Water Heaters - two new water heaters both provide less hot water

Here's a conundrum.. our house has 2 water heaters (it's a duplex). Within the last year, both of them sprung leaks, so the landlord replaced them. He's a handy guy, but no pro on this stuff.

After replacement, both heaters work but both provide FAR less hot water than the old ones did. I'm talking around half as much. We tried turning up the heat on one, and that helped somewhat, and the temp of the hottest water is now hotter than it was before, but it still runs out quicker.

I helped him do both installations, and didn't see him do anything wrong. But is it possible that he did something on both installs that is causing this problem?

Our original thought was that we were dealing w/ a bad heating element, but what's the chances we'd have that on both? And one of them is small (20 gallons, I think?) and do those even have 2 elements?

Thanks for any ideas!

M.

Welcome to the forums! 20 gallons??! That isn't enough for an RV, much less a normal living quarters. IMO you should have no less than a 40 gallon heater for each half. He didn't save much money by buying the 20 gallon heaters. If it were inspected, it would fail.

Sizing of water heaters is important. I live alone in a condo with 40 gallon water heater. It is sufficient for me. If I have a house guest, it is not. No washer/dryer hookup and have to go to laundro-mat. So that's not a drain on water heater.

If my guest and I want to take a shower, and my guest is showering while I fix breakfast, and do kitchen cleanup as I go, and then jump in the shower before meeting for breakfast with wet hair and robe, I get cold water.

And, I do not flush the toilet or run water in kitchen sink while someone is in the shower. That is a plumbing issue. I do not do this, so I meet breakfast guests in robe and appear a mess. Or, breakfast is delayed.

It is aparrent that you have an undersized water heater as I do.

Sorry, I should have made it clearer that he didn't change the size of either heater. So the one that's 20 gals was 20 gals. before, and it puts out a lot less hot water than it did then.

So whatever changed, it wasn't the size.

Any other ideas, anyone?

When you say less hot water...do you mean initial temperature (after it starts running hot I mean) or time of hot water flow? Basically temp or volume? It's hot but runs out quickly or it's just warm so we have to turn more hot water on the get the same temp from the faucet.

Its possible the replacements were of the wrong type (voltage wise) but unlikely as the wiring should have made that clear. What I mean is, if you replaced 220V WH's with 110V heaters, I THINK they would work, but very very poorly.

IIRC you should get about 75-80% of the rated volume out of a WH before the hot water runs out. (20 gal would give about 15-16 gal before it runs really cool) These numbers are approximate.

W/o having the old WH plate info, it might be hard to tell if they are the right models.

Feel like doing some testing? And looking at breaker panels?

Well, 20 gallons is too small, and around here the minimum allowed even for a studio is 30 gallons. Nonetheless, you say he replaced size for size. The voltage would be an issue, but only on time to reheat after use. You really only get 14 gallons of water heated to at least 20º below the set point, out of a 20 gallon heater. A higher set point would give a longer shower at say 105º.
On electric WH you are running only on initial delivery, because make up is too slow .
Something to check would be that the dip tube is still in place, and also that the hot and cold connections at the WH were not reversed.