How often should I change my furnace filter?

A 1-inch fiberglass or pleated filter needs changing every 1 to 3 months. A 4- or 5-inch media filter in a cabinet typically lasts 6 to 12 months. Homes with pets, allergies, or ongoing renovation work land at the short end of both ranges.

What MERV rating should I use?

MERV 8 catches household dust and pollen. MERV 11 to 13 also captures pet dander, mold spores, and fine smoke particles, which is where most Connecticut homes with allergy concerns should sit. Above MERV 13 you're into hospital-grade filtration that most residential blowers can't push air through without a properly sized cabinet.

Can a filter be too restrictive for my system?

Yes, and it's the most common mistake we see. Dropping a high-MERV 1-inch filter into a system designed for MERV 8 raises static pressure, starves the blower, and can freeze an evaporator coil or short-cycle a furnace. The fix is usually a deeper media cabinet with more surface area, which filters better and breathes easier at the same time.

Does the filter matter in summer too?

It does. The same blower and the same ductwork move your cooled air, so a clogged filter hurts AC performance exactly the way it hurts heating performance — longer run times, weaker airflow, higher bills.

Do you supply filters, or do I buy my own?

Either works. We stock the common sizes and can bring them to your tune-up, or we'll tell you the exact size and rating to order so you're not guessing in a hardware store aisle.

COMFORT CONTROLS · FILTRATION

A small part of your system does essential work.

Filter sizing, MERV ratings, and whole-home cabinets — matched to your ductwork so cleaner air doesn't cost you airflow.

Phil says: A filter that's too restrictive is worse than one that's too cheap. It's a sizing question, not a shopping question.

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BEFORE YOU DECIDE

Your air filter protects the blower and coil first and cleans your air second. The right choice matches MERV rating to what your ductwork can move — for most Connecticut homes that's MERV 11 to 13 in a 4- or 5-inch media cabinet, changed once or twice a year.

Key takeaways

1-inch filters: change every 1 to 3 months
4- or 5-inch media filters: change every 6 to 12 months
MERV 11 to 13 suits most homes with allergy or pet concerns
High MERV in a thin filter raises static pressure and hurts the system

OVERVIEW

Built around how your home uses propane.

Filters are graded by MERV, a scale that measures how small a particle the media can capture. Higher is not automatically better: a filter is a restriction in the airflow path, and a thin high-MERV filter can raise static pressure enough to freeze a coil, overheat a heat exchanger, or shorten blower life. Surface area is the way out. A 4- or 5-inch media cabinet holds far more pleated material than a 1-inch slot, so it captures more and resists less at the same time. We measure static pressure before recommending an upgrade, and we check the filter at every tune-up.

WHAT TO EXPECT

Propane delivery, handled.

Filter sizing & MERV recommendations
4- and 5-inch media cabinet installation
Static pressure testing before upgrades
HEPA bypass options for allergy households
Filter checks at every seasonal tune-up
Common sizes stocked on our trucks

EXPLORE

Programs & options

Indoor Air Quality

Purification, ventilation, and humidity beyond filtration.

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Thermostats

Filter-change reminders and smarter fan scheduling.

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Maintenance Plans

Seasonal tune-ups that include a filter check.

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More about this service

MERV ratings, plainly

MERV 6-8household dust, lint, pollen. The default in most homes.
MERV 9-12adds pet dander, mold spores, fine dust. A good target for allergy households.
MERV 13adds smoke and bacteria-sized particles. Needs adequate surface area to breathe.
MERV 14+commercial and clinical territory. Residential blowers generally need a dedicated cabinet or bypass to handle it.

Signs your filter is the problem

Weak airflow at the registers even when the blower is clearly running
An evaporator coil that ices up in cooling season
A furnace that heats in short bursts and shuts off early
Visible dust settling quickly on surfaces after cleaning

FAQ

Frequently asked questions

How often should I change my furnace filter?: A 1-inch fiberglass or pleated filter needs changing every 1 to 3 months. A 4- or 5-inch media filter in a cabinet typically lasts 6 to 12 months. Homes with pets, allergies, or ongoing renovation work land at the short end of both ranges.
What MERV rating should I use?: MERV 8 catches household dust and pollen. MERV 11 to 13 also captures pet dander, mold spores, and fine smoke particles, which is where most Connecticut homes with allergy concerns should sit. Above MERV 13 you're into hospital-grade filtration that most residential blowers can't push air through without a properly sized cabinet.
Can a filter be too restrictive for my system?: Yes, and it's the most common mistake we see. Dropping a high-MERV 1-inch filter into a system designed for MERV 8 raises static pressure, starves the blower, and can freeze an evaporator coil or short-cycle a furnace. The fix is usually a deeper media cabinet with more surface area, which filters better and breathes easier at the same time.
Does the filter matter in summer too?: It does. The same blower and the same ductwork move your cooled air, so a clogged filter hurts AC performance exactly the way it hurts heating performance — longer run times, weaker airflow, higher bills.
Do you supply filters, or do I buy my own?: Either works. We stock the common sizes and can bring them to your tune-up, or we'll tell you the exact size and rating to order so you're not guessing in a hardware store aisle.

DISCOVER MORE

Your next step starts here.

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Towns we deliver and service across Fairfield & New Haven Counties.

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Not sure what your system takes? We'll tell you.

Talk with a local Levco team member about fuel, service, or equipment for your home.

REQUEST A QUOTE (203) 533-8249