Heat Pump Water Heaters

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brenndatomu

Minister of Fire
Aug 21, 2013
6,276
NE Ohio

Rob711

Feeling the Heat
Oct 19, 2017
426
Long Island, ny
Looks good. Let us know how it works.
 

laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
So......my wife came home in a poor mood with warm water for a bath, and the thing is noisy! I have it set at 140 and it will take a day or so for things to level out. The hum however is terrible.
 

maple1

Minister of Fire
Sep 15, 2011
10,783
Nova Scotia
So......my wife came home in a poor mood with warm water for a bath, and the thing is noisy! I have it set at 140 and it will take a day or so for things to level out. The hum however is terrible.
It's the unit itself? Not some weird vibration harmonics thing that is amplifying somehow that a little insulation or something in the right place would fix? Our mini split outside units are on a deck, they made a heck of a noise until a couple of little insulation pad thingies got put in a couple of certain spots.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,276
NE Ohio
It's the unit itself? Not some weird vibration harmonics thing that is amplifying somehow that a little insulation or something in the right place would fix?
That's what I was wondering too...when I walk into the basement from outside and the HPWH is running, (same room) you almost have to walk over closer to it to tell if it's running for sure...not as quiet as a fridge, but close. I'm pretty sure the 80 gallon and the 50 gallon like mine use the same compressor too...just a bigger tank.
 
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laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
Yes, it's actually quieter in the basement. I've squeezed and followed around the unit and I havent found a single area on the outside that would quiet it. I can't hear it in the kitchen above but the sound radiates upstairs also. It's a humming sound. The fan itself is quiet and the compressor seems to be quiet.

I also am a little confused with the modes, but I ended up turning it up to 140 in energy saving mode. If the app is correct, I've used around 9 kwh since yesterday.

I'm considering getting some dynamat to maybe try to reduce the sound.
 

begreen

Mooderator
Staff member
Nov 18, 2005
88,198
South Puget Sound, WA
So......my wife came home in a poor mood with warm water for a bath, and the thing is noisy! I have it set at 140 and it will take a day or so for things to level out. The hum however is terrible.
Why no hot water? Our std hw heater is set to 130º and the water is plenty hot.

Well it's in! I'll be curious over the next couple months to see what happens.
Is this a Richmond (Rheem) unit?
 

laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
Why no hot water? Our std hw heater is set to 130º and the water is plenty hot.


Is this a Richmond (Rheem) unit?
Yeah it's a Richmond unit. Originally I had it set in heatpump mode only and was playing with the settings. It's now set at 140 in energy savings, which I realize uses both the elements and heatpump. Today things seem better so hopefully......

My wife takes scolding baths and we have a deep curved tub which has a capacity of 62 gallons. If it's not hot, she isn't happy!
 
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begreen

Mooderator
Staff member
Nov 18, 2005
88,198
South Puget Sound, WA
Ah yes, that would explain the slower recovery. You might be able to go heat pump mode in summer if the incoming water is warmer and a cooler shower is more refreshing than a hot bath.
I was thinking maybethe hum is due to vibration being transmitted thru the pipes. It looks like the unit is hard plumbed without any expansion couplings. I wonder if adding them would reduce noise transmitted via the plumbing.
 
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laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
Ah yes, that would explain the slower recovery. You might be able to go heat pump mode in summer if the incoming water is warmer and a cooler shower is more refreshing than a hot bath.
I was thinking maybethe hum is due to vibration being transmitted thru the pipes. It looks like the unit is hard plumbed without any expansion couplings. I wonder if adding them would reduce noise transmitted via the plumbing.
I thought the same thing about the vibrations. It wouldn't cost much to add a couple fittings and do flex lines. I notice that all of the noise comes from the intake side of the unit.
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,674
Wisconsin Dells, WI
My wife takes scolding baths and we have a deep curved tub which has a capacity of 62 gallons. If it's not hot, she isn't happy!
Sounds like the real problem is the wife! ;lol
 

woodgeek

Minister of Fire
Jan 27, 2008
4,373
SE PA
140°F is way too hot IMO for a HPWH.

I've kept mine at 120°F for 8 years now, and its still too hot to shower in (without a little CW added) when it comes out of the tap.

The COP drops hard as the temp rises. Heating the water from CW to 90-100°F has a super high COP like 5. Its pushing the last few BTUs into the HW that is so hard. This is also why we would never use solar or a 'tempering' tank to preheat water into a HPWH... terrible payback.

At higher temps, you will also get more scale and work the compressor harder (higher refrigerant pressure). I've flushed mine, and I have never seen any sediment come out.
 

laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
Sounds like the real problem is the wife! ;lol
I won't comment lol! I'm unsure to set to high demand about an hour before she comes home or energy saver (which gives time before her bath). If momma ain't happy, nobody is!
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,674
Wisconsin Dells, WI
If momma ain't happy, nobody is!
I hear ya, except being the hard headed person I am I tend to buck that way of thinking more than I probably should. ;lol Guys gotta keep some of his pride and not totally give into all the emoting. ;)

In fact, we'd still be burning LP if I hadn't "fought like hell" to put a wood furnace in. Now I get scolded if I don't have a fire going and the house is under 70. You bet I remind her of that too. ==c
 
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begreen

Mooderator
Staff member
Nov 18, 2005
88,198
South Puget Sound, WA
I thought the same thing about the vibrations. It wouldn't cost much to add a couple fittings and do flex lines. I notice that all of the noise comes from the intake side of the unit.
If you do go for braided flex connectors, seek out the highest quality possible and hopefully made in the US. I've had a failure with the stainless braided flex supply connectors from the hardware store. It wasn't pretty. Check the PSI rating. Fluidmaster makes some that may be ok. They have a longer warranty and higher pressure rating.
 
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EbS-P

Minister of Fire
Jan 19, 2019
799
SE North Carolina
I thought the same thing about the vibrations. It wouldn't cost much to add a couple fittings and do flex lines. I notice that all of the noise comes from the intake side of the unit.
Look into the ducting kit to purchase or make something your self. The intake could be then pointed in a better direction and insulated with sound insulation. They even sell duct silencers.
 

laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
Look into the ducting kit to purchase or make something your self. The intake could be then pointed in a better direction and insulated with sound insulation. They even sell duct silencers.
I thought about this. I do need to duct the unit for the exhaust blows on the ductwork. The noise comes from the intake, which I can duct more towards the floor. It will take some thinking, but I noticed it doesnt always run. Unfortunately it has to run when my wife get home lol.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,276
NE Ohio
I agree with isolating the hard plumbing if you are getting a hum noise upstairs.
We have ours set on heat pump only mode, set at 120*...my wife likes hot showers (she adds almost no cold...I can't stand it that hot!) and we have had very little issue with it keeping up....but it sounds like you guys use more hot water than us too, so...
 

velvetfoot

Minister of Fire
Dec 5, 2005
10,055
Sand Lake, NY
5 people in family and a soaking tub, daily, and propane infrastructure exists? Shoulda gone with propane.
 

EbS-P

Minister of Fire
Jan 19, 2019
799
SE North Carolina
In hybrid mode my compressor does not run when elements are on. This is probably the least efficient time of year for the heatpump side. Lowest incoming water temps and lower basement temps make means your compressor is running longer. I have often thought It would be a good feature to be able to set a time of day when the heat pump would not run.
Here is my rough estimate of how long it would take to heat up 80 gallons to 140F. I chose 1800w because the rated COP of the heat pump is probably close to 3 and runs at close to 600 W. The electric elements may be able to get to temp in half the time. And the quick recharge element could get the top of the tank up to temp even faster. YMMV. I’d be putting low flow shower heads and sink aerators throughout the house, and use the dishwasher delay if you have it just to make sure she is always happy

Evan
 

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laynes69

Minister of Fire
Oct 2, 2006
2,596
Ashland OH
5 people in family and a soaking tub, daily, and propane infrastructure exists? Shoulda gone with propane.
The house had a propane water heater years ago. When the wood furnace was installed, it took place of the water heater. We use a 500 gallon tank of LP about 4 to 5 years before filling. We have a 5 burner stove, furnace and dryer.

What I don't understand is having a 72 gallon tank showing full capacity and run around 30 gallons before the temperature drops off quite a bit. I'm saving alot of money and if I need to run high demand around bath time, I guess that's what I'll have to do. Our unit does run the compressor and elementa at the same time.
 
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Brian26

Minister of Fire
Sep 20, 2013
603
Branford, CT
140°F is way too hot IMO for a HPWH.

I've kept mine at 120°F for 8 years now, and its still too hot to shower in (without a little CW added) when it comes out of the tap.

The COP drops hard as the temp rises. Heating the water from CW to 90-100°F has a super high COP like 5. Its pushing the last few BTUs into the HW that is so hard. This is also why we would never use solar or a 'tempering' tank to preheat water into a HPWH... terrible payback.

At higher temps, you will also get more scale and work the compressor harder (higher refrigerant pressure). I've flushed mine, and I have never seen any sediment come out.
This is good advice. I connected my electricity monitor to my GE Geospring and monitored it for a year once. I was surprised how much less it ran turning the temp from 130 to 120. I only run it in heat pump only mode.

Also, make sure you flush and check your anode rod on your heat pump water heater. My anode rod was completely gone after 5 years.
20190713_090154.jpg
 

EbS-P

Minister of Fire
Jan 19, 2019
799
SE North Carolina
The house had a propane water heater years ago. When the wood furnace was installed, it took place of the water heater. We use a 500 gallon tank of LP about 4 to 5 years before filling. We have a 5 burner stove, furnace and dryer.

What I don't understand is having a 72 gallon tank showing full capacity and run around 30 gallons before the temperature drops off quite a bit. I'm saving alot of money and if I need to run high demand around bath time, I guess that's what I'll have to do. Our unit does run the compressor and elementa at the same time.
That seems suspect only getting half capacity of hot water. Quick thoughts are it’s not really 140F (easy to check) or the incoming cold water is really mixing and the tank is not staying thermally stratified. Only thoughts there are, something is not right with your tank internally or just a guess you water pressure is really high and the tub has fast flowing filler so the tank is really getting stirred up.
We can fill our large soaker tub up and the water temp doesn’t change. Run another bath for kids and dishwasher and it starts to cool off fast. Worth looking into.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,276
NE Ohio
You can pull up the internal tank temps on the display on this unit...it shows both lower and upper tank temps...