Help sizing water heater and recovery rates

Old 01-02-19, 07:09 AM
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 2
Received 0 Votes on 0 Posts
Help sizing water heater and recovery rates

My 18 year old AO smith is starting to leak. It is an 80 Gallon capacity. Since I haven't bought a HWH in a long time, I am surprised that there are few 80 Gallon ones out there. Most are 50 or 55. My question..if my 80 Gallon has a first hour rating of 81 and the 50 Gallon new model is also FHR 81, would that mean the 50 Gallon would be good replacement? Is the FHR really the key in picking a HWH? I'm sure they are much more efficient these days. I do have a family of 5, but, a few are in/out college wise. They take long showers though. lol I do have a garden tub, but, that isn't used that much. I'm just worried if I don't get a direct 80 gallon replacement, I might run out of hot water.
Old 01-02-19, 05:47 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,889
Received 1,480 Votes on 1,368 Posts
Welcome to the forums.

Are we discussing a gas or electric water heater ?
Old 01-02-19, 07:02 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
80 gallons only come in stainless steel tanks and are lifetime units AFAIK.

What we do is install 50 gal du to cost.Install a mixing valve or tank booster as they call them and turn the temps up on the heaters. Then temper the water to 120f at the mixer. The 50 gal acts as a 70 gallon heater now..

If gas tankless may be an option.
Old 01-03-19, 07:22 AM
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 2
Received 0 Votes on 0 Posts
Sorry, I should have said Electric, not gas. From my research, It looks like I should either get a 50 or 55 Gallon with high FHR. Install a 2nd tank if necessary. Pretty annoying they stopped making 80 Gallon or I should say there are only a few out there. The Heat pump model ones are just too expensive too. One last question...I see a 50 Gallon model with two 5500 watt elements and a 55 Gallon model with 4500 Watt elements. Will that matter? My current 80 gallon has 4500. I do have a 30 amp breaker and I think wire is 10/2, so, it can run either. Any real difference in running 5500 vs 4500?
Old 01-03-19, 05:27 PM
CasualJoe's Avatar
Join Date: Jan 2010
Location: United States
Posts: 10,815
Received 106 Votes on 94 Posts
Any real difference in running 5500 vs 4500?
The 5500 watt element model will heat the water a little faster and it will spin your electric meter a lot faster..

Here's an 80 gallon electric model, 4500 watts, at the big box.
Old 01-10-19, 11:57 AM
Join Date: Dec 2018
Location: USA
Posts: 48
Received 0 Votes on 0 Posts
The Heat pump model ones are just too expensive too.
keep an eye out for deals and depending where you are located there may be a significant rebate from your utility company. I recently ditched my tankless coil on my oil fired boiler and replaced it with an 80 gallon rheem heat pump unit. I ended up picking it up on sale right before the holidays for $350 off plus my utility company gave me a $750 rebate. Ended up getting the unit under for under a thousand dollars after everything was said and done. I have it in my unfinished basement with very drafty windows. Have had it in heat pump only mode. When the temp is abt 30 degrees outside. My basement hovers around 60 degrees with the water heater going. The plus side is that I am no longer running a dehumidifier in the basement because the heat pump is pulling the moisture out. May be something to think about.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: