Why Is My Apartment So Humid? 12 Ways to Fix It

High indoor humidity usually comes from trapped moisture, poor airflow, or leaks letting outside air sneak in. But the fix isn't one-size-fits-all, as it depends on what’s causing it.

In this guide, you’ll learn:

• What makes apartments humid (even with AC blasting)
• How to identify the real source of the moisture
• 12 smart ways to fix it—from simple DIYs to upgrades worth asking your landlord about
• When high humidity crosses the line from annoying to harmful
• How to know it’s time to call a pro

Whether you’re trying to protect your stuff, improve air quality, or just stop your hair from frizzing, it starts here.

Why Does My Apartment Get Humid?

Everyday Indoor Moisture

Your daily routine may be adding more water vapor than you think. Long showers, cooking without ventilation, air-drying clothes indoors, and even houseplants release moisture. Every person in the apartment breathes out up to a pint of water vapor per night.

Quick check: If you see fog on mirrors or windows after everyday activities, your humidity is likely building up from within.

Leaks, Cracks & Building Flaws

Older buildings or poorly maintained units may have leaky roofs, cracked walls, or gaps around windows and doors. Moisture can also seep up from the foundation in lower-floor units or basement apartments, a phenomenon called rising damp.

Look for: Warped floors, bubbling paint, or walls that feel cold and damp.

AC and HVAC Issues

Your air conditioner should remove both heat and humidity, but only if it’s working correctly.

Some of the typical problems include:

• Oversized AC units that cool too quickly but don’t run long enough to remove moisture
• Clogged filters or blocked coils
• AC drain pans not emptying properly

If it feels cool but clammy indoors, your AC might be the culprit.

Poor Airflow & Ventilation

Lack of bathroom exhaust fans, sealed windows, or rarely opened doors can trap humidity indoors. Cooking, showering, and even breathing in a sealed-up apartment can create a moisture buildup with nowhere to go.

Regional Climate & Seasonal Shifts

In warm or coastal climates, outside humidity often seeps in, especially during summer. In winter, condensation can form from indoor heating clashing with cold windows.

How to Diagnose Apartment Humidity

• Use a hygrometer (cheap digital models available online) to track indoor humidity levels
• Look for condensation on windows, musty smells, peeling paint, or mold spots
• Check closets and under sinks for damp or stagnant air

Ideal Indoor Humidity Range & Risks of Excess Moisture

The sweet spot for indoor humidity is between 30% and 50%. Go above or below that range, and your comfort and your apartment can take a hit.

What Happens When It’s Too Humid?

Humidity above 50% creates a breeding ground for:

• Mold and mildew on walls, ceilings, and clothing
• Dust mites and allergens that thrive in moist environments
• Peeling paint, warped wood floors, and structural damage
• Musty smells and lingering dampness that never quite goes away

It can even lead to health issues, like sinus trouble, worsened asthma, and fatigue from poor indoor air quality.

What About Dry Air?

While less common in humid regions, air that’s too dry (below 30–35%) can cause:

• Cracked wood floors or furniture
• Respiratory irritation, dry skin, and nosebleeds
• Static shocks and a generally uncomfortable living environment

The key is not to overcorrect. It’s tempting to run a dehumidifier non-stop or seal your windows tight, but over-drying the air can create just as many problems.

Use a digital hygrometer to monitor your levels and aim for the 30–50% humidity zone. That’s where comfort, health, and apartment durability all align.

12 Ways to Fix Apartment Humidity

1. Use a Dehumidifier

What it does: Pulls moisture out of the air, lowering relative humidity directly. Best use case: Small to medium rooms with persistent humidity, especially when AC or ventilation alone isn’t enough.

Caveats/tips:

• Match capacity to room size. Oversized or undersized units are inefficient.
• Always empty or drain the water tank to avoid overflow or mold.
• Higher energy usage. Look for energy‑efficient models.

Expert insight: Sites like Tom’s Guide point out that dehumidifiers often outperform AC in humidity removal when temperatures are moderate.

2. Run Air Conditioning/“Dry Mode”

What it does: As the AC cools, it also condenses moisture from the air. Best use case: Hot, humid months when you also want cooling.

Caveats/tips:

• Use “dry” or “dehumidify” mode if your unit has it.
• Raise the thermostat a few degrees to prolong runtime, which helps moisture removal.
• Clean coils, filters, and ensure the drain line is clear.
• Be cautious: if the AC cycles too frequently (on/off), it may not remove enough humidity.

3. Improve Ventilation & Use Exhaust Fans

What it does: Introduces fresh air and removes humid indoor air. Best use case: Bathrooms, kitchens, laundry rooms (areas where moisture is generated).

Caveats/tips:

• Run fans during and 10–15 minutes after use (e.g., showers, cooking).
• “Shock ventilate”—open windows briefly to push out humid air.
• Keep doors open to improve internal air flow.

4. Seal Leaks, Gaps & Cracks

What it does: Prevents outside humidity from entering your space. Best use case: Older buildings, units with drafty windows/doors, obvious cracks.

Caveats/tips:

• Use caulk, door sweeps, and weatherstripping.
• Check around plumbing, electrical penetrations, and window frames.
• Even small leaks can negate other fixes—seal first, then dehumidify.

5. Dry Clothes Outdoors or Use a Vented Dryer

What it does: Prevents indoor moisture from laundry from entering the living space. Best use case: If you have access to a balcony, clothesline, or a properly vented dryer.

Caveats/tips:

• Avoid drying clothes on racks indoors.
• Ensure dryers are vented outside (not recirculated).
• Use heater / ventilation in the drying area if unavoidable.

6. Limit Steam & Moisture Sources

What it does: Reduces the input of moisture to the indoor air. Best use case: Day‑to‑day habits in the kitchen, bathrooms, etc.

Caveats/tips:

• Use lids on pots while cooking.
• Take shorter, cooler showers and use ventilation.
• Reduce excess watering of indoor plants, especially large leaves.

7. Air Circulation with Fans

What it does: Helps even out humidity pockets and improves evaporation. Best use case: Rooms with damp corners or low airflow.

Caveats/tips:

• Use ceiling fans or box fans to keep air moving.
• Don’t place fans blowing directly on fabrics or walls. They can push moisture into unseen areas.
• Combine with a dehumidifier or AC for the best effect.

8. Use Moisture Absorbers/DIY Desiccants

What it does: Passively absorbs moisture in enclosed or small areas. Best use case: Closets, cabinets, bathrooms, corners.

Caveats/tips:

• Products: DampRid (calcium chloride), silica gel, charcoal, baking soda.
• Replace or recharge when saturated.
• Not a full solution for whole-room humidity, but helpful for spot treatment.

9. Upgrade Windows/Insulation

What it does: Reduces condensation by improving thermal barrier and sealing. Best use case: If you own the unit or landlord permits improvements.

Caveats/tips:

• Double-pane or low-E windows are better for insulation.
• Check window seals, frames, and weatherstripping.
• Add insulation in walls or around pipes where feasible.

10. Maintain HVAC & Ducts

What it does: Keeps your HVAC system running efficiently and reduces moisture build-up in ducts. Best use case: For units on HVAC or central AC systems.

Caveats/tips:

• Change filters regularly.
• Clean ductwork if mold or moisture has built up.
• Ensure drain lines are clear and condensation pans aren’t blocked.
• Use continuous fan/air handler mode to keep air circulating.

11. Control Indoor Temperature Consistently

What it does: Minimizes condensation caused by temperature swings. Best use case: In climates with big day/night temperature changes.

Caveats/tips:

• Avoid letting your thermostat swing wildly.
• Use heaters moderately. Very warm air holds more moisture.
• Keep a stable baseline temperature so surfaces don’t reach the dew point often.

12. Add a Whole‑Home Dehumidifier (if allowed)

What it does: Integrated dehumidification for multiple rooms via HVAC system. Best use case: Larger apartments or multi-zone units where localized dehumidifiers can’t cope.

Caveats/tips:

• Requires permission or landlord approval.
• Installation and maintenance costs are higher.
• Can work invisibly, integrated seamlessly with HVAC controls.

How to Choose the Right Humidity Fixes for Your Space

Not all fixes work for every apartment, and the best solution depends on why your unit is humid in the first place. Start by matching the fix to the root cause:

• If poor ventilation is the issue — focus on exhaust fans, open windows, and airflow.
• If moisture is coming from daily habits — limit steam, dry clothes outside, and use moisture absorbers.
• If the air feels cool but damp — your AC may not be dehumidifying properly. Try a dedicated dehumidifier.

Budget First, Upgrade Later

Many humidity fixes are low-cost, such as turning on fans, using lids, drying clothes differently. Start here. Then, move to higher-investment solutions like better windows or dehumidifiers if needed.

Temporary or Permanent?

• Short-term fixes: DampRid, fans, behavioral changes
• Long-term upgrades: Sealing gaps, HVAC servicing, whole-home systems (if allowed)

Combo Moves Work Best

No single fix is magic. You’ll often see the best results from combining 2–3 approaches:

For example, try a portable dehumidifier + window caulking + ventilation boost to cover moisture input, retention, and removal.

Track results with a digital hygrometer to know what’s working, and when you’ve hit that ideal 30–50% humidity zone.

When to Call a Professional for Apartment Humidity Issues

Sometimes, humidity is a symptom of a bigger problem.

Signs You May Need a Pro:

• You’ve tried DIY solutions and the humidity still won’t drop.
• Multiple rooms feel damp, not just one.
• You notice musty smells, peeling paint, rotting trim, or mold spots that keep returning.
• There’s evidence of leaks, even small ones, like water stains, bulging walls, or condensation behind furniture.

In these cases, it’s time to call a licensed expert.

Who to Call:

• Plumber: If you suspect pipe leaks, standing water, or drainage issues.
• HVAC tech: For AC systems not removing moisture properly or needing balancing.
• Waterproofing specialist: For basement-level units or ground-floor moisture infiltration.

It’s always worth keeping these emergency numbers in your phone as well, especially when you need a fix in a pinch.

Cost & Energy Considerations of Humidity Fixes

Managing indoor humidity can also affect your energy use and monthly utility bills.

Dehumidifier vs. AC: What Costs More?

• Dehumidifier: Generally more energy-efficient for removing moisture alone, especially in mild weather when you don’t need cooling.
• Air Conditioner: Uses more electricity overall, especially if you’re running it just to reduce humidity rather than for temperature control.

Tip: If your goal is strictly moisture removal, a modern, Energy Star-rated dehumidifier will likely be the most cost-effective choice.

Final Thoughts - Take Control of Your Humidity

Humidity problems in your apartment can sneak up and stick around if you aren’t careful. Whether it’s caused by your daily routines, building leaks, or poor airflow, the key is identifying the root cause before you try to fix it.

Use a hygrometer to check your levels, then layer simple solutions, such as improving ventilation, sealing gaps, running a dehumidifier, and tweaking your AC settings. Sometimes it’s a combo of small changes that brings relief instead of just one big fix.

Track your progress, keep an eye out for damage, and don’t wait if signs point to a deeper issue.

If it has become too big an issue to deal with and maintenance isn’t responding to your requests, it might be time to find a new place. Use Apartment List’s quiz to find apartments with better AC, airflow, and insulation, so you can breathe easier, right from day one.

Frequently Asked Questions About Apartment Humidity

Is 70% humidity normal in summer in an apartment?

It’s common, but not ideal. Indoor humidity over 60% can lead to mold, discomfort, and health issues. Aim to stay within the 30–50% range.

Will my landlord pay for a dehumidifier or repairs?

It depends on the lease and local laws. If humidity is due to poor insulation, leaks, or malfunctioning HVAC, your landlord may be responsible for fixes. Dehumidifiers are typically renter-supplied unless stated otherwise.

Can plants cause humidity?

Yes, especially in large numbers or when overwatered. Plants release moisture into the air through transpiration, which can raise indoor humidity slightly.

Does air conditioning remove humidity?

Yes. AC systems naturally pull moisture from the air as they cool. However, dirty coils or an oversized unit may be less effective. “Dry” mode can help reduce humidity without major cooling.

How long should you run a dehumidifier?

It varies. Start with 8–12 hours a day or until humidity drops below 50%. Use a hygrometer to track levels and adjust based on results.

What’s the difference between relative and absolute humidity?

Relative humidity is the percentage of moisture in the air compared to the max it can hold at a given temperature. Absolute humidity is the actual amount of water vapor in the air, regardless of temperature. Relative humidity is more relevant indoors.