Modern homes are tighter, more efficient, and better insulated than ever before. Even in brand-new Energy Star and LEED-certified high-performance home(s) humidity problems exist.
So what’s causing it?
In this episode of the HVAC ADHD Podcast, Jeremy Begley sits down with Nikki Krueger, Director of Marketing and Business Development at Santa Fe Dehumidifiers, to unpack why ventilation alone isn’t enough in today’s high-performance homes.
They dive deep into:
- Why exhaust-only ventilation often fails
- The hidden moisture problems in modern construction
- Why oversized HVAC systems create humidity disasters
- How ventilating dehumidifiers change the game
- Why dedicated latent load control is becoming mandatory
If you design, build, commission, or live in a high-performance home, this conversation explains why humidity control can no longer be treated as an afterthought.
Key Takeaways
- Tight homes often trap moisture instead of controlling it.
- Exhaust-only ventilation can worsen humidity problems.
- Air conditioners are increasingly poor at handling latent loads.
- Variable-speed systems may reduce dehumidification at part load.
- Ventilating dehumidifiers manage indoor RH more effectively than traditional ventilation systems.
- Dedicated dehumidification improves comfort, IAQ, durability, and warranty performance.
- Proper commissioning is critical for dehumidifier performance.
Why High-Performance Homes Still Feel Humid
Jeremy shares his early experience working on LEED for Homes projects in Cincinnati where nearly every efficient home developed summertime humidity problems.
These homes were:
- Tight
- Well insulated
- Energy efficient
- Using exhaust-only ventilation
And they were wet.
Homeowners complained about:
- Sticky indoor conditions
- Persistent musty smells
- Condensation
- General discomfort
The problem wasn’t necessarily infiltration alone.
It was uncontrolled moisture combined with HVAC systems that simply weren’t running long enough to remove latent load.
As Nikki explains, ventilation standards tell you how much air to move — not necessarily the best strategy for your climate.
The Problem With Exhaust-Only Ventilation
Exhaust-only ventilation remains common because:
- It’s inexpensive
- It satisfies code
- It meets ASHRAE 62.2 requirements
But in humid climates, it creates major problems.
By exhausting indoor air, the home pulls replacement air through:
- Cracks
- Penetrations
- Wall assemblies
- Attics
- Crawlspaces
That means humid outdoor air enters the building uncontrolled.
Jeremy describes it perfectly:
“Ventilation by adding infiltration is really all it’s doing.”
In modern tight homes, that moisture load accumulates fast.
Why Air Conditioners Alone Can’t Control Humidity
One of the biggest shifts happening in HVAC design is the disconnect between sensible load and latent load.
Modern homes have:
- Lower sensible cooling loads
- Longer shoulder seasons
- Shorter AC runtimes
- Higher moisture retention
That creates a dangerous condition:
Humidity stays high even when temperature is satisfied.
Nikki points out that many systems only perform well during peak sensible conditions.
But the real humidity issues occur during:
- Mild rainy days
- Shoulder seasons
- Partial-load conditions
- Nighttime setbacks
- Low runtime periods
This is especially problematic with:
- Oversized systems
- Single-stage equipment
- Variable-speed systems operating at low capacity
Many variable-speed systems struggle with latent capacity during part-load operation.
Ventilating Dehumidifiers Explained
Santa Fe’s ventilating dehumidifiers approach the problem differently.
Instead of only treating incoming outdoor air, they maintain the relative humidity of the entire living space.
Proper whole-home dehumidification allows the HVAC system to focus on sensible cooling while dedicated equipment manages latent load.
That distinction matters.
Traditional ventilating systems often:
- Bring in fresh air
- Temper incoming air
- But fail to actively maintain RH
Santa Fe systems:
- Bring in ventilation air
- Temper it with return air
- Monitor indoor RH
- Run dehumidification independently when needed
As Nikki explains:
“What we care about is the RH in the living space.”
That’s the core difference.
Why Dedicated Latent Control Matters
Jeremy makes a strong case for what he calls:
Decoupled latent strategy
Modern HVAC systems increasingly need separate sensible and latent control.
That means:
- Cooling handles temperature
- Dehumidification handles moisture
This becomes critical because many inverter systems:
- Reduce latent capacity at low load
- Prioritize efficiency over moisture removal
- Lack transparent part-load latent performance data
The result:
Homes maintain temperature while humidity climbs.
Dedicated dehumidification solves that gap.
Multifamily Housing Has a Major Humidity Problem
One of the most revealing parts of the conversation focuses on multifamily and affordable housing projects.
Common issues include:
- Oversized HVAC systems
- Minimal duct design
- High occupancy moisture loads
- Construction moisture
- Thermostat misuse
Jeremy describes apartments reading:
- 71°F
- 69–81% RH
…in brand-new unoccupied units.
That’s a serious building durability and IAQ problem before residents even move in.
Construction Moisture Is the Most Ignored Humidity Load
One of the best points in the episode:
Buildings dry for years after construction.
Fresh concrete, framing lumber, drywall, paint, and construction materials release enormous amounts of moisture.
Add:
- Rain exposure during framing
- Tight envelopes
- Reduced airflow
- Occupancy moisture
…and humidity compounds quickly.
This is especially problematic in:
- Multifamily
- Crawlspace homes
- Tight spray foam homes
- Senior housing
Why Senior Housing Faces Unique Humidity Challenges
Nikki highlights a major issue in senior housing:
Residents often prefer warmer indoor temperatures.
That reduces HVAC runtime dramatically.
Less runtime means:
- Less latent removal
- Higher RH
- Increased microbial growth risk
And residents shouldn’t have to choose between:
- Comfort
- Energy bills
- Mold prevention
Dedicated dehumidification solves that conflict.
Are Ventilating Dehumidifiers Worth It?
In humid climates and modern tight homes, absolutely.
Especially for:
- High-performance homes
- Variable-speed systems
- Multifamily housing
- Crawlspaces
- Encapsulated attics
- Florida-style construction
- Energy-efficient homes
Benefits include:
- Better comfort
- Lower indoor RH
- Improved IAQ
- Reduced mold risk
- Fewer warranty callbacks
- Better building durability
- Reduced occupant complaints
The industry is increasingly recognizing that:
Dedicated latent control is no longer optional.
Why Proper Commissioning Matters
A major theme throughout the episode:
Most failures are installation failures.
Common issues include:
- Incorrect wiring
- Missing dampers
- Improper duct layouts
- Poor airflow setup
- Incorrect ventilation programming
Jeremy emphasizes the importance of:
- Commissioning plans
- Startup verification
- Installation documentation
- Contractor training
Even great equipment fails when installed poorly.
The Future of HVAC Design (to prevent high-performance home humidity problems)
The HVAC industry is shifting toward:
- Smaller sensible loads
- Higher latent challenges
- Better ventilation standards
- Decoupled humidity control
- More precise commissioning
And homeowners are beginning to demand it.
Nikki references a recent NAHB survey where:
Dedicated dehumidification ranked higher than ventilation and filtration among homeowner interests.
That’s a major market shift.
FAQ: High-Performance Home Humidity Problems
Why are new homes so humid?
Modern homes are tighter and more energy efficient, which reduces natural drying and HVAC runtime. Moisture becomes trapped more easily indoors.
Can ventilation systems remove humidity?
Not necessarily. Ventilation systems exchange air, but they do not automatically maintain indoor relative humidity levels.
What is a ventilating dehumidifier?
A ventilating dehumidifier combines fresh air ventilation with dedicated humidity control to maintain indoor RH targets.
Are variable-speed HVAC systems bad for humidity?
Not inherently, but many inverter systems lose latent capacity at low loads, which can allow humidity to rise during part-load operation.
What indoor humidity level prevents high-performance home humidity problems?
Most building science professionals target:
- 45–50% RH ideal
- Below 60% RH maximum
Does a dehumidifier solve infiltration problems?
No. Dehumidifiers help control indoor moisture but cannot fix building leakage or condensation caused by infiltration pathways.
Why do multifamily high-performance home humidity problems exist?
Oversized equipment, short cycling, construction moisture, occupancy loads, and poor ventilation strategies
Guest Resources
Santa Fe Dehumidifiers
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