July 14, 2025
Though a small detail, your HVAC filter impacts comfort, cleanliness, and energy efficiency of your indoor environment throughout the summer. In this complete guide, we will cover everything homeowners and property managers in California should know about selecting the proper HVAC filter for summer.
Why Summer Calls for A Better HVAC Filter
The summer months can be tough on your HVAC system. It is about more than just cooling the air; it is about filtering it as well. Hotter air can contribute to a higher concentration of airborne particles such as:
- Pollen and dust
- Mold spores (especially with higher humidity)
- Pet dander and smoke particles
- Smog or wildfire-related particles (especially in parts of California)
When your AC system circulates air from day to day in your home, you can imagine how quickly these particles can build up indoors. A good HVAC filter can keep these particles from cycling through your system and supports:
- Better indoor air quality (IAQ)
- Prevention of dust from piling up on your HVAC hardware and components
- Lower energy bills, which is possible through maintaining good airflow
- Fewer allergy and asthma reactions
What is MERV & What Do You Need?
The MERV rating (Minimum Efficiency Reporting Value) is a standard that rates how well an HVAC filter captures particles. MERV ratings go from 1 to 20, with higher numbers meaning better filtration.
Here’s a basic breakdown:
|
MERV Rating |
Traps |
Use Case |
|
1–4 |
Large particles (dust, lint) |
Minimal filtration, low-efficiency systems |
|
5–8 |
Mold spores, dust mites, pollen |
Standard homes, low allergy risk |
|
9–12 |
Pet dander, exhaust fumes, fine dust |
Ideal for most homes in summer |
|
13–16 |
Bacteria, smoke, microscopic particles |
High-efficiency homes, people with health concerns |
|
17–20 |
Viruses, ultra-fine particles |
Used in hospitals and cleanrooms |
Recommended MERV Range for Summer: MERV 8–13
- MERV 8: Ideal for basic filtration and airflow and is generally optimal for homes where neither pets nor allergy sufferers live.
- MERV 11–13: Good to capture more allergens and smaller particles and is great for families with children, elderly, pets, or allergy sensitive individuals.
Note: MERV filters rated 14 or higher may be too restrictive for residential systems unless they are designed for that purpose. Filters that restrict airflow can add strain to the system and, if not installed properly, incur higher energy costs.
Popular Types of HVAC Filters (Pros & Cons)
When choosing HVAC filters, there isn’t a one-size-fits-all solution. Each offers different benefits along with varying levels of protection, longevity, and airflow.
1. Fiberglass Filters
- MERV Rating: 1–4
- Pros: Inexpensive, disposable, easily obtained
- Cons: Limited filtration. Not an effective solution for summer allergens.
Best for: Basic dust protection in situations where airflow is not a priority. Some think that a disposable fiberglass filter offers some additional protection during the California summer months with elevated pollen in the air and pollution.
2. Pleated Filters (Disposable)
- MERV Rating: 8–13
- Pros: Much better filtration, can trap smaller particles such as pollen, pet dander, and dust mites
- Cons: Have to change regularly (every 30–90 Days)
Best for: Most residential homes in the summer as the airflow and efficiency allow for adequate protection and good efficiency.
3. Electrostatic Filters (Washable or Disposable)
- MERV Rating: 8–10
- Advantages: Use static electricity to capture particles. Eco-friendly reusable versions.
- Disadvantages: Must be cleaned out correctly to be effective.
Best for: Households with allergies or pets. Also, good if you prefer a reusable option.
4. Activated Carbon Filters
- MERV Rating: Varies
- Advantages: Absorbs odors, smoke, and gases
- Disadvantages: Does not replace particulate filtration; usually used with another filter
Best for: Homes that have problems with summer wildfire smoke or musty odors.
5. HEPA Filters
- MERV Rating: 17–20
- Advantages: Hospital grade filtration. Removes 99.97% of airborne particles.
- Disadvantages: Not available for most residential systems because of airflow resistance
Best for: Specialized applications, homes with customized HVAC systems.
Filter Size
An improper filter size can allow air to bypass the filtration system altogether which decreases effectiveness and could damage your unit.
When Should You Change Filters in the Summer?
Summer months, especially when dust and wildfires rage in your area, can lead to a quick clog of your filters. Using the rule of thumb for filters:
- Standard Pleated filters (MERV 8-11): 60-90 days
- Home with dogs/cats/allergies: 30-60 days
- HEPA or Carbon filters: Follow manufacturer’s guidelines.
- Washable filters: Clean once per month.
Pro Tip: Mark your calendar or set a phone reminder to check your filters every month for the summer months.
Signs your filter needs replacing:
- You are getting warm air even when AC runs.
- Your electric bill spikes.
- Your indoor air is musty or dusty.
- You can see dust gathering around your vents.
- You have increased allergy symptoms while inside.
Advantages of the Right HVAC Filter in the Summer:
1. Healthier Air Quality
The air quality can get worse in the summer with added allergens and pollutants in the air. A high-efficiency filter can assist in keeping your family healthy by trapping allergens and pollutants from recirculating the air.
2. Energy Efficiency
The wrong or clogged filter will force your system to work harder which increases your energy bills. Having an appropriate and clean filter will help with airflow and reduce the strain on your HVAC unit.
3. Equipment Longevity
Airborne particles can cause issues for your HVAC components. Having a healthy filter protects air from manipulating so particles do not build up on the blower motor, coils, and fans, which lead to signs of failure.
4. Reduced Maintenance Costs
It’s less expensive to prevent a problem than to restore something that’s out of balance – if you schedule regular routine filter changes, you lower the risks of breakdown and avoid paying for (expensive) emergency services.
Green Tips for Using HVAC Filters
- Buy recyclable/reusable filters if possible
- Change to a smart thermostat to discourage excessive use of the HVAC system
- Use filters with air purifiers if your home has pollutants that are off-the-wall or if you live with wildfire exposure
- Seal duct leakage and insulate to improve the limits on cooling
Clear your mind this Summer with HVAC expertise
While replacing your filter is a great start, the first step in prepping your HVAC system for the summer heat is to have your entire HVAC system inspected. Fortunately for you, over here at RB HVAC Inc. we offer affordable Summer tune ups, which includes
- Inspection and change of air filters
- Charge refrigerant and check coils
- Clean blower components
- Calibrate thermostat
- Test airflow and inspect for duct leaks
These services improve system efficiency and help your filter perform optimally.
Conclusion: Choose Wisely, Stay Cool
Your HVAC filter provides your first line of defence from summer allergens, pollutants and more recently, exorbitant energy costs. Whether you live in the suburbs with higher pollen counts that resemble a vegetable garden gone nuclear or wild fire country in California, going with a better filter will have a significant change on you, your health and your wallet.
Need help choosing or installing your HVAC filter?
RB HVAC Inc. is just a call away. We help homeowners across California keep their air clean and systems efficient — even during the hottest months of the year.
📞 Call us today to schedule your summer HVAC tune-up or filter replacement.