Should you vent your clothes dryer inside your house? - Carolina Country

Should you vent your clothes dryer inside your house?

Determining where to vent the dryer may be more trouble than it’s worth.

By Arnie Katz

Should you vent your clothes dryer inside your house?

CAUTION: Since this article was originally published in 2011, venting dryers indoors is no longer considered a safe option. Clothes Dryers: Use Only as Intended provides more information on how to use dryers safely and efficiently.

Q My sister-in-law told me about a device she attached to her dryer vent that collects the lint and directs the air into the house instead of outside. She says it saves a lot of energy on heating and keeps the house from getting so dry in the winter. I'm thinking about getting one. Is this a good idea?

A: This is an idea that's been around for awhile. Back in the 1970s, I often advised my clients to vent their dryers into the house during winter. My reasoning was just what your sister-in-law says: save all of the heat from blowing outside, and use the moisture to help prevent excessive dryness in the house. I suggested tying a stocking to the end of the pipe to prevent lint from blowing all over the house.

Dryers are significant users of energy. They suck air from the house into the dryer, heat it up with an electric element or gas burner, and blow the hot air — along with the moisture from your clothes — out the vent pipe. All of the heat produced by the dryer is "lost" when you blow it outside.

Any time you exhaust air from your house, an equal amount will be sucked in to make up for it. This "make-up" air will come in through every available hole and crack in the house, mixing with the air you've already heated or cooled and causing your furnace, air conditioner or heat pump to work even harder.

In the summer, the air sucked in by the dryer tends to be hot and humid, making the air conditioner work harder. In the winter, the make-up air the dryer sucks in tends to be dry, making the air in your house dry. If your house is already very leaky and dry in the winter, this will just make it worse. Some people try to counteract the dryness by installing a humidifier to add moisture to the house. But the wisest ones (in my opinion) will spend that money sealing the house, making it less dry in the winter while reducing heating bills.

All in all, dryers can cost a lot to operate and create serious issues with moisture, comfort and even health.

So does it make sense to bypass all of this and re-route the dryer vent to the inside? Important note: Do not consider this if you have a gas dryer. The exhaust vent is also the combustion vent. You don't want the products of combustion (e.g., carbon monoxide) in your house.

If you have an electric dryer, there may be some houses during some times of the year where using this strategy could be beneficial. The problem is determining which houses and when. How do you know when the added moisture will make you more comfortable or lead to mold growth or even rot? This depends on a number of factors including how tight your house is, how big it is, what it's made of, how much laundry you do and what the weather is. For most of us, trying to keep track of all of that to decide whether to vent the dryer inside or outside is probably more trouble than it's worth.

There are some new, high tech solutions to this. Europeans have been using condensing dryers for a number of years. They don't exhaust air at all, so the problems associated with conventional dryers are eliminated. They tend to be smaller than most Americans are used to and take longer to dry the clothes, but otherwise seem to work well.

The latest high tech approach is the solar clothes dryer. I don't believe there are any tax credits for it yet, but it definitely shows promise. You take a special cord called a "clothes line" and stretch it between two poles outside in the sun. I've seen some research reports that there are even some special devices now available to pin the clothes to the line. This approach is experimental and highly controversial. It's even illegal in some communities. But if you really want to save energy on clothes drying, it may be worth looking in to.

About the Author

Arnie Katz is the former building science consultant for Advanced Energy in Raleigh.

Comments (10)

  • I would like more on venting gas dryer's indoors, and it's gas emmissions safety. I get sick from basement venting.

    PatK |
    May 29, 2014 |

  • Venting a clothes dryer inside is against national code for a reason. If you're worried about make-up air, seal your house. If you need more moisture in the winter, get a home humidifier. The devices that allow you to terminate the vent inside are a worst-case scenario treatment to allow you to have a dryer where one was never intended to be ( i.e., where there is no vent to outside). Venting inside compromises air quality, deposits uncontrolled moist air into the living space, and your insurance policy could void covering any moisture damage.

    Blake T. |
    October 18, 2017 |

  • I vent the dryer inside only in winter. It's down in the basement, with a dryer bag, to catch the lint, and does help put moisture in house, and helps with heating

    Tom Boehlke |
    December 28, 2017 |

  • No reason given.
    Saying to "seal your house" indicates lack of basic understanding of airflow. Dryers suck air from inside the house, heat it and vent it outdoors. The air has to come from somewhere. Sealing your house isn't going to stop it, it still needs to get outside air by lowing the pressure inside your house. If a house were 100% sealed, the dryer couldn't work, wouldn't be able to move any air and would overheat.

    David |
    February 04, 2018 |

  • This is an absolutely idiotic idea. By doing this you have exponentially increased the likelihood of a house fire.

    Tom Rason |
    March 05, 2018 |

  • How it that possible moist heat retards fire. You run a higher risk fire by not cleaning the duct switching winter summer would keep the duct clean.

    John |
    September 04, 2018 |

  • We have the electric dryer venting into the house rather than to outside because the dryer is in the middle of the house and the distance is too long for efficient venting. Every clothes drying cycle takes two or three cycles to dry a load of clothes - this is not a very large load either. My husband's solution is to put the stocking over the vent to avoid lint in the house. We have a standalone fan which is running in the washer/dryer closet in the hallway of the house to help disburse the humid air from the dryer. We constantly argue if the fan should be POINTED TOWARDS the source of the vent or AWAY FROM the vent to disburse the hot humid air around further into the house. I am in favor of pointing fan towards the source of airvent so it is eliminated/decreased as soon as it exits (hopefully). My husband argues that it works best pointing away from source for whatever reason. Any input? My best scenario is for moving the dryer/washer into the garage to avoid the problem of distance venting issues, but we would have to get a plumber/electrician to get that set up. Please help and offer some helpful suggestions before we get mold all over. It might already be in the vent we disconnected as water used to pool in the bottom of vent after each cycle and drain in a puddle onto the floor.

    Jen |
    June 10, 2020 |

    • Hi Jen,

      We passed your question along to Jonathan Coulter, senior consultant with Advanced Energy in Raleigh. Here's Jonathan's reply:

      "Regardless of the location of the clothes dryer within each home, in our climate we recommend to not ever venting the dryer inside the home. There are three options that immediately come to mind as possible next steps:

      Option 1 (possibly lowest cost): Replace existing flex ducting dryer vent with rigid, metal ducting; confirm dryer vent flap termination on outside of home can flap open and closed. Rigid metal ducting should be much smoother and easier for the air to move compared with flexible ducting.

      Option 2 (possibly more expensive): Relocate washer and/or dryer to garage, including new plumbing and venting.

      Option 3: Replace existing venting dryer with a newer vent-free dryer (also called ventless, condensing, or heat pump). These newer dryers are more efficient, Energy Star certified, do not require a dyer exhaust vent and redirect moisture from clothes drying into the same drain as the washing machine drain. Or you could buy a combination washer/dryer, upgrade both appliances and save more space in your laundry room or garage. But do ask around for reviews of the washer/dryer combos to better understand the features and benefits before you purchase.

      Whether you go with Option 1, 2 or 3, you can reduce the humidity in your home, move the fan out of the doorway (and no longer argue about which direction to blow the dryer exhaust air)."

      Carolina Country |
      June 19, 2020 |

  • I just installed a heat pump hot water heater in the same room as the electric dryer in the basement. The heatpump takes the heat and moisture and blows out cold air so i was thinking of adding an option to my dryer to vent inside instead outside. Just in winter.. I understand the concern was the moisture and mold but what about this case with electric water heater.

    Hugo |
    January 10, 2021 |

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