You know it when excess home moisture raises its ugly head.
You’ll spot foggy windows, smell a mildew or musty odor, or your skin feels clammy.
If it has been around for a while it had the chance to mark its territory. Damp spots, mold, and rotting wood are signs the soggy enemy is taking over the place.
But even if there are no indications (yet) your home’s atmosphere is too humid it’s wise to measure and control because..
- it will make you feel better both physically and mentally (studies show that how happy you feel is directly linked to humidity levels) and,
- keeping more money in your pocket due to reduced heating bills is also a nice reward.
So how to reduce home humidity levels?
Often, simple measures can make a big difference. In other cases more drastic actions are necessary.
Here’s an overview of simple tips and more radical solutions on how to combat excessive indoor humidity. Easiest applicable measures are mentioned first.
How to Lower Home humidity?
There are ways to lower the humidity once you become more aware of what is raising the level in the first place.
- First and foremost, ventilate. Especially the areas that create moisture, like the kitchen and bathroom. When vent fans are present, make sure to turn them on and/or leave them on longer. Especially in the kitchen, bathroom, and basement. If not, consider having them installed by an electrician.
Cooking as well as showering but also washing machines and dryers affect the amount of moisture found in the air, especially when people take long, hot showers.
- If you do not have exhaust fans or a ventilation system, you can crack a window for a few minutes to dry the air out, especially in the bathroom areas that tend to hang onto additional moisture for longer periods.
Mathematically speaking, it only takes between four and six pints of water to raise the humidity level inside of 1,000 square feet from a mere 15% to 60%.
The amount of people within the home can affect how much humidity is in the air as well. One person breathing produces about ¼ cup of water within an hour’s time.
- Ensure that exhaust fans in kitchens, bathrooms, and laundry rooms vent to the outside. Installing vents and attic fans can help too.
- Increase indoor temperature because warm air can hold more moisture (relative humidity decreases if temperature increases).
- Use fans to increase ventilation
- Take colder, shorter showers. Use a low flow showerhead or shower under a less powerful stream by not fully opening the tap. (personally, I find showering with the tap partially open just as pleasant)
- Becoming mindful of the indoor and outdoor temperature also can ease the concern of proper humidity within the home. What is the current temperature inside versus outdoors?
- Are you keeping your home much cooler than the suggested temperature? If that answer is yes, then minor adjustments to the humidity level are easily adjustable.
- Run the AC. Since this option is costly other possible measures are preferred.
- While cooking, try to cover your food and take full advantage of the exhaust fans in which your home is equipped. Oven and stove-top cooking produce more moisture. Slow cookers contribute less to indoor humidity.
- Vent clothes dryers outside.
- If there is a humidifier or vaporizer in the home, turn it off for a little while or simply turn it down. Most humidifiers or vaporizers on the market today have a turn dial, or button to adjust the level of vapor or water you would like dispersed into the air. (a no-brainer but added for the sake of completeness)
- It’s recommended to only use induced draft, sealed-combustion, or power-vented boilers, furnaces, and water heaters.
- Air-conditioning drain lines and drip pans should be kept clean and unobstructed.
- Temporarily place house plants outside or concentrate them in one room. Plants release moisture vapor to the air. Especially when you have lots of plants their role in home humidity levels can be significant. Also make sure not to overwater them.
- Freshly cut firewood contains large amounts of water that evaporates when stored indoors. Better keep it outside.
- Keep downspouts and gutters clean. Adjust downspouts so they carry water farther from the house. Restrict watering plants to bare necessity. Prevent water from pooling at and around the foundations by a descending surface.
- You may also want to use a dehumidifier if maintaining your humidity has become an issue or you live in an older, less ventilated building. Dehumidifiers are commonly placed in basements, since they are underground and do not get a lot of warmth or direct sunlight, or in bathrooms without windows or specific areas in the home that require moist removal. Dehumidifiers work best with closed doors and windows. In order to ensure proper circulation dehumidifiers need to be placed away from walls and furniture. Except for models that have an air vent on top.
Types of dehumidifiers
Various dehumidifiers exist. From small portable devices to large whole-house dehumidifiers utilizing basically three different technologies.
- Desiccant dehumidifiers use desiccants which are substances that naturally absorb moisture (i.e. the little packets of silica gel included in electronics). Best for lower temperatures and moderate humidity. Can withstand freezing conditions as no water is produced. A well-reviewed unit is the Eva-dry Renewable E-333 Wireless Mini Dehumidifer.
- Mechanical /Refrigerant dehumidifiers essentially work like your home’s fridge or airconditioning. Air passes across a cooled metal plate (coil) condensing the airborne moist which then drips into the water tank. Contrary to an AC these units slightly increase air temperature. Best suited for moderate to high humidity levels and moderate to warm conditions as this type of humidfier does not work well in cooler conditions. A popular choice is the best selling Frigidaire FAD704DWD Energy Star 70-pint Dehumidifier.
- Peltier dehumidifiers are usually recommended for small areas such as average size bedrooms, bathrooms, but also RVs and closets. Although they are somewhat less energy efficient these units are valued for being quiet and efficient. Recommended product using peltier technology: Gurin Electric Compact Dehumidifier
Things to adjust in and around the home.
- Carpet may retain moisture. If you’ve tried many things perfusely, consider replacing the carpet. Another benefit, humidity-thriving dust mites love carpet.
- The addition of tubular or wrap insulation on pipes will also help. Insulating tubing for cold water pipes help decrease “sweating”.
- Due to the warm surrounding air, and the cold water of the tank and pipes, toilet tanks and water pipes are another source of condensation. Adding a mixing value to the water supply line and rigid waterproof insulation on the tank, will reduce these effects.
- Cold surface moist can be controlled by adding storm windows, plastic film on the windows, making any repairs to windows or window frames, installing weatherstripping and caulking both inside and outside of the window. This will prevent cold drafts and lower heating costs.
- Vinyl wallcovering and other impermeable wallcoverings can trap moisture as well as keep it out. When moisture is trapped this can lead to mold growth.
- Insulate crawl spaces with a plastic vapor barrier.
- Concrete basement walls can be a huge source of excess humidity. If they haven’t been waterproofed from the outside you could try to waterproof them with products such as Xypex or Drylok. Results however are uncertain. Repair wall cracks.
- In order to have rain water flow away from the house ensure that the yard next to the foundation slopes away from it (generally at a rate of 1 inch per foot). This helps prevent water to enter crawl spaces and basements. This, however, does not solve the problem of ground water that’s pressuring its way up trough the basement flour and walls if these are not sufficiently waterproofed.
- To battle moist coming from the basement floor consider having a sump or a French drain installed. A sump is basically a hole with a pump in the concrete floor. A French drain, or perimiter drain is a piping drain system that’s an extensive version of the sump.
- Have your foundation treated with Hydroclay (the stuff that’s used to waterproof tunnels). This water absorbing clay seals the basement in the areas where the water infiltrates.
- Loose shingles and flashings may leak rain into attics, walls, insulation and other areas. Inspect the roof yearly to avoid such leaks.
What to do with humid crawl spaces?
Bare earth flours are a huge source of moisture. As moisture evaporates from the earth, houses built on such crawl spaces will experience higher humidity levels. Using a vapor retarder (polyethylene or heavy plastic sheets) as a ground cover in crawl spaces will prevent moisture problems. If a vapor barrier is not used, this humidity can become a breeding ground for mold, fungus, mildew and a host of other problems.
Proper crawl space ventilation is also essential.
- When there’s no vapor retarder, 1 square foot of free vent space is required for every 150 square feet of ground exposed crawl space.
- If a retarder is being used, the numbers change to 1 square foot of vent per 1,500 square feet of covered, ground crawl space.
- If the crawl space vents include louvers and/or screens, the double the amount of ventilation is required to make up for the reduced air circulation.
What you should know about dehumidifying house plants
You may have heard about houseplants that are known to absorb moisture from the air. Tropical plants called epiphytes such as English Ivy, Peace Lily, Reed Palm, Boston ferns and Tillandsia are plants that get all their water from the air instead through roots.
They are often touted as house plants that filter the moist out of the air thus reducing hazardous humidity levels in you home.
But you know what they say, if it sounds to good to be true…. it probably is.
All plants give off more water to the atmosphere than they absorb. Think about terrrariums and greenhouses where the air is always humid. So contrary to what is sometimes claimed, these plants are not natural air dehumidifiers. At most they add less to humidity then other types of plants.
Do not underestimate the importance of proper humidity levels
Improper indoor humidity levels are a common home hazard that is often underestimated. Dust mites and other sickmakers such as allergens, pathogens, and noxious chemicals are more abundant in humid conditions.
Allergies, headaches, asthma symptoms such as wheezing, shortness of breath or a chronic cough also indicate you could benefit a lot from lowering moist content in the indoor air.
Dehumidifiers, ventilation, air conditioning, humidity monitors, weatherstripping, caulking, insulation, interior adjustments and lifestyle changes can all help ensure ideal home humidity.
These actions may involve some costs but in the end they will safe you money and improve the health of you and your family members.
Don’t forget, ideal humidity levels for your home are less than 60% in the summer and between 25 40% in the winter.
- The bedroom requires about 50% relative humidity, all year round to reduce dust mites and allergens (source: PubMed.) Proper humidity levels, in other words, sufficient moist, is easier on your mucous membranes and experts claim it helps you sleep better too.
Got rooms in the home where the opposite (too dry air) is at play?