Indoor allergies can feel like something of a trick. When we’re in our homes, we expect to be free of allergic triggers like pollen, ragweed, and grass; because of this, we sometimes treat our homes as refuge from these things. However, a minefield of potential allergens awaits us in even the cleanest of homes. Frequent dusting and vacuuming are obvious solutions, but can be time-consuming and difficult to keep up with. However, there is one home addition that could help in the battle against indoor allergens: a dehumidifier.
Dehumidifiers, as the name would imply, remove moisture from the air indoors. This process has many benefits. From a comfort standpoint, dehumidification allows air in a space to feel cooler―a process that can lower your energy bills. Further, it reduces damage to your most prized of possessions―excess humidity in the home can cause damage to clothing and shoes, instruments, cameras, and other electronics. But, perhaps most importantly, it slows the development of several common allergens: dust mites, mold, and mildew all thrive under humid conditions. Remove the potential for humidity, and you can start to remove these household scourges.
As an aside: Dehumidifiers are not interchangeable with their counterparts, humidifiers. While humidifiers can provide some relief to allergy sufferers, they serve an altogether different purpose and are used under quite different conditions. Humidifiers are used to rehydrate dry air, generally common in the winter months when heaters are used often or when weather conditions reduce the moisture in the air.
Some signs that you need a humidifier might include dry skin and eyes, chapped or cracked lips, and frequent “shocks†in the home from metal devices or after being on carpet. From an allergy perspective, humidifiers can help to loosen dry coughs and soothe dry nasal passages, but must be kept clean or they could spread bacteria. What’s more, excess humidity in the air can feed some of the most prevalent allergens, so let’s talk now about how to best remove it, and the benefits which that can provide.
The Relationship Between Humidity and Allergens
Three of the most common causes of allergic reactions in the home are mold, mildew, and dust mites. As it happens, all three of these phenomena are helped by the presence of moisture in the air.
As we know, mold and mildew form on surfaces when excess moisture is present; it is why most bathrooms are equipped with fans to cycle moist air out of already damp spaces. But what you might not know is that dust mites, unable to drink water, instead absorb moisture from the air to survive and thrive. With such a ready source of sustenance available in humid rooms, it’s no wonder that warm months feel as though they summon the worst allergy symptoms.
How Do You Know If Humidity Is a Problem?
If you suspect that humidity is worsening your allergy symptoms, there are a two main ways 
that you can check to confirm these suspicions. The first is a visual test of your home. Some of the signs that humidity is present in unmanageable amounts in your home include: damp or wet stains on walls and ceilings; a stuffy feeling when entering rooms; signs of rotting wood in rafters or on exposed wood surfaces; condensation on windows; or a general musty smell.
Any or all of these observations are a clear sign that too much moisture has built up in your home. It need not progress to the point where you see fuzziness, or shades of green or black. Moisture damage can show up far more subtly, and should be caught early. What’s more, climates and seasons with thunderstorms or heavy rain can make these problems worse.
However, for more subtle cases, a tool called a hygrometer can help you determine if the air moisture is too high. A hygrometer will assess the moisture level in the air as a percentage of overall air volume. Depending on the time of year, an average reading for most homes is between 30% (in winter) and 50% in summer.
If your readings are above 50%―and we recommend taking readings at different points in the day, from different points in a given room―you may need to explore options for dehumidification of a space.
Considerations for Dehumidifier Purchase
Believe it or not, the decision to buy a dehumidifier is only the beginning of the process. Before you head to the store or online to buy yours, you’ll need to consider several factors that inform your purchase. All dehumidifiers are not created equal, and careful assessment of your allergen concerns, space considerations, and energy specifications will all affect your purchasing decision.
Room Size
Once you realize that dehumidification is needed in your home, your first instinct might be to 
buy the highest capacity machine possible, to put the problem behind you once and for all. However, such a rash solution may not be the right one for you, for any number of reasons. Take a closer look at where you struggle the most to remove humidity, how severe the problem is, and the most cost-effective solution available.
In general, there are three “types†of capacity ratings for dehumidifiers, graded by how many pints of water they can remove from the air in a twenty-four hour period. Small-capacity units can remove up to 25 pints of water per day, large-capacity units can remove 35-50 pints of 
water per day, and whole house units remove more than that (but are built into a home HVAC system).
It’s important for you to weigh your need for moisture removal, against the power of the machine you buy, lest you end up with a unit too small to handle your needs, or one far too large for the scope of your humidity problem.
In general, a 25 pint unit can serve a bedroom or smaller living space well; 35, 40, or 50 pint units are more appropriate for basements or rooms that have moisture generating features. Other
factors than can affect the capacity of a dehumidifier you might need for a space are the overall climate you live in (arid or humid?), foot traffic of a space (how many people spend time in it, and how often?), how many windows or doors there are in a space, and if there’s a washer or dryer nearby (generating additional moisture).
Water Removal Mechanism
As you can imagine, a machine that is pulling moisture from the air will eventually need to put 
that moisture somewhere else. There are three main mechanisms that dehumidifiers use to dispose of collected water: a removable collection basin, a floor-level water drain, or an internal pump that allows water to be pumped upward through a hose into a sink.
Keep the method of removal in mind as you explore what unit you need. Think not just about how much moisture that will be pulled out of the air, but also what method is easiest for you to remove that water.
If you prefer to not carry a basin, or will have trouble moving your unit somewhere that will accommodate a floor-level drain, then you will likely need a more sophisticated device to pump the water out. However, if you have lower levels of humidity or don’t mind a bit more manual labor in emptying your machine, a simpler model will do.
Energy Performance
Any new addition to the home electronics canon, especially ones that will be left running, have the potential to raise your energy bill and affect your energy spending. Dehumidifiers are no exception. As you explore your options, you’ll want to pay attention to EnergyStar ratings for each machine, and weigh the costs associated with operating it.
However, don’t let cost savings make you stingy; prolonged exposure to excess moisture can lead to wood rot and mold, which can be costly to remove. Weigh the cost of added energy, against potential repair or refurbishment costs.
Other Considerations
In all of this, remember to what end this investment is being made: the reduction of allergic 
triggers. And, while dehumidifiers will make a difference in the lives of most allergy sufferers, they’re not designed to be a cure-all. Dehumidifiers can address problems caused by mildew, mold, and dust mites, but do little to address any issues brought about by dust, cigarette smoke, dander, or other airborne allergens. To deal with these problems, an air purifier is a more appropriate acquisition.
Additionally, although a dehumidifier will aid in some cleaning needs, one should recognize that a dehumidifier won’t replace the need for periodic cleaning. The same regimen of sweeping, dusting, and cleaning mildew-susceptible areas like bathrooms and kitchens will need to be upheld. A dehumidifier will help address some deep-seated issues, but it will leave your day-to-day routine generally intact―just with more relief!
If that will be difficult, consider adjusting your home so less traffic runs through that space, or enforce house rules on leaving doors and windows in that area closed.
And, finally, use this opportunity of inspection and investigation to examine how airtight doorjambs and window frames are, as well as the frequency of open doors and windows in dehumidified spaces.
Even the most powerful dehumidifier won’t be able to efficiently make up the ground lost from carelessly opened doors and windows. This is doubly true if you live in a humid climate, or in an area experiencing heavy rains or frequent thunderstorms.
Before you place a dehumidifier in a room, take stock of how likely it will be able to “work†uninterrupted.
Care for Your New Dehumidifier
Even as you incorporate your new dehumidifier into your life and household, its use is far from 
a “set it and forget it†enterprise. Its positioning, cleaning, and operation conditions all play a part in how well it can do its job. To give your home the best chance at being properly dehumidified, pay close attention to the following tips for optimal use:
- When setting up a dehumidifier unit, place it at least 6 inches away from the wall providing power, ensuring that air can move freely around it. Close all doors and windows in the room where it’s operating, to keep it working efficiently.
- For the first few days it’s running, leave it on its “driest†setting to allow it to pull moisture from room furnishings and fixtures. After the initial few days, it can be turned down; most of its hardest work will already be done.
- As we’ve mentioned, the troubles with allergies tend to worsen during warmer seasons, like spring and summer. Moderate your dehumidifier use around those seasons, and only leave it running in temperatures of 70.5 degrees Fahrenheit (or 21.4 degrees Celsius). If the unit is left running at lower temperatures―65.5 degrees Fahrenheit (18.6 degrees Celsius) or lower―frost may form on the machine’s coils, reducing its efficiency.
- And, speaking of the coils, these should be cleaned every three months with a soft cloth or brush, to prevent particulates from slowing down the machine’s processes. Additionally, any grills or louvers on your dehumidifier should be cleaned monthly to prevent any dust, mildew, or bacteria from forming inside. After all, that is what we’re trying to avoid!
Whether you’re hoping to rely less on pills, drops, and shots to manage allergies, or simply want to breathe easier in your own home, a dehumidifier is a useful solution for a number of reasons. It naturally reduces several root causes of allergy attacks, while also protecting your home and the items in it.
There can be a learning curve when deciding what type of dehumidifier to buy, and a second one when learning how to operate it optimally, but the research and investment will be worth it when you can inhale deeply without fear of coughs, sneezes, or itchy eyes.
