My great tumble dryer debate

Leew1988

Hi all

This is a post about my washing / drying clothes and energy savings, main objective is that my clothes do not smell because I usually wash my clothes on a 1600 spin and then hang on an air maiden in my spare room, but winter is coming so the thicker cotton clothes dont like to dry fast enough. 

I have become fixated on buying a new tumbler dryer because I have an older White Knight vented dryer that doesnt even have sensor drying, its got a low or high heat setting with a turnable timer knob and a start button, thats it. 



Have been reading articles about the differences saved between vented and heat pump dryers, the difference seems massive but before I jumped the gun I thought I would do my own test.

This is my smart meter showing when tumble dryer was off for a fair comparrison 



So then I turned my tumble dryer on, on low heat



And then on high heat it is this 




I had it on for half an hour just to give my clothes abit of a boost in dryness last night before I put them on the air maiden to finish off, 1 full hour would be a fully dried cycle so I am not sure what I am missing here 

Either why is mine so cheap? According to that article snip above and others very similar, my vented dryer is half the price that these claim and is closer to the heat pump dryer, so yesterday after seeing this I decided I would just keep my vented.

What am I missing here? Quite eye opening or just confused im not sure

daveyjp

We had a heat pump dryer for 4 years, when it failed we went back to a condenser.  No noticeable change in electricity use.  Condenser takes 45-60 minutes, heat pump 2-3 hours.  

lohr500

What is your electricity cost per kW/H at the time when you did the test (+/- 19:45)? Are you on a single tariff electricity rate or some form of time of use tariff? 

Was there any supportive information further on in the snip you pasted stating what cost per kW/H had been used for the comparison? Just wondering if the comparison was done at the point when electricity costs were at their highest.
 
Can you switch the in home display to show kW instead of cost? Then repeat the test and see how much power the drier is using?

MultiFuelBurner

As a comparison our vented tumble is 2kwh to run for an hour on full. On eco 1kwh an hour and can dey everything about 0.5kwh cheaper that going full blast for an extra 30 mins of runtime.

Today it will be on for four hours as the tracker price is 11pkwh so 90p roughly for three loads of bedding towels and darks. The washing machine is 1kwh so that's roughly 35p.

vic_sf49

I suspect the calculations in that example at the top, are because the dryer was on for 2 or more hours.

It just says "per cycle" and also doesn't state if they're filling it with 8kg of wet clothes. 

Your 88p-13p, (this would be easier seeing it in kw/h) = 75p/hour, so about 2.7kw/hour. (based on electric being about 27p per unit) 

So double or triple this 75p, for two or three hours respectively. 

(No clue what tariff you're on, or what you're paying for electric.) 

My dryer is also rated at 2700w, so two hours would give 5400wh, or 5.4kwh ish. 

I don't think mine runs at 2700w for the full time, but I've never checked it with a Tapo / similar plug.

(If people want to sanity check my maths, that'd be good, thanks.) 

Leew1988

Ah I understand, OK I have just obtained the requested infos 

So this is tumbler off



This is on low heat



This is high heat



And this is my tariff

Leew1988

I guess what I am wanting to know is my tumbler as stupidly expensive as these articles make out with it being a vented or is mine fairly cheap because it seems fairly cheap to me? I can put a full bed set in mine on high heat for 60 minutes and its bone dry

Do I jump the gun on a heat pump dryer thats going to save me loads of money in energy after splashing out £400 to buy it... or do I just keep what I have O_o

Sorry I get too fixated on this sort of stuff, I need like-minded people to help decide for me sometimes or show me the facts at least

MultiFuelBurner

Yes you will recover the cost of a heat pump tumble dryer with a 5 year warranty if you use your vented tumble dryer regularly. The only downside is maybe the time to get the best efficiency from a heat pump tumble dryer 2-3 hours per cycle.

It has been discussed here in the past.

Gerry1

Welcome to the forum.

So the power drawn is 1.442kW low and  2.688kW high.  However, what you really want to know is the energy in kWh used to dry that load.  It's not straightforward because the thermostat will mean that it will switch off and on throughout the drying cycle.

A better way would be to take meter readings at the start and finish.  However, that would include the background usage (fridge, freezer, standby etc) so not fully accurate.  You could take another reading after the dryer had been switched off for the same length of time that it had been on and subtract the increase.  It's a bit rough and ready because the fridge and freezer might have been working most of the time.  You could repeat the test over a few weeks and get an average, or switch off the fridge and the freezer during the test (keeping their doors closed).

A better way would be use a plug in energy monitor so that only the dryer's usage was measured.

Incidentally, your background use is high if only the fridge and freezer were in use.

Finally, having a sensor may be slightly disappointing.  I had a White Knight gas dryer with the same low/high switch and rotary knob timer and it was easy to set it according to the load.  I now have the version with a sensor with and digital controls and umpteen programmes but even on the driest sensor setting it usually fails the mirror test and needs a few more minutes.

I don't know the relative efficiencies of the new types of dryer but I suspect that the payback time of upgrading will be long.  May be better to wait until the existing dryer fails: my original White Knight lasted 30 years and just needed a few cheap thermostats which were cheap and easy to fit.  I doubt whether a modern hi-tech machine would do so well.

wild666

I have a heated airer and it's rated at 1000 W and uses between 1.75 and 2 kWh to dry a load. I could have bought a smaller one that was rated at 600 W but I opted for the larger one.

Rodders53

My heat pump dryers consumes about 600-750 Watt-hours per washing load * .  (Usually spun at 1400rpm).  Sometimes less if smaller loads (e.g. a few shirts to save creasing / need to iron).

Not to 'bone dry' levels but folded/hanging clothes then sit in our airing cupboard (with our HW tank) for a day or two before being put away properly.

* Measured with a plug in energy monitor.  Get one to find the real use of your dryer with the loads you dry in it.