Heil Furnace Filter Location and How to Replace It

The article explains how to find the Heil furnace filter location, the types of filters used, steps to replace them, and maintenance tips to keep a Heil furnace running efficiently. It covers common Heil models and troubleshooting tips that help homeowners quickly locate and change filters for improved indoor air quality and system longevity.

Heil Model Or Series	Typical Filter Location	Common Filter Types
Heil Split System Air Handler	Return Air Plenum Or Air Handler Cabinet	Disposable 1″–4″ Filters, MERV 8–13
Heil Packaged Unit (Rooftop)	Access Panel Near Blower Or Return Opening	1″ Disposable Filters Or Washable Panels
Heil Furnace (Gas/Forced Air)	Blower Compartment Or Return Duct Boot	1″–5″ Disposable Or Pleated Filters

Why Knowing The Heil Furnace Filter Location Matters

Finding the correct Heil furnace filter location is essential for proper maintenance, efficient heating and cooling, and healthy indoor air. A clogged or improperly installed filter reduces airflow, increases energy consumption, and can damage the blower motor or heat exchanger.

Key Benefits include improved efficiency, lower utility bills, longer equipment life, and better allergy and dust control.

Where To Look First: Common Filter Locations On Heil Furnaces

Heil furnace filter location varies by model, installation, and whether the system is a split unit, packaged unit, or single-piece furnace. The most common locations include the return air grille, the return air plenum, the blower compartment inside the furnace cabinet, and the air handler compartment.

Return Air Grille Or Wall/Return Vent

Some installations place a filter behind the return air grille on a wall or ceiling. This is common when space constraints prevent locating the filter inside the furnace cabinet. Filters here are usually thin 1″ panels or washable screens.

Return Air Plenum

The return plenum, the wide duct that connects the home return to the furnace, often contains the filter slot. The filter may be inserted into a dedicated slot or housed in a filter rack that slides out for replacement.

Blower Compartment Or Furnace Cabinet

Many Heil furnaces place the filter in the blower compartment inside the furnace cabinet. To access the filter, the service panel or blower door must be removed. This location typically accommodates thicker pleated filters when a filter rack is present.

Air Handler Or Packaged Unit

In split systems, the indoor air handler often houses the filter in a removable drawer or slot near the blower. Packaged rooftop units and certain indoor packaged models use a filter behind an access panel near the intake.

How To Identify The Filter Slot On A Heil Furnace

Visual clues help identify the filter slot. Look for a removable grille, a narrow opening with a frame, or a labeled filter access panel. Some Heil models have a plastic or metal arrow showing airflow direction near the slot.

Tip: If unsure, consult the model’s data plate or owner’s manual, which often lists the filter location and required filter size.

Step-By-Step: How To Replace A Heil Furnace Filter

The following steps apply to most Heil furnaces. These steps are written for safety and general applicability; users should consult their owner’s manual for model-specific guidance.

1. Turn Off The System: Switch the thermostat to OFF and turn the furnace power switch off to prevent the blower from starting while the filter is being changed.
2. Locate The Filter: Check the return grille, plenum, or furnace cabinet as described. Look for a slot, drawer, or panel that opens.
3. Remove The Old Filter: Slide the filter out carefully to avoid releasing dust into the air. Note the airflow arrow on the filter frame; the new filter must be installed in the same direction.
4. Check Filter Size: Read size markings on the old filter or measure width, height, and depth. Common sizes include 16x20x1, 20x25x1, and thicker pleated sizes such as 20x25x4.
5. Install The New Filter: Insert the new filter with the arrow pointing toward the furnace or blower (airflow direction). Ensure an airtight fit in the slot or rack to prevent bypass.
6. Close Panels And Restore Power: Replace any access panels securely and turn the furnace power back on. Reset the thermostat to the desired setting and check that the system runs normally.

Choosing The Right Filter For A Heil Furnace

Filter selection balances airflow and filtration efficiency. Higher MERV ratings capture smaller particles but may restrict airflow if the system isn’t designed for them. Match the filter thickness the system is built to accept.

Common Options: 1″ disposable fiberglass filters (low cost), 1″–2″ pleated filters (MERV 8–11), and 4″–5″ pleated media filters (MERV 11–13). Consult the furnace manual for maximum recommended MERV rating and thickness.

Filter Sizes And MERV Ratings Explained

Filter size is expressed as width x height x depth. Accurate sizing prevents bypass and maintains system performance. MERV (Minimum Efficiency Reporting Value) rates capture efficiency from 1 to 16 for residential systems.

Practical Guidance: For most homeowners, MERV 8–11 offers a good balance of air quality and airflow. Higher MERV (12–13) helps with allergies but may require a more powerful blower or thicker filters designed for less resistance.

Maintenance Frequency For Heil Furnace Filters

Recommended replacement intervals depend on filter type, household conditions, and usage. Replace standard 1″ disposable filters every 1–3 months. Pleated 2″–4″ filters often last 3–6 months, and 4″–5″ media filters can go 6–12 months.

Factors To Adjust Frequency: Pets, smoking, high dust, allergy sufferers, or heavy use may require more frequent changes.

Signs The Filter Needs Changing

Common signs include reduced airflow, higher energy bills, increased dust on surfaces, frequent furnace cycling, and unusual noises from the blower. Visually inspecting the filter monthly helps catch problems before they affect the system.

Troubleshooting Filter-Related Issues

If the furnace still performs poorly after replacing the filter, check for misinstallation, filter bypass, or a wrongly sized filter. Inspect return ducts and registers for blockages and ensure the blower compartment is clean.

When To Call A Technician: Persistent airflow problems, abnormal furnace noises, or error codes on the unit may indicate a failing blower motor, blocked heat exchanger, or electrical issues that require professional diagnosis.

Model-Specific Notes For Popular Heil Furnaces

Heil’s product lines include split systems, packaged units, and gas furnaces. Unit-specific filter locations can vary: unitary rooftop models emphasize access panels, split systems use air handler drawers, and gas furnaces often place filters in the blower compartment or the return boot.

Advice: Locate the model and serial number on the furnace data plate and consult Heil’s online manuals or contact a licensed dealer for exact instructions tailored to the model.

Safety And Best Practices When Replacing Filters

Always turn power off before opening the furnace cabinet. Wear gloves and a dust mask if the filter is heavily soiled. Dispose of used filters responsibly in sealed bags to prevent dust dispersion.

Seal Gaps: Ensure filter frames and slots have proper seals to prevent bypass. Use the correct filter size and check that access panels are securely fastened after replacement.

Cost Considerations And Where To Buy Heil Furnace Filters

Filter costs vary by type and size: basic 1″ filters are inexpensive, while high-efficiency 4″ media filters cost more but last longer. Buying filters in bulk reduces per-filter cost.

Where To Buy: Home improvement stores, HVAC supply shops, online retailers, and authorized Heil dealers sell compatible filters. Confirm dimensions and MERV rating before purchasing.

Frequently Asked Questions About Heil Furnace Filter Location

How To Tell Which Way The Filter Should Face?

Filters have an arrow indicating airflow direction; the arrow should point toward the furnace or air handler/blower. If no arrow exists, the side labeled “Air Flow” or the wire-backed side on pleated filters typically faces the return.

Can Changing The Filter Improve Heating Performance Immediately?

Yes. Replacing a clogged filter often restores airflow, reduces furnace run times, and can lower energy use immediately. If performance doesn’t improve, further diagnostics may be necessary.

Are There Filters That Fit All Heil Models?

No universal filter fits every Heil model. Many models use standard sizes, but some installations require custom racks or sizes. Measure the slot or consult the manual to choose the correct filter size.

Is It Safe To Use High MERV Filters?

High MERV filters are safe if the system is designed to handle increased resistance. Confirm with the furnace manual or an HVAC technician; upgrading to a thicker filter media often delivers better filtration with less pressure drop than a high-MERV thin filter.

Additional Resources And Documentation

Heil provides manuals and installation guides on its official website and through authorized dealers. Local HVAC technicians can show the exact filter location and recommend compatible filter types based on the system and home conditions.

Recommendation: Keep the furnace model number and installation details handy when ordering filters or seeking technical support.

Maintenance Checklist For Optimal Filter Performance

• Inspect the filter monthly, especially during heavy usage seasons.
• Replace 1″ filters every 1–3 months; thicker pleated filters every 3–6 months; media filters every 6–12 months.
• Keep return vents and intake grills clean and unobstructed.
• Seal gaps around the filter slot or return plenum to avoid bypass.
• Schedule annual professional HVAC maintenance to check blower, heat exchanger, and airflow.

Following these practices ensures the Heil furnace filter location is used effectively to protect system components, improve indoor air quality, and maintain energy efficiency.