Hello, on my house with 2.5 baths, laundry and dishwasher I've got a Rheem 38 gal electric WH that cannot supply enough hot water to fill a Kholer Devonshire bathtub 60"x21"x32" followed by a regular shower. After I balked at the $3000K + cost of adding a dedicated propane fueled tankless WH for the primary bath, my plumber recommended eemax AutoBooster model number HATB007240 which retails for ~$350 and claims to boost capacity by 45%. Which i can install DIY per spec in after the 38 gallon tank.
Then i remembered that years ago on my class A motorhome i added a Stiebel Eltron Mini 1.8 kW Point-of-Use Tankless Electric Water Heater in series with my 6 gal OEM propane tank which gave me unlimited hot water because the Stiebel gave me a temp increase of about 30 degrees and the 6 gal tank gave me another 15 degrees or so after the hot water in the tank was depleted. This way the inlet water at the beach resort in SC was 70 degrees and we had toasty warm unlimited showers around 115 degrees. the whole thing ran at about 1.5 to 1.7 gpm. it was fabulous. no stacking effect, unlimited hot water. i put the tankless before the tank heater in this configuration.
I've seen photos and plumbers have told me that in luxury homes they put small tanks inline with tankless heaters to take out the stakcing effect so i know im not compltely crazy suggesting this following idea...
instead of a eemax autobooster which i think cuts power to the tank heater when it is in operation (otherwise it would trip the breaker if both units came on at the same time and why else would it require you wire the tank heater through it?)...
Here's what I am thinking.
leave the 38 gal tank in place, leave it set at 125 degrees
buy a tankless and size it for 2 showers at the same time (about 3.5 to 4 gpm) as if there was no tank heater
install the tankless (normal installation) but put it after the tank heater and set it at 120 degrees or there about.
the idea is to use the tank to fill the big bath tub, and then the tankless will work as needed to supply unlimited hot showers to the two bathrooms after the tank is depleted and reheating.
have you ever done this? does it work?
would you put the tank or the tankless first? if you put the tankless first it is going to run any time the hot water is on and it costs alot to operate compared to the tank i think. (efficiency on tankless comes with gas fueled from what i understand).
thank you
Then i remembered that years ago on my class A motorhome i added a Stiebel Eltron Mini 1.8 kW Point-of-Use Tankless Electric Water Heater in series with my 6 gal OEM propane tank which gave me unlimited hot water because the Stiebel gave me a temp increase of about 30 degrees and the 6 gal tank gave me another 15 degrees or so after the hot water in the tank was depleted. This way the inlet water at the beach resort in SC was 70 degrees and we had toasty warm unlimited showers around 115 degrees. the whole thing ran at about 1.5 to 1.7 gpm. it was fabulous. no stacking effect, unlimited hot water. i put the tankless before the tank heater in this configuration.
I've seen photos and plumbers have told me that in luxury homes they put small tanks inline with tankless heaters to take out the stakcing effect so i know im not compltely crazy suggesting this following idea...
instead of a eemax autobooster which i think cuts power to the tank heater when it is in operation (otherwise it would trip the breaker if both units came on at the same time and why else would it require you wire the tank heater through it?)...
Here's what I am thinking.
leave the 38 gal tank in place, leave it set at 125 degrees
buy a tankless and size it for 2 showers at the same time (about 3.5 to 4 gpm) as if there was no tank heater
install the tankless (normal installation) but put it after the tank heater and set it at 120 degrees or there about.
the idea is to use the tank to fill the big bath tub, and then the tankless will work as needed to supply unlimited hot showers to the two bathrooms after the tank is depleted and reheating.
have you ever done this? does it work?
would you put the tank or the tankless first? if you put the tankless first it is going to run any time the hot water is on and it costs alot to operate compared to the tank i think. (efficiency on tankless comes with gas fueled from what i understand).
thank you
