How to Calculate Bathroom Exhaust Air

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April 30, 2025

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How to Size Bathroom Exhaust

In this article, we’ll walk you through how to size commercial bathroom exhaust fans based on the 2024 Uniform Mechanical Code, the 2024 International Mechanical Code, and ASHRAE Standard 62.1.
We’ll take you step-by-step through real examples for a men’s and women’s public restroom.”

How to Size Bathroom Exhaust

Proper exhaust fan sizing in public restrooms isn’t just about odor control. It’s critical for indoor air quality, moisture removal, and meeting mechanical code compliance.
Undersized fans can cause lingering odors, humidity issues, and even damage building materials over time.

2024 UMC on Restroom Exhaust:

Light-use public toilet rooms require 50 CFM per water closet or urinal.
Heavy-use areas like stadiums or airports may require 70 CFM per water closet or urinal.

2024 IMC Exhaust Rates

50 CFM per water closet or urinal if the fan operates continuously.
70 CFM per fixture if the exhaust system runs intermittently.

ASHRAE Standard 62.1 supports similar rates but emphasizes overall airflow balance and indoor air quality targets.

Public Restroom Exhaust Air Rates per Fixture

Now let’s size the fans CFM for a real-world example.

Men’s Public Restroom:

5 water closets
5 urinals
Total: 10 fixtures

Women’s Public Restroom:

5 water closets
Total: 5 fixtures

Step 1: Determine which code applies.

For our example we’ll use the IMC 2024 which using the terminology of continuous or intermittent operation. Determine if ventilation will be intermittent or continuous.

In this case, we’ll assume intermittent operation — the fans turn on with the lights or an occupancy sensor.

Step 2: Apply the exhaust rate.

Using IMC 2024 for intermittent operation of exhaust system for the restrooms gives us: 70 CFM per fixture.

Step 3: Calculate the total airflow:

For the men’s restroom:
10 fixtures times 70 CFM equals 700 CFM required

For the women’s restroom:
5 fixtures times 70 CFM equals 350 CFM required

Step 4 Determine Exhaust Makeup Air Method

Providing makeup air for exhausted air is essential to maintaining proper pressure balance. ASHRAE recommends ensuring air doesn’t flow from dirty areas into clean spaces and maintaining a negative pressure. This means providing enough make-up air from adjacent spaces or dedicated systems.

Common Exhaust Makeup Air Methods Include:

Transfer Air: Air from adjacent spaces flows into the bathroom via door undercuts or grilles.
Dedicated Conditioned Air: Supplied directly to the restroom through the HVAC system.
Combination Method: A mix of transfer and limited conditioned air.

Step 5: Select exhaust fans.

Size fan or design ductwork to meet or exceed these total CFM requirements.

ASHRAE 62.1 - 2022 Table 6-2 — ASHRAE 62.1 – 2022 Table 6-2

To summarize:

For private use restrooms the required exhaust is 25 CFM for continuous or 50 CFM for intermittent system operation.

Size exhaust fans based on fixture count and usage intensity.

UMC 2024, IMC 2024, and ASHRAE 62.1 work together to guide airflow requirements.

Always confirm whether the fans operate intermittently or continuously, and if using UMC, whether the public use is light or heavy to apply the correct rates.

Toxic Chemicals in Kids’ Mattresses: What Every Parent Should Know

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MEP Academy Instructor

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April 22, 2025

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Toxic Chemicals in Kids Mattresses

Could your child’s mattress be affecting their health? A new scientific study just revealed something alarming about the air around children’s beds — and every parent needs to hear this. This channel is dedicated to good indoor air quality, so we thought this would be important for our readers and their friends and families to be aware of the toxic chemicals in kids mattresses.

Researchers from the University of Toronto, in collaboration with the Green Science Policy Institute, conducted a study measuring air quality in the bedrooms of 25 children aged 6 months to 4 years. They discovered elevated concentrations of harmful chemicals, including phthalates, flame retardants, and UV filters, particularly in the air surrounding children’s beds.

A companion study analyzed 16 commonly available children’s mattress brands and found that all contained concerning levels of these chemicals. Notably, one mattress was composed of 3% flame retardants by weight, and another exceeded Canada’s legal limit for a specific phthalate by more than double. Checkout safer options.

Health Risks Associated with Chemical Exposure

The chemicals identified in the study are linked to various health issues:

Phthalates: Used to make plastics more flexible, these compounds are associated with hormonal disruptions, reproductive harm, and developmental issues.
Flame Retardants: Added to meet flammability standards, certain flame retardants have been connected to cancer, neurological damage, and lower IQ levels in children.
UV Filters: Used to prevent fabric discoloration, some UV filters are suspected of causing hormonal disruptions and other health concerns.

Children are particularly vulnerable to these chemicals due to their developing bodies, higher respiration rates, and behaviors such as frequent hand-to-mouth activity

Recommendations for Parents

To minimize children’s exposure to these harmful chemicals, experts suggest the following measures:

How to Protect your Children from Toxins in Mattresses

Choose Safer Mattresses: Opt for mattresses made from natural materials like organic cotton or wool, which are less likely to contain harmful chemicals.
Use Protective Barriers: Place a protective cover, such as a terry cloth towel, between the child and the mattress to reduce direct contact with potential toxins. Checkout safer options
Allow Off-Gassing: Air out new mattresses in a well-ventilated area for several days before use to allow volatile compounds to dissipate. Some chemicals take years to dissipate.
Regular Cleaning: Wash bedding and sleepwear frequently to remove any accumulated chemicals.
Limit Bed Items: Reduce the number of items like pillows and stuffed animals on the bed, as they can absorb and re-emit chemicals.
Air Purifiers: Use air purifiers to remove as much toxins as possible with a HEPA and Carbon filtration unit. Checkout the latest Air Purifiers.

While these steps can help reduce exposure, researchers emphasize that the ultimate responsibility lies with manufacturers to eliminate the use of toxic chemicals in children’s products. Get a Free Checklist below on what to look for to make a safe choice.

Calls for Regulatory Action

The study’s authors and health advocates are urging for stricter regulations to prevent the use of harmful chemicals in children’s mattresses. They highlight that many of these substances are not essential for meeting safety standards and pose unnecessary risks to children’s health

As awareness of indoor air quality issues grows, especially concerning children’s health, it’s crucial for both consumers and policymakers to advocate for safer manufacturing practices and more transparent product information.

Free Toxic Chemicals in Kids Mattresses Checklist – Protect Your Child’s Health

Want to see which chemicals to avoid and what safer alternatives to look for? Download our free checklist below and subscribe for more updates on indoor air quality and family safety.

📥 Kids Mattress Toxic Chemicals Checklist (PDF)

HVAC Piping Labor Analysis

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MEP Academy Instructor

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April 15, 2025

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If you’re involved in HVAC piping—whether you’re an estimator, project manager, or contractor—there’s one critical skill that can make the difference between winning profitable jobs and constantly playing catch-up: labor analysis.

In fact, labor is often the largest and most unpredictable part of any mechanical piping estimate. And yet, it’s the area where most mistakes are made.

That’s why we created our online course: HVAC Piping Labor Analysis—a focused training designed to help you analyze labor accurately, avoid costly estimating errors, and take full control of your project’s financial outcomes.

Table of Contents

Why Labor Analysis Matters

Materials are easy to price. Equipment comes with a quote. But labor? That’s where the real challenge begins.

Misjudging labor can lead to:

Underbidding jobs
Lost profit margins
Frustrated crews and delayed schedules
A reputation for missing the mark

HVAC Piping Labor Analysis gives you the tools and structure to prevent that. It’s not about guesswork—it’s about using real-world historical feedback data, industry knowledge, and practical estimating logic to create accurate and reliable labor projections.

What Impacts Labor in HVAC Piping?

Our full course dives deep into this, but here’s a high-level view of what you’ll need to understand (and what we train you to master):

Conditions Affecting Field Labor – Learn how jobsite access, working heights, climate, and project congestion impact crew productivity.
Pipe Rigging Methods – Explore how your choice of installation method can dramatically change labor hours.
Crew Size – Bigger isn’t always better. Understand how crew composition affects productivity rates.
Field Labor Productivity – Measure and apply realistic productivity factors instead of relying on generic charts.
Labor Analysis – Learn how to break down labor by system, area, and activity to pinpoint your true labor burden.
Estimating Review Meeting – Know how to present and defend your labor numbers in meetings with clarity and confidence.

These are the real-world estimating conversations that are happening every day. And if you’re not on point with your labor numbers, someone else will be.

The Missing Tool Most Estimators Wish They Had

What really sets this course apart? We’re not just teaching concepts—we’re giving you the tools to put them into action.

Every student gets access to our exclusive HVAC Piping Labor Productivity Calculator, a customizable Excel spreadsheet that helps you analyze, adjust, and calculate labor more accurately—every time.

Whether you’re building budgets, validating subcontractor quotes, or trying to tighten your bid margins, this tool saves time and increases confidence.

Take Control of Your Labor Estimates

If you’re serious about mastering HVAC piping labor estimation, don’t rely on guesswork, old habits, or outdated multipliers.

👉 Enroll in HVAC Piping Labor Analysis today and get the knowledge, system, and calculator you need to estimate smarter.

This course is ideal for:

HVAC Estimators
Project Managers
Mechanical Contractors
Engineers moving into estimating roles

Stop leaving money on the table. Start estimating labor with precision.

https://youtu.be/54AqeRyA41c

Best Whole House Air Purifiers: Top Picks & Buying Guide

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MEP Academy Instructor

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April 12, 2025

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When it comes to improving indoor air quality, a whole house air purifier is one of the most effective investments you can make. Unlike portable air purifiers that only clean the air in a single room, whole house units are designed to work with your HVAC system to treat the air throughout your entire home. In this guide, we’ll compare some of the best whole house air purifiers on the market, break down the features that matter, and explain how to operate them for maximum effectiveness.

Be aware that the advertisements like to flaunt the square footage that the air pruifier can cover that isn’t based on the rated CFM, but on what the unit can do in an hour.

“As an Amazon Associate, we earn from qualifying purchases.”

Top Whole House Air Purifiers (2025 Picks)

Here are some of the most recommended whole house purifiers based on performance, filter technology, ease of use, and value:

1. Levoit

Filter Type: 3 in 1 Filter with HEPA
Coverage: 635 sq. ft. (59 m2)
CADR: 410 CFM
Key Features: Combines electrostatic charge and HEPA filtration, efficient at removing allergens and viruses.
Best For: Allergies, dust, and smoke.
Price Range: $250 to $300. Check current Pricing for Levoit Air Purifiers

2. Winix 5510

Filter Type: Pre-Filter, HEPA and Carbon Filtration
Coverage: 392 Ft2 (36 m2)
CADR: Smoke 253, Pollen 247, Dust 252
Key Features: LED Air Quality Display, 5 fan Speeds, 99.99% True HEPA
Best For: Homes with pets or smoke concerns.
Price Range: $150 to $200. Checkout current pricing for Winix Air Purifiers

3. NuWave

Filter Type: True HEPA + Activated Carbon
Coverage: 586 sq. ft. (54 m2)
CADR:
Key Features: Excellent VOC and gas removal, top-tier particle filtration.
Best For: Homes near industrial areas or high-pollution zones.
Price Range: $500 to $600. Checkout the current pricing for a NuWave Air Purifier

What to Look For in a Whole House Air Purifier

✅ MERV Rating

The Minimum Efficiency Reporting Value (MERV) tells you how well the filter captures particles. Look for a MERV 13 or higher for effective filtration of dust, pollen, mold spores, and even viruses.

✅ Filter Type

HEPA Filters: Capture 99.97% of particles 0.3 microns in size. Ideal for allergens.
Carbon Filters: Absorb odors and VOCs (volatile organic compounds).
UV Lights: Kill bacteria and viruses, especially useful in humid climates.
Electronic Filters (EACs): Reusable filters that charge and capture particles.

✅ Maintenance Requirements

Some units need filter replacements every 6–12 months, while others (like EACs) just need washing. Consider ease of maintenance and cost of replacement filters.

✅ Integration with HVAC System

Choose a unit designed to be installed directly into your HVAC system for seamless air treatment. Some are compatible with smart thermostats and home automation.

✅ Noise Levels

Whole house systems are generally quiet since they’re located within the HVAC system, but it’s still worth checking decibel ratings or user reviews.

How to Use a Whole House Air Purifier for Best Results

Run Your HVAC Fan Continuously
Most purifiers only work when air is moving through the system. Set your fan to “On” instead of “Auto” to keep filtering air even when heating or cooling isn’t active.
Seal Air Leaks
Air purifiers work best in a well-sealed home. Seal leaks around windows, doors, and ductwork to prevent unfiltered outdoor air from entering.
Keep Filters Clean and Replaced
Dirty filters reduce effectiveness and can strain your HVAC system. Set calendar reminders or use filter monitoring apps (some units include these features).
Supplement in Problem Areas
For extra protection in bedrooms or areas with poor circulation, consider using a portable HEPA purifier in addition to your whole house system.

Additional Considerations for Buyers

🔄 Initial vs. Long-Term Costs

Upfront Costs: $500 to $3,000 depending on brand, type, and installation.
Maintenance: Budget for filters ($40–$200/year) or electricity if using UV or EAC.

🌿 Allergy or Asthma Concerns

If someone in the home has respiratory issues, prioritize a HEPA filter combined with carbon and UV technologies.

🛠️ Professional Installation

Whole house purifiers usually require ductwork modifications or integration with your HVAC. Unless you’re experienced, professional installation is recommended.

🌎 Energy Efficiency

Choose ENERGY STAR certified units when available. Efficient models reduce your utility bills and are better for the environment.

Final Thoughts

A whole house air purifier is a powerful ally in maintaining a clean, healthy indoor environment. Whether you’re concerned about allergies, wildfire smoke, or simply want to reduce dust and odors, choosing the right unit depends on your home size, HVAC compatibility, and specific air quality concerns.

Checkout the current Air Purifier Prices

Top Tip: Before buying, schedule a home air quality test or consult an HVAC pro to get personalized recommendations.

How to Size Bathroom Exhaust

2024 UMC on Restroom Exhaust:

2024 IMC Exhaust Rates

Step 1: Determine which code applies.

Step 2: Apply the exhaust rate.

Step 3: Calculate the total airflow:

Step 4 Determine Exhaust Makeup Air Method

Common Exhaust Makeup Air Methods Include:

Step 5: Select exhaust fans.

Toxic Chemicals in Kids Mattresses

Health Risks Associated with Chemical Exposure

Recommendations for Parents

Calls for Regulatory Action

Free Toxic Chemicals in Kids Mattresses Checklist – Protect Your Child’s Health

Why Labor Analysis Matters

What Impacts Labor in HVAC Piping?

The Missing Tool Most Estimators Wish They Had

Take Control of Your Labor Estimates

This course is ideal for:

LEVOIT

Winix

NuWave

Top Whole House Air Purifiers (2025 Picks)

1. Levoit

2. Winix 5510

3. NuWave

What to Look For in a Whole House Air Purifier

✅ MERV Rating

✅ Filter Type

✅ Maintenance Requirements

✅ Integration with HVAC System

✅ Noise Levels

How to Use a Whole House Air Purifier for Best Results

Additional Considerations for Buyers

🔄 Initial vs. Long-Term Costs

🌿 Allergy or Asthma Concerns

🛠️ Professional Installation

🌎 Energy Efficiency

Final Thoughts

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