50 gallon hybrid hot water tank too small
We were given a Bosch hybrid hot water tank from our power utility for free, it was brand new but very old, has to be one of the first ones on the market.
The unit is discontinued and works perfectly fine imo, but my wife is already complaining about losing hot water after 15 min during her scolding hot 40 min showers. (140)
We had two 50 gallon tanks that were monster energy users, $633 a year on the energy guide sticker.
We have a 1k gallon propane tank that is just used for the propane fireplace so I’ve been contemplating tankless propane. The cost of a tankless propane would equate to just buying another 50g hybrid electric, we have terrible well water with a softener, so the tankless would probably need to be descaled every couple months to be safe.
Would you tie the tankless heater into the hybrid discharge so it would turn on when it senses the water temp dropping?
I really should have just kept one of the old electric tanks and used it as a storage tank in series with the hybrid 😑
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I replaced all the shower heads in the house with 1.25 GPM High Sierra heads:
https://www.amazon.com/gp/product/B09W3X634N
The hot water lasts twice as long as with 2.5 GPM standard heads. I thought for sure I'd get complaints but so far everyone is happier.
I'd try that before anything else.
Yes! That reminds me I ordered a flow restrictor valve off Amazon I need to put on our shower head in the master, when we first moved here I removed the restrictor because there wasn’t enough pressure but it was just a dirty sediment filter.
I was skeptical but the High Sierra heads really are good, much better than a flow restrictor.
Is that a circulation pump connected to pex with no insulation? I would not use a circ pump with a hpwh tank and I believe Rheem and others specifically state to not use one. I believe it has to do with the tank temperature sensors and they usually cause the hpwh to run nearly 24/7.
If it is a circ pump turn it off for a week and I bet you will see a huge difference.
Yes, and this was right after installation so the insulation wasn’t on. The hot water circulating pump is in a smart outlet, it only runs couple hours a day 8 pm to 11 pm.
Most likely the propane heater wouldn't be able to modulate down low enough until the water temp dropped significantly. I tried this with a solar tank which has a backup element and is piped into our pre existing rinnai. Works great when there is a significant delta in temp but otherwise not good. Maybe if the mixing valve was moved downstream from the tankless it would be better. Could then crank up the tankless to a higher temp. At this point considering turning up the thermostat in the tank and just removing the rinnai.
40 minute showers?
I’m guessing you don’t have daughters or a wife? Or know any women at all?
The average shower in the US is 8 minutes. 40 minutes is not normal and I don't think any tank-style water heater is capable of keeping up with that, though gas-fired ones might be able to. https://www.epa.gov/sites/default/files/2017-02/documents/ws-ourwater-shower-better-learning-resource_0.pdf
Idk I grew up with 4 sisters and they all took long ass showers
It is not about whether 40 minute showers are normal
It is about his wife thinks 40 minute showers are normal
You're right. I live in my mothers basement, have no building experience and have never been married or even lived with a woman.
Alternatively, 40 minute showers are ridiculous.
Still, happy wife, happy life!
With a 2.5 gpm shower head, the tank has exhausted it's preheated hot water. HP's take a while to recover. I'm not even sure a regular 50 gallon electric DHW could recover fast enough for a shower that long with 2.5 gpm flow rate.
What you need is a tankless hot water heater. My propane tankless never runs out and is extremely efficient.
Let’s do some math
How many dollars does it cost to take a 40-minute shower 3 times a week per year?
Let’s do some math
40 minutes X 2.5 gallons = 100 gallons.
Each gallon weighs 8.34
100 X 8.34 = 834.00 pounds
If the incoming water is 45° on average and she demands 140° shower.
140° - 45° = 95° increase.
95° X 834 Pounds = 79,230 BTUs required to heat the water.
79230BTUs / 3412 = 23.22 kWh for a restive heater.
23.22 kWh .23 = $5.34 per shower for resistance at electric national average price per kWh
$5.34 X 156= $833.04 per year for resistance at electric national average price per kWh
23.22 kWh .23 /4=$1.34= per shower for heat pump electric at electric national average price per kWh
1.34 X 156= $209.04 per year for heat pump electric at electric national average price per kWh
79230 BTUs / 91502 = .866 x 1.42 = 1.24 gallons of propane with a 70% efficient heater.
1.24 gallons X $2.69 = $3.34 per shower for propane
$3.34 X 156 =521.04 per year for propane at the national average price
$833.04 per year for resistance
$209.04 per year for heat pump
521.04 per year for propane
Or maybe you could convince her that 40 minutes is excessive and 40 minutes is not about cleaning.
Walta
Lol thanks for the calculations. Our rate is around .08/kWh, propane is 2.38/gallon here but nonetheless heat pump water heater is the winner.
140 degree
skin peels off
deeply flawed numbers
I have to deal with a 40 min shower a day person and we don't spend that on hot water in a year total
Or, 7 showers a week at 100 gallons per shower (2.5 x gpm x 40 min.)= 700 gallons per week for one person showering. 52 weeks= 36,400 gallons per year.
A 20 foot x 44 foot swimming pool holds 33,000 gallons.
Just from an environmental perspective that's excessive. Hope you're not paying for water too.
You can't shower in 140° water. So the tempering valve mixes cold in to prevent scalding. So 50 gallons of 140° water provides probably 80-90 gallons of shower water at 108° or so.
Hi Ryan: your application may be well suited for 1)1.25 gpm showerheads (I use the Niagara Earth Chrome 1.25 gpm model N2912CH, $20 or so on line, multiple spray patterns selectable) also 2)a drainwater heat recovery device, if you have sufficient vertical drainpipe access. See https://renewability.com The Power Pipe R3-54 model claims to recapture 50% of the heat BTUs otherwise going down the shower drain. Other models specifications see https://renewability.com/wp-content/uploads/2021/05/Power-Pipe-Spec-Sheet-Rev2.0.pdf
The orange big box retailer sells Power Pipe devices which in effect double your hot water tank capacity at much lower cost than a second hot water heater. Zero moving parts, zero fuel cost (if its installation is feasible in your particular situation of course). Jan
"but my wife is already complaining about losing hot water after 15 min during her scolding hot 40 min showers. (140)"
May I humbly suggest to replace wife? If she is still alive after a 140f shower she is a bona fide witch and nothing good will come out of it. Ha!