Home Services Indoor Air Quality
Indoor Air Quality

The Air Inside
Your Home Is
5× More Polluted
Than Outside.

Dust, allergens, VOCs, mold spores, and CO₂ accumulate in sealed Seattle homes year-round — invisible to you, but real in their effects. We identify what's in your air and fix it.

Air Quality Testing
Advanced Filtration
Whole-Home Purification
Humidity Control
Get a Free Air Assessment (425) 648-7887
Free In-Home Air Quality Assessment♦ MERV-16 Whole-Home Filtration♦ 4.9★ on Google♦ Allergen • Mold • VOC • PM2.5 Control♦ Whole-Home Humidifiers & Dehumidifiers♦ Licensed & Insured in Washington State♦ Free In-Home Air Quality Assessment♦ MERV-16 Whole-Home Filtration♦ 4.9★ on Google
The Invisible Problem

What's Actually In Your Air

Seattle's tight, well-insulated homes trap more than just warmth. These pollutants accumulate with every breath — and most homeowners have no idea.

2.5μm
particle size

Fine Particulate Matter (PM2.5)

Tiny particles from cooking, candles, outdoor traffic, and your HVAC system. Small enough to bypass normal nose and throat defenses and deposit deep in the lungs.

Sources: cooking smoke, candles, outdoor infiltration, dirty filters
400+
known VOC types

Volatile Organic Compounds

Emitted by paint, flooring, cleaning products, furniture, and adhesives. Many are odorless. Long-term exposure is linked to headaches, respiratory irritation, and liver stress.

Sources: new furniture, flooring, paint, cleaning products, adhesives
60%
of US homes affected

Allergens & Dust Mites

Dust mite particles, pet dander, pollen, and mold spores circulate through your duct system every time your HVAC runs — spreading allergens to every room in the house.

Sources: duct system, bedding, carpets, pets, outdoor air
50%+
relative humidity

Mold Spores & Bacteria

Seattle's wet climate makes humidity management critical. Mold thrives above 50% relative humidity — exactly where many Seattle homes sit in fall and winter. Evaporator coils are a common growth site.

Sources: high humidity, HVAC coils, crawlspaces, bathrooms
1,000
ppm threshold

CO₂ & Stale Air

CO₂ builds up in sealed, well-insulated homes. Above 1,000 ppm — common in Seattle bedrooms — research shows measurable declines in cognitive performance, sleep quality, and focus.

Sources: occupant respiration, poor ventilation, tight building envelope
30–50%
ideal range

Humidity Imbalance

Too high: mold, dust mites, musty smell, wood damage. Too low: dry skin, static electricity, cracked woodwork, increased virus survival. Seattle swings between both extremes seasonally.

Both extremes are addressable with whole-home humidity control
Read the Signs

What You're Noticing — and Why

Symptoms you've probably seen in your home, mapped to their likely air quality cause.

What you're noticing
Likely IAQ cause & fix

Dust constantly reappearing on surfaces

Even after cleaning, it's back within days

Overloaded or wrong-MERV filter

Upgrading to MERV-13+ captures fine particles before they recirculate. Combined with duct cleaning for severe cases.

Allergy or asthma symptoms worse indoors

Sneezing, congestion, or wheezing at home

Allergens circulating via duct system

HEPA-grade whole-home air purifier + filter upgrade + annual duct inspection addresses the source.

Musty or stale smell — especially in winter

Rooms feel heavy, closed-off, or smell off

High humidity + mold on coils or ducts

Whole-home dehumidifier + coil cleaning + UV germicidal light installation eliminates the source.

Poor sleep, morning headaches, fatigue

Feel more rested after nights away from home

Elevated CO₂ in sealed bedroom

Energy recovery ventilator (ERV) or fresh air intake brings in outdoor air without losing conditioned temperature.

Condensation on windows, damp walls

Moisture forming on glass or window frames

Indoor humidity above 55–60%

Whole-home dehumidifier integrated with your HVAC system. Condensation is mold's warning shot — act before it appears.

Dry skin, nosebleeds, static electricity

Worse in winter when the heat is running constantly

Indoor humidity below 30%

Whole-home humidifier mounted on your furnace or air handler. Unlike portable units, it treats every room automatically.

Any of these sound familiar? A free air quality assessment tells you exactly what you're dealing with.

Book a Free Assessment
Our Solutions

What We Install & Service

Every IAQ solution we offer works with your existing HVAC system — no separate equipment to maintain.

Air Purification

Whole-Home Air Purifiers

Unlike portable room purifiers, whole-home units mount inside your air handler and treat every cubic foot of air that circulates through your system. They remove particles, VOCs, bacteria, mold spores, and viruses continuously — without you changing anything.

iWave & Reme Halo systems
99.97% particle capture
Kills mold & bacteria
Zero ongoing maintenance
Get a Quote
Whole-home air purifier installation
Works with any HVAC system
Retrofit or new install
HVAC filter upgrade Seattle
MERV-8 → MERV-16
The single most impactful upgrade
Advanced Filtration

High-MERV Filtration Systems

Standard 1-inch MERV-8 filters catch large particles and protect your equipment. They do almost nothing for PM2.5, allergens, or mold spores. A 4- or 5-inch media filter upgrade — installed properly to avoid airflow restriction — makes a night-and-day difference.

Aprilaire & Honeywell systems
Up to 95% particle efficiency
Filter change every 6–12 months
No airflow penalty when sized right
Get a Quote
Humidity Control

Whole-Home Humidifiers & Dehumidifiers

Humidity is one of the most overlooked IAQ factors in Seattle — and one of the most damaging when out of range. Our whole-home systems integrate with your thermostat and maintain 35–50% humidity automatically, year-round, in every room.

Aprilaire humidifiers & dehumidifiers
Thermostat-integrated control
Prevents mold & structural damage
Whole-home, not room-by-room
Get a Quote
Humidity control system Seattle
Ideal: 35–50% RH
Maintained automatically
Choose Your Level

How Much Cleaner Do You Want?

Every level is a real improvement. We'll help you choose based on your home, your health needs, and your budget.

Essential

Filter Upgrade

Replace your basic 1-inch filter with a 4- or 5-inch media filter cabinet. The single highest-impact, lowest-cost IAQ improvement available for any home with ductwork.

MERV-11 to MERV-16 efficiency
Captures dust, pollen, mold spores
Filter change every 6–12 months
Doesn't address VOCs
Doesn't control humidity
Get a Quote
Enhanced
Most Popular

Filter + Purifier

Media filter upgrade plus a whole-home air purifier. Handles particles, allergens, VOCs, bacteria, mold spores, and viruses. Comprehensive coverage for most Seattle households.

Everything in Essential
Kills bacteria, mold, viruses
Reduces VOCs from materials
No filter to change on purifier
Doesn't control humidity
Get a Quote
Premium

Full System

Filter, purifier, humidity control, and ERV ventilation. Complete indoor air quality management — every threat addressed, every variable controlled. Ideal for allergy sufferers and newer tight homes.

Everything in Enhanced
Whole-home humidity control
ERV fresh air ventilation
Addresses CO₂ buildup
Get a Quote

Not sure which level fits? We assess your home for free and give you an honest recommendation — no upselling.

Real Results

Seattle Families Breathing Better

★★★★★

"My daughter has had asthma since she was three. After Next Phase installed a whole-home purifier and upgraded our filter, her inhaler use went from weekly to almost never. I'm not exaggerating."

KP
Kelly P.
Redmond, WA
★★★★★

"The free assessment was eye-opening. Our air quality score was terrible and we had no idea. Within a week of the install the musty smell was gone and we all started sleeping better. Incredible difference."

BW
Brian W.
Bellevue, WA
★★★★★

"We added a whole-home humidifier and dehumidifier — both. The difference in winter is remarkable. No more nosebleeds, no more static, and our wood floors stopped creaking. Worth every cent."

ML
Maria L.
Kirkland, WA
★★★★★

"Just the filter upgrade alone made an enormous difference. I had no idea my old MERV-8 filter was doing almost nothing. Dust in the house dropped dramatically in the first week."

DH
David H.
Auburn, WA
★★★★★

"We have a new build with a tight envelope. Stuffy rooms, constant headaches in the bedroom. Next Phase installed an ERV and it's like the house can breathe now. Highly recommend."

JT
Jason T.
Sammamish, WA
★★★★★

"My daughter has had asthma since she was three. After Next Phase installed a whole-home purifier and upgraded our filter, her inhaler use went from weekly to almost never. I'm not exaggerating."

KP
Kelly P.
Redmond, WA
★★★★★

"The free assessment was eye-opening. Our air quality score was terrible and we had no idea. Within a week of the install the musty smell was gone and we all started sleeping better. Incredible difference."

BW
Brian W.
Bellevue, WA
Questions

Indoor Air Quality FAQ

Common signs include persistent dust, allergy symptoms that are worse indoors, musty smells, condensation on windows, poor sleep or morning headaches, and visible mold anywhere in the home. A free in-home assessment with air quality testing gives you actual numbers rather than guesses.

Yes — significantly. A room air purifier treats one space. A whole-home unit treats every cubic foot of air that passes through your HVAC system — which is the entire house multiple times per day. It also works continuously without you needing to remember anything.

MERV (Minimum Efficiency Reporting Value) rates how well a filter captures particles. MERV-8 (most basic filters) catches large dust and pollen. MERV-13 captures fine particles including PM2.5. MERV-16 captures almost everything including some bacteria. Higher MERV filters require proper sizing — forcing high-MERV through a system designed for MERV-8 restricts airflow and damages your equipment.

Yes. Seattle's energy-efficient, well-insulated homes are airtight — which means pollutants have nowhere to go. High outdoor humidity in fall and winter drives indoor humidity up, creating conditions for mold. We also spend more time indoors here than in sunnier climates, increasing exposure time to whatever's accumulating.

A media filter cabinet upgrade starts around $400–600 installed. A whole-home air purifier runs $800–1,400 installed depending on system and size. Whole-home humidifiers and dehumidifiers are $600–1,200 each installed. A full Enhanced system (filter + purifier) typically runs $1,200–2,000 for a standard home. All pricing is provided upfront before any work begins.

Start Breathing Better

Your Home's Air Quality
Can Improve Today.

We assess your home for free, tell you exactly what's in your air, and give you an honest recommendation. No obligation, no pressure.

Get Free Air Assessment (425) 648-7887

Free in-home assessment  ·  No obligation  ·  Serving Greater Seattle  ·  Licensed & insured

Call Now Free Assessment