Heat pump clothes dryer

[rickwai]

Ah I had no idea these were all ventless with no option for vented, but I guess it makes sense. Here is a study meta analysis that actually goes into some minor detail about the process. The main advantage is capturing some of the heat out of the waste stream and recycling it in the process. Hybrid heat pump dryers with standard electric heating elements along with the heat pump came out to be the most efficient. The median payback period on the energy savings from one study mentioned was 22.1 years. The one trick they seem to miss as far as I can see - they did not compare them to unvented operation of standard electric dryers where the process heat is also recaptured at basically 100%. The bonus over a standard dryer in that case would be very low, most likely zero. Since most people only operate dryers that way in the winter, it would at least have a part-year efficiency bonus in most installations.
Heat pumps in unvented space/appliances don't make heat more efficiently than a simple heating element in an unvented appliance of course, and that's always the rub... Your just stealing exact same quantity of lower quality heat out of the room, increasing the energy quality temporarily for a constrained high entropy process, where the entropy of the compressor is also useful to the process. It takes the exact same amount of energy to evaporate the water out of the clothes, no matter how you spin it (heh heh) - all that matters is how much energy is wasted to the exterior of the process/building/etc. The energy state in any unvented appliance install where heat/energy does not exit the main containment vessel (home/reservoir) will always be at equilibrium.

I was thinking along the same line. You are using conditioned air inside from your home that you paid once to condition for the heat source. It would be interesting to see whole home usage before and after to see what the true savings are. I have a heat pump on my inground swimming pool. It is a no brainer, I am using the free heated outside air for my heat source.

 

[ManitobaSky]

I can’t see a ventless heat pump costing you anymore for heating the room in the winter. Remember the heat it takes from the room never leaves the room, the only way you could lose heat is the water it pumps down the drain. In the summer could be a different story, but any dryer is adding some heat to the space in that case. My current ancient electric vented dryer is on it’s last leg. My house is all electric baseboard heat on Mysa thermostats and I can see a spike in the baseboard draw when the dryer is running. I’m seriously looking at a heat pump dryer as a replacement. The Lg and Samsung compact sets are basically the same cost as the vented version, Bosch and Miele are of course way more money.

 

[ManitobaSky]

Well I ordered the LG pair way back in February and it finally arrived the end of September! Done a few dozen loads with it now, seems to work fine. Dry time for a “normal” load and the eco setting is 1 - 1.5 hours. No signs of a spike in humidity in the room and less then a degree of temperature change. At some point I’ll measure kwh usage per load.

 

[Brian26]

Well I ordered the LG pair way back in February and it finally arrived the end of September! Done a few dozen loads with it now, seems to work fine. Dry time for a “normal” load and the eco setting is 1 - 1.5 hours. No signs of a spike in humidity in the room and less then a degree of temperature change. At some point I’ll measure kwh usage per load.

I couldn't turn down this LG Inverter heat pump dryer display model marked down 50% for $449 at Lowes. I have it hooked up to my Emporia energy monitor. It's soft starts just like a mini split and ran around 300-325watts. Easily could be run off a battery or generator. Total electricity consumption for an average load has been around 750 wh. Pretty incredible it uses less than 1kwh of electricity. My old Samsung dryer would use close to 2.5-3 kwh a load and the 4.5 kw elements used 14 times the electricity. You can see my old 4.54 kw peak demand on the Emporia from my old dryer.

 

[EatenByLimestone]

Does it take longer to dry than the old one?

 

[semipro]

Ours has worked for 2+ years now without issue and the maintenance has been relatively easy (cleaning out 2 easy-to-access lint filters).

 

[ManitobaSky]

Does it take longer to dry than the old one?

Yes 1.5 hrs vs 50 minutes or so in my case, but it still only uses about a 1/4 to 1/3 power per load.

 

[begreen]

Chatter about HWHP etc moved to new thread on Energy Recovery. Let's keep this one on dryers.

 

[EbS-P]

Chatter about HWHP etc moved to new thread on Energy Recovery. Let's keep this one on dryers.

What if I hook my dryer vent to my HPWH intake?

 

[EatenByLimestone]

Please take video!

 

[semipro]

What if I hook my dryer vent to my HPWH intake?

We've effectively been doing this for over 10 years now.
Our HPWH has shared a room with both an open-circuit ventless Bosch clothes dryer and now a closed-circuit Samsung HP clothes dryer. In both installations, any heat produced by the dryer was available to the HPWH via warmed air in the room.
I've also installed other equipment that creates heat (e.g. solar PV inverter, freezer) in that same room.
The dryers exhausted water into a nearby utility sink and any other moisture that might escape the dryers is quickly removed from the air by the HPWH.

 

[begreen]

Catching up on YouTube videos, I found this one relevant to this discussion. I like that the pros and cons are both explored.

 

[Brian26]

I don't think people realize how efficient these dryers are. I have yet to top 1 kwh with an average load. 750 wh has been the average.

Estimated yearly consumption off the yellow energy star rating is 155 kwh a year with the new unit. My old Samsung was 825. With electricity prices in the .30+kwh here in New England the savings are astronomical.

https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a

Also, these numbers don't factor in a traditional vented dryer sends an obscene amount of conditioned air outside. ..

 

[DBoon]

The heat pump dryers are very nice, and very efficient. I looked into getting one of them but the price premium didn't make sense for me because I don't use my dryer that much. I opted for a ventless dryer instead, which is about half the per load electric consumption of a regular dryer (but twice that of a heat pump dryer). It also doesn't exhaust to the outside, which was my key consideration, and the air exhausted inside isn't very hot and is not humid (it will warm the house up in the summer, but that is what the clotheslines and dryer racks can help avoid).

 

[RichBenn]

I’m a “low hanging fruit” kind of guy. It seems to me, that unless you use your dryer alot, there are many other areas and ways to save much more electricity. Of course, if you need a new dryer anyway….

in my own case, I use a clothesline, except for the winter.

 

[peakbagger]

I have never owned a drier. When I bought my house I bought a high efficiency horizontal axis washer made by US company called Staber. They were making rugged horizontal axis washers long before the big names came out and have a very fast spin that drives out most of the water from the clothes. The clothes are dryer out of the washer and that means shorter drying times. I have a line set up in unfinished room in the summer and down in my basement near my wood boiler in the winter. The only thing I miss out on is a dryer tends to fluff clothes and make them softer.

Staber still makes the same washer but they do not advertise and the price is high. They dont have dealers they ship direct. They dont have transmission, just a belt that is easy to replace if it ever needs to be. Its heavy gauge stainless steel drum and it used mechanical timers and switches. Despite being a horizontal axis machine its top load so no seals to leak like many of the front load horizontal axis machines. Mine is 33 year old and I have never needed to do anything to it. It comes with a complete repair manual and parts are a phone call away since they have kept the same design for a very long time.

I expect it would pair well with a heat pump dryer as the clothes come out so much drier out of the washer than with a conventional washer.

 

[begreen]

Yes 1.5 hrs vs 50 minutes or so in my case, but it still only uses about a 1/4 to 1/3 power per load.

Was the old one run on high heat or low heat?

 

[twd000]

I couldn't turn down this LG Inverter heat pump dryer display model marked down 50% for $449 at Lowes. I have it hooked up to my Emporia energy monitor. It's soft starts just like a mini split and ran around 300-325watts. Easily could be run off a battery or generator. Total electricity consumption for an average load has been around 750 wh. Pretty incredible it uses less than 1kwh of electricity. My old Samsung dryer would use close to 2.5-3 kwh a load and the 4.5 kw elements used 14 times the electricity. You can see my old 4.54 kw peak demand on the Emporia from my old dryer.


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that's a great price; I'd jump on that if I could

unfortunately all the HP dryers I'm seeing are $1200 and I would only saving $100/year compared to conventional electric dryer