  We have also tried the Pfister Eco-Pfriendly which was well received, but did not like the hard-water at our test property.   Our goto showerheads now are by Niagara Conservation {Note: they are in the process of rebranding this part of the business as AM Conservation Group} namely the Earth (1.25 gpm & 1.5 gpm versions), Spa (1.5GPM) and Spoiler (1.5 GPM) models.  The Spa and Spoiler showerheads come in tamperproof versions so your tenants will not be able to swap the shower head {easily}.

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

Thanx guys! I think I'll try the low flow shower head. Whats a good psi, or watever they go by? I thought the normal was like 2.0

gpm, not psi probably lol. 

@Ralph Pena

You want to look for a showerhead of 1.75gpm or less.   The ones I listed above are all 1.5 or 1.25 gpm (half a traditional showerhead).

We have had buildings where, after replacing fixtures (low-flow toilets, showerheads, faucets) we have reduced the water bill by 40 - 50%. ... one was over 60%, but we had also replaced the laundry units.

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

Sounds like one of the heating elements in your electric water heater is not working.

A new electric water heater will cost under 250 including parts and will take you 2 hrs or less (if you have a pump) to replace. I recommend the shark-bite supply lines.

this was the lowest pressure they had at Lowes 

How old is the existing electric hot water heater?

At least 5 years old. 

I'm not sure what the results was after you changed your existing shower head to a low-flow head (1.5-1.75 GPM), was there any change? If you had sufficient hot water flow to your existing shower head prior to this issue, chances are, the problem exists in your water heater and not a shower head flow rate. 

Residential electric water heaters typically have two heating elements, one in the middle and one at the bottom of the tank. These are a common thing to fail on electric water heaters. Typically these elements are designed to cycle on one at a time, so my guess is that your bottom one could have failed causing minimal hot water output. You can ohm these out after shutting the breaker off and checking continuity in the element. If you've determined that an element has failed and would like to change it out, make sure you first turn off the breaker and you've drained the water in the system. Heating elements are a pretty common part to find if you decide to replace it. If you don't feel comfortable with servicing your heating elements, contact a HVAC or plumbing service contractor. Don't let them sell you on a new system for something so simple ;) 

Keep me posted on the outcome. 

Best of luck, 

Tim 

Didn't get to replace it yet. Will do so asap. Tenant doesn't bother me much so i give them their space as well. Will do so later this week.

@Tim Baird  

+1 sounds like 1 of the 2 elements has burned out. Spend $25 at Home Depot and a couple YouTube videos, back in business.

If the element actually did burn out, chances are the second element is not far behind it. May consider changing both....

Love tankless but only if it's natural gas.  

If you are up to spending $12, try the following low-flow shower head:

Delta (available at Home Depot)

Although I live in upscale homes (and my wife will not allow me to equip them the way I used to equip my more frugal homes), I love that shower head!  You will find that the flow rate really does make a huge difference in how long your hot water lasts.

We have debated about tankless water heaters for some time now.  The cons are that, unless you choose a hybrid unit (with a built-in mini-tank), you can't effectively use your recirculation pump.  A recirculation pump is what keeps the hot water flowing through the hot water pipes, even when you're not using the hot water; what this means is that when you actually turn the hot water faucet on, you get hot water without having to wait for the now-cold water in the hot water pipe to run off.  In other words, a recirculation pump does exactly what it says - it recirculates your hot water in a closed loop, so that you'll have hot water when you turn on that tap in a part of the home furthest from the water heater.

So, what are the problems with tankless heaters?  As I said, not all tankless heaters lend themselves well to a true recirculation pump (some have to constantly cycle to service the recirculation pump - defeating the energy savings).  Another problem is the fact that these are on-demand systems... they have to detect water flow (in the hot water pipe) in order to trip.  If you want a weak stream of hot water (or mixed hot/cold), there may not be enough flow to trip the tankless heater.  That, in itself, seems to be anti-conservation - you can't simply use as "little" hot water as you please - since the tankless heater may not sense it.

Rinnai seems to be a good brand (it's the only brand my commercial HVAC friend installs).

Bear in mind, it is sometimes easier to relocate the (tankless) water heater so that it is sitting against an exterior wall (so you can easily vent it) and re-run the plumbing to it, than trying to get the necessary large vents (which typically cannot be shared) run to an exterior wall.

@Lew Payne

When living/working in Europe it was common to find on-demand water heaters distributed at/near point of use rather than a centralized whole home approach as is favoured in N.A.   When the water heater is in the bathroom or under the kitchen sink, you eliminate the need for recirculation.

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

Originally posted by @Roy N. :

@Lew Payne

When living/working in Europe it was common to find on-demand water heaters distributed at/near point of use rather than a centralized whole home approach as is favoured in N.A.   When the water heater is in the bathroom or under the kitchen sink, you eliminate the need for recirculation.

Correct... but the person asking is in Pennsylvania, and homes in the US are already plumbed to distribute water from a central location (the water heater), rather than for on-demand use at each hot water tap.

Originally posted by @Lew Payne :
Originally posted by @Roy N.:

@Lew Payne

When living/working in Europe it was common to find on-demand water heaters distributed at/near point of use rather than a centralized whole home approach as is favoured in N.A.   When the water heater is in the bathroom or under the kitchen sink, you eliminate the need for recirculation.

Correct... but the person asking is in Pennsylvania, and homes in the US are already plumbed to distribute water from a central location (the water heater), rather than for on-demand use at each hot water tap.

 Yes, but most homes in the U.S.A., or Canada, are not plumbed for recirculation either (though there are cheater/bleeder valves out now which allow you to fake it to a certain degree).   Adding on-demand heaters at point of use is often easier and less expensive than recirculation.

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

Originally posted by @Roy N. :
 Yes, but most homes in the U.S.A., or Canada, are not plumbed for recirculation either (though there are cheater/bleeder valves out now which allow you to fake it to a certain degree).   Adding on-demand heaters at point of use is often easier and less expensive than recirculation.

Those same homes that "are not plumbed for recirculation" generally are also not wired for 240V in the bathroom (where the shower is), or enough amperage at 120V to sustain an electric on-demand tankless heater with sufficient capacity (after calculating winter drop temperature vs flow rating), much less plumbed for natural gas to support a non-electric model (which is the only type I'd recommend).

@Lew Payne

Certainly point of use would be easier when there is already 220v circuits in-place, but even where 220/240v is the standard (such as in Europe) a dedicated circuit would be run for an electric point-of-use heater.  In most situations, running an electrical circuit is easily accomplished with minimal damage and rework.

120v in-line heaters are meant to be used as boosters for water that has already been pre-heated but where additional rise in temperature is required - the most common examples would be in washing machines which have steam clean or sanitary cycles and in dishwashers.  They are also employed in point-of-use situations where the hot water run is sufficiently long that there is an unacceptable drop in temperature between the central hot water heater and point of use.

I do agree that in a centralized, whole home, on-demand application a natural gas fired heater is really the only adequate choice if you are geographically in a place where source water temperature is <=10C (such as winter in all of Canada and the northern U.S.A.).   While I have seen electrical in-line heaters in an industrial setting easily handle the required lift in water temperature to make hot water (50C) or steam (100+C) the amperage required could run much of a city block.  I too have yet to find a domestic in-line electric heater which provides acceptable performance, unless the water has been pre-heated.

We do have a small building where each unit has an in-line/on-demand hot-water heater which provides the final amount of lift from a common solar thermal system with a 100gallon storage tank.  In this set-up, the electric heaters work well, but they are never providing more than 20C in temperature lift and many times do not fire at all.  

All that said, I have always been sceptical of the centralized approach to domestic hot water as being efficient.  As we continue to move our renovations towards the energy goals of Passivhaus / EnerPHit, distributed versus centralized domestic hot water is an area in which we are experimenting to see what works best given the social expectations and hot-water usage patterns of Canadians - and those in the U.S.A. - and how much behaviour can be {relatively} painlessly modified to improve energy efficiency. 

Medium greenapartmenthires 1024x1024Roy N., Louer Louer Ltd. | 1.506.471.4126

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