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A Surprisingly Common Cause for High Energy Bills

A Small Simple House With High Electricity Bills

She lives in a small, simple house in southern Mississippi.  It’s only 1700 square feet.  Why then, she wondered, were her summer electricity bills running more than $600?  She didn’t have anything that could be a big energy hog, like a swimming pool, and she didn’t do stupid things like leave all the doors and windows open while she ran the air conditioner.  What could it be?

She called her electric company, one of the co-ops in Mississippi, and they sent someone out to investigate.  Utility companies get calls like this all the time, and they’ve learned from experience what most of the main causes of high bills are.  When the utility investigator arrived arrived at the house, he asked her to tell him anything she knew that might help him.

“Well,” she said, “the air conditioner runs all the time, but the house won’t even cool down to 80 degrees.”

“Ah, that helps to narrow it down a bit.”  He went to work, and it didn’t take him long to find the problem.  He measured the temperature drop across the air conditioner coil and found that the air on the “cool” side wasn’t much lower than the air on the warm side.  And both were much warmer than they should be.

disconnected duct high energy bills

OK, that could be a disconnected duct in the attic, he thought, like the one from a different house that you see above.  A look in the attic, however, showed that wasn’t the case here.  Besides, a disconnected duct would increase the bill, but it almost certainly wouldn’t quadruple it.

electric resistance (strip) heat

His next step was to turn off the breaker to the electric resistance heat (a.k.a. strip heat) in the HVAC system.  This is basically a giant toaster inside the air handler.  Heat pumps use it for supplemental heat.  In some homes, it’s used as the primary heat source.  It’s not cheap, though, especially considering that the same electricity going into a heat pump will yield two or three times more heat.

Anyway, the utility investigator turned off the breaker to the strip heat and watched what happened to the meter.  In the summer time, turning off the strip heat should have no effect at all on how fast the meter spins because it shouldn’t be running.  Strip heat is for cold weather.

beetle bug trail woods 300In this case, the meter went from spinning fast enough to saw wood to moving as slow as a horned passalus (photo at right) going for a walk in the woods.

“Well, we found your problem, ma’am,” he told her.  “Your heating and cooling system was doing both at the same time, making you spend a lot of money to stay uncomfortable.”

This problem often results from a thermostat wired incorrectly so that the system kicks on the strip heat when it shouldn’t.  Since anyone can go down to the home improvement store or the Interwebs and buy a thermostat, a good number of these problems result from DIY jobs.

It seems crazy to think that someone wouldn’t notice that the heat is running in their home in summer, but they don’t feel heat coming out of the vents.  That heat gets mixed with the cool air from the air conditioner.  They cancel each other out, both using even more energy because they’re fighting each other.

Got high electricity bills in summer that you don’t understand?  Check your strip heat.  And a good way to keep an eye your strip heat as well as other electrical loads is to use a device that monitors the electricity used in your house, circuit by circuit.  The Emporia Vue* is a good one, and I use it in my house to monitor my heat pumps, electric car charger, heat pump water heater, and more.


Buy the Emporia Vue Smart Home Energy Monitor on Amazon*

Emporia Vue smart home energy monitor


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This Post Has 61 Comments

  1. I’m not one to advocate
    I’m not one to advocate frivolous lawsuits, but I sure hope this woman nails the contractor responsible for this.

  2. A thermostat must be GROSSLY
    A thermostat must be GROSSLY mis wired to have heat come on with strips. Something like hooking the white wire to the G or R terminal. 
    A more common problem that would cause this is a stuck sequencer, the element would be on 24/7, cycling off on high limit when the blower isn’t running. 
    But this issue isn’t “surprisingly common”, typically high power bills are caused by other things.

  3. Been there, done that. Tech
    Been there, done that. Tech who came before me to a similarly situated client tried to sell her a bigger air conditioner! 
    First thing to ask is whether the homeowner has replaced the thermostat. Big box stores sell thermostats, and brave, intrepid homeowners will have a go in order to save a service call. 
    After I “fixed” the OBVIOUSLY undersized air conditioner (white wire was landed one screw position off) I asked the homeowner for her last electricity bill. 
    She provided it, dated 3 weeks before. Bill in hand, I read the meter…UH-OH! 
    A 10 kW heat strip had been duking it out basically continuously with the 3.5 ton AC compressor for 3 weeks, to the tune of 6,000 kWh! 
    I made sure to cash our service call check before the next light bill arrived. 
    I gotta say, the humidity in that house was excellently low!

  4. Craig B.:
    Craig B.: I have a feeling you won’t be the only one who reads this article and has a similar story.  
    David B.: I didn’t hear about that part of the story, and I’m not sure if the utility rep knows either. 
    Bob: Well, perhaps I should have said “surprisingly more common that you might think” or “surprisingly not uncommon.” Still, I’ve been surprised at how many times I’ve heard this story. 
    Curt K.: Yeah, that’s one way to keep the humidity down all right. 

  5. As a utility rep we did see
    As a utility rep we did see this more than you might expect. Often had been this way for months. Happens in heat pumps & staight elec furnaces. AC guy ALWAYS wanted to replace and upsize system. Never check electric side unless no power found. 
    Another source if heat stip running is a water heater. A) strip shirts but does not trip breaker. Result is no extra heat, so only symptom might be slow recovery. Even that may not be noticed, or may not occur. B) is a short that does run heat strip. Result is pressure valve hissing to relive pressure. If pressure not released, the water tank becomes a science exoeriment and could turn into a rocket. I saw pictures of a tank that blasted off in the basement, punched through two floors and the roof, then splashed down in back yard. C) is a leak that causes heat strips to run constantly trying to keep water hot. Depending on size and location of leak, there could be no symptoms noticed. However; a high water bill will coincide.  
    I saw one case where this situation was happening for two years! The retired woman had the maint guy, A/C, and plumber (she heard water running) to investigate several times. Took me 5 minutes to find, including time to interview customer. Leak was under slab and puddle did NOT show from outside building. There was however, a ward spot in living room floor. (Hmmm? A clue?) 
    Good news was; the Apt Mgt pulled up slab to repair, AND, refunded the woman’s expense for ALL elect and water for previous two years!

  6. Okay, as one who teaches
    Okay, as one who teaches pyschrometrics, my alarm went off while reading replies, so please forgive me for my following reply: 
    I must point out that electric heat being stuck on with a/c won’t make the house any “drier” than if the heat strips were not running. The fact that the house indoor temperature likely ran higher than set point, thereby lowering the relative humidity, is true. But no different than if the a/c was shut off, the house sealed, and the air allowed to warm up to the same temperature naturally.  
    Heat strips (and gas furnaces and heat pumps in heating mode) have no way to dehumidify. 
    There. Alarm silenced. 🙂

  7. @Cameron, all true, except
    @Cameron, all true, except for the fact that the AC was likely running (and dehumidifying) 24/7 with strips acting as reheat. Even at higher entering dry bulb, increasing the run time that much is going to pull out more moisture.

  8. Bob S.: I
    Bob S.: I think this problem probably makes up a significant portion, possibly even a majority, of the really high energy bill complaints, although I haven’t seen data.  
    geoff h.: Good point about electric water heaters. And great outcome for that one woman! 
    Cameron T.: Ah, but I think the air in the home will be drier. Yes, if all you do is heat the air, the absolute humidity won’t change. The relative humidity will be lower, though, and that’s what our bodies respond to. More important, though, the absolute humidity will be lower as well in this case because now the home’s air will keep cycling through the AC and getting drier every time through. Right? More run time means drier air. It’s like an AC that gets extra dehumidification with lower temperatures and reheat, except it doesn’t have the lower temperatures. But yes, you’re absolutely right that “Heat strips (and gas furnaces and heat pumps in heating mode) have no way to dehumidify.” 

  9. I knew I was among a sharp
    I knew I was among a sharp bunch, here. 🙂  
    Allison and David, all true. Only reason I brought it up is because all too often I hear “I hate forced air heat…it dries out my house!” I’ve also heard it called “scorched air heat”, in reference to how dry a house feels heated by a furnace or electric heat. 
    But yep, in my semi-knee jerk reaction I failed to account for the increased run time of the unit with electric heat strips engaged alongside a/c. So yeah, it will dehumidify better in that sense, but boy at what cost! 🙂

  10. I figured my super dehu
    I figured my super dehu remarks would trigger some conversation. While all y’all were yakking I was out on another “high bill call”, in this case $300+ / month for 1100 square foot home in North Florida 
    As usual I checked heat strips and reviewed water bill – nothing out of sorts with either. 
    What I did measure was a grand total of 192 CFM being delivered by a 2 ton system! That’s a new low for me – 96 CFM per ton. 
    The system has been without an air filter for many moons, by the look of it. 
    I relate that story in this thread because in my neck of the woods, drastically reduced air flow is to blame in a majority of “high bill” complaints.

  11. 96 CFM per ton + no filter =
    96 CFM per ton + no filter = dirty ice

  12. @ Curt Kinder  &lt
    @ Curt Kinder 
    Really surprised you’re not also relaying a story about a dead compressor at the 96 CFM per ton house.

  13. @Curt, that suggests large
    @Curt, that suggests large duct leakage, and that the 192 CFM reading was at the registers, not the coil. I gathered from your previous comment that low airflow was due to lack of a filter (e.g., which could easily lead to blocked evap coil). Now I’m guessing it was a combination of duct leakage and dirty coil. Fun stuff.

  14. I didn’t spend a bunch of
    I didn’t spend a bunch of time; it was a $75 diagnostic call, but I did note a 25*F indoor air temperature split, consistent with low air flow. 
    When I ran blower with AHU cover off, flow jumped dramatically, so much so that the tenant thought I’d fixed it…”ah, no ma’am” 
    I could have checked static, but $75 brings only so many tools out of the van. 
    We’ll see if they bite on cleaning coil and blower wheel. 
    The system is oversized, 1.5 T would certainly better match the ducts and load. 
    ODU very weedy, 1100 rpm fan seemed to be turning about half that fast; 12*F outdoor air temp split even with very low load on dirty indoor coil.

  15. With today’s dew point in the
    With today’s dew point in the mid-to-high 60’s (and in the mid-70’s in past days), if coil wasn’t icing, you probably have at least 500 to 550 CFM at the coil, maybe more, and lots of duct leakage. But I agree, $75 doesn’t buy much.

  16. Dirty Coils/Blower Wheels are
    Dirty Coils/Blower Wheels are a FAR larger issue that causes high utility bills. The A-coil stays until it leaks refrigerant, and is rarely cleaned over the course of its lifetime.  
    Extremely common, just think of all the condenser swaps done instead of installing a complete system. If the coil starts freezing just overcharge to get the suction pressure up. As long as the compressor isn’t making too much racket from sucking in liquid refrigerant the customer will be happy with their choice to use a dry condenser “repair part” to get them up and running as cheap as possible..

  17. While I agree that normally
    While I agree that normally 100 CFM per ton would quickly ice an AHU coil, in this case I suspect an overcharge may be keeping that from happening. I didn’t put a set of guages on it since airflow was so low as to render charge analysis meaningless. However, paperwork shows a prior tech added 2 lbs. 
    I don’t think duct leaks are a major player in this since when I had the blower compartment cover off, airflow seemed to about triple or so; in other words, the air flow restriction is at the AHU coil. 
    The supply duct is a short ductboard trunk in an interior soffit within the conditioned envelope – a rarity in my area. 
    The owner will need to accept a proposal for cleaning coil and blower wheel as well as some maintenance before I check charge or run a duct leakage test.

  18. I work in the energy
    I work in the energy management department for a local co-op. Many times this happens with the change out of the wrong thermostat. A heat pump needs a thermostat for a heat pump (there is an extra wire and an extra setting; Emergency Heat). I find that a high number of people do not know what they have for heating; whether it is an electric furnace or heat pump or even gas furnace.

  19. i have a very small apt and
    i have a very small apt and my heating bill is usually very low. but this year the maintance man hooked my heater up to run only on supl heat. before it ran on reg head. my bill is tripled and I want to know why I can only get heat to blow out hot if the thermostate is on supl heat. please comment. I know something isn’t hooked up right and the apt owners don t care how much our head cost. some of the apts are heated from a boiler room I believe. I had a new motor and blower installed last summer when my air didn’t work now my heater only works on this setting. why is that? 

  20. every year when i go from
    every year when i go from heat to ac and ac to heat i have to call someone to come fix my unit.In the winter my bill is around 600 to 700 dollars they come this Friday to fix it but i still have to pay my bill $655.00 i also have a ten year warranty on my unit what could i do to make them fix this and take care of my bill

  21. @Dawn, you need someone to
    @Dawn, you need someone to diagnose your high bills, not just “fix” whatever it is that’s causing your unit to need servicing every season.  
    There’s no way to advise you in an online forum. Too many variables. Contact me privately with your location and I’ll try to provide a referral.

  22. what would make ur light bill
    what would make ur light bill higher in the winter then the summer. my light bill is around 170amo in the sum er but in the winter it’s almost 300amo the unit is only about 2 years old

  23. I moved into a 1700 square
    I moved into a 1700 square foot barbershop in May 2014. My electric bill each month was about 123.00 a month with the ac running. This winter I turned the heat in to 65 and in December I got a electrical bill for 329.00. In January my next bill was 455.00 which actually trippled. I noticed there was no filter in the Hvac unit. What’s causing my electric bill to sky rocket? Should the Hvac unit been serviced prior to them leasing me the building? Need help!

  24. Had new goodman 4 ton
    Had new goodman 4 ton electric ac/heat pump and return airflow furnace installed after last one surged out. Would of never noticed but bill was about 5000 kwh for that month. With new system I’m on pace to hit 4900 kwh when I averaged 1700 kwh before old unit went bad. Not understanding why new unit is pulling so much KWH. Also they did not replace any of the wiring from the 20 year system to the thermostat that they did replace. Any ideas would be greatly appreciated.

  25. I wish one of you lived close
    I wish one of you lived close to central Florida. Years. Yes years. I’ve been trying to find what consumes 3Kwh to 5Kwh a month in a 1500 sq. ft. home. 4 years ago a new AC made it worse. A year ago my husband passed away. I could no longer afford the mtg. and the power bill. Hired Electrician, he couldn’t find the problem. Had Duke Energy out 15 times, they couldn’t find the problem. Sold everything of value I had left to replace the AC again with a 15 seer. It is only a few months old and already…. problems. Excessive power usage still. 
    I finely had to turn breakers off. New energy efficient Fridge, one TV, 3 LED lights, a laptop, modem and cable box are all that is on with the new heat pump. Still 1500 to 1899kwh bills. I have shut my hot water off, the pool pump off, the stove off…. etc. Living in one little room with two breakers on. 
    NO ONE can find the problem. Power company even sent an engineer out with heat equipment and replaced my meter three times….. nothing. 
    Oh and forgot, all windows replaced double pane insulated. Block home, blown in insulation. Just about ready to bulldoze the whole thing and start over.  
    Now here is the kicker. This new AC guy used the “New expensive thermostat from the new unit 4 years ago”. Could this be my problem all along?

  26. Do you have a smartmeter
    Do you have a smartmeter installed? If so does your local utility give you access to daily use data? 
    If you still have a analog meter you may have to do your own “energy audit”. Turn everything off for an hour an see how much the meter moves. if the meter moves when you think everythign is off, then it’s time to start turning off breakers and isolate the problem. It’s time consuming, but you will find your issue. 
    Do you have high power bills in the “off season” when the AC or heat isn’t being used? How many tons is your heat pump? What temp do you keep your heat set at?

  27. @Barbara, if your block walls
    @Barbara, if your block walls are uninsulated, that’s going to contribute to your high power bills, especially in winter. The new thermostat is not the problem, but it may have been wired or configured incorrectly.  
    Since your kWh usage dropped by more than half by switching off all non essential breakers, you likely have other large loads (other than the heat pump) contributing to your high bills.  
    As Bob said, checking your meter with various breakers switched on and off can help you isolate the problem. Here’s a website that explains how to read various types of meters. 
    If you contact me off=list, I can help you determine if the heat strips are running more than they should due to a miswired or misconfigured thermostat.

  28. Should a new Goodman 13 seer
    Should a new Goodman 13 seer 4 ton ac/heat pump with 4 ton air handler use more kwh than a 20 year old unit I believe it was a 2.5 ton

  29. @Paul, without knowing the
    @Paul, without knowing the efficiency ratings of the respective systems, it’s impossible to say which one would have a higher instantaneous power draw. But the new system should consume much less energy over the course of a year since its efficiency rating will be a lot higher than all but the highest efficiency systems available 20 years go. 
    The fact that your new system has 60% more capacity will make it a bit less efficient in summer than one that’s properly sized. But the bigger issue is what that much extra capacity does to comfort and especially moisture (humidity) control in summer. Your heating bills should be MUCH less with the new system since a 4 ton HP requires much less supplemental heat than a 2.5 ton HP in the same house.

  30. Re Goodman vs old air handler
    Re Goodman vs old air handler — no . It SHOULD not draw more power, but might If [several posibilities] were to occur. I have see 30 yr old ststems using very little energy, and brand bew ones caysing super high bills

  31. Thank you David. The home is
    Thank you David. The home is 2000sq ft so the contractor insisted on the 4 ton. Just couldn’t understand how kwh was so abnormally high with new unit. Contractor now believes he wired wrong.

  32. @Bob, I have a smart meter
    @Bob, I have a smart meter but Duke says they can’t provide me data from it. I just purchased a TED 5000 two days ago. So far pretty much the only thing drawing energy is the heat pump. At 6AM it went from a normal 7kwh draw from the compressor to over 22000kwh draw. The inside unit started popping and “venting”. I shut it down. Talked to the AC guy this morning and he’s trying to tell me that is “normal”. 
    With my AC on, power bill can be anywhere from $250-550. With it off all month, that drops to $80-120. Of course that is with everything off except basics. 
    The electrician replaced the whole box and all the breakers. Upgraded everything. Duke did every energy audit that they provide. 
    What ever the problem is, doesn’t happen all the time. It’s intermittent and we just can’t seem to catch it when it happens. 
    Walls are insulated, ceiling has extra blown in insulation on top of the original insulation.

  33. @David, I know that site well
    @David, I know that site well. LOL I have hundreds of reading per day with me standing at the meter with a stop watch. I then got the watts plug and tested everything plugged in my home that was on 110. I then went systematically through the whole breaker box one breaker at a time to see what each one drew. I then went out and bought a clamp meter, unplugged and turned off everything to see if there was any kind of load left. There was none. 
    Today, I went and bought a new thermostat that is “non-programmable” for heat pumps. Since the AC guy says he “may or may not” be able to get here by Friday, I’m seriously thinking of installing the new thermostat myself. It was the only thing NOT replaced this time around.

  34. Definitly looks like heat
    Definitly looks like heat strips. 
    Also, get a new A/C guy. – fire old one first- The operation you describe is not “normal.”

  35. Barbara wrote: “I have
    Barbara wrote: “I have hundreds of reading per day with me standing at the meter with a stop watch.” 
    Ah, a kindred spirit! 
    “At 6AM it went from a normal 7kwh draw from the compressor to over 22000kwh draw.” 
    Ok, now we’re getting somewhere. Even the largest residential heat pump available (5 tons) won’t draw anywhere close to 7kW! You said your new unit is 15 SEER. As an example, a 5 ton Carrier Comfort 15 system draws about 4.5KW at 57F (less at colder temperatures) including the indoor unit. The outdoor unit alone (what you were probably measuring) draws less than 4kW. 
    Your readings suggest you have a two-stage electric heat kit(7kW and 15kW) with a sequencer. Fairly common. A miswired or misconfigured thermostat could be bypassing the heat pump altogether, using only the strips to heat your home. 
    Another possibility… In your initial post you said you had a new “AC” installed, but later referred to it as a heat pump. Is it possible you have a straight air conditioner with an electric furnace? If you have a heat pump, the outdoor unit should always be on whenever the thermostat is calling for heat. If not, post the outdoor unit’s make and model # and I’ll confirm if it’s an AC or HP.

  36. AirTemp 15 seer Heat Pump
    AirTemp 15 seer Heat Pump Model VT4BE-030K 
    AirTemp Airhandler Model B6EMMX30K-A 
    2 1/2 Ton 
    I don’t know how to do it, but I’ve got a screenshot of the KWH from TED. Every time the unit turns on it hits around 7 kwh and stays there, then has “episodes of over 22,000 kwh (yes I typed that right) 
    I apologize, I tend to use AC and Heat Pump interchangeably. It is because here in FL the AC is always running. (-:

  37. @Barbara, in heat mode, your
    @Barbara, in heat mode, your system’s specs show total system draw of 2.2kW @ 40F and 2.3kW at 50F (includes air handler). 
    Did the 7kW & 22kW TED readings include outdoor AND indoor units? They’re nearly always on separate circuits, which means you’d have to combine two TED channels (two sets of clamps) to get a combined reading. 
    “episodes of over 22,000 kwh (yes I typed that right)” 
    From your various comments, it’s clear you’re talking about kW, not kWh. Instantaneous power draw is measured in kW, while kWh is the accumulation of kW’s over time. That said, if your TED display actually shows 22,000 kW, then something is obviously wrong with the TED configuration! 22 kW would be more in line with what some electric strip kits might draw.

  38. David – Doesn’t TED read the
    David – Doesn’t TED read the meter (total) not circut specific? – sounds like heat relay is activating. Posibly randomly?? Since the total comes and goes. Cause could be loose conection or faulty switch? Definitly not Normal.

  39. First of all, THANK YOU so
    First of all, THANK YOU so much for your time and patience! 
    You are correct, it is KW. 
    The Teds unit does have two clamps. I have the main (total reading) and the second clamp on the outside compressor lines. 
    I just now put the clamp meter on the outside lines (from inside the electrical panel) each leg was pulling 12.3amps and 12.2 amps. Teds read the outside unit pulling 3.7kw with a total of 7.8 kw being pulled off the main lines. When the heat pump goes off, TEd goes back down to 287 watts. (which is right now two lights, cable modem and laptop. 
    3.7 kw for outside unit 
    287 watts for laptop and lights 
    leaves 3.813 kw on the air handler 
    Is that correct? So far today, as of midnight, I’ve used 34.9kwH 
    There have been a total of 5 spikes up to 22000 kw since midnight. The thermostat is set at 70. Right now the outside temp is 68. I think it got down into the 50’s last night. But two of the spikes were in the middle of the day. 
    By the end of 24 hours, I am averaging about 52 kwh with everything shut down except the items listed above. Even the circuit to the fridge is off. The only thing in it was condiments any way. lol 
    On a side note, my brain has KW, KWH, Watts, Amps, and $ dancing around like stars over a cartoon characters head. 

  40. 287W is high for just laptop
    287W is high for just laptop and lights. Are you still running the old incandescent bulbs?

  41. Finally came to conclusion
    Finally came to conclusion that my 1997 house isn’t keeping heat in for long. Heat pump runs 5 kwh and when heat strips kick in its 15kwh. Nights have been in low teens and thermostat is constantly kicking on and off due to heat loss? Will insulating my crawlspace ductwork help with getting the most bang for my buck. It does build up moisture and vented.

  42. @ Bob, I’m using LED lights.
    @ Bob, I’m using LED lights.  
    An interesting thing is, I’ve now shut the whole system off and I’m running a space heater. Radiant heat that doesn’t even have a fan. My house is warmer than it has been in months, I also turned the fridge breaker back on and turned the TV on. I’m pulling 1.201 kw. using a space heater.

  43. @Barbara, 12.3 amps doesn’t
    @Barbara, 12.3 amps doesn’t jive with 3.7kW. Depending on the power factor and RMS voltage, 12.3 amps correlates with about 2.6 or 2.7kW.  
    Out of the box, TED should be accurate within about 5%, so either your clamp-on amp meter is off, or something’s wrong with TED. 
    But more to your concern, your air handler shouldn’t draw more than a few hundred watts for the blower. So if your reading, even if it’s off, confirms the strips were operating.  
    Moreover, if your overnight low is in the 50’s, you definitely shouldn’t need any strip heat.  
    Until you get this resolved, I recommend that you disable the strips, especially given the popping sounds you mentioned. Some air handlers have separate breakers for strip heat mounted on the AHU itself. Otherwise you can disable by detaching the white wire (W) from the thermostat base terminal strip. I only mention that because you don’t seem intimidated by the prospect of replacing your own stat ;=) 
    If you do that and your heat pump alone can’t keep your house warm when it’s in the 50’s outside, then there’s a problem with your heat pump. You should see at least a 25F rise (return air to supply air) under those conditions.  
    Based on your comments, I’m wondering if it’s wired wrong and actually running in cooling mode?!

  44. I need a new AC guy. Upon my
    I need a new AC guy. Upon my insistence, he came by and “checked the system”. Said everything was fine. Told me that the 7 kw and the 22 kw that the system keeps pulling was the defrost kicking in. That it was a normal cycle and that heat pumps work with the heat strips, not alone. He said that even when it is only in the 50’s that the heat strips are supposed to come on and supplement the heat pump. When I asked him about the outside unit freezing up and shutting down at 8 am this morning when it was 58 degrees outside, and the 52kwh that the system pulled from midnight to 8 am, again he said the outside unit froze and stopped because it was in the middle of a defrost cycle. That the high kwh was because of the two phase 10k heat strips “was defrosting” the outside unit. When I insisted on him changing the thermostat to a non-programmable heat pump thermostat, he wasn’t happy and told me I would have to pay him to do it. Then he changed some settings inside of the air handler. Said he lowered the fan speed. So far, it seems to be running a lot better. It is only pulling a total of about 3kw now. I’ll know by morning. It still feels like it’s blowing cold air and running a lot. Being a new unit and still under warranty, can I call someone other than the installer to check it out? 
    He also said it was normal for the wires going to the breaker for the air handler to get hot to the touch, that doesn’t sound right to me, but hey, I’m not an electrician.

  45. One last thing. I so very
    One last thing. I so very much appreciate the help and support that I’ve received here. Thank YOU! I’m not an HVAC professional or an Electrician but I am a person who desperately wants to be energy efficient. I’m in a position in my life that I have to choose which appliances I can use in any given month and still be able to pay the mtg. It isn’t just a “want”, it is basic survival. I’ve diligently and obsessively researched and read every possible way of conserving energy. I’ve contacted every person I know to help me with that. From the power company, electrician, HVAC, well man….etc. and I’m blown off pretty much. Just an old lady that wants to get her power use in a reasonable and affordable range. All any of them really want to do is defend. It’s not my meter the power company says. Maybe it’s the AC, you need a new AC, then it’s not the new heat pump, the HVAC man says. It’s not the well…. you get the point. Each one just seems to want to sell me something and move on. 
    So how? How do I find someone who will take me seriously and actually help me find where excessive energy use is coming from? How do I find an HVAC person that will spend the time to make sure my system is operating as it should? 
    I swear, it is worse than trying to find a good doctor. 
    How do you find an Energy Professional to help when all else fails?

  46. Barbara M. – Yes, you need a
    Barbara M. – Yes, you need a new HVAC contractor. – BTW, freezing up at 50 outside temp is a sure sign the unit is not right. 
    Suggest starting at Florida Chapter of Air Conditioning Contractors of America ( – Homeowners then Find a Contractor. Look for accreditation as “Quality Assured.” QA helps narrow search to those that are trained to follow standards and should be higher caliber. That said, if you can’t find a QA contractor in your area, at least contact several ACCA members and pre-interview them to select someone who sounds willing to focus on resolving you orobkems, not selling more stuff.. 
    THat said, the tech at your door may not know everything the owner or QA trained staff. ASK, no firmly request the company’s best troubleshooter, and explain why. The receptionist or dispature may not feel your pain. If you are uncertain, ack to speak to the owner or manager to make sure they understand what you need.  
    Finally, the technician should talk with you in detail BEFORE starting any diagnostics! If they walk to unit and apply gauges first, send them home and do not oay for the visit. Gauges are last. You may not know electronics, or physics of system, but only you know what the history is. 
    Good luck. You deserve it. Sad thing is, your story is way too common.

  47. I’m up near Jax, Fla., so
    I’m up near Jax, Fla., so probably not close enough to send help.  
    A heat pump whose outdoor coil freezes while ambient temps are 50s definitely has a problem; either loss of charge or a defective metering device. 
    Heat strips should come on under only two circumstances…1 during a legitimate defrost cycle , 2) if thermostat setpoint exceeds room temperature by 2 or so degrees in heating mode. 
    TED spikes to crazy high values may indicate noise in the communications wiring. 
    If you do disconnect any control wiring such as “W” as advised above, please turn off power to air handler first and put a wire nut or tape onto any exposed wire end.

  48. @Barbara, a properly
    @Barbara, a properly functioning heat pump should not require supplemental heat when outside temps are in the 50’s. On the other hand, the coil can develop frost in the 40’s (coil is always colder than ambient), but not when in the 50’s. That’s why all heat pumps have a defrost cycle that kicks in from time to time. The defrost timer is disabled above a certain temperature, typically in mid-40’s, but some models have defrost lockout as high as 50F. 
    Defrost turns off the outdoor fan and reverses the refrigeration cycle, temporarily turning the HP into an AC. The heat strips are energized during defrost to prevent cold air from blowing in the house. Your contractor is wrong when he says the strips are being used to defrost the outside unit. 
    When looking at TED graphs, you can tell defrost cycles from supplemental heat calls by the duration. Defrost typically only lasts a few minutes, less if no frost on the coil. For a lot more about defrost, check out this article by Allison
    I agree with Curt… if your unit actually froze and stopped with outdoor temps in the 50’s, there’s something seriously wrong. But it’s possible the contractor was just explaining defrost operation. I also agree that TED has a propensity to log phantom spikes, way above anything reasonable. So if you literally meant 22,000 kW in your earlier comment (eg, 22,000,000 W), then that’s a TED glitch. 
    Regarding Curt’s comment about heat strips coming on when setpoint exceeds room temp by 2 degrees… That used to be true for electro-mechanical thermostats, but most modern thermostats energize strip heat based on the rate and direction of change (the thermostat senses temperature in tiny fractions of a degree), rather than an absolute difference. Some do this so well, the displayed ambient temperature may never vary from the setpoint. 
    (BTW, thanks Curt for the reminder about wire nutting the disconnected wire.) 
    As to your question about warranty, a unit under factory warranty does NOT have to be serviced by the installing dealer. There are two caveats to that. In case the problem turns out to be a covered defect, make sure the other dealer is authorized for warranty repairs on your system. But if your issue(s) are installation related (more likely), it’s on the installing dealer. Only he can warrant that. But since you’ve already given him adequate chance to find the problem, you’d have a strong case for shaming him into covering another company repair bill if there’s a problem that’s obviously his fault.

  49. When heat pump goes into
    When heat pump goes into defrost mode should the 20 kW heat strips be pushing warmer air out then the heat pump. I have had my hvac installer out several times due to wiring issues and it’s very concerning. First heat pump and strips would kick on together. Next it was heat pump would kick on but during defrost but blow cold air. Lastly it’s been heat pump kicks on but auxiliary heat doesn’t seem to be warm enough for heat pump to want to stop running. Blames thermostats? But to me it seems like wiring.

  50. Just to let everyone know, I
    Just to let everyone know, I am making progress. After making the HVAC contractor change out my thermostat to a non-programmable heat pump thermostat, the power consumption went down from 52kwh (24 hrs.) to 32kwh. 
    I then used that little white wire test. Leaving it off reduced the power consumption down to 28kwh (estimated) and my house is actually warm. The unit runs a little longer but sounds a thousand times better. 
    The electrical wire to the airhandler in the main box no longer gets hot. 
    Before changing the thermostat that breaker was pulling 42 amps on one leg. After, it is pulling l.6 amps on one leg. 
    I’m not there yet but I’m getting there. HVAC guy doesn’t want to talk to me. (-: 
    Hooked the white wire back up last night and the unit is going through “defrost” cycles when the lines aren’t even frosted over. Twice in the middle of the night it “defrosted” and kind of stuck there for about 20 min. Power usage surged. Nothing like before changing the thermostat but still “not right”. 
    So I’m getting there. I’m trying to find the wiring schematics for my unit. Don’t worry, I’m not going to touch anything, but I am going to look. 
    Then I’m going to consult with my HVAC guy one more time before I contact someone else. 
    Thank you for your help.

  51. Presence / absence of white
    Presence / absence of white wire from thermostat terminal block should not affect outdoor unit’s defrost behavior. White wire from stat to AHU allows stat to call for resistance heat. White wire from ODU to AHU “tells” AHU that ODU is in defrost mode (compressor in coooling mode / outdoor propellor fan off) AHU reacts by activating resistance heat to avoid cold air blowing. 
    It sounds to me as though ODU has a bad or mis-configured defrost board or bad / loose defrost termination thermistor.

  52. @Barbara, as Curt said,
    @Barbara, as Curt said, neither the thermostat, nor white wire at the stat, have anything to do with defrost operation. The defrost control on the outdoor unit will independently energize the strips, so disconnecting the white wire only solves part of your high load problem.  
    It’s hard to say which one (defrost, vs. supplemental heat calls) represents the largest contributor to your high energy bills, but you need to have strip heat during defrost calls. 
    Also note that the defrost controller operates on a timer, when outside temp is below a pre-set limit. It has no way to know if there’s actually any frost on the coil. So it’s not unusual for defrost cycle to start when there’s no frost. BUT, in that case, the cycle shouldn’t last more than a minute or so. If that’s not happening then either your unit has a poorly designed defrost control, or the liquid line sensor is defective. Typically, there’s a sensor on the liquid line that terminates the defrost cycle quickly when there’s no frost. 
    Also, you do NOT need 20kW of strip heat during defrost cycles. A strip kit that large will have more than one stage (possibly a 7kW first stage?). So the control sequencer shouldn’t allow the full 20k in the beginning of a call for strip heat. In any case, I suggest having your hvac tech disconnect the 2nd stage, as I doubt seriously you’ll ever need it in your climate.  
    One final comment, if your defrost is energizing when temps are in the 50’s, then you either have a poorly designed defrost control or a defective ambient temperature sensor. Those things sometimes need to be calibrated.  
    This discussion is getting way too detailed and technical for an online forum. Contact me off-list if you’d like further assistance.

  53. Just turn off one of the
    Just turn off one of the breakers at the air handler to cut the AUX heat in 1/2. One will have the blower also, so be sure to get the correct breaker.

  54. I’m having extreme
    I’m having extreme electricity usage when my electric heater is running. I’ve narrowed it down to that by looking at my smart meter data. When no heat is being used (turned off)my daily usage drops to about 10-12 kWh a day (I’m frugal)and jumps to 115 and over when heat is on. I live in Houston and it has not been that cold here! 
    I’ve had two HVAC calls and a number of friends take a look and no one has found a problem. Any hints to guide me as to what to do? It’s tough to pay HVAC as I have to pay the high electric bills and that leaves me broke. It is warm enough now that I can leave the heat mostly off but I’d like to get this fixed.

  55. Long distance guess – system
    Long distance guess – system is straight cool and so relies on electric aux strips as sole cource of heat, OR it is a heat pump with a major problem such that the compressor won’t run properly in heat mode 
    I would also look for a gross duct leak in an unconditioned space…you could be trying to heat all outdoors!

  56. @Donna, amplifying on Curt’s
    @Donna, amplifying on Curt’s comment, you didn’t say if you have a heat pump (which is the topic of the article here). If’s you’re not sure, check to see if the outdoor unit is operating during heating calls.

  57. Hi, I’m looking for any
    Hi, I’m looking for any advice or suggestions regarding my current energy situation. My family moved into a house that was built in 1974 in December 2013. The previous owners had put in a Lennox Electric Furnace & heat pump in 2006. We are in South Dakota and our winter months getting pretty cold. In the first few months we moved in our electric bills ranged from $700-$1000 each month. We had several techs out that couldn’t find anything wrong, and the 3rd person that came out said the unit had wires that were connected wrong. This wasn’t until April 2014 that this was found and by that time the weather was getting nicer. Our summer bill usage averaged last summer around 1600 kwh each month. Once winter hit again the monthly kwh usage went from 6,404 to 7,479 to 8,444. I had another tech out this month and he found a wire was burnt out, but said everything else looked good. I’m wondering if this seems unusual to anyone else for an electric furnace or if there are any other suggestions on what I could do? We have a 2 story house (2,000 sq feet) and an unfinished basement (750 sq feet). We also replaced all of our lighting with LED bulbs, and have brand new energy star kitchen appliances and washer/dryer.

  58. @Stephanie, there’s no way to
    @Stephanie, there’s no way to diagnose in a forum like this, but it’s possible the heat pump may be configured to shut down when the electric furnace turns on, perhaps at a pre-set outside temperature.  
    A lot of hvac techs think this is the correct way to configure a heat pump, but it only leads to much higher energy bills.  
    At 0F, a 2006 vintage heat pump is still approx 2x more efficient than an electric furnace. But it doesn’t have enough capacity to keep your home warm at that temperature, thus the need for supplemental heat.  
    The other possibility is that your heat pump has a problem. Now that the coldest part of the winter is past, you can easily test this by having the tech temporarily disconnect the electric furnace. If there’s a separate breaker for the electric heat elements (vs. the air handler) you can simply turn off that breaker until it drops below freezing again.  
    The heat pump should be able to keep your home warm when it’s in the 40’s or above outside. That way you can be sure your heat pump is working properly.

  59. I have had this exact same
    I have had this exact same problem. My house wasn’t going below 85 and it was unbearable. I’m curious if I am just doing something wrong or if there is a loss of connection. Thanks for the article.

  60. Update. HVAC guy is coming
    Update. HVAC guy is coming back out again today. He’s been here off and on 3 times since I last posted. It is getting better. The heat pump and air handler power consumption is now only about a third more than it should be. He got upset with me and bought the tools to test static pressure. (aren’t they supposed to have these tools?) My static pressure is way off. Changing out the reversing valve…. again. 
    In the mean time, by utilizing my TED unit, I found two major massive power draws and “house burn down” problems. The main breaker (outside disconnect), was melted and burnt. It couldn’t be seen without the meter pulled. And I found a wire going to the outside lights that had melted the supply, neutral and ground wires together. It was pulling 1.5kw per hour. I’m a very lucky person that it didn’t catch fire.  
    My power bill went from 2800kwh down to 419 this month with the AC off.

  61. I had much the same problem.
    I had much the same problem. SO, I got rather a lot of 240v baseboard heaters (surplus and wayfair sales) and ran them on 120v, knowing that they’d produce only 25% of their rating and be a LOT safer to use (no furniture arrangement troubles). These I hooked up with either Honeywell disc type thermostats or digital thermostats (with fan mode engaged so its either on or off). I used many of all of the above so that nothing could possibly overrun considerably. The thermostats are mounted in short depth boxes, surface mounted at floor level so as to do really relevant measuring.  
    The electric bill fell by 75%.  
    The inconvenience is that changing the temperature means visiting each station. That was an initial challenge until everything was set. Afterwards it has maintained suitable temperatures all year long without any additional labor.  
    An additional limitation is that if the heat is shut off for vacation, the house will not reaheat quickly and may take more than a day (were it not for some help from space heaters and the oven); however, were that not the case, indeed the 25% powered baseboards with high accuracy thermostats will hold up in the very worst winter conditions down to 38 below without varying the room temp more than 1 degree.  
    Apparently, physical bulk and heat at floor level are key factors for resistance heat. Of course, heated floor could have been more efficient, but I wasn’t really motivated to replace all of the floors.  
    Physical bulk could be in the form of my undervolted baseboards or modern radiant panels or heated floors, all of which are far more efficient than anything with a blower.  
    In my opinion ductwork with resistance heat is a request for horrid bills and whatever you do, just don’t do that.  
    It is notable that the shoppers at amazon have been routinely using the 600W big panel heaters along with plug-in digital thermostats, and I see that the heaters are positioned low enough to suck cold air off the floor, meanwhile the thermostats are on typical outlets low-positioned close to the floor, which almost guarantees fair accuracy. Not surprisingly, it takes a lot of units and their bills fell dramatically.  
    Resistance heat operates efficiently when it is at least 2% of the room’s total bulk, when there is no blower involved and when the sensors are close to the floor.  
    So, by all means, disable the heat-strips in those awkward ductwork systems.  
    That is all.  

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