Not particularly.

The only substantial advantage to newer machines is in those equipped with electronic moisture sensors for the auto-dry cycles, instead of thermostatic sensing which is not as accurate and consistent.

Some newer dryers do have stronger blowers and/or higher airflow, but that depends on the brand/model.

And a few have dual heating elements, one higher wattage and one lower. At higher temperatures (cottons, towels, denim, etc.) both elements operate. At lower temps (delicates, sometimes Perm Press) only the the lower-wattage element may be used.

Of course, the drum, door, and exhaust seals on an older dryer may be worn/leaky, so some increased efficiency may be gained with a new dryer on that point.

I just add that you will not recoup the cost of a new dryer in any savings even if there are any. I'd keep the dryer you have until it dies and then buy a new one. There's no guarantee of savings with a new dryer. There's too many variables involved.

There's no HE dryer... they're all "efficient"

Depending where you live, there's the usage cost of electric vs. gas

Here in Wisconsin, electric dryer usage would cost me almost 3x the cost of gas dryer usage.

I agree with everything said so far. Just to add...

Your venting efficiency can play a large roll in overall drying efficiency. We went from a longish 2 x 90 degree bend venting (still within venting specs) to a 4 foot straight run and found the drying time reduced substantially. Sometimes your just stuck with a bad setup with no good options, but if that can be improved it can have an impact. Also keeping it clean helps a lot. I've also played with varying the drying temp on our new gas dryer. It seems like I can dry at lower temps with only a small increase in overall runtime. The increased air movement probably plays a sizable roll.

In terms of other electric dryer technology, there have been development and sales of heat pump based dryers in Europe. They were expensive and complex. Don't know if they are still offered or not (companies like V-Zug and Blomberg).

Electric resistance heat is no more or less efficient than it was 50 years ago. Blower and drum motors have become more efficient and some would say modern bearings have less friction than previous designs but NONE of those things compare with heat-generation in terms of overall energy use -- which is what most people mean when they talk about "efficiency".

Basically, I'm saying keep what you've got if it's working. If you want something new because of capacity or convenience features or controls, by all means go ahead. However, don't expect to make sense of it by lowering your electric bill. Nothing significant will happen there.

Agree with other poster about short/clear vent.

To increase my electric dryer system efficiency, I am thinking of adding a heat exchanger and positive intake and output ducting. Maybe a heat exchanger like this:

http://www.americanaldes.com/HRVRes.html

They are made for air exchange, but I think it would do a lot to recover the waste heat and increase the system efficiency.

Here are my assumptions:

1) Up-front dollars do not matter. This is an experiment.

2) I'll have to filter the lint very well to avoid plugging the heat exchanger.

3) I'll have to modify the dryer so it takes in all its air at one location (this may be problematic). I may try to enclose the dryer a bit, or open it up and see if I can run a duct to the fan intake.

4) The dryer will no longer suck warm, room temperature air (that I have paid to heat with expensive propane) and force it outside the house.

5) In the winter, I would hope to see something like this:

____ a) outside air is 0 F
____ b) dryer output air is 130 F
____ c) heat exchanger warm outlet (input to dryer) should be at around 100 F
____ d) exhaust air to outside should be around 30 F
____ e) air coming into the dryer would be very "dry" since it has been heated in the exchanger

(please note, I have not done the math, I'm just shooting from the hip)

6) The condensation is handled in the heat exchanger, it has a drain tube.

7) In extreme cold weather, the condensation in the heat exchanger might freeze up. There might have to be switchable a warm air (from inside the house) inlet if this proves to be an issue.

8) In the summer time I am worried that the intake air to the dryer (warmed up by its exhaust) might be too hot.

OK, so there is my idea. Pile it on.

ref:
http://www.google.com/search?q=heat+exchanger+clothes+dryer+-patent
http://www.homeenvy.com/db/5/405.html
http://www.freepatentsonline.com/7213349.html
http://www.laundrysystems.electrolux.com/Files/pdf/Heat%20recovery%20pipes.pdf
http://www.rototherm.net/art_01.html
http://www.halfbakery.com/idea/Dryer_20Heat_20Recapture

Also been thinking along these lines the past several years. However, don't have the time or money to experiment. If you do it, let us know how it's going.

Big concern is lint build-up as you might find it difficult to filter the air well enough without boosting air flow to overcome static pressures. As the air inside the Hx goes below the dew point you'll get not only condensation but the thing gunked up with lint (assuming it's impractical to filter the lint enough).

Personally was considering a MUCH simplier setup with concentric vent pipes with heat sinks attached to the inner tube (exhaust). Wouldn't have the ultimate heat recovery, but could be easily cleaned out with a standard 4" vent brush. At least in the winter was considering drawing air from the attic where heat already lost from the house is keeping the uninsulated attic somewhat warmer than outside air.

Interesting bit here:

" . . . Two modes of using an air-to-air heat exchanger for heat recovery were considered. The first is to preheat the inlet air with heat from the exhaust air, which resulted in 20 to 26% energy savings. . . "

http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6972604

The biggest thing about the efficiency will be to clean the vents and keep them clean.

I replaced my old dryer with one with a temp sensor. I think that made a difference it that the dryer doesn't run any longer than it has to.

Thanks for all of the responses. I don't have a choice of natural gas in my neighborhood or I would be using that. I do keep the vent clean. Based on your comments I will keep "old faithful" until it dies!

THe biggest savings will be realized if you are replacing a dryer with only a "timed dry" cycle. Timed dry is an incredibly inefficient means of drying clothes. Many times you have to add more time, but more frequently, you over estimate and are wasting energy. Any of the newer models with humidistats in them will probably pay for themselves in a year or two if replacing a model with timed dry only.

The best way to save on the energy used by your dryer would be to extract more water from the laundry before drying. You didn't mention if your washer was 20 years old too, but if it is, then buying a HE washer with a high spin speed would help. Then the dryer would be able to run for less time and use less electricity to dry the clothes. If you don't want the expense of a new washer, you could use a spin dryer before loading the laundry into your tumble dryer. A negative is that they can be pricey and add extra steps.

Joe

Here is a link that might be useful: Spin Dryers

whole-house heat exchangers

Those heat recovery ventilators are designed for essentially clean air in and out of your entire home. They are not designed to safely manage the lint blown out of your dryer. Read: clogging and fire hazard.

Roughly speaking, heat exchanger efficiency rises with increased exchange area. Also, lint-catching rises with exchange area, even on smooth pipe walls.

energycitations
the techniques in that abstract are intriguing. The main difficulty lies in ducting the air into the dryer. Most dryers have a large, scattered intake. If you can knock together some tin to duct the intake, then you can build a simple counter-flow heat exchanger around the exhaust pipe into the dryer. Like, a simple 6 or 7 inch pipe around the 4 inch exhaust pipe for intake air.

Hmmm... might be fun... now where did I put my Dad's 60 year old sheet metal shears and crimps...