Efficient 65k BTU/hr water heater? Running out of hot water with 40k BTU/hr

[stainlesssteel]

I manage a 9 unit apartment building in temperate San Diego. One water heater handles seven bathtub/showers among 5 apartments. I would like to upgrade to about 50% greater shower capacity: occasionally we've had tenants run out of hot water for showers.

 

The 2014 model Kenmore 50 gallon has about the same BTU/hr as our existing 2002 Kenmore 50 gallon 153.330552 Power Miser, which has started leaking. The crawlspace walkway by the water heater is 47.5" wide with a lowered area 37.5" wide. The next step up Kenmore is a 75 gallon--a full 26" diameter vs. 22" for the 2014 50-gallon and 20" for our existing 50-gallon, making it harder to walk in the crawlspace:

 

Note the water leak.

 

 I've narrowed it to 50 and 63 gallon Rheem models, 22 and 23" diameter: 

 

 

first hour delivery gals | recovery@90deg rise gal/hr | BTU/hr | energy factor:

 

50 gal Rheem G50-50N powered damper: 87/50.5/50k/0.67

63 gal Rheem G63-65N heavy duty: 115/65.7/65k/0.55

 

2014 50 gal Kenmore equivalent: 88/40.9/40k/unknown energyfactor

 

The 63 gal vs. 50 gal powered damper would give 

 

65/50 = 1.3x better recovery@90deg gal/hr

115/87 = 1.32x better first hour delivery gallons

 

But it's much less efficient at 0.55 vs 0.67. 

 

Does anyone know of a 63 gallon 65k BTU/hr model that's at least 0.67 energy factor?

 

The 50 gal Rheem powered damper vs 50 gal 2014 Kenmore has 50.5/40.9 = 1.23x better recovery @90deg gal/hr, apparently due to its large 50k BTU/hr vs. 40k BTU/hr burner. But about the same 87 vs. 88 first hour delivery gallons. Would this give noticeably faster recovery to showers? Or should I just waste energy and go for the inefficient 63 gal Rheem?

 

I've blown about 6 hours on this over 3 days, and have to decide soon before the slow leak turns to a fast one....

Edited March 7, 2014 by Samurai Appliance Repair Man

[telefunkenu47]

How about a Rinnai Continuum. I have installed many over the years, not a single clinker in the bunch. the gas supply line needs to be upsized to a 3/4 inch because they ramp up as high as 149000 btus.I  usually use  black iron but you can use the newer armorflex type products. It's  also a a good opportunity to upgrade your existing gas lines in the home for future expansion. The difference in price is less than 400 dollars and the savings are immediate. zero standby loss. Call a few heating professionals in your area and get some free estimates.  This is the best time of year for having something like this done as the heating guys are hungry as hell !

My average installed price is 12 to 1700 sheckles depending on the complexity of the installation.

Energy is simply too damn expensive to fool around with wasteful heating and cooling appliances anymore.

It is the cheapskate that pays the most. Also, there may be some rebates in your state( directly proportional to the number of greenie weenies in your statehouse.)

Good luck!

[AaronFong]

Yes, I agree with @telefunkenu47.

Energy is simply too damn expensive to fool around with wasteful heating and cooling appliances anymore. That's why you should get in contact with the heating professionals in your area and get some free estimates. My neighbor had installed a walk-in bathtub by the professional of a walk in tub Spokane. Walk-in bathtub had an inline heater that keeps the water temperature at a consistent level during the entire bath period.