Electrical Usage Puzzle in Gardner, MA

[Potluck_Crew]

I'm multitasking, so if I list something you've already tried, forgive me for not reading carefully, but here's the low tech, non-spreadsheet, non-smartphone approach I'd use first in investigating the issue:

There are some metal roof valleys, and some entire metal roofs that are heated in a way that would not be visible from the exterior. They're normally thermostatically controlled and could use a ton of power once the weather gets cold. If you have thermostatically controlled heating tapes on your plumbing, that could also be the culprit. Heated downspouts and drain lines are included possibilities here.

It looks like you have an old style rotating dial meter. Those make it pretty easy to watch the usage change as you turn breakers on and off. I'd account for what any breaker that causes the meter to spin significantly in cold weather is doing with the power, starting with the 220v breakers. This would be best done at night when your solar is offline. Alternatively, turn off all of the breakers, and just turn one on at a time, maybe with the obvious big loads like the fridge, water heater, heat sources turned off or unplugged at the unit. You can measure most of those with your watt meter at the unit to know what they're up to.

I'd wonder what the mini-splits are doing. Could they be doing frequent power sucking defrosts? Could they be going into a backup resistance heat mode?

Slim chance, but I wonder about the hybrid HWH. The water temp coming into my house varies a lot seasonally, dropping to near freezing at mid-winter. Could colder water coming in be causing the HWH to kick into resistance mode frequently? I think that can be programmed out to test. I know my water heating load also goes up a lot in the winter, both because of cold inlet temperature, and because of the tendency to prefer warmed water when it's cold. Plus, anything mixing hot and cold for a desired temp (shower, washing machine) is going to need more hot and less cold for the same temp.

The thing about a hybrid HWH, is if it's using inside air, not only will the unit use power, but you're going to need some form of heat to replace what it's taking from the home, so you have to pay for the heat one way or the other in the winter. I would expect that to create a significant difference season to season all by itself. They're a good idea, that makes far more sense in the South, than the North.

Is your house lit up like a sports field inside and out during the long dark days of winter? Some I see I would need sunglasses to live in!

Have your kids secretly taken up cryptomining as a winter hobby?

Good watt hunting!

Thanks for your response! Gives us further ideas.

No roof or electrical heating tapes.

The rotary style meter is the solar production meter. The Net Meter is outdoors and is digital. If Net Meter were a rotary one, I could see testing it as you spoke of.

The mini splits, it is a mystery what they are doing. They are I believe about 15 years old. We turned almost completely off in late Dec. We've had some experience with a brand new mini split system in our old house, going through one year of use.

The hybrid HWH...I am awaiting a digital manual from Rheem. It is located in our basement, where hubby says temp is between 40 to 50 degrees since heating season began.(We do not have any heaters in the basement.) It is a 2014 model. Water is municipal supply with supply line coming in very close to heater. I do imagine it is much colder in winter than summer. We do have HWH set on the Energy Saver mode, which I believe will use heat pump feature and switch to electric when no longer efficient. Have it set at 120. It is good for one 10 minute shower.

Our house can shine brightly when my daughter visits, but not as a football field! We had changed all the bulbs to LCD before the Kwh usage went haywire. And have several motion sensor or timed lightbulbs in various locations(closet, rooms where lights are left on....). Several of the rooms have the built in ceiling fans with about 5 bulbs. But we don't burn all those bulbs!

It seems that our next step will be to install one of the Emporia Vue 2 monitors on the Main electrical panel. That will permit us to test all the appliances in questions. When I talked today to the Solar Rep at National Grid, she did not even know something like this existed. Thank goodness for this Forum!

And no to the Kids and Cryptomining! They actually live nearby(age 34-special need twins). Son only stops in when there is food offered and daughter stops in too much!

I have attached clarifying images of meter as well as the Solrenview data logger that shows up on web address: https://www.solrenview.com/SolrenView/mainFr.php?siteId=522

Thanks again, I will keep you updated.

 

[Potluck_Crew]

If your heat pump water heater has a setting that you can switch off the resistance back up heat (that most have), I'd do that and see what that does to your kWh consumption.

I am irritated that I don't have the manual and have to ask for it online. Likely did not come with a printed manual which is why the previous homeowner did not have. We are in the process of ruling out various systems. But thus far have only been able to test 110V appliances with our Kill A Watt! Looking at the Emporia Vue 2 suggested in the threads above. Then we can test the HWH!

 

[Potluck_Crew]

My heat pump hot water tank can be selected hp, hybrid, or resistance. It made a $80 jump in the electric bill when I changed it from hp only to hybrid...it got changed back!

Mine are energy Saver, heat pump, electric only. I guess my energy saver translates to hybrid. I want to see the operations specs in regards to min air temps before I test the hp mode. Our Rheem is located in our basement, which has no "official" heat, only the boiler benefit, and the radiant heat in the ceiling, although insulated under the radiant pipes. Temps rainge from 40 to 50 since the beginning of heating season.

I am awaiting the manual via email. Can't seem to find one online.

Thanks

 

[Potluck_Crew]

A 5 kW array in the northeast is is likely to generate, on average the energy a typical household generates in an average month. In MA, probably about 5.5 to 6 MWh/year.

I can easily see heat requirements via mini-splits or heat pumps for a 2000 square foot house running at 500 kWh in November and 1000 kWh (or more) in January. Add in electric hot water (colder input water means more electric usage to heat it, or use of electric resistance means to heat it instead of the heat pump on the water heater) and it is easy to see how your electric usage could go up a lot in the wintertime.

Our solar array historically has generated about 6.5 MWh the last 6 years according to our solar logging website.

We know how mini splits can cause increased usage in cold temps. We have one year of mini splits under our belt...outfitting our old house with them before selling.

We thought in Nov/Dec that we were using sparingly, not as the main source of heat...We shut all but one down. It is used about 2 hours a day. We are using Pellet stove and oil radiation & radiant as heat source mainly. Tested pellet stove using kill a watt. Max increase in Kwh about 125Kwh/month.

Boiler Kwh is unknown yet.

In regards to the the heatpump vs hybrid setting of Rheem HWH. What is the min efficient temperature? We have it on "Engery Saver" which I believe is Hybrid. Our basement is 40 to 50 degrees. Awaiting a digital copy of manual from Rheem.

We will be getting an emporia Vue 2 which will let us test the non 110V systems.

Thanks for your thoughts.

 

[Solarguy3500]

A 5 kW array in the northeast is is likely to generate, on average the energy a typical household generates in an average month. In MA, probably about 5.5 to 6 MWh/year.

I can easily see heat requirements via mini-splits or heat pumps for a 2000 square foot house running at 500 kWh in November and 1000 kWh (or more) in January. Add in electric hot water (colder input water means more electric usage to heat it, or use of electric resistance means to heat it instead of the heat pump on the water heater) and it is easy to see how your electric usage could go up a lot in the wintertime.

Agreed.

After reading through this thread again, I think it's likely there is nothing wrong or out of the ordinary as far as energy usage is concerned. @DBoon makes some really good points here, as others have as well. This time of year the solar is not contributing much. My 15.2 kW array only produced 355 kWh in January.

The thing that really caught my eye reading through the OP again is that there are 5 heat pumps that are 15 years old. I missed the 15 years old part the first time I read through. I think those are most of your culprit. 15 year old heat pumps are not nearly as efficient as newer ones and probably not cold climate ones, so they'd have to work really hard (use a ton of energy) for heating when the temps get low.

@Potluck_Crew you said earlier that you shut the mini splits off after you got the December bill, but in a more recent post you say you are still using one of them. I really think they are what is causing the majority of the high energy usage, as well as other things mentioned previously such as the water heater working harder due to colder inlet water, etc .

 

[Potluck_Crew]

Agreed.

After reading through this thread again, I think it's likely there is nothing wrong or out of the ordinary as far as energy usage is concerned. @DBoon makes some really good points here, as others have as well. This time of year the solar is not contributing much. My 15.2 kW array only produced 355 kWh in January.

The thing that really caught my eye reading through the OP again is that there are 5 heat pumps that are 15 years old. I missed the 15 years old part the first time I read through. I think those are most of your culprit. 15 year old heat pumps are not nearly as efficient as newer ones and probably not cold climate ones, so they'd have to work really hard (use a ton of energy) for heating when the temps get low.

@Potluck_Crew you said earlier that you shut the mini splits off after you got the December bill, but in a more recent post you say you are still using one of them. I really think they are what is causing the majority of the high energy usage, as well as other things mentioned previously such as the water heater working harder due to colder inlet water, etc .

Thank you.
The one mini split we use is for 2 hours a day to bring bathroom up to temp. Before the " Mostly shut down," had several hours a day on a couple of splits.

There are 3 outdoor units, installed in stages. I don't think I have in the house paperwork the install info. After solar install, which was 2008. Will have to see how I can document ages and such! I will have to wade through snow for outside look at one of the units.

We will be getting that Vue 2 monitor and it will help to give us some answers! Thanks!

 

[Brian26]

The Vue 2 will let your figure it out easily. Its also been extremely cold in New England the last month and the Fitchburg Airport which is the closest climate station to you was way below normal. Your hot water heater and boiler have been working way harder than normal especially with all the well below normal night time lows. Its just simply been a really cold month. I bet there have been many nights where your boiler has been running nearly continously.

 

[RockyMtnGriz]

FWIW, I just got a meter installed this fall that appears all but identical to your service meter. Mine is not a NET meter, but the same otherwise. Mine has 3 or 4 little bars at the bottom left that mimic the movement of the old spinning disc. They move left to right, then annoyingly disappear for a while before starting at the left again as power is consumed. It's not as easy to judge load as the good old disc, but still possible. You might check to see if yours has them too. Worst case, there's patience combined with the KWH counter.

When you say that your HWH has a "heat pump" mode, that makes me think that it's at least part of the issue. I'm almost certain that it's going to be able to run the backup resistance elements in "energy saver" mode. Plus, the fact that you know it's only good for a 10 minute shower leads me to think that you're pushing it near its limits often enough to know that. Unless it's in heat pump only mode it's going to kick the resistance elements on long before (and after) it gets to cold shower temps. See if you can live with "heat pump" (only) mode. If nothing else, it'll give you a clue about how much past the heat pump capacity you're currently going. Strangely, turning up the temp could also help in energy saver mode if it keeps the water hot enough in your normal use to avoid having the resistance elements kick on (if that helps, it won't really matter if it's in heat pump or energy saver mode - it's effectively just heat pump mode with a higher temp setting). And, while the thought alone is depressing, maybe you need a low (at least lower) flow shower head?? They make a difference. Adjustable flow heads are a good compromise between depression and hedonism.

When you say that your HWH is in the basement, but with no heat there, that really isn't going to make a difference. Think of the whole space inside the home as one sealed space (at least for this purpose). You can't take any heat from any space anywhere inside your home without affecting the total heat in your home. If you lower the total, you're going to have to make that up. It's more efficient to make it up with a heat pump than other methods (usually), but it's still going to cost you somehow.

You got me thinking, so I pulled out my power bill for a little comparison. I have a 3.500 - 4,000 sq ft home in a very cold climate. It's just my wife and I, but we work from home, so we're always here, computers and tvs are on a lot. What I think is interesting about the comparison is that I have almost nothing that uses electricity specifically to produce heat. We have all the normal electronic gizmos, and a fridge and a freezer in the garage big enough that Jimmy Hoffa could be in the bottom of it and I wouldn't know. That's in addition to the biggest semi-normal fridge/freezer my wife could find, in the kitchen. All are 8-15 years old. We don't have a well pump, or anything else to add noise to the electric bill. The only thing that is a problem is I do have my roof ringed with roof cables, which I use as sparingly as possible, and they can really suck up the juice when I have to use them. But I'm able to correct for that use pretty well. Hot water comes from wood, except for a short time in the summer when it's propane.

Looking at my bill, it ranges from about 300-350 kwh in the June to Aug ust area, to 400-500 kwh in Jan or Feb. Around 40% higher in winter. The need for some extra roof cable use in the warmer months of Oct. or March and April, can kick it to almost 500 too, but that's just wasted heat outside the house. I just plugged my wood furnace into the Kill a Watt, and it's 265 watts for the blower and HWH pump. If that's running 100% of the time, as it can get close to doing in the dead of winter, that's about the entire 200 kwh increase. There might be some slight need for roof heat, and a little engine heater use, but my garage fridge and freezers go into a coma to the point where I have to rotate warm water jugs into the fridge daily to keep it from becoming a freezer too. So, it probably somewhat balances out.

The point of all of this is that my bill bumps 40% ish in the winter, and while the heat from that ends up in my house, I don't have the bill bump from using electricity as a significant heat source. For the heat part, I'm burning around 7 cords of wood, very efficiently, and maybe 50 gallons of propane in the range which, being unvented, is also very efficient. I'm probably in a much colder climate than you, but keep in mind that my target house temp is 60 degrees +-3, - upstairs. I'll let someone else convert my wood and propane to KWH, as I'm sure somebody here has the conversion at hand. If you knew how many KWH hour equivalents of pellets and oil you're burning, that would be an interesting comparison as well.

Depending on how much pellet and oil fuel you're using, it might not be unreasonable for your electric use to triple in the winter. You're actually getting heat from your usage. I spend the short summer cutting wood. I don't have a mini-split (yet), but I'm guessing it puts out much more heat than a simple space heater, and I know that if I were to run a space heater a couple of hours a day, it would definitely help with my heat load. You've cut down the electric draw by cutting down the mini-splits, while probably increasing the electric draw from the pellet stove, and the oil burner, yet all the while burning oil and pellets you're also going to have to pay for.

First, you need to make sure you don't have something subtle or strange that's derailing you. There's a ton of ideas in the previous posts. You don't really need an "app" for that. The service meter is the ultimate arbitrator that your utility is billing you from. Weather it is easy to watch with an easily observed disc, or difficult because it only reads KWH, you can get the same data, it just might take more time and patience. Watch the meter, and flip the breakers, or install an electronic alternative, it's your time and money and up to you.

If you don't find a big problem, and even if you do, you should do some calculations yourself. I will suggest that maybe you're doing it wrong (no disrespect - it takes time to figure out this complicated stuff). Cutting the mini-splits at the expense of running the pellet and oil burners may be the wrong approach, depending on the cost of electricity, fuel, and the COP of the mini-splits at the temperatures you're experiencing. You need to figure out the break-even points between the heating options you have. With a COP of say, 3.0 and an equivalent cost of 1.5x electricity vs. (fuel cost + electricity use on the fuel burner), it should cost half as much to run the mini splits. COP varies by temperature though, so if it's a 50 degree afternoon, it's an easy bet you're way ahead with the mini-splits running. You should probably even run them to a few degrees above your desired temp to bank heat for the colder night (similar to turning up the HWH to save $). If it's -25, well, you'll know for sure if you've done the math, but there's a good chance you're ahead with a fuel burning device. If you calc it out, you'll know when it's time to switch from one source to another, or generally seasonally if you prefer not to make a profession out of heating your house. This site can also be a huge resource in helping you to improve efficiency.

In the end, the sad truth, I think, is going to be, that energy ain't free, in fact, it's pretty expensive, yet maybe in the perceived moment, cheaper than it should be. If you want the big house, the fast car, or generally, the carefree - I'll consume it if I feel like it - lifestyle, you're going to have to pay for it. The opposite of that is the mindful, conserve it where you can, and where it doesn't hurt too much, approach. You will probably find the ultimate solution in turning down the thermostat, taking non-orgasmic showers, turning off the lights when you're not absolutely using the light, killing the vampire loads, putting easily available wood into the woodstove, and choosing the right heat source for the job to be done at the time - those kind of things.

Don't take this wrong - yes, I exaggerate, but you get the point, it's a lot of small efforts, as long as they are not offset by a few big mistakes. You're getting monthly electricity from your solar panels equivalent to what I just paid $62 for. I know people who have $400+ monthly electric bills, and they're not in all-electric homes. They have more "spare time", but have less financial security, or have to work harder to make money. If you want to live the same life as my friends, you're effectively going to have to come up with the extra $338 a month. How you do it is your choice. Or, do this work, and have the small bill, and maybe retire earlier or better, or at least more securely.

I think you're trying have the small bill, that's why you're here, and I commend that. It's worth it, and doable, but if it was easy, it would be more popular. So far, I have a house that has room for my business, in a very cold place where I spend zero for A/C, and average of $40 a month for electricity, and every 5 years or so, I buy a few hundred gallons of propane when it's around $1 a gallon. That's savings i can put to much better use. And, I cut a fair bit of wood, which starts out free, though it doesn't end quite that way, yet it keeps me in shape, and beats the hell out of a real job.

Keep at it and you'll figure it out!

 

[gthomas785]

One thing I haven't seen mentioned is that cold climate heat pumps (including mini splits) usually have a compressor heater that keeps the compressor oil liquefied when it's not running. That way it is able to start in freezing conditions. Just turning the mini split "off" may not actually save that much energy compared to flipping it off at the breaker.

Just be careful when you turn it back on, and let it warm up for a few hours before starting it or you could damage the compressor.

 

[Potluck_Crew]

One thing I haven't seen mentioned is that cold climate heat pumps (including mini splits) usually have a compressor heater that keeps the compressor oil liquefied when it's not running. That way it is able to start in freezing conditions. Just turning the mini split "off" may not actually save that much energy compared to flipping it off at the breaker.

Just be careful when you turn it back on, and let it warm up for a few hours before starting it or you could damage the compressor.

That is a move I can make! Thanks

 

[RockyMtnGriz]

I made a rule some time back, that insomniac ramblings should be edited (or deleted) by someone who has not been awake for more than 24 hours. I see that I've broken that rule again.

 

[Potluck_Crew]

I made a rule some time back, that insomniac ramblings should be edited (or deleted) by someone who has not been awake for more than 24 hours. I see that I've broken that rule again.

But you give me lots to think about.

Yes, I want the lower bill! But what I really want is an explanation for a jump of approx 200% in usage from Oct to Nov. Is it something I can address and modify? We loved this house when we looked at it because of all the green energy options built in. Something Green has turned RED! We still LOVE the house!

Awaiting the Vue 2 Energy Monitor to arrive.

 

[gthomas785]

But you give me lots to think about.

Yes, I want the lower bill! But what I really want is an explanation for a jump of approx 200% in usage from Oct to Nov. Is it something I can address and modify? We loved this house when we looked at it because of all the green energy options built in. Something Green has turned RED! We still LOVE the house!

Oh, the joys of heating a house through the New England winter!

Your electric usage does seem high for non-electric resistance heat.

Not a great referene for comparison... but in our 2500 sqft, poorly insulated house which is also in MA, we used 800 kWh in December. That was with 1 mini split running, a bunch of christmas lights, electric stove baking, 2 wood stoves, gas hot water. An average month for us is closer to 500-600 kWh. We don't have solar.

I believe that with a bit of patience and deductive reasoning you will find the culprit, and I would bet it's a resistive heating element somewhere.

 

[EbS-P]

But you give me lots to think about.

Yes, I want the lower bill! But what I really want is an explanation for a jump of approx 200% in usage from Oct to Nov. Is it something I can address and modify? We loved this house when we looked at it because of all the green energy options built in. Something Green has turned RED! We still LOVE the house!

Awaiting the Vue 2 Energy Monitor to arrive.

View attachment 291307

I looked up the heating degree days for Boston. Something like 5600. Cooling degree days is less than 1000. Here we have 2300 cooling degree days and I can use 1500kw hours with a base load of about 700 kw hr for an all electric house.

Back of the napkin math says my cooling is 800kw hr a month for 2200 cooling degree days. Let’s say double that plus 20% (defrost and crank case heaters). If I were to take my house up north to Boston where they have twice as many heating degree days. . I would estimate my heatpump to consume 2000 kw hr a month.

It’s not specific to your house but in general winter is just expensive when it comes to electric consumption. I will leave you with my latest snapshot of what the average 3000 sq ft hime built in the 1960s with heatpump heat consumed last billing cycle. 2200 kW hrs!! Yep. That’s down south 2300 heating degree days.


Don’t give up you will find it what’s consuming all the power. I don’t think it’s just one thing. Think of it this way 100w crank case heater run 24-7 is 75 kw a month. I know my heatpump water heater runs 30% more just because the incoming water temp drops 20 degrees or so during the winter. Lights are on more as daylight hours are shorter. We bake in the electric oven more. Xmas lights List could go on.

 

[woodgeek]

I seem to recall that the older (Gen 1) Rheem HPWHs (like more than 7-8 years old) switched to regular electric at a higher air temp than other models. Like 60°F? It was one reason why I didn't buy that model back in 2012.

HPWH report:

That could be good for 200-300 kWh/mo when it got cold.

 

[Potluck_Crew]

I looked up the heating degree days for Boston. Something like 5600. Cooling degree days is less than 1000. Here we have 2300 cooling degree days and I can use 1500kw hours with a base load of about 700 kw hr for an all electric house.

Back of the napkin math says my cooling is 800kw hr a month for 2200 cooling degree days. Let’s say double that plus 20% (defrost and crank case heaters). If I were to take my house up north to Boston where they have twice as many heating degree days. . I would estimate my heatpump to consume 2000 kw hr a month.

It’s not specific to your house but in general winter is just expensive when it comes to electric consumption. I will leave you with my latest snapshot of what the average 3000 sq ft hime built in the 1960s with heatpump heat consumed last billing cycle. 2200 kW hrs!! Yep. That’s down south 2300 heating degree days.


Don’t give up you will find it what’s consuming all the power. I don’t think it’s just one thing. Think of it this way 100w crank case heater run 24-7 is 75 kw a month. I know my heatpump water heater runs 30% more just because the incoming water temp drops 20 degrees or so during the winter. Lights are on more as daylight hours are shorter. We bake in the electric oven more. Xmas lights List could go on.

View attachment 291309

I seem to recall that the older (Gen 1) Rheem HPWHs (like more than 7-8 years old) switched to regular electric at a higher air temp than other models. Like 60°F? It was one reason why I didn't buy that model back in 2012.

HPWH report:

That could be good for 200-300 kWh/mo when it got cold.

Thanks for the info. Ours is a 2014 model and rated down to 40 degree ambient temp. We have turned it to heat pump only as of last night. We will see how it behaves!

 

[Brian26]

I seem to recall that the older (Gen 1) Rheem HPWHs (like more than 7-8 years old) switched to regular electric at a higher air temp than other models. Like 60°F? It was one reason why I didn't buy that model back in 2012.

HPWH report:

That could be good for 200-300 kWh/mo when it got cold.

Or maybe more. I just installed the Emporia Vue 2 and connected my 8 year old GE Geospring circuit. Its been really cold here the last few weeks and my incoming city water has been ice cold. I did some experimenting running in heat pump only mode and all electric element on days with similar temps. I was really shocked how much more electricity I used in electric element only mode as you can see from this chart. It also shows how much savings the heat pump can provide. Heat pump only mode consumed about 2-4 kwh day compared to a whooping 8-10 in electric only mode.

Its just my wife and I so I could imagine with kids the usage could be huge running electric elements.

 

[woodgeek]

Thanks for the info. Ours is a 2014 model and rated down to 40 degree ambient temp. We have turned it to heat pump only as of last night. We will see how it behaves!

You'll need to read the manual. The Gen 1 switched to electric resistance at 60°F irrespective of what mode it was in! Because the air coil was undersized and would start to frost up at that temp, and HPWHs generally don't do defrost cycles.

 

[Potluck_Crew]

You'll need to read the manual. The Gen 1 switched to electric resistance at 60°F irrespective of what mode it was in! Because the air coil was undersized and would start to frost up at that temp, and HPWHs generally don't do defrost cycles.

Will do. Thanks.

 

[EbS-P]

Will do. Thanks.

I had an issue with mine where it was using the element in heatpump only and a hard reset corrected it.

 

[Potluck_Crew]

I had an issue with mine where it was using the element in heatpump only and a hard reset corrected it.

Did you pick up on that through energy monitoring?

 

[Potluck_Crew]

Agreed.

After reading through this thread again, I think it's likely there is nothing wrong or out of the ordinary as far as energy usage is concerned. @DBoon makes some really good points here, as others have as well. This time of year the solar is not contributing much. My 15.2 kW array only produced 355 kWh in January.

The thing that really caught my eye reading through the OP again is that there are 5 heat pumps that are 15 years old. I missed the 15 years old part the first time I read through. I think those are most of your culprit. 15 year old heat pumps are not nearly as efficient as newer ones and probably not cold climate ones, so they'd have to work really hard (use a ton of energy) for heating when the temps get low.

@Potluck_Crew you said earlier that you shut the mini splits off after you got the December bill, but in a more recent post you say you are still using one of them. I really think they are what is causing the majority of the high energy usage, as well as other things mentioned previously such as the water heater working harder due to colder inlet water, etc .

So, I found the manual and the temp rating for heating. But honestly I don't know how to interpret this information.
And the the "without any frost"?

Any help is appreciated!
Again, we are thinking these are likely about 15 years old?

 

[woodgeek]

Did you pick up on that through energy monitoring?

With mine, I can obviously hear the compressor and fan going when its in HP mode, and when it goes to the element the fan turns off and it makes a little boiling noise like a regular electric HWH. If the fan is not running after you take a shower, its probably using the element.

My 10 yo AO Smith only does that when it gets to 40°F in my attached tuck-under garage, which is only during polar vortex events.

 

[EbS-P]

Did you pick up on that through energy monitoring?

Yes. A constant 6kw load is pretty easy to spot.

 

[EbS-P]

So, I found the manual and the temp rating for heating. But honestly I don't know how to interpret this information.
And the the "without any frost"?

Any help is appreciated!
Again, we are thinking these are likely about 15 years old?

View attachment 291395

So you can see that the TC shows heat produced so at 45 dedgres wet bulb temp outside you and get 22.2 k btus (at 70 degrees inside temp) consuming 1.6 kw. At 5 degrees wet bulb you get half of that 10.3 k btus using 0.87 kw. I’m not sure why they use wet bulb outside.

With out any frost comment I assume is meaning no ice on the outside coil causing the unit to defrost.

And you said you have 5 of those 1.5 ton units? Even at at 15 degrees you have over 60,000 btus of heating capacity. And could consume 6kw. Now they all might not runn at the same time or at full output.


Here is a similar chart for my unit. Outdoor temps on the left column indoor return temp is along the top.