How much a clothes dryer cost to use? Again ......

[terry]

Our very conventional old style tumble dryer timer runs for some 45 minutes per load.

With heater cutting in and out (estimating it's on say 80%?).

Heater elements are either 3000 watts or maybe 4500, haven't had this one apart yet, since I got it in exchange for a dozen beer!

Our domestic electricity costs a little over 10 cents per k.watt hr.

So one load of clothes 45/60 x 0.8 a cost of electricity = 0.75 x 0.8 x 0.12 = 7 cents per load.

Occasionally it is necessary to run a 'heavy' load, towels and blankets etc. part of a second run.

So maybe that could be say 12 to 15 cents per load. In summer we hang bedclothes and towels on outside lines.

[amdx]

I think your math is wrong. I'll split the difference on the heating element wattage and call it 3750 watts. If you ran it 1 hr that would be 3.75kwh. But, you only run it 45 minutes. so 45/60 x 3.75 = 2.8125kwh And, it's only on 80% of the 45 minutes. So, .8 x 2.8125khw = 2.25kwh Then 10 cents x 2.25 kwh = 22.5 cents Mike

[Jules]

I think Mike's right - that should be 45/60 x 0.8 x 0.12 x kW:

3kW works out as 0.75 x 0.8 x 0.12 x 3 = $0.22 4kW works out as 0.75 x 0.8 x 0.12 x 4 = $0.29

... ours is on off-peak so gets 6c/kWh, but I can't remember the wattage on the heater for ours either (and it normally runs for about an hour for a full load)

I don't even know where to begin figuring out how much of that heat is being lost into the house (rather than vent outside) and therefore how much useful work it does for the six months of the year we need to be heating the home anyway.

Yes, same here, when we can be bothered. Sometimes we're lazy and just run the dryer anyway :-) Maybe for the summer I should be painting the thing black and running it outdoors ;)

cheers

Jules

[Existential Angst]

Also, don't forget the draw of drum motor.

As per a previous thread, proly better to divide the electric bill by the total kwhrs, and you will find your kwhr cost is double or triple what the stated rate is. Here in NY it winds up being triple the stated kWhr rate.

So the amount per load in NY could easily be 75c.

You can drastically shorten your drying times/costs with a front loader wash machine. Front loaders are a win-win x 10 situation, drastically reducing the costs/consumption of everything involved in washing: detergent, water, electricity, drying time, wear/tear on clothes (less lint in the dryer), and proly a longer lasting machine due to much simpler mechanisms, drive train. Why they cost so g-d much up front is another story.....

[terry]

Yes Mike and Jules, you are correct, my wrong math. It's more like two to four times my original number. Thanks.

[Tony]

Sounds right to me. I had done a search not long ago and found the average cost to dry a load of wash was between $0.25 to $0.50 depending on your electricity cost. Ten cents is on the low side and it goes up a little over $0.20 in some areas.

[Existential Angst]

Try $1.00, past the initial bullshit low-balled "tier" levels. mebbe 10c for the first 10 kw.... heh.

[E Z Peaces]

Weigh the load going in and coming out. Each pound lost takes 0.285kWh. Some cotton garments are very heavy going into the dryer, and they probably cost a lot to dry.

You would have to add the cost of turning the drum and blowing the air. I could get the wattage by timing my power meter after switching off all my other circuits and starting a load in with no heat. After the load dried, I'd run it without heat again and check the wattage again. I'd take the average and multiply it by the time a load ran.

The exit air is warmer than the entrance air. Without knowing the volume of air my dryer blows, I can't tell if that adds much to the cost.

[Existential Angst]

I think the Kill-a-Watt EZ will do all that. I believe it measures instantaneous wattage AND accumulates kWhrs.... about $25 at Costco. I have one, but haven't used it yet.

[Tony]

Maybe for you, but I take my total electric bill for last month (extra low despite the colder than normal weather because I was away for over 1 week and I don't heat the whole house even when I am here), $125.74 divided by the total KWH's used, 1540 and get my real price at $0.082/KWH That is the total including any taxes, surcharges no matter how many KWH I use, there is no tiered pricing. So using the formula above, drying one load of wash would only cost me about $0.182 , yes, less than 19 cents/load.

Maybe YOU fall for the "initial bullshit low-balled "tier" levels", but that doesn't mean everyone does.

[Bob F]

You have a 110 V dryer?

[Existential Angst]

Heh.... good point.... I wonder if you could use two Kill-a-Watts, on different 120 V legs.... :) I might try that, cuz I bought one for my BIL.

[Bob F]

Mine is 15A max also, so that could limit you too.

[Existential Angst]

FOUR killawatt thingies, then?? googawd, nuthin is simple....

[E Z Peaces]

I just checked mine. My meter is stamped 7.2Kh. Before I turned on the dryer, a meter revolution took 62 seconds, for 418 watts. With the empty dryer turning without heat, it was 42 seconds, for 617 watts. So the motor uses about 200 watts empty. Where I live, that's less than 2 cents an hour.

Next time I dry a load, I can see what the motor uses with a wet load. With the heat on, I can use an IR thermometer to check the temperature of the galvanized vent pipe, which would probably be near that of the air flowing inside. Then if I can estimate the volume, I can estimate how much that adds to the cost.

Suppose it's 5000 liters of air per hour (1.4 liters per second) at

122F. If room temperature is 68F, That would be 192 watts to warm the air. That's about what the motor uses. I wonder how much of the power that goes into the motor ends up heating the air.

If I put in a wet load at 20 pounds and take it out at 10 pounds half an hour later, that's 2.85kWh to evaporate the water and perhaps 0.25kWh for the motor and warm exhaust. In this case, 92% of the cost would come from the weight of water, which could be determined by weighing the laundry.

[blueman]

It's amazing (to me) that our cost is almost 3x as high. The total cost per kwh (including tax, generation, transmission, fees) is a whopping 17.7 cent/kwh without any possibility of off-peak.

It's hard to believe that the "free market" price (in the absense of governmental regulation) would be 3x as large particularly given that electricity is: - An almost pure commodity (a volt is a volt is a volt) - Transportable (and relatively efficiently too with new power line technology) - Easily buyable/sellable - Mature technology

[blueman]

Yeah but isn't the 220 draw from hot to hot with the only current returning through the neutral being the 110v leg that typically runs the light and the motor. So, I'm not sure that hooking up two of them would work (plus I'm pretty sure they are not rated at the 35A or so amperage of a dryer).

I think the easiest thing would be to put a clamp-on ammeter on it -- which shouldn't be too hard since one typically has easy access to the dryer end of the cord where the wires terminate. Don't forget to measure current in both legs of course.

Actually, with a clamp-on meter, would you get an accurate rating of

220v current if you clamped around both hot legs but with the direction of the wire in one of the legs reversed 180 degrees -- my thinking is that reversing the wire direction would make both currents appear in phase and hence be additive...

[dpb]

blueman wrote: ...

Where do you think there's an absence of regulation that affects utility pricing regardless of where you are (which w/o knowing either makes specific reasons for rate differences impossible but)...

- there's still voltage drop and line losses

- there's very little installed new power line w/ advanced technology that makes much difference as yet (it's coming, and there is some installed, but it's quite insignificant amount in overall scheme as yet)

- but not storable so it is used as generated (and therefore required to have the capacity to generate however much is needed to be used at any specific instant)

- a great deal of which is "excessively mature" in terms of thermal efficiency owing in large part to regulation that makes replacement such a difficult process (read expensive) that it isn't done as frequently as otherwise would be. Something otoo 65% of generation facilities are 40+ yrs old

--

[Pete C.]

About a quarter is what I calculated a few years ago. My time to hang and remove clothes from a clothes line is worth more than a quarter, I'll stick with the dryer. The re-wash after the occasional bird crap incident or being blown off the line in a wind gust also negates any cost savings.

[trader4]

There you go again. As Tony pointed out to you, just because that's how your electric company pricing is structured, it doesn't meant that it's that way everywhere. Here in the next state over, NJ, my residential rate is fixed at a flat rate per KWH.

Most of us here would say the large upfront price differential should be factored in before concluding that front loaders are a win-win situation. And I'd say if you do that and factor in the time value of money, in most cases they come out to be a losing proposition.