Heat Pump Tumble Dryer v De humidifier

[dgethin]

I am having a debate with my son-in-law. He has got a Samsung dv80ta020ae heat pump tumble dryer, I am using a 300w de-humidifier for drying clothes. He says his Samsung is cheaper to run.
Im not so sure, is anyone capable to explain if he is correct.
Hope I have got the correct forum!
Many Thanks

 

[James]

The heat pump tumble drier is probably cheaper to run.

a dehumidifier is useful to remove water from the air, this in turn makes it quicker for the clothes to dry by releasing their moisture to drier air that can hold more water than more humid air.
however, air can hold more moisture when it is warmer and water will evaporate quicker in warmer air. So to dry clothes at any reasonable speed, not only do you need the dehumidifier to dry the air, you also need to be adding heat to the room from another energy source like a radiator or open door to other part of a warm house. This adds an unknown but not small cost to the operation.

a heat pump tumble drier basically does the same thing but in a smaller and more controlled environment and is likely to be more efficient.

 

[snowhead]

Without doing a test run in the same location with identical loads it would be impossible to say.

A basic dehumidifier with no ability to tumble clothes will take a lot longer to dry them.

And a heat pump tumble drier isn't exactly cheap to buy, or repair if it breaks, out of warranty.

 

[dgethin]

The heat pump tumble drier is probably cheaper to run.

a dehumidifier is useful to remove water from the air, this in turn makes it quicker for the clothes to dry by releasing their moisture to drier air that can hold more water than more humid air.
however, air can hold more moisture when it is warmer and water will evaporate quicker in warmer air. So to dry clothes at any reasonable speed, not only do you need the dehumidifier to dry the air, you also need to be adding heat to the room from another energy source like a radiator or open door to other part of a warm house. This adds an unknown but not small cost to the operation.

a heat pump tumble drier basically does the same thing but in a smaller and more controlled environment and is likely to be more efficient.

 

[dgethin]

I normally use the de hunidifier in a small room without any heating. I can dry a load of washing in about 2 hrs!

 

[Lucien Nunes]

It would be interesting to know, but I agree that without tests and measurements it would be difficult to guess the answer to the original question. We dry clothes with a dehumidifier here and find it effective, and suitable for clothes that don't like being tumbled. Since stopping using the tumble drier, I have a distinct impression of them lasting longer.

not only do you need the dehumidifier to dry the air, you also need to be adding heat to the room from another energy source like a radiator

This only applies if using a split-unit air conditioner in dehumidify mode, which dumps the heat outside. All stand-alone dehumidifiers (desiccant and refrigerant types, and single-unit aircons in dehum mode with their hot exhaust returned to the room) actually output slightly more heating power than they consume in electricity. You get both the full input power, plus a few percent extra from the enthalpy of condensation of the moisture. As one of my old mentors used to say, with regard to storage and workshop spaces, the best anti-condensation heater isn't a heater. If you can use the heat that the machine outputs (typically 300-600W) then the dehumidification itself costs nothing.

 

[Hugh the Boatman]

I normally use the de hunidifier in a small room without any heating. I can dry a load of washing in about 2 hrs!

I do the same in my bathroom, and find a 30W fan standing on the floor and a normal sized wash load hung on several spans of retractable washing line dries down to 45% rh in a few hours. I keep a lookout on Freecycle for preloved Ebacs, even ones that "don't work anymore", as there are several faults that can be easily fixed in an hour or two. These include clogged filters and matrices, ice sensors that need regreasing and seized fan motors that just need taking apart and lubrication of the bearings. I'm presently using a 2006 Ebac Homedry.
To compare the electricity consumption of various methods I guess you could plug all the items into a cable reel and plug that into one of those V/A/kWh power usage gadgets.

PS I preheat the bathroom by having a nice long bath while the washing machine is doing its work.