How to Meet the 2019 Title 24 MERV 13 Requirement

California’s Title 24, Part 6, update requires high-efficiency filtration and low pressure drop performance. It’s essential for builders and HVAC contractors to look at the best option to meets this code.

California’s Title 24 update, the harbinger of tough codes for the rest of the country, will
bring 50% more stringency to residential housing in just one code cycle. For the category, the filtration efficiency and pressure drop performance metrics an HVAC system must meet are the most aggressive in the country.

“Currently in California there is a requirement for MERV 8 filtration, and the filter must be accessible from the living space – which typically requires a return grille since most
systems are in the attic,” explains Joseph Hillenmeyer, Channel Marketing Manager
for Residential New Construction at Aprilaire, a division of Research Products Corp. “But the 2019 code requires MERV 13 filtration. While MERV 8 filtration can be achieved with a one-inch filter, MERV 13 poses new obstacles and HVAC system design changes will likely be required in most new homes.”

According to Hillenmeyer, the new MERV requirement will add significant pressure drop
to systems relying on a one-inch filter. Furthermore, there are very few options on the
market for a one-inch filter with a MERV 13 rating because the static pressure is just too
great. “Your choice is to either add significantly more return grilles per home or drastically increase the size of them beyond 20 x 30” Hillenmeyer says. “We provide the only solution on the market which provides a high-efficiency MERV 13 four-inch filter measuring as small as 16 x 25.”

The Aprilaire MERV 13 4” filter provides over 27 sf of surface area; over 14 times the
area of a one-inch pleated filter. This allows for extremely low pressure drop so systems
can be designed with smaller and/or fewer filter grilles.

The Aprilaire Filter Grille Air Cleaner Hillenmeyer refers to offers the best option to comply with the new code. Regardless of system tonnage and CFM, Aprilaire filter grilles deliver the highest performance.

The code requirements are a big change for HVAC contractors who will most likely go to the four-inch format because it’s the simplest way to meet the standard. Hillenmeyer sees the Aprilaire product as a no-brainer for meeting California code as well as an upgrade option for progressive builders around the country, such as Meritage Homes, which already specs a MERV 11. “Builders, particularly those in areas demanding high- performance homes, will be interested in this product,” he predicts.

Hillenmeyer points out the Aprilaire Filter Grille Air Cleaner’s unique design and low-
maintenance features. “The grille has tabs that make it simple to change the filter,” he
says. “A bonus is that the filter, because of its depth, won’t have to be changed as often
as a one-inch filter.” (See chart below.)

The Aprilaire MERV 13 4” filter provides over 27 sf of surface area; over 14 times the area of a one-inch pleated filter.

The four-inch filters are effective for 6-12 months compared to the traditional 1-3 month one-inch filter, and they are collapsible, which means, unlike the stiff one-
inch panel filters that can get damaged in transit, the product stays protected in its
more compact packaging.

Another advantage of the Aprilaire product is that in addition to being more efficient,
offering healthier indoor air, and trapping more pollutants, it can prevent expensive call-
backs, by providing much greater protection for the HVAC system. “The self-sealed
technology, with the lowest static pressure in the industry, is designed to make filtration
more efficient and protects the system by not letting pollutants leak out into the system,
Hillenmeyer says. “There is leakage with the one-inch filters, which can gum up the HVAC.”

The Aprilaire Filter Grille Air Cleaner is perfect for new construction in markets where
attic installations are prevalent. Unlike typical panel filters that clog in a matter of days
from drywall dust and other post-construction debris, Aprilaire filters will protect the
newly installed equipment between construction completion and home buyer occupation
and beyond. Visit to learn more.

More Details

Aprilaire Filter Grille Air Cleaners (1625FG13 and 2025FG13)

This product removes most common airborne allergens including dust, pollen, mold
spores, bacteria, pet dander, and dust mites. The filter protects the HVAC system while providing high efficiency.

Available in 20 x 25 and 16 x 25 models, the Filter Grille Air Cleaner ships complete with frame, removable grille, filter locks, and a MERV 11 Aprilaire filter which is easily upgradable to MERV 13. For California contractors, Title 24-Compliant MERV 13 models will ship as standard beginning January 2020.

Changes to Ducts and Filters in 2019 Title 24, Part 6

The new code has four changes related to ducts and filters:
● An exception for ducts in support platforms and wall cavities to be uninsulated.
● Minimum 2” filter (larger face area formula will allow for 1”)
● Minimum MERV 13 filtration
● Filter not required if 10 feet or less of ductwork. MERV 13 filter not required for
alterations to existing systems, only to new systems (new ducting, AHU and

To see all the changes in the 2019 Title 24 code, click here.