Please explain the 29" dryer thing

[jerrod6]

Fear not - Energy Star to the rescue

Energy star has developed ratings for dryers. I think it is effective in 2017. For some reason they are asking gas dryers to express their ratings in Kwh. I can't get that. The last thing I will do is base the consumption of my gas dryer on how much energy it would use if it was as electric dryer since I pay less for gas than electric. My thought is that if they didn't do that gas dryers would be shown to much more efficient that electric.

Anyway there are now energy standards for dryers so perhaps we should get prepared for loads that are under dried.

https://www.energystar.gov/sites/de...mitment Criteria and Eligibility Criteria.pdf

 

[launderess]

With front loading washing machines and or top loaders with higher final extraction speeds (a or >1000 rpms) the need for baking all that moisture out via dryers is becoming less.

Truth to tell ever since more modern top loaders replaced wringer washers final extraction has been improving. Not every machine reached the "Rapid Dry" of Frigidaire fame, but still even 700 rpms beats the 200 or so of a wringer.

Again commercial laundries have known this for ages; the best place and most efficient place to remove moisture is via extractors/spin drying. It saves energy in both tumble or other drying and or ironers.

In ideal situations laundry should come from the machines with just enough moisture to go through ironers and emerge dry. Tumble drying should not take long periods as again much of the water as possible should have been spun away.

Also we have to take into account clothing and other textiles are often much lighter weight than say even the 1950's.

Percale has replaced heavy muslin sheeting. Aside from perhaps denim jeans much of today's wardrobes are made up of lighter weight cottons and other fabrics that need less drying. The growth of polyester/cotton and other blends if not outright totally manmade fibers has also not only lightened textiles but make for easier laundering. Polyester does not hold and trap water like natural fibers such as cotton, linen, wool, etc... The more if it there is in a textile, less retained moisture there will be after laundering.

 

[Marky_Mark]

Jerrod6: you could choose to measure power in Watts or BTU/h.  Similarly you can measure energy consumption in kWh or BTU regardless of whether we're talking about gas dryers, electric dryers, light bulbs, water heaters, cooktops etc.

 

In order to compare dryers, it's best to choose one system and stick with it -- in this case, power in kW and consumption in kWh.

 

Gas dryers are not more efficient than electric dryers.  In fact, they actually use slightly more energy due to the combustion process and its moisture being drawn through the drying chamber.   But of course gas is cheaper and typically emits fewer greenhouse gasses even when compared to heat pump dryers depending on the energy mix in your region.  

 

So Energy Star figures might show something like this:

Electricy cost: 14 cents per kWh

Gas cost: 4 cents per kWh

Electric vented dryer: annual consumption 500 kWh costing $70 carbon footprint of 100 kg

Electric heat-pump dryer: annual consumption 250 kWh costing $35 carbon footprint of 50 kg

Gas dryer: annual consumption 600 kWh costing $24 carbon footprint of 40 kg

[this post was last edited: 11/12/2017-15:25]

 

[jerrod6]

Looking at gas dryers on the energy star site show that they use 658 kWhs, and some on the site use 685 kWhs. Nothing about how much natural gas they will use. I guess the ones that use 685 kWhs use more gas. I am not likely going to consult energy star for anything anyway, but some consumers will.

So if someone multiplies 658 by their electric rate they can see how much the dryer would cost by using electric, but not how much the dryer would cost using their current gas rates.

I am not sure people will be comparing gas against electric anyway. If you have natural gas in your house and it is cheaper why use electric for drying clothes? I have natural gas heat and would never use an electric dryer--just me though.

 

[askolover]

Same here Jerrod. 

 

[Marky_Mark]

It's telling you that they used 658 or 685 kWh of gas.  Would you prefer this be in cubic feet, therms  or BTU?  Electricity could be measured like that too if you prefer.  But to compare between dryers you need to pick a single system and use it for both.  So the dryers you're referring to use 658 kWh and 685 kWh of gas.

 

When I lived in Phoenix, AZ from memory the cost of my utilities was as follows:

 

Natural gas: 4 cents per kWh

Electricity: 6 cents per kWh off-peak (weekends, holidays and weekdays 7pm through midday)

Electricity 22 cents per kWh winter peak-rate (weekdays midday through 7pm)

Electricity 25 cents per kWh winter peak-rate

 

So if a dryer used 658 kWh of gas, that would cost me 658 x 4 = $26

If an electric dryer used 658 then it would obviously depend on when I was using it.  But could be well over $100 if I often used it during the peak rates.

 

[this post was last edited: 11/13/2017-01:47]

 

[johnrk]

jerrod6

I have gas for cooking, water and heat, but electric for the dryer in this house. I'm not sure I've ever seen a gas dryer in anyone's home. And you'd think down here in the Houston area that they'd be everywhere.

What I never understood was why gas refrigerators lost popularity, since the fridge eats to much electricity, even in its present state. I've never seen one of those either in a home, though I have in hospitals.

 

[Marky_Mark]

If you only know the price you pay for gas per therm, divide that by 29 and that will give you the price per kWh. Then you can easily compare gas and electricity.

 

[earthling177]

John (Johnrk) said: "What I never understood was why gas refrigerators lost popularity, since the fridge eats to much electricity, even in its present state. I've never seen one of those either in a home, though I have in hospitals."

We need to decouple several concepts here, particularly efficiency, cost and reliability. People often put a lot of weight on one or more of them and then complain about suboptimal results.

But the reason(s) that gas refrigerators lost popularity even though electricity is more expensive, is that by burning fuel inside your home, a gas fridge generates heat that is often unwanted, particularly during summer. Also, most homes do not provide a good flue to remove the heat and the results of combustion out of the room. That can be tolerated rather easily in a commercial building like hospitals, that may have good exhaust hoods, chimneys and good A/C systems, but in a home (or worse, a small apartment) the electric fridges won and you could get an interesting perspective by going to a library and reading the Consumer Reports issues from back in the 30's and 40's when the battle was still being fought.

(Also, the expected maintenance has shifted over the years: nowadays you can find fridges with "never clean" condensers that, although they *do* need cleaning, it's a very infrequent thing and much easier than previous radiators. Fridges that burn fuel need a lot more maintenance than that to keep running safely and economically.)

Cheers,
   -- Paulo.

 

[mark_wpduet]

All this talk about gas

it's interesting I've never lived anywhere that had gas - everywhere I've lived has been all electric. I seriously wouldn't even know what to do with a gas range.

Anyway - Sometimes I feel guilty about using my dryer the way I use it. The past few years, the washer holds so much more than the dryer, so I will often dry half loads. They dry more quickly and much less wrinkling. I've never paid attention or done the math as to how long the dryer actually ran drying the 1/2 loads vs if I had put the load in and dried the whole thing at once. I'm sure the dryer runs more doing 1/2 loads though - I don't always do this. I've gotten to where when I do laundry, I break the loads up more so they aren't so large. Essentially, my dryer dictates how I'm doing laundry. It's not mismatched set either

 

[launderess]

As noted gas or electric, it really comes down to a few factors including what is available and cost.

Here in NYC area gas dryers dominate due to our high electricity rates. However in some instances (portable, some apartment buildings, etc...) electric is the only way to go since gas lines for a dryer aren't present.

Gas dryers also require venting, which also factors into some peoples equations.

 

[gelaundry4ever]

airflo

I noticed that newer dryers from lg and whirlpool have good airflow.