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Community and Q&A

Heat pump dryer

Ryan Magladry Ottawa, Ontario | Posted in Green Products and Materials on

Not so much a question but a review on a “green” product.

Recently purchased the Whirlpool YWED7990FW heat pump dryer with matching washer for new home construction.

I ran 3 loads of laundry through the pair, the washer worked ok, it was louder than our current Kenmore model (6 years old).  Very basic features, laundry was clean, so we can’t really complain about its function.

The dryer on the other hand really disappointed me.

There are 4 temp settings on the machine “High, medium, low, and extra low”.   Thinking the heat pump would dry on a relatively cooler setting, and thus thinking it would take a longer time to dry.  My first load consisted of a single standard queen set bed sheets.  The high setting was very hot – very similar to a conventional electric dryer on medium/high.  The load took about 60 minutes to dry.  Not bad.  Main complain is that there is a “cooling vent” on the rear of the unit, not used to vent the humid air from the clothes, but used to vent the waste heat from the heat pump.   There is a small fan in this opening, that assists in moving air over the heat pump.   The heat pump runs very hot, and the discharge air from this vent is very warm.  By the end of my first load, the laundry room (8×5) was 92*.  The room has double doors.
Second load, was another set of sheet, this time i tried the “extra low” setting, hoping it would use cold air to cool the clothes.  Nope, just a slightly less hot setting, but still hot.   The room was still being pumped full of hot air, I even left the doors open to help ventilate the room (but that’s not really the point of a laundry room is it?)  The room was still so hot, that i worried about the long term affect on the walls.  This disappointed me.  the dryer works, it only dry’s hot, it takes a bit longer than normal, but it discharges a crazy amount of hot air into the room.   My indoor relative humidity level seems to jump up by about 3-4%, about 25 feet away.

I find it really hard to believe that generating all this heat (even by heat pump) would be more energy efficient than a conventional electric dryer set to dry on “air fluff/cold dry” setting.

Needless to say, we managed to get our dealer to agree to a 25% restocking fee, and exchanged the paid for an LG set that was on sale.  I will now be cutting a hole in my rim joist and installing a heartland airtight dryer vent cap to try to keep outside air out.

For everyone interested in the vent-less heat pump models, hopefully this review helps in their decisions…

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Replies

  1. Jonathan Lawrence CZ 4A New Jersey | | #1

    Ryan,

    Thanks for sharing. I had to buy a new dryer about 6 months ago (forgot to take a screwdriver out of my work pants and it screwed up the dryer) so I took the plunge and bought a Miele heat pump dryer. I am very happy with it. It drys clothes in about the same time as the previous dryer. It does raise the temperature of the room, but only by a few degrees.

  2. Chuck Baynton | | #2

    Is a heat pump dryer the same thing as a condensing dryer?

    1. Jonathan Lawrence CZ 4A New Jersey | | #3

      No. The following is from LG:

      A heat pump dryer is one of the new terms being used to describe ventless dryers. Heat pump dryers tend to use what is known as air-to-air condensation drying technologies. The heat pump is designed to recycle and reheat the air within the dryer rather than blowing the heated air outside. By recycling the heated air within the dryer itself, it cuts down on energy usage and is more energy-efficient.

      Another term being used to describe ventless dryers is condensing dryer. This term is rather popular in the United Kingdom and other places in Europe, where ventless technologies have been around longer than they have been in the United States. A condensing dryer uses water condensation drying technologies to dry clothes.

      Water condensation drying also uses heated air, but, rather than using cool air to remove the moisture from the warm air, it uses cool water. The colder water cools the heated air and causes the moisture within the air to turn into water. The water is then pumped out of the dryer, down the same discharge drain used for the washer.

      It is worth mentioning that a heat pump dryer also extracts moisture and converts it into water, which is pumped out the dryer and down the discharge drain. The only differences between the two technologies is how they dry the clothes by either using air-to-air condensation or cool water condensation. Both types of dryers are much more energy efficient than conventional vented dryers, and they do help reduce energy bills.

  3. User avatar
    Stephen Sheehy | | #4

    For what it's worth, our Whirlpool heat pump dryer works fine. I haven't noticed any unusual heat in the laundry/ mechanical room. We usually set it on "eco" mode, rather than choosing a temperature.

  4. Alan B | | #5

    An unvented dryer will release heat into the room equal to the electricity it uses. Mine uses about 2-3kW/load so its putting that exact amount of heat into the room. In winter it saves a bit of heating, in summer it adds a bit.
    So your device was acting 100% normally.

    The conventional dryer sucks conditioned air out of your house which gets replaced by unconditioned air. But it does not heat up a room appreciably because it throws your heated air outside.

    You can do the math but i suspect you will come out ahead with the heat pump dryer, it uses 25-50% less energy, in winter you get some free heat but in summer you will have to add some energy to remove the extra heat. Assume 33% extra with a COP 3 air conditioner. But if your saving 25-50% of the electricity then 33% extra is probably going to be not a huge loss or even a slight gain. So you actually win in any 4 season climate that goes below room temperature during the year otherwise its probably a wash.

    Is this a FUD post?

  5. Jonathan Lawrence CZ 4A New Jersey | | #6

    I will put my Kill-A-Watt back on my dryer, but I recall that is was using around .75kw/load.

    1. Alan B | | #7

      You have a 240V kill a watt?
      Also 0.75kW unless we have vastly different units that can't be right, mine uses 1500W for 1.5-3 hours a load. I use mine on normal which iirc is medium heat for a mixed load, a towel or two at most and regular clothes.

      1. Jonathan Lawrence CZ 4A New Jersey | | #10

        Alan,

        My dryer 120v. The dry times are 1 hour max. I am very impressed with the unit especially considering there are a lot of less than stellar reviews of HPD.

        What brand do you have? Mine is Miele.

        1. Alan B | | #11

          Ah, for some weird reason i assumed you had the same Whirlpool as i do.
          Your numbers are amazing though, do you have a link to your model, i am curious how it works and uses so little power.

  6. Ryan Magladry Ottawa, Ontario | | #8

    It's an honest review, many visit this site looking for input on this and that with respect energy efficiency. We did. We tried it. We weren't happy with its impact on our 8x5 laundry closet with 2 double doors open. I should say that the laundry room is fully insulated with Rockwool for sound deadening, and leaving the doors open for added ventilation completely defeats the purpose of having a laundry room/closet. For the last 6 years my wife and i have done 90% of our clothes drying on "air fluff/cool dry" setting. very little heat. You can open the dryer door the second the dryer signals it is done, and the load is luke warm at best, slightly above room temp.

    I have no doubts that the heat pump dryer is X more efficient than a conventional electric, at however the standard dryer ratings are measured. I don't dispute its ability to dry, it did with heat. I do, without quantitative evidence, find it hard to believe that even in heat pump mode, generating all of this heat is more efficient than the air fluff/cooling dry method that our family is accustomed to. The energy used for the motor to tumble dry should be equal, fan to move air through dryer should be equal. And if heat imput is 5x (?) lower on air fluff/cool dry settings compared to standard electric, but heat pump with 3x efficient heat source compared to standard electric + pump for water discharge energy, i doubt there is much energy difference when comparing how we use a standard electric versus how we attempted to use the heat pump dryer...

    1. Alan B | | #12

      So hold on, you put it in an insulated room, introduced 2-3kW of heat in a short time and wonder why the small room got hot?
      The answer is simple thermodynamics [facepalm]

      If you don't want to believe math thats your business but we have yet to find a way to defeat the law of conservation of energy. The reason a regular dryer does not heat up your laundry room is that its throwing the heat outside using indoor air to do it which means exterior air comes in to replace it form elsewhere in your building. Being in Ottawa much of the time thats going to be below room temperature which compounds (but shifts) your losses.

      I can understand you might not like the sound of laundry and the fact your solution is a headache for ventless but it does save energy and no laws of nature are being broken here. If you wish to test this then leave your dryer exhaust in the small room instead of venting it outside (while closing off he now open route to outside temporarily) and your room will get even hotter then the ventless. This will cause lots of other problems from amazingly high humidity to lint/dust issues which could lead to health issues but doing it once should be instructive and relatively low risk. Just leave the door open afterwards to let out the humidity which will cause your appliances to rust and clean up the lint.
      You can use this kit to reduce the dust problem somewhat, though long term this is a bad idea but if you really want to understand what i am saying it would be $20.94 + tax well spent.

      On second thought this won't even work because at 100% humidity your going to have condensation issues plus your clothes will never dry. So you will need to add dehumidifier, even more wasted energy, but seeing is believing...

  7. Trevor Lambert | | #9

    Keep on mind that the conventional dryer is venting all that hot air outside. If it was keeping it in the room, you would notice it getting a lot hotter than you experienced with your heat pump dryer. They do use a lot less energy, that's pretty much a fact.

    If you live in a climate with a significant heating season, the extra air brought into the house to be heated as a result of long cycle runs on cool/fluff would be significant, and I suspect might actually use more energy than just running a hot cycle on a conventional dryer. I tired drying clothes on one of those cool cycles once and it took forever. Literally, I gave up after what seemed like all day and just dried the load hot.

  8. Joe Dwyer | | #13

    We've been using the YWED7990FW heat pump dryer for over two years now. It works, but has some limitations. First, this large size (7.4 cubic feet) unit is a heat pump only model and doesn't have backup 'hybrid' electric heat strip for supplimental drying. It's the cheaper of the two models, but also less ability to quickly dry clothes. Second, it does take 50%-100% longer to dry clothes compared to standard vented electric clothes dryer. Third, it dries at a lower temperature- 105F on low temp. setting to 130F on medium or high temp. setting. Our old vented electric unit was 128F on low and 'baking' on high. Air dry on old unit was just room temp. air and useless. Finally, the major limitation of this unit is lint buildup on the interior coil, after going through two filters, without an easy way to clean it out. There is a video online of someone in Romania? taking one apart to get to the coil and it doesn't look fun. This is a major overlook by Whirlpool!!! I have a service contract that will be utilized soon for this issue, which results in longer cycle times.

    Energy wise, vented clothes dryers suck a huge amount of conditioned air from homes. I estimate app. 1 kWh/load average as energy savings from not venting here (zone 4). This amount goes up pretty quickly with sub zero temperatures further north.

    We need a better engineered model with more lint filtration capacity and/or easy access for cleaning the coil.

    1. Alan B | | #14

      I noticed that there is a buildup inside the unit that i can't get to. Not sure what to do about it
      This may explain why i was able to dry in 1 1/2 hours when it was new but takes 2 hours minimum now.

      1. Trevor Lambert | | #15

        After reading these reports (there's a couple on Whirlpool's website as well), I took a look inside my dryer. I see the problem in mine as well, and it's a major design and/or build quality f-up. There's a lint screen in the usual spot, then a filter assembly just before a screen, then the coil. The screen in front of the coil is like bug screen in terms of grid spacing, so I'm guessing it's there just to keep large objects from getting put inside. The problem is lint gets past the filter. From what I can tell, some amount bypasses it completely. There's always lint on filter assembly on the downstream side of the seal. I think I will try putting an additional filter in front of the screen, maybe a couple of layers of cheese cloth. I don't expect this to be a complete fix, but hopefully it will lengthen the time between coil cleanings to something more manageable.

        1. Zephyr7 | | #18

          Probably best to use a non-lint like material for the extra screen. I’d use wire mesh. Here is a link to a source I’ve used for wire mesh in the past:
          https://www.twpinc.com/wire-mesh-material/stainless-steel?size_option=4&surface_finish_coating=72
          They have lots of options, I’d use stainless steel (since it’s stiff), some kind of fine but not too fine mesh size.

          There is a great flexible duct cleaning attachment for a drill that I found somewhat by accident at Lowe’s a month or so ago. It’s great for clearing out lint that you can’t quite reach. It looks like several types of brushes that screw onto the ends of flexible plastic rods.

          Bill

  9. Rick Evans | | #16

    Looks like Whirlpool is the only option for a full size heat pump dryer. The others are all approx 4 cubic feet models.

    Has anybody used these? I'm wondering if my family of 2 (wife and me) could manage with such small appliances.

    1. Trevor Lambert | | #17

      My in - laws have a 24" matching pair. We lived with them for a year, a total of 4 adults and a toddler. I found the size annoying for that amount of people, though we certainly still managed to get all the laundry done. I suspect for two people it would be fine. On the other hand, I only ever did laundry for three of us. So I found it annoying for three, but I know my in laws are perfectly happy with it for the two of them. It's subjective.

      1. Rick Evans | | #19

        Thanks for the feedback Trevor!

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