If this is new construction, then running both a gas line and a dedicated electric circuit is pretty easy to do. The incremental cost should be trivial and it does future-proof things.

Having said that, resistive electric heating is insanely inefficient. We still use a lot of fossil fuel for power generation. This means, you are burning fossil fuels to generate heat, using that heat to drive a turbine, which in turn powers a generator. You then transform and transmit the electricity to the house, where it is turned back into heat energy. Overall fuel-efficiency is often no better than 20-30%. On the other hand, burning gas at point of use can get much closer to 100% fuel-efficiency. This usually, but not always, is reflected in energy costs. There are some markets where electricity is extremely cheap (e.g. if hydro-electric power is very readily available). Everywhere else, a gas powered dryer is probably much cheaper to operate. Of course, that doesn't help, if natural gas isn't available at the property. And the math for propane is more complicated.

Things look much better for heat pumps. Resistive heating can at best be 100% efficient for the final step of converting electricity to heat, but heat pumps regularly can be 400% efficient. This makes up for a lot of the other energy losses at the power plant.

They do make dryers with heat pumps. But quite frequently, these are a lot more expensive than traditional dryers. And these also tend to be vent-less dryers. In principle, that's awesome. There is a lot of heat that can be recovered from the exhaust vapor. In practice, vent-less dryers get very mixed reviews.

I think, it's mostly an engineering issue. At the current time, traditional gas-powered dryers are a very mature technology and work well. Vent-less heat-pump dryers are likely going to be a technology of the future. But hard to predict when they will become mainstream -- and in general, the US tends to lag behind on these type of trends.

I prefer the simplicity of electricity. Just hook up the vent and plug it in. If the vent hook up leaks it's not that big of a deal.

No wrenches, no pipe dope, no leak detection, no ball valve that can get stuck open or leak.

We've had and friends have also had multiple homes with simple gas dryers over many years. I've never experienced or heard from any friends of a leak in any pipe fitting or valve whether open or closed. When the probability of an occurrence is very low or near zero a logical discussion gives no weight to it. We're not talking about a radiation leak here so no catastrophic danger. Possibility is only the first step in an analysis. Probability is the important step. The one beyond elementary level.

Springtime builders,

I have severalyears experience with dryers that don’t need an exhaust. The ones I have used all have water reservoirs that fill with hot water when the dryer runs. If I recall properly, when the reservoir gets full, the dryer stops until the reservoir is emptied. Helps to have a sink nearby. Need to be careful not to scald oneself. Another big consideration is that dryers that have exhausts expel hot moist air to the outside. Dryers without exhausts fill the laundry room with hot humid air. Not very pleasant. Dryers that do not require exhausting air to outside are good solutions when exhausting to the outside is not possible, but not something I would choose otherwise.

Venting a typical dryer indoors through a water lint trap is NOT what I recommended and would only consider it as a very temporary solution.

I was suggesting heat pump dryers but I think condensing dryers may be the preferred terminology. They use heat pumps to take the moisture out of the laundry and dump it down the washing machine drain. There is no air vent whatsoever.

They are more expensive upfront but costs are easily recovered and they could be a very good investment if the appliance has a decent life (probably mainly dependent on keeping filters clean). Most importantly in new construction you can subtract the hvac contractor's venting infrastructure costs. If comparing with gas, you can take out the gas pipe drop charge as well. Might as well subtract the entire gas infrastructure from the street, it's an increasingly outdated energy source with better alternatives available for every appliance.

Condensing dryer lint cleaning maintenance is kept right at the applance's filters. No need to fuss with accumlation in the ducts, kinks and termination caps. We have had homes where venting the dryer near the heating and cooling heat pump was the best location but directing lint at heat pump compressors can be problematic. A condensing dryer would be a good choice in these situations. Same for homes where we need to locate dryer termination on the roof resulting in unsightly lint streaks and tough to access termination caps, the location that clogs the most.

The biggest complaint facing this newer technology is that it takes longer to dry clothes. Sometimes more efficient processes take longer.

If you aren't aware of the dangers imposed by combustion appliances in efficient homes, then I suggest keep learning before choosing them. The main risk is not leaks, its backdrafting, or when forces like other exhaust appliances suck combustion exhaust into the home. It happens often, even in leaky, inefficient homes. The threat of low level CO poisoning is very real and it's why most builders and designers with good knowledge of building science and home performance are striving for all-electric homes.

Electric.

Gas in the whole cycle is more efficient. But electricity will get better over time and gas will not.

In my area (cheap electric), gas is uncommon. It will cost more and not necessarily be in stock when you need to replace. A rare event for sure.

The piping for gas is not free and will generally cost significantly more than electric but not a huge item either way.

The exhaust for a gas dryer vents along with lint. It is up to you to decide if that is a good idea. It isn't for me.

I had gas dryers, first a rather cheapo Kenmore and then later an LG to match the HE Frontloder. I was lucky, while my home was originally all electric, when they ran gas lines through our neighborhood the gas company offered us pretty healthy incentives to install gas appliances (we wanted the furnace and the stove, but also got the hot water and dryer). At the time, they covered running all the gas lines. I only ended up paying for the appliances which they financed attractively on my bill.

Thanks all, some good points. M, interesting idea about the efficiency and how energy is converted multiple times with electric.

My laundry room is on the first floor on an exterior wall, the dryer will be right next to the exterior wall, so it would be a very short vent run to the outside. Maybe 3'? I think it would be easy to clean out the vent pipe.

IAQ is important to me though... And the thought of possibly exposing dryer lint to a flame concerns me. Where does the combustion air for a gas dryer come from?

A gas dryer is the default choice providing you have gas.

Combustion air for gas dryers is from indoor house air via cracks in the appliance. The same place that combustion exhaust is pulled into the home by backdrafting forces like other exhaust vents, wind, stack effects or their combinations. So yes, if you want the added risk of CO poisoning, gas dryers are default choice.

Springtime. Gas and electric dryers both require gobs of inside air for operation. CO risk is noteworthing but not typically a worry to most homeowners. Both appliances require the same periodic maintenance to keep them operating safely and efficiently

"Not typically a worry" is why I'm a persistent poster here. It should be. It's a major problem and building codes are only beginning to address it.

Condensing dryers are "electric " but do not require ductwork. See post above.

Every house should have smoke and CO detectors all over the place anyway. In the highly unlikely event that a properly installed and maintained gas appliance starts producing CO, you'll get advance warning. Yes, it does happen, occasionally. And if undetected, it can be really dangerous. But millions of households safely use gas appliances every day. No need to be irrationally fearful. You don't freak out about the possibility of electric appliances electrocuting you either.

Condensing heat-pump dryers are certainly an option. And for some households, they are the preferred option. I like the technology in principle, and feel that it has a lot of untapped potential. But that's not to say that they are always the best choice. They have their downside too. If interior air quality was a major concern, a condensing dryer wouldn't be my first choice right now. All the ones that I have used did leave the room noticeably warmer and more humid. On the other hand, I have seen people install their dryers outdoors on a deck, and that worked awesome. I am sure the technology is going to improved steadily. But so far, you are disingenuous if you claim that condensing dryers are that much superior. They are merely one of several valid options.

Springtime Builders,

People have been using gas ranges for, ummm, quite a lot of years, unvented (except perhaps for a range hood, which isn't a direct-vent like a dryer). I'm curious what makes a dryer more concerning?

I don't mean to promote irrational fear, simply trying to educate and make people aware of indoor air pollution sources.

EPA estimates only half of known CO poisoning cases could have been prevented with detectors. CO detection is tougher than smoke. All detectors are not equal, they have short lifespans and homeowners are notoriously bad at this type of maintenance. It's not catastrophic, but low level exposures over time that needs more awareness.

A home without combustion appliances or an attached garage completely eliminates the need for CO detection. It's not irrational to eliminate pollution sources, especially when better options exist.

Never declared condensing dryers superior just making the case for another option to explore.

Gas ranges are a much bigger concern than gas dryers. Their contribution of CO and NO to indoor air is well documented and makes vent hood design very important for these appliances. LBNL and Building Science Corporation are good research resources.

If you want a declaration of superiority: choose induction cooktops instead.

If I understand @Springtime Builders correctly, he worries that modern buildings are getting increasingly more air tight. This is potentially a concern, as it is more likely that a gas appliance would start depleting all available oxygen, and eventually start producing CO in addition to CO2. (he didn't mention this, but this also causes concerns about humidity built-up that can result in mold).

Additional, there is concern about causing backdrafts that force combustion products into the buildings interior. This is not a huge worry for older buildings that have lots of natural cracks and gaps in the exterior walls. But in a modern building, this could require installing a make-up-air system.

And yes, in principle he is correct. Changes in building technologies cannot be made in isolation. If you seal all existing air entry-points, then at some point you'll have to figure out how to get oxygen into the building. In practice, this is neither a new problem, nor an unsolved problem. It's something for the architect/builder to worry about, when first starting work on the house during initial construction. If they get it wrong, you'll probably find out pretty quickly.

Gas stoves burn very efficiently. In normal use, about the only time they produce noteworthy amounts of carbon monoxide is when the flames are contacting the bottom of a pan or pot. If the bottom of your pans are getting coked up from high flames, you're not burning the gas completely and producing unnecessary CO. Gas ovens can produce more CO and it's not a bad idea to crack a window or run a vent.

Dryers that don't vent well will go into a downward spiral. The lack of venting will cause a build up of exhaust gas at the burner, resulting in less oxygen to burn and more CO. As the process continues it amplified by the increasing levels of CO and the burner will produce less heat meaning the dryer needs to run longer. A dryer is pressurized by the blower motor and it can spill a lot of gas out of leaks in the dryer and vent system.

Homes are not nearly tight enough, even most new ones. No such thing as too tight. The tighter the better.

Backdrafting of combustion appliances is the problem and it happens in old, leaky houses all the time. Ask any home performance contractor or energy rater. They can be done correctly, but it's easy to eliminate them.

Isn't the interior of a dryer is at negative pressure WRT to the room? The blower sucks air (typically excess of 200 cu ft/min) into the machine, through the heater box, drum, filter, and blows it out the exhaust.

The other gas appliances in my house are all direct vent - the furnace, fireplace, and tankless hot water heater. If I can't get direct vent on the dryer, I think I am going electric.

Just for the record, houses can in fact be too airtight. This was a big problem in the early 1990s, when Europe developed the first prototype residential "zero energy" houses. These houses fortunately didn't have gas appliances. But they still suffered huge problems with interior air quality, as they simply didn't exchange any significant amount of air with the outside.

As of end of this year, European building codes require similar energy standards across all new construction. But fortunately, the construction industry has learned in the last 25 years, and they now know how to deal with air exchange without compromising energy efficiency.

Dryers are surprisingly less popular in Europe. And for various other reasons, externally venting dryers are even rarer. But they do exist. And where they are in use, gas appears to be prevalent, as electricity is prohibitively expensive in many European markets

I suppose it is semantics. Too tight yes - but then you ventilate.

"Build tight - ventilate right."

Controlled ventilation vs uncontrolled.

Theory is great. Reality is that condensing dryers are pretty miserable to actually use.

The best dryer is solar powered. But HOAs have regulated them out of existence. As have chapped hands, and lack of time for the operators. Taking down frozen clothes from the line is also a miserable end user experience.

Sophie can you elaborate on condensing dryers are miserable to use? Want to be sure I'm making the right choice in my personal home. Smaller size and longer dry times seem to be the main complaints which I'm prepared for.

The longer time is directly related to the lower temperatures, and one of the biggest benefits of these machines: they are more gentle on clothes.

Found the attached article and it points out that there is a difference between heat pump and condensing dryers but neither need to be vented and both are more efficient and easier on fabrics.

http://laundry.reviewed.com/features/everything-you-need-to-know-about-ventless-dryers

"Isn't the interior of a dryer is at negative pressure WRT to the room?"

You're right, I'm not going to claim to be the most articulate person out there. Intake side of the blower will be negative pressure and the outflow side will be positive. By putting the blower after the drum there doesn't need to be a latching system that keeps the door from popping open. The ducts in the dryer after the blower aren't always all that well sealed and why the "engineering space" of the dryer fill with lint.

Sophie. "Reality is that condensing dryers are pretty miserable to actually use." Do you own or have experiencing using one?

Thanks for posting the above link - it is very helpful! I'm seriously considering a ventless due to lack of viable efficient venting options.

I have used condensing ventless dryers multiple times when travelling. This was in all sorts of different countries. So, I don't recall if they had the same brands that we have access to in the US. I also have no idea whether these were just condensing, or whether they were condensing w/ a heat pump. I have experience with both stand-alone dryers and with combined dryer/washer units.

For combined units, my experience was almost exactly the same as what Sophie said. For stand-alone dryers, things were a little better. Capacity generality was bigger, but still not as big as from my gas-powered dryer at home. Also, clothes dried better and weren't quite as wrinkly. This most likely is a direct result of the bigger drum.

The extra heat and humidity that got dumped into the room was definitely not pleasant. It made for really poor indoor air quality. That probably explains why I saw so many units that were installed outdoors. Especially in Asia, it seems common to put laundry facilities on the balcony behind a trellis or door of some sorts.

And honestly, this is all really expected. If you produce heat, you have to dump it somewhere. Condensing gaseous water vapor releases additional heat that needs to be dumped. With an outdoor vent, that's easy to do. Without a vent, ultimately it ends in the house. And for energy efficiency reasons, condensers are never 100% effective; so, humidity ends up in the room too. This could in principle be addressed by adding more cold water. But environmental regulations frown on wasting domestic fresh water for cooling purposes.

Combo washer-dryers are known to leave the dried clothes wrinkled because a full wash load doesn't have enough room to tumble when drying.

Isn't it fantastic that such a seemingly simple question becomes so complicated?

Who knew?

Thanks guys. Have done a bit more research and concluded that heat pump dryers are highly preferable but at this time, hard to find and are early adopter status, at least here in N. America. Vast majority of negative heat pump dryer comments are first world variety timing expectations but enough mechanical problems with current Whirlpool (discontinued?) and LG offerings to hold back enthusiasm. Looks like the LG still needs venting, not a big deal for replacement, but defeats the purpose for ventless goals. Reviews on energy-use related websites of heat pump dryers are very favorable.

Condensing dryers shouldn't add that much more humidity than regular dryers, if so total deal breaker. They do add heat, but so do regular dryers which also suck 100-300 cfm of conditioned air out of the home. I saw conflicting accounts of added heat and energy use but apparently condensing dryers could be less efficient in some homes. Complicated indeed.

Right now, my choice is between Bosch's 800 series condensing dryer and Blomberg's heat pump dryer.

Found this helpful condensing dryer outline here on Houzz but the heat pump dryer comment at bottom needs update: https://ths.gardenweb.com/discussions/2767055/what-is-a-condenser-dryer#addAnswer

No question. Get gas. I've had a natural gas dryer for 24 years and never had a problem with it. Instant heat, plenty of it and very cheap compared to the electric dryer it replaced.

Get a Speed Queen.

dancw. Speed Queen. The proven name in dryers.

I think if I were building new I would set it up for both. You never know what technology will bring down the road but for me personally after nearly 45 years of owning dryers I prefer gas. At one time you could pay for the dryer after just a few years difference in utility costs depending where you live. Wife prefers it too because the laundry always came out better handled by a gas dryer. Maintenance costs were always lower on our gas dryers. I bet I never spent more than 20 dollars on parts for any one of the gas dryers. Things change over time though. I swore I would never be buying LED lighting for the house. Now thats all I have with few exceptions. For now though, I have gas dryer, range, water heater, furnace.

We've never had a gas dryer in the past however built for both in the new home though DW is wary about a gas dryer. Comparing running costs (in our area) electric is 10c/KW and gas 80c/therm. Using an online calculator 7.5 loads/week at 45 mins/load is $0.33/load electric and $0.20/load gas resulting in annual cost of $129 vs $77 for electric vs gas. I like the fact gas dryer run times are supposed to be shorter due to faster heat besides being gentle on clothes etc. Still undecided though I'm leaning towards gas however DW will have the final say.

I just installed a fancy new gas dryer and am hoping for the best. Im mildly concerned about venting. Particularly because I have this huge conditioned make-up air unit they put in the attic spec'd for 600cfm. I worry that that would overpower the smaller gas dryer venting motor and draw fumes into the house. When the gas team was at my home installing the dryer I expressed my concern and they off course said there is absolutely nothing to worry about, and as an added measure I could just make sure the laundry room door stays shut when the dryer is in use.

If its a makeup air unit, wouldn't that bring 600 cfm of air into the house, and help push the dryer exhaust out?

Depends on how MUA unit is configured. Usually, they are only tied to oversized kitchen vent hoods. If a vent hood is pulling 1000, then the house is still depressurized by ~400 CFM, bringing gas dryer exhaust into risky territory. Yes, closing the laundry door and opening a window in there reduces concern, but that seems silly to try to coordinate with vent hood and why I would prefer to eliminate the pollution source altogether.

Gas dryer proponents don't seem to acknowledge or understand the combustion exhaust issues.

Springtime Builders: You bring a good point about gas dryer exhaust in case we go that route. We are installing a 20KW heated 1200CFM MUA to compensate for our 1200CFM hood. Not sure if we'd need something bigger if also installing a gas dryer; perhaps reason enough to stay electric for us.

It seems that most MUA units provide much less than rated capacity. It's highly dependent on duct design and install skills. Vent hood ratings suffer too but seemingly not as bad. The only way to know for sure is with commissioning, like you get with Energy Star certification.

Vent hoods are the main culprit but there are other conditions that suck combustion exhaust into the home.

Pinebaron. Your MAU may have been sized for your kitchen exhaust and not for a combination of other exhaust devices i.e., clothes dryer and bath ventilators. I have doubts that you will be able to endure hood sound levels as the capacity reaches rated output. At the most for limited periods of use. You will probably find that running at half capacity will vent your stove area efficiently leaving plenty of MAU volume for any subsequent supply air demand. Keep in mind electric dryers require about the some amount of free air for efficient operation as gas dryers. Difference being, gas dryers produce CO and electric one do not. If DW prefers a gas dryer then a good practice of delaying use during cooking times might be in order. Also due to your square footage, window count, mechanical perforations to the exterior, and recessed lighting I would speculate that your MAU would seldom sense a deficit in indoor pressure.

fixer687: Our MUA will be linked directly and only to the Hood with current sensing and setup for multi-speed hood. I doubt we will use 1200cfm hood exhaust or rather need to refrain from using 1200cfm hood exhaust while using the dryer and use the hood at a lower speed; DW prefers electric, no gas. Final purchase TBD.

Pinebaron. Do you mean your MAU is coupled to your hood and senses motor speed and not ambient pressure?

fixer687: Motor current and speed. Motor current sensor to trigger MUA, and motor speed to control MUA output. MUA heating has it's own temperature sensors to monitor intake air temperature set to heat MUA output only when intake air temperature is below 50 degrees.

Just a thought....if one is approaching retirement age or planning to live in your home a long time...My father ended up on oxygen in his latter years of life and we were told not to operate a gas stove or gas dryer around his oxygen unit. They also checked to see that our gas water heater was not inside. but located in our garage. We were told by the medical supply company providing oxygen services that gas appliances could cause an explosion with the oxygen tanks. No one knows the future of unpredicted health challenges, so I would recommend electric over gas if approaching senior years in your home is a possibility.

I've had two different gas dryers over the last 18 years. I like them. No issues I know of. Current one is Miele I've had for almost over 7 years. I read that gas produces a more moist heat and I've never had a static issue with mine.

I did an extensive search of death causes in the US for the last 25 years and cannot find a single instance where a death was attributed to CO from a clothes dryer.

I had a gas GE dryer (Profile, 1996) which had very satisfactory performance. However, I could never conclude that it was more economical to run than my previous electric dryers, and since its performance was equal to but not better than them, I never bought another gas dryer in subsequent years. For me, it boils down to not wanting to pay more for a gas dryer over an electric one. Many times it is personal choice and I certainly believe in that. It would be interesting to hear from other users currently if there are municipalities that charge much less for natural gas than electricity and if that is factory beyond drying performance.