Diamond Certified Companies are Rated Highest in Quality and Helpful Expertise.

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Diamond certified companies are top rated and guaranteed

Why Trust Diamond Certified Indoor Air Quality Companies Rated Highest in Quality and Helpful Expertise®?

Whether you want to add more comfort to your home environment or ensure proper filtering and ventilation, a Diamond Certified indoor air quality specialist can provide a solution that fulfills your particular needs.

You are the customer. If your goal is to choose an indoor air quality company that will deliver high customer satisfaction and quality, you’ll feel confident in choosing a Diamond Certified indoor air quality specialist. Each has been rated Highest in Quality and Helpful Expertise® in the most accurate ratings process anywhere. And you’re always backed by the Diamond Certified Performance Guarantee. Here’s why the Diamond Certified ratings and certification process will help you find a top rated indoor air quality company and is unparalleled in its accuracy, rigor and usefulness:

1) Accuracy: All research is performed by live telephone interviews that verify only real customers are surveyed, so you’ll never be fooled by fake reviews.

2) Statistical Reliability: A large random sample of past customers is surveyed on an ongoing basis so the research results you see truly reflect a Diamond Certified company’s top rated status.

3) Full Disclosure: By clicking the name of a company above you’ll see the exact rating results in charts and read verbatim survey responses as well as researched articles on each qualified company.

4) Guaranteed: Your purchase is backed up with mediation and the Diamond Certified Performance Guarantee, so you can choose with confidence.

Click on the name of a Diamond Certified company above to read ratings results, researched articles and verbatim customer survey responses to help you make an informed decision.

More than 200,000 customers of local companies have been interviewed in live telephone calls, and only companies that score Highest in Quality and Helpful Expertise®–a 90+ on a 100 scale–as well as pass all of the credential-based ratings earn Diamond Certified. By requiring such a high score to qualify, the Diamond Certified Resource eliminates mediocre and poorly performing companies. Read detailed information about the ratings and certification process.

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Chris Donzelli is owner of Perfect Star Heating and Air Conditioning, a Diamond Certified company. He can be reached at (510) 244-4356 or by email.

Chris Donzelli

diamond certified contributor profile and expert article

Chris Donzelli: HVAC Star

By James Florence, Diamond Certified Resource Reporter

CONCORD — Chris Donzelli was in between jobs when he decided to start from scratch and enter a new professional field. “It all started when I answered a newspaper ad placed by a local HVAC company,” he remembers. “I knew nothing about the field, but I was willing to learn, so they gave me a shot. During the next few years, I learned how to service and install residential heating and cooling equipment. Today, after 16 years in the industry, I own my own company. It just goes to show what you can accomplish when you put all your effort toward a goal.”

As owner of Perfect Star Heating and Air Conditioning, Chris says his favorite part of his job is developing his team. “I love teaching my employees and helping them hone their skills and knowledge in the industry. I’m very passionate about developing people—it’s extremely rewarding to see them grow and succeed.”

A resident of Brentwood (where he lives with his wife and two children), Chris expresses his appreciation for life in the Bay Area. “The weather isn’t harsh like in other parts of the country. Also, everything is close by—we’re just a couple of hours away from the snow, the beach and the wine country.”

Outside of work, Chris spends most of his free time having fun with his family. “We enjoy playing games together—pool, ping pong and chess are some of our favorites,” he details. “We’re also pretty outdoorsy and love to go camping and boating.”

In his life and career, Chris espouses the value of perseverance. “Get rid of powerless words like ‘can’t’—they won’t get you anywhere,” he advises. “Usually, when someone says they can’t do something, the truth is they just won’t do it. In reality, with plenty of effort and the right attitude, you can do anything you want.”

Ask Me Anything!

Q: What are your favorite sports teams?
A: The San Francisco 49ers, the San Francisco Giants and the Golden State Warriors.

Q: What kind of music do you like?
A: All kinds, from classic rock to country to hip-hop.

Q: What’s your favorite restaurant?
A: Melo’s Pizza & Pasta in Brentwood. However, if we’re going to splurge, it’s Ruth’s Chris Steak House in Walnut Creek.

Q: If you could travel anywhere in the world, where would you go?
A: Italy. I’m interested in the history, especially since my ancestors came from there.

Q: What’s your favorite snack?
A: Beef jerky.

Read more

The Importance of HVAC Unit Maintenance


CONCORD — If you can’t remember the last time your heating and air conditioning system was professionally serviced, chances are it’s overdue for maintenance. Much like your car, your home’s HVAC system needs regular tune-ups to maintain optimal performance. You’d… Read more

Expert Video Tip

Video: The Air Scrubber Plus® Advantage

Complete Video Transcription:

CONCORD — Host, Sarah Rutan: If you’re looking to maximize your home’s indoor air quality, look no further than Air Scrubber Plus. To learn more, we’re in Concord… Read more

Brian Waskow is a 37-year veteran of the HVAC industry and owner of Hometown Heating & Air Conditioning, a Diamond Certified company since 2013. He can be reached at (925) 456-4967 or by email.

Brian Waskow

diamond certified contributor profile and expert article

Brian Waskow: Career 2.0

By James Florence, Diamond Certified Resource Reporter

CONCORD — For most people, retirement means the end of a career, but for Brian Waskow, it was also the beginning of another. “I had a ‘20 years and out’ deal working as a refrigeration mechanic for the plumbing and pipe fitting union, which enabled me to retire in my early 40s,” he relates. “Since I was still fairly young, I wanted to find another industry to get involved with, so I answered a newspaper ad posted by a local heating and air conditioning company. As a former refrigeration mechanic, I found the HVAC industry to be a natural transition.” Over the next 12 years, Brian would learn from “some of the best mentors in the business” while working for “some of the most successful companies in the Bay Area,” before founding Hometown Heating & Air Conditioning in 2012.

Today, Brian says a favorite aspect of running his business is the new faces he meets on a daily basis. “I get to meet all kinds of interesting people, from World War II veterans to CEOs of Fortune 500 companies to ordinary, working-class folks like myself, so it’s always exciting to see who I’m going to meet next.” Additionally, he appreciates the fact that the company has become a genuine family affair. “My daughter, Jessica, is our operations manager and my other daughter Nicole’s husband works here as a service rep, so we’ve really earned our designation as a family-owned and operated business.”

Brian was born in the North Bay and currently resides in Contra Costa County with his wife, Yvonne. An avid outdoorsman, he considers the Bay Area an ideal location for pursuing some of his favorite pastimes, which include hiking, fishing, and water and snow skiing. “Living in the Bay Area, I could actually go water skiing and snow skiing in the same day if I wanted to,” he muses. “It’s also a great area for boating. One of our favorite things to do is take our boat to Angel Island and go hiking. Overall, we’re really active outdoors people, which everybody in the Bay Area should be.”

In his life and career, Brian espouses the importance of surrounding one’s self with good people. “There’s an old quote that says, ‘People make the party,’ and the same goes for a business,” he explains. “What differentiates a truly great company is the people who comprise it. I’m very fortunate to have not only some of the best professionals in the business working for me, but also some of the best people I know.”

When asked the first thing he’d do if he retired (again) tomorrow, Brian says he wouldn’t change a thing. “Ever since I started my own business, I don’t feel like I’ve worked a single day, just because I enjoy what I do so much. Plus, I already take enough vacation time as it is!”

Ask Me Anything!

Q: Would you ever skydive?
A: I already have, actually. On one of my birthdays, my daughters and I went skydiving in Monterey and landed on the beach. It was a wonderful experience.

Q: What’s your favorite smell?
A: Bacon.

Q: Are you an early bird or a night owl?
A: An early bird—I’m at the gym at 5am most days.

Q: If you could talk to anyone living or dead, who would it be and why?
A: General Douglas MacArthur, just because I think he’s a fascinating historical figure.

Q: What’s your favorite snack?
A: Beef jerky.

Q: What was your favorite Halloween costume as a child?
A: Superman.

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Tips to Improve HVAC Air Filtration


CONCORD — Air filtration is a crucial HVAC feature that affects everything from system performance to indoor air quality (IAQ). Consider the following tips for improving your HVAC system’s filtration: Check the MERV rating. Air filters are rated on a scale of… Read more

Home Applications for Smart Technology


CONCORD — By increasing comfort, energy efficiency and security in the home, smart technology is improving the lives of modern-day homeowners. Here are a few examples of how this revolutionary technology is being applied: Lighting control Whether you want to turn… Read more

The Benefits of Proactive HVAC Maintenance


CONCORD — Whether in regard to your car, home or personal health, it’s always better to be proactive rather than reactive about maintenance. When it comes to your home’s heating and cooling system, a great way to exercise pro-activity is to… Read more

The Importance of HVAC System Filtration


CONCORD — A critical aspect of maintaining heating and air conditioning systems is proper filtration. Furnace and A/C units have air filters that help keep the systems clean by collecting dust, dirt, and airborne particulates. As a filter collects more and more… Read more

Benefits of a Programmable Thermostat


CONCORD — If you’re looking for an economical way to save energy with your HVAC system, consider installing a programmable thermostat. Not only can a programmable thermostat reduce your heating and cooling bills, it can also simplify your daily routine and increase… Read more

Expert Video Tip

Video: Programmable Thermostat Advantages

Complete Video Transcription:

CONCORD — Host, Sarah Rutan: If you want to save time and money with your HVAC system, your first step should be to get a programmable thermostat.… Read more




Lennox Home Air Filters
Honeywell Air Cleaners & Filters
DuPont Air Filters
Trane Indoor Air Filter Systems
Bryant Air Filters
Oreck Air Purifier
3M Filtrete Air Filters
Ionic Pro Air Purifier
Alen Air Purifiers
IQAir HealthPro Air Purifiers
Austin Air Purifier
BlueAir Air Purifier
AllerAir Air Purification
Vornado Air Purifier
Holmes Air Filters
Aprilaire Air Filters
Filters Fast Air
Hunter Air Filters
Trion Air Filters
White Rodgers Air Filters
AccuClean Air Filtration Systems
Delta Air Cleaners
Coway Air Filtration Systems
Fresh-Aire UV Air Filtration Systems
Miracle Air Room Air Purifiers
Pure Air Filtration Systems
HealthMate Air Purifiers
Enviracaire Air Purifiers
Biozone Air Filtration Systems

home air filters
home air cleaners
commercial air filters
furnace filters
HEPA air purifiers
complete air filtration systems
air conditioner filters
allergen air filters
ultraviolet / UV air purifiers
single room air cleaners & purifiers
replacement air filters
ionic air purifiers
indoor air quality testing
electronic air cleaner
carbon air filter
permanent air filters
air cleaner replacements
smoke air filters
whole house air filters
asthma air purifiers
electrostatic air cleaners
filterless air purifiers
filterless air cleaning systems
whole house air purifier systems
air quality testing
indoor air pollution removal
air sterilizers
clean air delivery systems
home air purification system repair

Castro Valley
Komandorski Village
Mount Eden
Russell City
San Leandro
San Lorenzo
Union City


ASA American Subcontractors Association (http://www.asaonline.com/)
BBB Better Business Bureau (http://www.bbb.com/)
CSLB Contractors State License Board (http://www.cslb.ca.gov/)
DCA California Department of Consumer Affairs (www.dca.ca.gov)
EPA US Environmental Protection Agency (http://www.epa.gov/)
ACCA Air Conditioning Contractors of America (http://www.acca.org)
CPSC US Consumer Product Safety Commission (http://www.cpsc.gov)

Know What You Want
What to Ask Yourself Before Hiring a Home Air Quality Contractor

Your quest for a more comfortable, safer home air environment starts by identifying areas to improve. You can start by asking yourself the following questions.

  • Do you want a Diamond Certified company that is rated best in quality and backed by the Diamond Certified Guarantee?
  • Are there rooms in your home that are routinely noticeably warmer or cooler than the rest of the house?
  • How old is your heating or air conditioning system?
  • When is the last time you had your duct system cleaned and checked?
  • When is the last time your home was tested for carbon monoxide leaks?
  • Do you live in an excessively humid or dry area?
  • Do you live near other water sources that increase humidity and increase the likelihood of mold?
  • Is your bathroom ventilation system adequate for reducing the risk of mold?
  • Do you have pets or smokers in the family that affect air quality?
  • Does your heating or air conditioning unit routinely shut down before the farthest reaches of the home are sufficiently warm or cool?
  • When was your air filter last cleaned or replaced?
  • Do you have trouble with seasonal allergies or are you allergic to mold?
  • Do you find yourself suffering from chronic sinus problems or asthma?
  • Does your home have recessed can lighting, an attached garage, an attic, or a basement?
  • Do you live near a major thoroughfare or in a metropolitan area with poor outdoor air quality?
  • What is your timeline for a completed air quality renovation?
  • What is the best price you can find for any new HVAC units you are considering? What other materials are required for installation, and how much will they add to the total cost?
  • What is your budget for the entire project, including materials and labor?
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What To Ask In Person
What to Ask Alameda County Air Quality Contractors

Finding the right Alameda County air quality contractor for your project requires you to ask a few simple questions. Air quality and HVAC contractors have unique qualifications, specializations, and experience, so it is important to find a contractor that has the expertise in your specific area of need and will provide you with quality work in a timely manner.

  • Has your company earned and maintained a Diamond Certified rating?
  • How much experience does the air quality contractor have?
  • Is the air quality contractor experienced in and equipped to perform every aspect of your project (for instance, duct cleaning, sealing, air conditioning unit installation, and Infiltrometer testing)?
  • Does the contractor have any technical input on your specific project? What specific features would best accommodate your specific needs? What are the relevant considerations with regards to the age, size, and layout of your home?
  • Does the contractor have references I may contact?
  • What is the contractor’s timeline for bidding, contracting, and completing the work?
  • Does the air quality contractor have current workers’ compensation and liability insurance coverage?
  • Will the contractor provide a free written estimate?
  • How does the contractor price parts and labor?
  • What type of warranty does the contractor provide?
  • Will permits be needed for any installations or modifications? If so, who will be responsible for getting them?
  • Do the contracting company’s employees actually complete the work, or do they hire subcontractors for certain aspects of the job? Can the air quality contractor complete all phases of the job?
  • How and when do the contractors clean up after their work?
  • Will the contractors provide a written contract detailing costs, payments, and a plan for necessary unforeseen modifications?
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  • What To Ask References
    Learn from Previous Home Air Quality Customers in Alameda County

    It’s best to choose a Diamond Certified air quality contractor because all certified companies have passed an in-depth ratings process that most other companies can’t pass. If you want quality from an air quality contractor in Alameda County and the Greater Bay Area, you can have confidence choosing a Diamond Certified company. Diamond Certified reports are available online for all certified companies. And you’ll never be fooled by fake reviews. That’s because all research is performed in live telephone interviews of actual customers.

    If you can’t find a Diamond Certified air quality contractor within reach, you’ll have to do some research on your own. If you do, it’s wise to call some references provided by your air quality contractor. Keep in mind, though, that references provided to you by the contractors themselves are not equal in value to the large random sample of customers surveyed during the Diamond Certified ratings process. Instead, contractors will likely give you a few customers to call that they know are satisfied.

    Request a list of the contractor’s five most recent customers and contact them with questions about their experience with the contractor and satisfaction with the finished product.

    Some relevant questions include:

    • What was the nature of your air quality renovation project?
    • If you installed new heating or air conditioning units, what features, models, or manufacturers were you especially impressed by? Are there any additional features you wish you would have selected?
    • Was the work completed in a timely manner?
    • Were you satisfied with the quality of the work you received?
    • Did you encounter unanticipated costs or contractual disagreements?
    • Did you feel you received a fair price?
    • Why did you choose to work with this specific air quality contractor?
    • What were you most pleased or displeased with?
    • Would you hire this HVAC contractor for another project?
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  • Review Your Options
    Hire a Good Air Quality Contractor for Your Home or Business

    The Diamond Certified symbol has been awarded to companies that scored Highest in Quality in an accurate ratings process.

    Now that you have all the available information in front of you, including estimates, references, credentials, and if available, the endorsement of Diamond Certified, you’re ready to select the contractor that provides the best fit for your air quality project.

    First, consider the following questions:

    • Which contractor’s estimate is within your budget?
    • Which contractor has the most experience for your particular job?
    • Which contractor’s Diamond Certified reports and previous customer responses are the most enthusiastic?
    • Which contractor is able to complete the work within your desired time frame?

    With a Diamond Certified rating in your corner, you are well on your way to the safest, most comfortable and energy efficient home environment.

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  • How To Work With
    Obtain and Compare Free Written Estimates of All Costs Involved in Your Project

    After you have discussed your air quality needs in detail with prospective licensed Alameda County contractors, you should obtain a complete, written estimate of charges for all labor and itemized costs of all materials involved.

    This may include sealants, cleaning services, Infiltrometer testing, new filters, and brand new heating, air conditioning, or dehumidification units.

    Be sure to also get an estimate of labor hours for each phase of the project along with the cost per hour.

    Write a Contract for Air Cleaning Services
    Once you’ve decided which air quality contractor best suits your needs, the last step before work begins is to negotiate and sign a contract. A contract is a written legal agreement that outlines and protects the interests of both parties involved in the project.

    This indispensable step will make sure that both parties are clear about what a job will entail in costs, payments, and timeframe. Your contract should detail how and when the work will be done, which materials are required, and how much each item costs. A good contract can spare you legal headaches down the line.

    Start your contract by making a list of all responsibilities of both parties. For example, is the contractor in charge of purchasing and moving materials? Who is going to obtain the permits, if necessary? Next, solidify the agree-upon price for all the required materials and labor.

    This is where you can refer to your preliminary pricing research. This list may include sealants, cleaning services, Infiltrometer testing, new filters, and brand new heating, air conditioning, or dehumidification units. If you found materials cheaper elsewhere, tell your contractor where.

    Also, don’t be afraid to refer to estimates that other contractors provided you, if they are lower than the contractor you’ve selected. This can help in negotiating a better price for installation and cleaning services.

    Finally, review the estimate your chosen Alameda County air quality contractor has provided and recommend any changes. Be sure to include a clause dictating that you wish to approve any costs above the agreed-upon amount. Finally, a guarantee of the quality of the work and all warranty time periods should be specifically noted.

    Once you have settled on a cost that fits your budget, a timeline in which the work is to be completed, and a schedule for submitting payments, your contractual agreement is ready and your contractor can begin your air quality improvement project.

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  • Be a Good Customer
    How Can You Be a Good Alameda County Air Quality Company Client?

    It’s your air quality contractor’s responsibility to provide you with quality services using the best possible installation techniques. But you play a big part in the success of your air quality improvement project, too.

    Here are some steps to ensure that you’re a good customer when hiring a Alameda County contractor.

    • Be clear and upfront with the contractor. Let them know what you want from your air quality system, the long-term outcome you’re expecting, and specific ways they can satisfy your expectations.
    • Remember, a friendly smile goes a long way!
    • Before you hire an air quality contractor in Alameda County restate your expectations and goals, and reiterate to the representative your understanding of the agreement. Most problems with local contractors occur because of a breakdown in communication. By being clear about your expectations and theirs, you can avoid most conflicts.
    • Ask your air quality contractor if you should reach out to check on the progress or if he will contact you with updates.
    • Be sure your service representative has a phone number where they can reach you at all times while they’re working on your project. The work will move along more smoothly if your Alameda County contractor can reach you for any necessary updates, questions, or work authorizations.
    • When your contractor contacts you, return calls promptly to keep the project on schedule.
    • Pay for all materials and services promptly according to your contract.

    Why would you want to be a good customer? Air quality contractors in Alameda County appreciate customers who are straightforward, honest, and easy to work with. Things may very well go more smoothly and any problems may be more easily resolved because your good behavior will help create an environment conducive to a good relationship.

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Check The Work
Inspect and Verify the Completion and Quality of the Work Against the Written Invoice

The last step in your Alameda County air quality improvement project is to make sure that the work you receive is the work you desired.

It should be visibly apparent if your contractor has installed a heating, air conditioning, or dehumidification unit that is different from what you selected or that do not meet your specifications.

In addition to this, be sure to inspect that all parts are in working order. Check buttons, thermostats, and filters to ensure all new materials are functioning properly. If you notice odors or don’t see an improvement in the temperature distribution, air purity, or humidity over time, follow up with your contractor and let him or her know.

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Written Warranties
Save Copies of All Warranties in Writing

Ask to keep copies outlining the details of all warranties and guarantees that apply to both the materials used in your air quality project and the service provided.

Complete written warranties should include:

  • A physical address for the manufacturer or service provider.
  • A list of all products or services covered by the warranty.
  • What your responsibilities include in the event that products or services received are defective.
  • The length and transferability of the warranty term.
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Top 10 Requests
Popular Indoor Air Quality Cleaning Services and Products

Air quality projects address a wide range of areas and problems, from duct cleaning to asbestos removal.

Some of the most commonly requested Alameda County air quality services are:

Infiltrometer Testing
This immensely useful test is often the first step in air quality improvement. An Infiltrometer is a device created by the U.S. Department of Energy to tests air tightness and identify air leaks. It is set up in an outside doorway and creates a 15 MPH wind on all sides of your home, using sensors to determine the precise locations of any internal air leaks.

The test only takes about an hour, and once leaks are pinpointed, they can be sealed using fiber-reinforced elastomeric sealants. This quick fix pays for itself by lowering utility bills, evening temperature distribution throughout the house, and preventing contaminated air from infiltrating your home.

Installation of Air Purification Systems
One of the best ways to ensure that the air you breathe is healthy and safe is installing an air purification system. Unlike a filtration system, which simply filters out airborne particles, a purification system uses ultraviolet light or electrical charge to actually clean the air, removing irritants, contaminants, pollutants, germs, viruses, mold, and other elements down to 0.01 microns in size.

In such a system, larger particles are first removed through filtration, then smaller particles are irradiated or electrically charged, effectively removing them from the air.

Air Duct Cleaning
Your ductwork is the delivery system for cooled or heated air, and if it is dirty or blocked, it cannot delivery air efficiently. The ductwork in many homes is plugged with years of built up debris, mold, mildew, pet dander, dust, and dirt.

Your ducts should be inspected at least every two years for defects and cleanliness, and your entire duct system should be cleaned every 5-7 years, depending on indoor air quality factors such as the age of your home or the presence of pets.

Air Duct, Garage, Attic, and Thermal Bypass Sealing
Air duct leaks are common, and result in a drastic decrease in HVAC efficiency and much higher utility bills. Similarly, improperly sealed garages, attics, and thermal bypasses allow outdoor air to leak into your indoor environment, compromising temperature distribution and control.

Your Alameda County air quality contractor can locate any leaks using an Infiltrometer test, then seal them using fiber-reinforced elastomeric sealants. This quick, relatively inexpensive fix pays for itself by lowering utility bills, and provides the added benefit of evening temperature distribution throughout the house.

Routine HVAC System Maintenance
Just like an automobile, your heating and air conditioning system needs a regular tune-up, especially when heading into high activity seasons like summer and winter. In addition to ensuring that your unit is working as efficiently as possible, this will also reduce the likelihood that your HVAC system will break down when you need it most.

Installation of Energy Efficient Replacement Heating or Air Conditioning Units
Like all other appliances, heating and air conditioning systems wear out over time, resulting in loss of efficiency, higher utility bills, and lack of effective climate control. Properly sized, energy efficient replacement units come with enhanced features such as humidity sensors, customized room-to-room control, and air purification/filtration options.

In addition, they help eliminate uneven temperature distribution, improve ventilation, and can reduce pressure imbalances. If your HVAC system has more than 12 years of use, and you don’t intend to sell your home for a few years, a new system will provide a safer, more comfortable and reliable alternative, and can be up to twice as energy efficient, saving you money in the long run.

Asbestos Removal
Asbestos is found most often in steam pipes, boilers, furnace ducts, flooring, roofing, and siding in homes built before the 1970s. The danger of asbestos only arises when it is tampered with or deteriorates, which releases asbestos fibers into the air. Airborne asbestos fibers are known to increase the risk of lung cancer and cause scarring of the lungs.

If you suspect your home contains asbestos and you are unsure of the condition of the material, the best thing to do is leave it alone and call an air quality professional who can assess the situation and provide removal services if necessary. In some cases, if the asbestos bearing material is intact, tampering with and removing it poses a more serious health hazard than leaving it untouched.

Carbon Monoxide Testing
Carbon monoxide leaks, even at a low level, can have lasting health implications, and consumer detection units are less reliable and ill-equipped to detect low level CO leaks. Leaks can come from a variety of sources involving combustion or burning, such as gas heaters, chimneys and furnaces, gas stoves, automobile exhaust, or old boilers.

Such leaks are virtually undetectable without the proper equipment and can lead to fatigue and chest pain at low levels, and impaired vision, headaches, dizziness, nausea, and death in high concentrations.

The typical consumer CO detector only lasts 2-4 years and gradually loses its effectiveness, leaving you vulnerable to undetected leaks. A qualified Alameda County air quality contractor will have the equipment to detect and locate even the smallest CO leak, eliminating this common home health hazard. Have a trained professional perform an annual carbon monoxide inspection of your home.

Installation of Enhanced Humidity Control Systems
Both low humidity and high humidity can contribute to health and comfort issues, so it is important that your air quality system monitors humidity levels at both ends of the spectrum. Mold and dust mites thrive in high humidity, but die when humidity stays below 50%. In humidity below 30% however mucus membranes can dry up, asthma may become aggravated, and nosebleeds or infections can result.

An enhanced humidity control system will keep your indoor humidity levels within the 30-50% range suggested by the EPA, AMA, and CDC. Options include an enhanced dehumidification air conditioning unit for high humidity areas and seasons or a central humidification system for dry areas and seasons.

Installation of Enhanced Mechanical Ventilation Systems
Pressure imbalances can result from a lack of ventilation or air return mechanisms in rooms that are closed off from the rest of the house, or from unduly large exhaust fans and leaking ducts. This causes impure air to be drawn into the room through any existing air leaks, or prevents even temperature distribution and air circulation.

Having an appropriate balanced number of air returns and sends eliminates pressure imbalances and greatly improve air circulation and quality. They also help dehumidify and filter, likelihood the presence of mold and mildew.

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Glossary Of Terms
Glossary of Terms Used By Local Indoor Air Quality Companies

In your quest to perfect your home air quality system, you’ll encounter a large volume of extra features and technical specifications. The following glossary provides definitions and descriptions of all the air quality related jargon you need to know:

air conditioner
The air-cooling unit that is typically located outside the home, and provides dehumidification, ventilation, and temperature regulation.

air handler
The part of an air conditioning system that regulates and directs air through ductwork, distributing air throughout the home.

airflow volume
The measurement of an air conditioner’s air output, typically in cubic feet per minute. This should be sized appropriate to the area of your home.

A naturally occurring mineral that was prevalent in insulation in many homes built before the 1970s. Asbestos is found around steam pipes, boilers, furnace ducts, and can also be used in vinyl flooring, roofing, and siding.

When air is drawn into a depressurized environment, for instance, a home or gas burning appliance, leading to potentially dangerous concentrations of gases.

The part of an heating system that circulates heated air throughout the home.

Also known as: furnace blower

carbon monoxide
A deadly, colorless, odorless, poisonous gas produced by burning of coal, wood, charcoal, and natural gas.

Also known as: CO, CO gas

CFM (cubic feet per minute)
The amount of air that flows through an air conditioning system.

The part of an air conditioner that pumps refrigerant into the system.

The equipment or feature that extracts water content from the air by cooling air until water vapor turns to liquid condensation, which is then removed.

dry bulb temperature
A measurement of heat independent of humidity. A measurement of the raw heat content of air.

The system of pipes that transports air of the desired temperature from the heating or air conditioning system to the rest of the house.

Also known as: duct work, air ducts

energy efficient
The transfer of energy from one source to another without loss.

Environmental Protection Agency, a U.S. Federal government agency that promotes energy efficient, environmentally friendly equipment.

exhaust system
A pipe and/or fan system that expels or exhausts gases, directing them outside or away from a combustion environment such as those present in HVAC systems.

filtration system
A system that removes airborne particles of varying size from the air by trapping them in layers of various filtration materials.

Also known as: filter

The part of an HVAC system or fireplace that vents out exhaust gases.

Also known as: flue pipe

A heating system that burns fuel to produce heat which is then distributed by air throughout a home.

A device that adds water vapor or moisture to the air. Typically used in dry environments.

Stands for Heating, Ventilation, & Air Conditioning. Most HVAC contractors perform air quality related work.

ignition system
The part of a heating system that starts the combustion process by lighting a gaseous mixture.

A device created by the U.S. Department of Energy to test air tightness and identify air leaks. It is set up in an outside doorway and creates a 15 MPH wind on all sides of your home, using sensors to determine the precise locations of any internal air leaks

Material that blocks the transfer of heat, used in homes to surround hot water pipes and prevent heat from escaping the interior home environment.

ionization system
A device that purifies air on a microscopic level by using high voltage to electrically charge and “magnetize” airborne particles, causing them to attract to grounded surfaces like walls, floor, and ceilings, or surfaces housed within the purification device.

Also known as: ionic air purifiers, air ionizers

pressure imbalance
A state in which neighboring air environments are not equal in pressure, causing air to flow from an area of higher pressure into one of lower pressure.

purification system
A system that cleans the air either chemically (usually through ozone) or electrically (through ionization), rather than simply trapping airborne particles in a filter.

Also known as: air purification system, home air purifiers

return vent
The part of an air conditioning system that prevents a pressure buildup within an enclosed area by providing an “outlet” for air to counteract the supply vents which blow air into a room.

Also known as: air return

A water based or putty like material that provides air tightness within a home environment by sealing of ducts, garages, and other porous areas, and preventing infiltration and loss of heated or cooled air.

Also known as: fiber-reinforced elastomeric sealant, duct sealant

supply vent
The part of an HVAC system that blows heated or cooled air into an area of the house.

temperature distribution
Refers to the uniformity of the temperature in different regions of a home. Even distribution occurs when all areas of the home are heated and cooled equally, while uneven distribution occurs when some areas of the home are warmer or cooler than others.

thermal bypass
An area within exterior walls of the home in which there is no insulation, allowing heat to escape.

A device that allows users to monitor and regulate the temperature and settings of an HVAC system.

ultraviolet purification system
A purification system that disinfects and purifies air using ultraviolet light, eliminating mold, bacteria, and other harmful airborne substances.

Also known as : UV purification, UV air purification

ventilation system
A system that facilitates the circulation of air into and out of a room or building.

Also known as: ventilation return, ventilation supply

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Frequently Asked Questions
FAQ for Local Air Quality Testing Companies

Q: Why choose a Diamond Certified air quality contractor?
A: Diamond Certified helps you choose an air quality contractor with confidence by offering a list of top rated local companies that have passed the country’s most in-depth rating process. Only air quality contractors rated Highest in Quality and Helpful Expertise® earn the prestigious Diamond Certified award. Most companies can’t pass the ratings. American Ratings Corporation also monitors every Diamond Certified company with ongoing research and ratings. And your purchase is backed by the Diamond Certified Performance Guarantee, so you’ll feel confident choosing a Diamond Certified air quality contractor.

Q: What is the difference between purification and filtration?
A: Air purification consists of actually cleaning, sterilizing, and/or disinfecting the air using ionization, UV light, or ozone to eliminate harmful bacteria and particles as small as 0.01 microns from the air. Filtration on the other hand, simply traps particles in a system of fibrous materials, and typically does not remove particles as small as those that purification systems remove.

Q: What should I do if I suspect that my home contains asbestos products?
A: Asbestos was used in many homes built before the 1970s, often found around steam pipes, boilers, and furnace ducts. It can also be used in vinyl flooring, roofing, and siding. A common misconception is that the presence of any asbestos poses a health hazard. In fact, the danger of asbestos only arises when it is tampered with or deteriorates, which releases asbestos fibers into the air.

Airborne asbestos fibers are known to increase the risk of lung cancer and cause scarring of the lungs. If you suspect your home contains asbestos and you are unsure of the condition of the material, the best thing to do is leave it alone and call an air quality professional who can assess the situation and provide removal services if necessary. It is possible that, if the asbestos product is still in good condition, the safest way to maintain air quality is to leave it as is.

Q: How long does a typical air quality project take?
A: This depends on the nature of your project. An Infiltrometer test only takes about an hour, while a complete HVAC system overhaul can take several weeks. Expect simpler procedures like air conditioner installation or duct cleaning and sealing to take no more than 2-3 days. Add to this a few weeks of additional product selection and shipping time.

Q: How often should I have my ducts inspected and cleaned? How do I know it’s time for a new HVAC unit entirely?
A: Depending on the environment you live in, your ducts should be inspected every 2-3 years and cleaned every 5-7 years. The older the home, and the more pets and smokers present, the more frequently the ducts should be cleaned. Most HVAC units begin losing efficient functionality after 10-12 years. Your qualified contractor can assess condition and efficiency of your unit and recommend repairs or upgrades.

Q: Will my air quality contractor be able to help me choose materials and obtain permits, if necessary?
A: Qualified, licensed air quality contractors will definitely offer expertise in the decision-making process, steering you clear of manufacturers that may not fit your budget or quality criteria, and lending their advice on various features and types of air quality systems. They will also know the ins and outs of obtaining building permits.

Q: How much can I expect to spend for an air quality project?
A: Once again, this varies widely, according to the nature of your project. An Infiltrometer test is often complimentary if you purchase other services from the contractor. A duct cleaning can cost between $100-1000, depending on the size of the area and the kind of equipment used. An air conditioning unit typically costs between $1500-5000, depending on the number of enhanced features and the size of the home area.

A new furnace typically costs $2000-5000, once again depending on the energy efficiency, features, and size of the home. A central humidifier/dehumidifier is typically $100-300, while filtration systems are $150-500, and purification systems range between $500-2500 or more, depending on the type of purification and number of features.

Q: What is a typical project payment schedule?
A: Most contracting firms will require 30-50% up front at the time the contract is signed, an additional 30-40% upon delivery of the materials, and the balance upon completion.

Q: What is a typical warranty for HVAC units and contracting services?
A: Many contractors guarantee their work for one to five years after completion of an installation. You can expect most heating units to come with a warranty of up to 20 years, while air conditioning units typically have shorter 10-year warranties. Warranties on purification and humidification or dehumidification systems vary widely.

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