HPHW Heater vs What do I have now?

DefStatic

I apologize as HVAC is not my thing. I am fairly technical though so I can try to answer any questions that would help get me the best answers.

I live in Northern New England in a house built in 1960. Family of 4. No dishwasher. Kids do take baths which they put a strain on my setup now.  It's ok insulated home. Not bad not great. I purchased it 5 years ago and when we did the first walk through the realtor noticed the boiler setup and said it was brand new and considered the Cadillac of boiler setups. I can get any and more info asked. 

Long story short this is out heat source for the home as well as hot water. From what I understand the setup is considered indirect oil hot water? From what I understand it's a 95% efficient setup. The basement is an unfished basement that get pretty cold in the winter, I would say about 55f which I plan to start monitoring. And stays fairly cool in the summer. When I fill my oil tank up towards the end of winter (around April/May) I never have ti worry about it again until November. I've never really watched it well enough to really measure my usage.

My state has a program right now where you can basically get a HPHW setup for nearly free. However electricity prices are going up as well. IDK if in these crazy times if when petroleum goes down again if electricity rates will as well. 

Anyways, I am trying to figure out if a HPHW setup is right for us or not. Before the price of oil skyrocketed I was spending about $1600 a year on oil. From what I have read, HPHW makes sense in places where it is warmer, not so much where it was colder. 

I guess i just don't know enough about HVAC to make a decision and I don't trust the people who are contacting me to install these HPHW devices. 

Am I better off keeping my current setup? Would I be breaking even switching ot doing better or worse?

Also, should I be doing any maintenance on my current hot water tank?

Rich_49

If the unit will be in your cold basement I would not suggest it since you already run out / fall short of hot water now . What kind of boiler , Make model and indirect water heater do you have now . Just because the state or whatever agency has some rebates does not mean you have to be their prey in an attempt to take advantage of a program . NOTHING is FREE and the incentives and rebates everyone offers are poorly thought out and executed and were designed to benefit those who manufacture and distribute , not the end user

Jamie Hall

I would say that there are situations where heat pump water heaters make good sense. I'm not at all convinced that yours is one of them. If your present usage pattern puts a strain on your present hot water, in fact, a heat pump hot water heater won't help. What happens with them is that when there is a fairly significant use -- such as, for instance, a nice warm bath -- they switch to electric resistance heat to try and keep up (or they simply don't keep up), and electricity is expensive, as well as not being particularly green (not as green as your oil burner, for instance) unless it is being used in heat pump, not resistance, mode.

So I'd send the dream merchants on their way, and stick with what you have -- which does, indeed, sound as though it is one of the better systems out there.

DefStatic

I dont want to get into a debate and I agree that sometimes things benefit one thing or another, and sometimes things aren't black and white.

I never really paid attention to this stuff as much as I should and maybe I should have been. Apparently I have a SuperStor Ultra Stainless Steel Indirect SSU-45. This is heated by a Riello 40 F3. All of this was installed right before I bought the home including the 280 (I think) gallon tank. I have it cleaned every two years and the guy always says it looks good and I watched him do it once and he seems to do a very thorough job.

I am guessing the tank is 45 gallons which might explain some things. The only time I struggle with hot water is when my kids take a bath. 

What I am also seeing is I don't know what tank they were installing, but if it's bigger than 45 gallons it better be fat and not tall because it would never work where the existing tank is. They would probably have to move the location to the other side of the boiler or something. The ceilings may be 6.5 feet and the existing tank sits on some blocks and has pipes inches above it.

From what I have read, HPHW makes sense for places below New England. The idea is sound.

Jamie Hall

They make sense in some applications in New England, too. But like so many other things the complete job has to be evaluated. The hot water heater is only one part of the system, and it all has to work together to meet the needs of the customer. It's not plug and play.

Larry Weingarten

Hi @DefStatic , In general, I'm a fan of heat pump water heaters, because it looks like we are getting rid of fossil fuels in the US, and why pay for equipment that may have to be replaced before it fails of "natural causes"? But, because of the cool basement and low ceiling height, it doesn't sound like a good fit for you. Perhaps a simpler approach for now, is to add a second tank to increase your hot water storage. Any well insulated tank should work. I like Marathon tanks because they stand up to aggressive water, have 3" of foam, and no need for an anode rod.

Yours, Larry

ethicalpaul

People here don't seem to want to hear this, but heat pump water heaters are amazing (at least my recent vintage Rheem is).

I have it set on "heat pump only" so it never goes to resistive heat. It costs me about 25 cents per day (two person household). My wife fills the soaker tub with 80 or so gallons and I've never had it run out of hot water.

I keep it at about 130 degrees a little hotter than the default setting.

It is near my boiler so it's plenty warm down there in the winter, and of course it's warm enough in the summer. It takes that heat and puts it into the tank. It takes a little moisture out of the air during the summer (condensation goes to my utility sink next to it).

I bought it from HD I think, free delivery, installed it myself (plug and play) in 2020, had it inspected by my town, and got a nice state check from new jersey.

There's a nice app that gives usage data. Here is last month:


Just get a large size if you're worried about using a lot of hot water, then it can recover at night.

To burn oil ALL SUMMER to heat your domestic hot water via a massive iron boiler and then pay again to remove that heat from the house with A/C is insane to me but people keep wanting to do it, I have no idea why. Your situation does sound different in that you have less waste heat from your boiler, but if your current boiler is straining to heat your water, I think this is a good option.

Jamie Hall

As I said in the other current thread on this topic, it depends on the application. In some applications -- such as yours, @ethicalpaul , they work well -- sometimes spectacularly well. In others they don't work satisfactorily, if at all. You absolutely have to evaluate the whole picture.

EBEBRATT-Ed

It's like a mod con.

It's great while it works

When it breaks it will cost more to fix/replace that all the energy savings it saved


And who will fix it? the average homeowner isn't going to buy a vac pump and recovery machine to fix a refrigerant leak,

A plumber can't fix it

It's a complicated machine that will need an HVAC tech or appliance technician to fix

So it becomes a throwaway like a refrigerator

And it has to be in a basement that can absorb the cooling effect.

California, down south fine go for it

ethicalpaul

I have a 5 year warranty, they send a tech if needed. It is exactly like a refrigerator or a dehumidifier, not too complicated. I've never had a fridge fail due to a refrigerant leak, maybe I'm just lucky.

There's no noticeable cooling effect. Mine can't tell it's not in California or down south.

I'll let you all know when it breaks. How long are NG water heaters lasting these days? And how repairable are they when they start to leak?

EdTheHeaterMan

If you are getting a new HPWH for "Nearly Free", then I would go for it. BUT I would not remove the SuperStor. I believe that has a limited lifetime warranty... (it's going to last a long time)

I would keep both and do some creative piping to install both tanks to have the ability to be the primary heat source leaving the other tank to be a buffer or "pre-heating to room temperature" tank. This way you don't have to take the Cold water directly into the water heater and the primary water needs not require a 70° temperature rise, but reduce it to a 55° or 50° rise. This will result in a slight increase in recovery time, and you may even be able to operate on HP only without electric backup.

If you discover that the Almost Free Tank is insufficient for your needs, you can operate both sources to increase your total demand for DHW.

here is the piping arrangement is suggested for a similar post on this forum

See how the A tank (your new Almost free tank) is the primary.



In this configuration the The B tank (the existing SuperStor) can be the Primary.

In both cases the pre-warming tank is still used to keep the water from being stagnant and reduces the possibility of bacteria forming. A manual switch must be added to the SujperStor thermostat to cut off the need to use the oil burner to heat that tank when used as the pre-heat tank.

If the State is giving away stuff, you might as well take it. (you already paid for it in your utility bill anyway).

Mr.Ed

Dave H_2

So, its a situation of "if it aint broke, don't fix it"

Indirect tanks typically have a long life. If the existing system needed replacing, then yes consider it. However your DHW system may just need a little tweaking in order to get more out it.

I would consider installing a thermostatic mixing valve to the delivery side and bumping up the storage water temp to give you more hot water if the current situation is struggling to keep up with demands.

Also, if it's fuel economy you are looking for, just make sure the boiler and equipment are tuned and setup properly....cold start, outdoor reset, are a few things that can be added for relatively few dollars.

Dave H

JakeCK

In agree with @EdTheHeaterMan set it up so you can use both. Winter run the boiler and indirect and heat with that. Ultimately the heat the HPWH gets comes from that anyways. In the summer shut down the boiler and let the HPWH do the work. Get the largest tank you can fit down there. 

DefStatic

First I want to thank everyone for responding. I feel I have learned a bunch and feel a little better about whatever way I go.

I do of course have a bunch more questions now... I should say this is an even tougher decision because recently my state allowed PUs to Jack all the electricity rates. Nearly everyone in the state not on low income power saw their electric bills double. 

It's a 45f day outside and my basement near my boiler is 58f. I have never really monitored this, but I would imagine on a really cold day that fluctuates a bit lower. Possibly right at 50f. Isn't that going to make a HPHW less efficient?

With thar said, in the summer, while I use obviously WAY less oil, it obviously has to come on every time I drain my existing tank. How much does that really heat up the rest of my house causing me to use more AC?

Jamie Hall

The rise in electricity rates shouldn't surprise you. It does cost money to create electricity, and someone has to pay for it.

The basement temperature will have a small -- but very small -- effect on the heat pump efficiency. Not something to worry about. As to heating up the rest of the house, no -- although it may reduce the rate at which the house cools. However, that said, a heat pump water heater won't warm your basement any more than any other water heater would -- possibly less. Running the boiler does, but the effect is small.

JakeCK

DefStatic said:

First I want to thank everyone for responding. I feel I have learned a bunch and feel a little better about whatever way I go.

I do of course have a bunch more questions now... I should say this is an even tougher decision because recently my state allowed PUs to Jack all the electricity rates. Nearly everyone in the state not on low income power saw their electric bills double. 

It's a 45f day outside and my basement near my boiler is 58f. I have never really monitored this, but I would imagine on a really cold day that fluctuates a bit lower. Possibly right at 50f. Isn't that going to make a HPHW less efficient?

With thar said, in the summer, while I use obviously WAY less oil, it obviously has to come on every time I drain my existing tank. How much does that really heat up the rest of my house causing me to use more AC?

Not an expert, just a home owners views.

Yes, cooler ambient temps in the winter will hurt it's COP. So will the drop in supply water temp later in the winter. The water coming into my house goes from the low to mid 60's in late summer to upper 30's in late winter. Another reason you want to run the indirect in the winter. It will take considerably longer to recover in February then summer. Like wise the HPWH will help to cool the house and if you run a dehumidifier it will lighten the load on that as well in summer. And that's a two for one benefit there. Dehumidifiers use electricity to lower the RH by both removing moisture and rasing the temperature. Laws of conservation dictate that in the summer the energy usage to heat my hot water from the ambient heat in the house will negate the energy used by my ac to cool the house by the same degrees and it's actually double energy saved when it comes to the dehumidifier since I use energy to remove the moisture and raise the temp and then use energy to remove that heat. My dehumidifier will bring my basement up to 80 degrees all summer long, and I try to keep the house in the mid 70's. 

And I bet everyone would be surprised by how much heat leaks from an indirect in the summer. My old boiler has a standing pilot on it that I turn off in spring. I also have a couple temp sensors strapped on to the return and supply lines coming right off the boiler. I can see a decent rise in temperature with that pilot lit vs off. That is heat that is getting directly shuttled to the rest of the house all summer long if left on. Now you won't have that issue with a pilot and you'll have zones that if piped correctly should isolate the house from the indirect, in theory. But nothing exists in a vacuum. I'd be willing to bet an indirect at 130f dumps more heat into your house via the closed valves all summer long than my standing pilot does. 

This summer I really hope to install a reverse buffer tank to resolve some issues with the oversized boiler and use it for DHW in the winter for for these reasons. I installed a HPWH in October and have been happy with it for the most part. My only gripe is that it keeps forgetting the schedule but that might be caused by voltage fluctuations. I've complained to CEI multiple times for that. Makes all my UPS' go nuts too.

EdTheHeaterMan

DefStatic said:

With thar said, in the summer, while I use obviously WAY less oil, it obviously has to come on every time I drain my existing tank. How much does that really heat up the rest of my house causing me to use more AC?

This illustration I made for another post but it explains two of the ways operating the boiler in the summer will add to your AC cost.

1. Adding the actual heat of the flame to the boiler to make DHW. Once the water tank is satisfied, that leftover heat dissipates into the home.
2. During the run cycle, and for some time after shut down, the chimney draft is removing air conditioned air (you paid to cool) from the home. That air is replaced by infiltration, unless you have a fresh air recovery system or are using a direct vent (with outside combustion inlet). This infiltration is indicated by the blue arrows.

Your oil or gas heater needs combustion air for proper operation. and since it is vented to the outdoors, at some point in the cycle, the combustion air must therefor, come from outside.

DefStatic

It seems like the concensus is either I should stick with what I have or run some sort of hybrid setup. That my indirect setup is probably better for the winter and the HPHW better for Spring Sunmee Fall.

And someone mentioned the water temp in the winter. I forgot about that. Come November suddenly you don't need to add any ice to the water because it is so cold LOL.

pecmsg

Your basement should be around 55° + or -5° unless it's really leaky.

What temperature is the super store set for? Is there a mixing valve on the outlet?

Heat Pump water heaters work and work very well, the problem is
a) lowering the basement ambient
b) Recovery time, it will need several hours to reheat all the water and
c) finding someone that can work on them. Finding someone that understands air to air is getting difficult, air to water is pushing it.

If replacing an electric water heater, it's a No Brainer a super store I wonder in the winter is it worth it?