Tag Archives: hygrometer

Humidity in the home

Condensation on window. Image by Natasha C Dunn-Some rights reserved.

“My name is Jeremy and I have a humidity problem.”

Solving moisture problems in the home can seem like a 12 step process. First, you need to need to admit there is a problem.

This time of year, many people are very willing to admit to the problem. Actually, a lot of people are calling out for help to fix the problem, afraid their homes are quickly turning into petri dishes. Continue reading

Dryer vents

Some things never cease to amaze me when doing these audits. One is how few people know how important it is to clean their dryer vents.

Not only does allowing them to clog reduce the efficiency of your dryer but it is a fire hazard as well. Remember when you were in college and the laundry rooms would, on a semi-regular basis, catch fire because someone forgot to clean the lint vent – for a week?

Well, when was the last time you cleaned your exterior vent?

Obviously the screen in the dryer itself is your first line of defense and should be cleaned every time you add or remove a load of clothes, but a lot of lint gets past that screen and gets stuck on your vent. Once there it continues to build and trap ever more fibers until, in some cases, the whole thing gets blocked off. At a minimum, the “flapper” gets stuck in the open position, allowing cold air into your house 24/7/365.

I’ve also seen many times (but never remembered to take photos) people venting their dryer out the basement window (for which they had to bust a pane) but not beyond the window screen. As a result the lint all gets caught between the vent and the screen – no chance for the lint to escape even if it wanted to.

If your dryer is venting into the home – hire someone to fix this ASAP, and read the note below.

If your dryer is on the second (or higher) floor there likely isn’t an easy way to clear the vent. Most people have their dryer in the basement though, so here are a few simple steps to cleaning them.

1. Locate your dryer vent – you might be surprised how many people don’t know where it is outside the house.

2. Using just your fingers, push up the flapper or louvers (the two most common styles).

3. Using your fingers or a flat-head screwdriver, scrape off what lint you can.

4. For flappers, make sure to get all the way up to the top where even a small amount of lint keeps them from closing.

5. For louvers (three horizontal pieces layered atop each other) you can actually pry one or more of the pieces out – pull in the middle of the louver so the piece arcs. Clean each of the louvers off and you can actually stick your hand into the duct and pull more lint from the sides.

6. Go back inside and turn the dryer on to a no-heat mode. Sometimes this is “fluff-no heat” or “timer-no heat” or similar. Go back outside. With the louvers off or the flapper open, try to reach your arm in and pull any additional lint out from the sides. The air flowing through the ducts makes it easier to get all that gunk out, but watch out for your eyes – it comes flying at you.

7. Louvers should be reinstalled. You’ll see pegs at each side. Put one peg in, arc the piece (bending at the center again), and put the other peg in. Repeat for all three louvers and the order (top, middle, bottom) doesn’t matter.

I typically recommend homeowners clean their vents every month or two.

*****UPDATE***** I’d long suspected but never been certain that the IRC residential building code says not to vent a dryer indoors. Bob’s comment and another offline got me to do the research and indeed, indoor venting is against code. Thanks to the good folks at Green Building Advisor and their avid readers I got the answer I needed. (If you’re interested in these issues check them out – they’re one of the best resources I’m aware of.) Emphasis below is mine.

M1502.3 Duct termination. Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. If the manufacturer’s instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.

NOTE to people venting dryers indoors: If you’ve got a gas dryer venting indoors you’re blowing lots of hot moist gasses, including carbon monoxide, into your house. If you’ve got an electric dryer venting indoors it isn’t anywhere near as dangerous as a gas dryer, but it is still a very bad idea.

Think about how much moisture is in your clothing when it goes into the dryer. Not sure how much? How heavy was your laundry before it went in the wash as compared to after? Yeah, it’s about that much water.

All that moisture is now going into your home where it can cause mold, mildew, rot and other safety issues. The fancy contraptions available online are designed to catch lint, not stop moisture from entering your home. Especially if you’re trying to make your home safer and more efficient (why else would you be reading this?) you do not want to add moisture to the house.

Still don’t believe me? Spend a few bucks on a decent hygrometer. Check the humidity before and after running the dryer. If you’re willing, drop a note in the comments with what you found.

Cool in the summer part II – Its the humidity

It's not the heat, it's the humidity! Photo courtesy TheKarenD. Some rights reserved.

That annoying saying, “it’s not the heat, it’s the humidity” is true. The heat wave we’re currently experiencing in Arlington is a double-whammy with high heat and high humidity (humidity was over 90% Saturday morning around 6 am.)

What to do?

To remove humidity from the house there is only one energy efficient alternative to an air conditioner or dehumidifier, but there are some important things you can do to prevent your home from becoming more humid.

The most efficient way to reduce humidity is to open a window, as long as it is dryer outside than inside. Even during heat waves (in MA) the overnight temperatures will usually drop, but humidity goes up. Environmentally, it’s a better deal to open your windows for the cool air and turn the AC off. Your air conditioner or dehumidifier are the only choices to reduce humidity in really sticky weather, especially during the heat of the day.

How to keep your home from getting more humid.

  1. Run your exhaust fans. When you shower or cook with gas, you release water molecules into the air -the last thing you want to do in a heat wave. (It also adds various unhealthy gases.) Turn on the exhaust fan while showering/cooking and make sure it stays on for several minutes after you’re done. Make sure your fan exhausts outside rather than into your attic, which creates a mold issue. If you don’t have an exhaust fan get one soon, your home will thank you.
  2. If it is still hot and humid in the morning, then contrary to what I said in a previous post,  keep those windows closed. Most online weather sites will tell you the humidity outside.
  3. Buy a hygrometer. Hygrometers (commonly, but incorrectly, referred to as hydrometers) measure the humidity in your home. Unfortunately the inexpensive models seem to be of poor quality. I’ve found them to be off by as much as 10% when testing them (testing/calibrating requires only salt and water, Google: calibrate hygrometer). You can buy decent digital models for around $20.
  4. Dehumidify. Depending on which “expert” you listen to your indoor humidity should be between 30-60%. This keeps your home more comfortable and prevents mold from growing. Dehumidifiers are costly to run but less expensive than mold damage or health issues. Unfortunately dehumidifiers produce heat, so during heat waves they’re best left in the basement.
  5. Air conditioners don’t just cool the air, they take moisture out. Use them wisely, set them at high temperatures (75+), and try to use all the energy saving methods listed earlier first.

-Jeremy