Dryers: gas vs electric redux 2022

So how do I calculate the actual savings of Gas vs. Electric if doing about 5 loads a week on average?

  • Gas prices seem to be rising but so are electric prices.
  • Recently seeing that a gas dryer is probably less green than an electric. This makes me think electrics have gotten a lot more efficient. This is another factor I have to weigh seriously.
  • We will get a model either way that senses dryness. This is a great feature.
  • I’ll only buy Energy Star either way.
  • as to brand, LG seems likely, Consumers rated them very reliable. No one else gets a 5 rating.
  • From what I’ve read, gas dryers generally seem to last longer than new electrics.
  • Venting is not an issue, all set for that already.

I plan to have a gas qualified plumber come in to run a gas line to the deck with 2 outlets so I can run the grill regularly and a generator when needed. So the extra cost for the dryer run will be negligible. I already have gas for heating & hot water.

Older threads on this subject

So far it looks like Gas is still the overall winner if planning to use it for 5+ years and average of 5+ loads per week.

Gas costs more up front but is more efficient.
Gas is sufficiently more efficient that it is probably cleaner than electric unless solar/wind. Though fracking worries me a lot.
Gas is quicker, maybe as much as half the time!
Gas creates less static? (Can I stop using dryer sheets?)
Gas is slightly more dangerous.
Gas costs more to repair countered but Gas dryers are generally more reliable. But there is a difference of opinions on this. Seeing gas dryers are expected to last 13 years. Seeing 14 or 7 years for electrics.

Some articles:

I’ve had an LG gas dryer for about 10 years, and have never had a problem with it. Like every other dryer I’ve ever used the auto-dryness settings stops when things are damp, so I generally just run it as “more-dry” and then it’s fine.

It is very cheap to operate. In the summer we only use gas for hot water and the dryer, and are basically paying the minimum amount for simply having it connected. Don’t forget to add the expense of additional CO/explosive gas/smoke detectors for the laundry room.

I didn’t know it at the time, but getting the gas dryer also allowed me to repurpose the 240V dryer outlet for electric car charging.

If your electricity comes from coal or natural gas, burning the gas in your dryer may be more efficient than burning it at a power plant then converting the electricity back to heat in the dryer.

If you want the use of the dryer to be as environmentally friendly as possible, then a condensing dryer is the way to go. A regular electric dryer will produce 1 watt of heat for 1 watt of energy that goes into the heating coils. Because a condensing dryer is moving heat, it can move 3 watts of heat into the dryer for each 1 watt the condenser uses (or whatever the numbers are).

In conclusion:
Greenest: condensing dryer with solar on the roof, hydro, wind, or grid solar
Second greenest: conventional electric with green power
Cheapest initial: regular electric dryer
Cheapest long term: gas dryer

In California there’s a movement to ban gas hookups in new construction. It hasn’t gotten that much traction yet, but at least one city, Berkley, has done so. The main argument as I understand it is that with gas you’re locked into burning a fossil fuel for at least the life of the dryer (or furnace or stove or water heater). Whereas if the electric grid keeps getting greener over time then the electric appliances effectively become greener over time.

I believe that Energy Star is going to stop certifying gas appliances, so if that is a must, you may not have a choice. It’s not about energy efficiency, burning gas emits CO2.

Electric is essentially 100% efficient - other than the motor and controls, all of the electricty used is turned into heat. There is no way to make it more efficient other than a heat pump which would add hugely to cost and complexity.

The efficiency loss with electricity is not in the electricity → heat part, it’s in the heat → electricity part.

For applications where you want heat, burning a fuel is likely to be more efficient than electric. Because the way we get a lot of electricity is by burning fuel to make steam to turn turbines. And that process is not efficient. Instead of burning natural gas in power plants and transmitting the power over electric lines and then turning it into heat via resistance, you could just burn the natural gas in your house. That will always be more efficient (if you have gas at your house, obviously. The infrastructure for that isn’t free).

Gas isn’t necessarily always going to be cheaper, though. Electric costs could drop below gas costs because there are cheaper or more efficient ways to generate electricity (solar, etc.) than burning gas.

Back of the envelope: as long as it’s economical to run gas-fired power plants, gas dryers will be more efficient than electric ones.

There are lots of ways, actually. Drying doesn’t necessarily involve heat–heat just happens to be one way to separate the water from the clothing. You could also pump the clothing down to a vacuum to let the water boil away at ambient temperatures.

Heat pump clothes dryers exist, at any rate.

TIL …

Thanks, Doc.

However, that process can be much more efficient than the process used in the household. A good gas turbine might be 60% efficient at turning gas into electricity. If that’s used for a resistive heater, then sure, you’d be better off burning the gas directly. But a heat pump might have a coefficient of performance of 2 or 3, turning that 60% into a relative efficiency of 180%. And alternate technologies that run on electricity might be even better.

Sure thing. They’re a relatively new technology, or at least fairly new to the US. You can get heat-pump water heaters as well.

As for vacuum drying, there is this:

Doesn’t seem to be shipping yet, so I can’t tell if it’s one of those semi-scam Kickstarters or something real. The basic idea behind the tech is real, though.

It is news to me that there are heat pump dryers! Cool. I was only aware of the resistive heat ones.

That review is pretty good. My understanding is that condensing dryers often fail to get clothes really dry. Looks like the economics aren’t quite there yet for most people, but I expect that to improve over time.

I first ran into condensing dryers about 20 year ago. Condensing dryers don’t use a vent, just a drain. The electric dryer in my condo back then just vented into the room, so I investigated replacing it with a ventless condensing model. At the time, the only thing available was from weird (to my US sensibilities) European brands, and were $1200+.

The primary complaint was that they didn’t get clothes really dry, to which the manufacturers said “you’re doing it wrong.” The load size for a condensing dryer is about half that of an equivalent sized heat dryer.

It gets even worse. There are combination washer-dryers that are a single unit (not stacked units—one box) that can wash the clothes and then dry them using a condenser dryer, all in the same spinning drum. These are reasonably common in Europe, and would be perfect for my condo. However, the max load size for the dryer cycle is half the max load size of the washer cycle. So, either always run half full, or always take out wet clothes.

Perhaps things have improved.

People can eventually learn to use different technologies with different limitations, but it’s pretty awkward that the dryer can’t dry the clothes that fit into the washer.

Aside from using a drain rather than a vent, I thought some heat pump dryers could run on a 120V circuit. So in certain circumstances, like where running a vent or running a 30amp dryer circuit is an issue, the extra cost of a heat pump dryer might make sense.

Also, if we’ll permit a bit of a tangent: Why can’t a condensing dryer with more clothes in it just run twice as long? If the process can actually get a small amount of clothes totally dry it should eventually work on a larger amount of clothes, right?

Actually, even greener than any of these is:

  • hanging on a clothesline

My mother, and most of her generation, did that almost all the time. I still do it myself, for some items, in the summer.

Obviously hanging clothes is greener, but has nothing to do with this thread.

Well, that’s true only if the electric generating plant is next door*.

Otherwise, there is significant lass in transmitting the electricity from the generating plant to your dryer. (About 6% - 10% lost in transmission. Of course, gas distribution also has losses, but seem slightly less: 4% - 7%)

  • With solar panels on your roof, the ‘generation’ is next door, so loss is negligible. Assuming you have enough panels to feed the electric dryer, plus the rest of the house. (Mine only cover about half that.)

My point was that generation of heat from electricity is 100% efficient, disregarding losses in power generation and transformation. The original quote that I responded to was:

Electric heat has been 100% efficient since it was invented. Heat pump dryers do break the model since they can be MORE than 100% efficient with a Coefficient of Performance above 1:

Heating and Cooling With a Heat Pump (nrcan.gc.ca)

I had never seen or heard of a Heat Pump based dryer, although this thread brought them to my attention.