Air filter questions, answered.
Don't see your question? Contact our team. We're happy to help you pick the right filter.
Choosing the right filter
How do I find my filter size?+
Pull your current filter out of the return grille or furnace. Look at the cardboard frame. It usually has the nominal size printed on the edge (e.g. 16x25x1). That's the size to order. No filter to check? Our sizing guide shows how to measure the slot.
What MERV rating should I use?+
MERV 8 is fine for everyday dust. MERV 11 is the sweet spot for households with pets or allergies. MERV 13 catches smoke and the finest everyday particles. Most modern residential systems handle it; if yours is older, call us first. Our MERV guide compares all three.
Will a higher MERV strain my HVAC system?+
On a healthy modern system, no. Quality pleated filters are designed to keep airflow strong. If you have an older system or a return grille that's undersized, start with MERV 11.
How often should I change my filter?+
It depends on your household: every 30 to 90 days for 1-inch filters, depending on pets and allergies, and every 6 to 12 months for 4-inch filters. Our replacement guide has a schedule by household type. We also made a short video on why monthly changes matter in busy homes. Watch it below.
Buying by the case
How are your filters sold?+
By the case of 12. Each case has one price, and shipping is included in it. A case of 12 is a year of filters for a home that changes one filter a month.
Can I buy just one filter, or a smaller pack?+
Not online. Every online order is whole cases of 12. You can put more than one case, and more than one size, in the same order.
Is shipping really included?+
Yes. The price you see for a case is the price delivered. There is no shipping charge at checkout. Orders shipped to a Kentucky address also pay 6% Kentucky sales tax, added at checkout.
My size says "Call for price". What does that mean?+
We show prices online for the most common sizes. For any other size, call (270) 534-5492 or send the short form on that size's page and we will get you a price.
Can you make a non-standard size?+
Often, yes. Send your dimensions on the Custom Size page and we'll check what our supplier can make, then reply with price and lead time.
Yearly subscription
Do you offer a subscription?+
Yes, one: the Filter Club yearly subscription. We send a new case every 12 months and charge your card the same case price each time, until you cancel. To start one, choose "Subscribe yearly" at checkout. To cancel any time, call (270) 534-5492 or email mstoll@advancedthermalconcepts.com.
When am I charged?+
When you check out, for your first order. After that your card is charged the same price once every 12 months, until you cancel.
How do I cancel?+
Call (270) 534-5492 or email mstoll@advancedthermalconcepts.com. No fees. Once you cancel, your card is not charged again. If a renewal just charged and your case has not shipped yet, call us and we will refund it.
Does the subscription cost more than buying once?+
No. The case price is the same either way, and shipping is included in both.
Shipping & returns
How fast do you ship?+
Most orders ship the same or next business day. We email you a tracking number when your order ships.
Where do you ship?+
To the lower 48 US states. We cannot ship to Alaska, Hawaii, US territories, or military APO, FPO, and DPO addresses.
What if you send the wrong thing, or it arrives damaged?+
We fix it free. If we sent the wrong size or grade, tell us within 30 days. If it arrived damaged, email a photo to mstoll@advancedthermalconcepts.com within 7 days. Either way we make it right at no cost to you.
I ordered the wrong size. Can I return it?+
Yes. An unopened case can be returned within 30 days of delivery for a refund of the case price. We don't accept returns on custom sizes, since they are made to order.
Not sure which size to order?+
Call (270) 534-5492 before you order and a tech will confirm your size. It takes about two minutes.
Contractor & bulk orders
Do you work with contractors and property managers?+
Yes. Tell us what you install and how often on the Contractors page, and we'll follow up about pricing and delivery.
Still have questions?
We answer every message within one business day.