Hot Water Tank Efficiency

[BrokeFarmerJohn]

Thinking about replacing my hot water tank, my current tank is a 40g, it's a Rheem offbrand and says it uses $503 per year average.

My tank works just fine, this is solely for energy efficiency.

The unit that caught my eye was this

Rheem Performance Performance Platinum 5-Gal. Hybrid Electric Tank Water Heater—High Efficiency, Mobile Alert Compatible and 1-Yr Wty XE5T1HD5U at The Home Depot - Mobile

By my estimates based on average usage, it will take a bit over 4 years to pay itself off at that price, I will be ordering a tank threw a supply house at a much cheaper rate for the same product.

That being said what are your guys thoughts? Worth fooling with?

Basically my current uses for hot water are showers and faucets, I buy tide cold water and have been happy with how cloths come out not to use hot water in the Maytag front load washer.

If I can buy a tank that will pay itself off in let's say 4 years or less and efficiently works for 10-15 years, I feel that's worth doing.

My current water set up is city water, I have a whole house carbon wrapped 10in filter off the main. I put in a CSI duel tank water softener last year, it runs threw that and goes into the hot water heater. So the tank should last a long time with minimal limescale.

Also I will be converting the furnace to a high efficiency 92% I believe natural gas furnace and keeping the heatpump, that will run off my Honeywell 8000 series Tstat with a wired outdoor sensor, I want to set it to just run emergency heat under 32 degrees. I could also convert the hot water tank to natural gas if I wanted but I feel that would be more effort than it's worth.

I will be doing all this myself so my cost is only supplies.

 

[kenmac]

The only way I know of they can get more efficiency out of the WH is lower amp draw from the elements (smaller elements) and add insulation to the tank.
You could do this with your old tank.

I remember when they boasted about higher efficiency out of a gas WH. What they did was to basically go from a 40,000 BTU imput burner to a 32,000 imput burner.
It effected recovery rate of the WH

 

[shui5612]

Only thing more efficient about this hot water heater compared to a normal one is that the "normal" (cheapest) ones come with less insulation however if you get the slightly upgraded version it would have the same insulation as this one.

There are hot water tanks that use an Air conditioner circuit in reverse to heat the water and cool the air at the same time, making them more efficient than standard hot water tank heaters. I believe Sears made one. Downside is that the room gets cooled and if you live in a cold climate then the heating will cost the same (unless you're heating off natural gas or propane, then it becomes debatable).

Will this "smart" heater save money? Only if you program it so that it is on when you need water and off when you don't (I.e. at night) but a regular timer could do the same for a lot less.

In my opinion, I would go for a normal hot water tank, not the "cheapest" version but something like a "plus" or "extra" model that has the cold water intake at the bottom, with good insulation,buy a sheet of 2" rigid foam and place the hot water tank on it, then get a roll of "double bubble insulation" which is essentially two layers of bubble wrap with a layer of aluminum foil on either side and wrap the boiler with it, and then add a timer which you can program.
This will result in the most insulated, efficient tank for your money that you should replace every 10 years.
I would like to add that if your hot water tank is located someplace cold then the added insulation will help a lot. However if it is stored in a location that is kept above 15C or 60F then the break even point will only be at around the 7-8 year mark (insulation alone) when you include the cost of insulation. And around 5-6 years with the timer and insulation. (This is compared to a standard hot water tank).

I'm not sure if they sell Giant hot water tanks near you but they have a model called the EcoPeak which has 3 elements instead of 2, one for 800w another at 3000 and the last one at 3800. The idea is that it can turn on the 800w one to maintain the heat. And if it senses that the temperature falls below a certain limit it turns on the 3800w one only.
Other hot water tanks may have 1 element at 3000w or two by 1500w. Which usually turn on at the same time.

Just throwing an idea out there since that hot water tank will cost less than the one you posted but more than the standard one.

Hope I helped

 

[BrokeFarmerJohn]

All About Heat-Pump Water Heaters | This Old House

Here's more about the heatpump water heater.

In HVAC the most efficient source of heating is a heatpump above 32 degrees.

 

[kenmac]

Well, If you want the cold water intake to enter at the bottom (dip tube does the same thing on the standard WH)
You just remove the drain cock, add a T ,plumb in your cold water line to the T,and re install the drain cock

 

[Raspy]

I personally would never buy that Rheem heat pump water heater. It is very complicated and if even a small sensor goes out, you'll be paying a service call so your phone can get updates from the water heater. It's big risk to think this thing will actually save you money in the long run. BTW, it has a standard electric element in it too, so the savings may be less than you expect.

If you are interested in using less energy, but don't care so much about the cost, it may work if you use it in the most effective way. Read the reviews before you buy one!!!!! If it is not 100% reliable, it will frustrate you and cost a lot more in the long run.

So many people these days are looking for connectivity. If you are willing to pay for it, fine, then ten years from now when the water heater starts to leak, it will call your phone. That to me is absolutely crazy. And by then you will have paid for it a couple of times in service calls. Be sure to download the ap, so that in ten years it can call you. And to make sure that is how you notice the leak, don't look at it as you walk by it every day, wait for it to call you.

If you want true efficiency and are willing to pay for it, try a solar hot water system that preheats your water before it goes to the water heater. The most satisfying showers have water heated by the sun. I turn my electric water heater off for about eight months a year.

 

[Tractor Seabee]

Number and size of elements and burners are only relevant to recovery time, not efficiency. It takes X BTUs to heat a gallon of water to the set temperature. Those BTUs equate to KW for electric and CF for gas. Energy source selection effects cost; each fuel has a BTU content and thus a price per BTU. That difference varies a lot depending on location and prices for the various energy sources. It is not simple as you would think, to decide. The most expensive energy is that which is wasted. They make furnaces and WHs that are 98% efficient. My WH choice is the on demand condensing (98%) type if using gas. My school is still out on the heat pump type electric WHs.

We are currently looking at houses after selling the ranch and downsizing. I will replace WH, furnace, and AC no matter what we buy, probably with gas source. On demand WH naturally. For HVAC my choice is the Variable Refrigerant Flow VRF) Heat Pumps. They operate down to 0 degrees outdoor temp so no maxillary heat source is needed here in my area. I have been doing a lot of research on this subject.

Ron

 

[Deere Dude]

If you are getting NG for your furnace I would get a 40 gallon NG water heater. They are cheap to operate and with a quick reheat time.

I can't believe you will use $150 a year for gas, unless you leave the hot water valve on all the time.

We burn wood for heat in a fireplace but have a gas furnace, a gas stove and LP gas water heater. For the whole year the gas bill was only $150 or so, with very minimum furnace time.

We just got a new LP water heater from Home Depot instead of Lowes because the reviews were very good on their heaters.

We put the heater in our garage to save room in the house and I did not put extra insulation on it, but we are in Tennessee. We can go camping for a week and just leave the pilot on and the water is still hot when we come back. Those heaters are insulated very good from the factory.

 

[BrokeFarmerJohn]

I personally would never buy that Rheem heat pump water heater. It is very complicated and if even a small sensor goes out, you'll be paying a service call so your phone can get updates from the water heater. It's big risk to think this thing will actually save you money in the long run. BTW, it has a standard electric element in it too, so the savings may be less than you expect.

If you are interested in using less energy, but don't care so much about the cost, it may work if you use it in the most effective way. Read the reviews before you buy one!!!!! If it is not 100% reliable, it will frustrate you and cost a lot more in the long run.

So many people these days are looking for connectivity. If you are willing to pay for it, fine, then ten years from now when the water heater starts to leak, it will call your phone. That to me is absolutely crazy. And by then you will have paid for it a couple of times in service calls. Be sure to download the ap, so that in ten years it can call you. And to make sure that is how you notice the leak, don't look at it as you walk by it every day, wait for it to call you.

If you want true efficiency and are willing to pay for it, try a solar hot water system that preheats your water before it goes to the water heater. The most satisfying showers have water heated by the sun. I turn my electric water heater off for about eight months a year.

The connectivity stuff is extra and not something I care about, that's why I went with a wired outdoor sensor and 8000 series Honeywell that is not wifi, I like smart stuff that's wired.

This tank essentially takes heat out of the basement air to heat the water down to a 67 degrees air space. It dehumidifies that space also. So it would actually help with cooling in the summer being I have a return down there which is currently closed off. In the winter I will have a cold basement but that happens already, it's unfinished anyway.

No service calls, I can service the unit, hot water tanks are simple, add the heatpump and it's no different than any other system just smaller. My background is in HVAC, I'm universally certified so that doesn't bother me, the heatpump will be hermetically sealed anyway, would only fail if something catastrophic happened to that loop. If that happens I can braze in a new coil or replace the compressor if needed ext. so that part doesn't scare me.

 

[BrokeFarmerJohn]

If you are getting NG for your furnace I would get a 40 gallon NG water heater. They are cheap to operate and with a quick reheat time.

I can't believe you will use $150 a year for gas, unless you leave the hot water valve on all the time.

We burn wood for heat in a fireplace but have a gas furnace, a gas stove and LP gas water heater. For the whole year the gas bill was only $150 or so, with very minimum furnace time.

We just got a new LP water heater from Home Depot instead of Lowes because the reviews were very good on their heaters.

We put the heater in our garage to save room in the house and I did not put extra insulation on it, but we are in Tennessee. We can go camping for a week and just leave the pilot on and the water is still hot when we come back. Those heaters are insulated very good from the factory.

My dad is pushing a NG tankless system, its yearly rating is an average $174, the heatpump tank is $151.

The heatpump water heater has a lifespan of 10-15 years, the tankless can be twice that. What I'm not a fan of is punching another concentric out the back of the house, I will already have one for the furnace, there draft induced flue so they can't be tied in together. Plumbing the gas line would be no prob.

So for that reason I'm trying to avoid a NG water heater.

 

[BrokeFarmerJohn]

So I did some math today and it looks like this, some mistakes on it but I'm not rewriting it lol.

So that's the total KW usage of last year, they say that the hot water tank is an average of 18% of the bill, I used that in this figuring.

Long story short I'm looking at 8.5 years to make my money back on the heatpump tank at the home depot price. With the supply house I would guess that would be closer to a 6 year return on the investment after it's all said and done. But that's all based on my current usage, there's only two people living here right now, if kids come later the savings would be sooner. The heatpump tank is 3.3x more efficient than the current tank.

 

[CADplans]

That water heater is a "heat" - "pump",,,

Like a hydraulic pump moves oil,, a heat pump moves heat.

So, if you have a hydraulic pump,,, and the hydraulic pump empties the oil supply tank,,,
what do you have to do?,,, You have to get more oil.

When a heat pump removes the heat from your house to warm the water in the winter,,,
guess where the heat will come from to replace the energy the heat pump water heater grabbed.

You guessed it,, your heating system has to replace the heat the water heater grabbed.

I guess these would be a good concept where you only need to air condition your home?

 

[Zerk]

Scrapping a good item, spending money to buy something more efficient, is typically a bad idea . Unless you are doing it to save baby penguins, and not save money.

This comes up a bit with cars. People think just cause the new car will save them $50 month, it is worth spending thousands


4 year pay back sounds poor to me. Wait until dies.

 

[BrokeFarmerJohn]

That water heater is a "heat" - "pump",,,

Like a hydraulic pump moves oil,, a heat pump moves heat.

So, if you have a hydraulic pump,,, and the hydraulic pump empties the oil supply tank,,,
what do you have to do?,,, You have to get more oil.

When a heat pump removes the heat from your house to warm the water in the winter,,,
guess where the heat will come from to replace the energy the heat pump water heater grabbed.

You guessed it,, your heating system has to replace the heat the water heater grabbed.

I guess these would be a good concept where you only need to air condition your home?

You are correct on that but If the basement is below 67 degrees or where ever that cut off is, it runs in normal mode so during the winter months it will prob just run mostly in normal water heater mode.

Yes in a warm climate this type of system would do very well, I'm thinking to fully utilize the cooling, it would need to be in a open space with a return near it and no supply, the non conditioned air would have to be pulled threw a door or something to reheat the space around the tank, that way it would work in sync with the A/C.

Put it in a closet and it would cool the space too quickly and just use regular mode until the heat loss from the unit reheats the air.

 

[BrokeFarmerJohn]

Scrapping a good item, spending money to buy something more efficient, is typically a bad idea . Unless you are doing it to save baby penguins, and not save money.

This comes up a bit with cars. People think just cause the new car will save them $50 month, it is worth spending thousands


4 year pay back sounds poor to me. Wait until dies.

A 4 year payback is pretty good actually, if you look at a new furnace and A/C that someone can spend 6-15k on, there return is often 10 years or more on a system that will last 15-25 years.

But there's also government tax rebates and a increase in property value, that can be calculated in the cost of replacement as well.

My electric furnace works just fine but granted I'm swapping that with a used NG 92% efficient unit that was pulled off a job site. It's sitting in my barn and is 8 or 9 years old I think. It will cost me plumbing in the concentric, gas line and a new A/C coil because the old one is too wide so I'm gonna cut it out and braze me in a new one that matches this furnace.

I like my heatpump but the emergency heat strips aren't efficient what so ever. The new heatpumps are good running down to 0 but I'm cutting mine off at 32. I feel below 32 I'm just trading dollars for hours on my equipment.

With my smarter Tstat I put in, I don't need a fossil fuel kit either, the stat is smart enough to keep the heatpump off while the furnace runs, only exception is defrost mode, the reversing valve clicks to A/C and the furnace has to run to compensate while the exterior coil thaws.

 

[Zerk]

A 4 year payback is pretty good actually, if you look at a new furnace and A/C that someone can spend 6-15k on, there return is often 10 years or more on a system that will last 15-25 years.

Who told you, those were a good idea?
4 year may be so-so. But 10-15 years is stuff I am not allowed to say about people.

Could you imagine if your 401k took 10-15 years to double?


Replacing something that works, typically just feels good.

Refrigeratorsee are big consumers. Spending $$$ your lamp is again words I am.not allowed to use.

Problem is people don't want to feel dumb, or admit it. So they don't admit it.

Most can't do math. The ones that attempt to, often get question numbers. Put to questionable use.

Remember I'm school how story problems kicked everyone's butt. Life is a story problem.

Average, means most people.

 

[BrokeFarmerJohn]

Who told you, those were a good idea?
4 year may be so-so. But 10-15 years is stuff I am not allowed to say about people.

Could you imagine if your 401k took 10-15 years to double?


Replacing something that works, typically just feels good.

Refrigeratorsee are big consumers. Spending $$$ your lamp is again words I am.not allowed to use.

Problem is people don't want to feel dumb, or admit it. So they don't admit it.

Most can't do math. The ones that attempt to, often get question numbers. Put to questionable use.

Remember I'm school how story problems kicked everyone's butt. Life is a story problem.

Average, means most people.

Financially investing it's not good, but the return in a home standpoint is a decent one.

I was always told that the worst two things to invest in are cars and houses lol. This proves to be correct.

I'm not going to replace my tank unless the return makes sense.

It's funny because I looked up what the cost of the supposedly high efficient hot water heater yearly usage is and its higher than the one I have! I'm like F that, until I came across the heatpump heater and liked the idea of it, but at the end of the day it's still a metallic tank that has a expiration date.

Rheem does have a nonmetallic tank that they claim will last forever and has a lifetime warranty on. But I wouldn't gain anything by switching to that tank, it's usage is about the same as mine if not a little more.

 

[BrokeFarmerJohn]

Marathon Water Heaters by Rheem

Rheem Marathon 5 Gal. Lifetime Warranty Electric Water Heater with Durable Design MR5245 at The Home Depot - Mobile

That one uses $50 a year more electricity compared to what I have now. But I found the technology to be interesting.

 

[Zerk]

Why do you think investing in stock market and investing in house is different? Either way you are taking chunk of money out of your savings to buy something.


If the return on a furnace is so far out that you could put that money in a mutual fund and be ahead, then you have more money.

You have to factor in taxes, installation cost, ect.

Like I said, buying another car to save gas, when you have one is often a bad idea. But it feels good. To someone who doesn't think much they are saving money every day.


The averase person can't do math. The heart wants what it wants.

 

[BrokeFarmerJohn]

Why do you think investing in stock market and investing in house is different? Either way you are taking chunk of money out of your savings to buy something.


If the return on a furnace is so far out that you could put that money in a mutual fund and be ahead, then you have more money.

You have to factor in taxes, installation cost, ect.

Like I said, buying another car to save gas, when you have one is often a bad idea. But it feels good. To someone who doesn't think much they are saving money every day.


The averase person can't do math. The heart wants what it wants.

I just looked, my tank is a Richmond and manufacture date is in 2012 so it's 4-5 years old. Unless I find a tank that blows mine away on efficiency, not likely to justify replacement, I still have 10 years of life on this one, maybe more.

Due to water issues I have had to replace the elements in it twice. That's been resolved since I replaced them this last time.