Gas fireplace vent too close to air conditioner compressor/condenser unit (C) Gas Fireplace Direct Vent Termination Cap Clearance Distances

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Direct vent chimneys or exhaust for gas fireplaces & gas fireplace inserts:

This article gives typical clearance distance requirements between the termination cap of a gas fireplace or fireplace insert and other building or site features such as windows, doors, other mechanical system components, air intakes, exhausts.

This article series describes side wall vent systems for conventional & mid-range-efficiency heating boilers, furnaces & water heaters. We include for comparison, low temperature side wall vent systems used by high efficiency or condensing boilers, furnaces & water heaters.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Clearance Distances for the Exterior Vent Termination of a Direct-Vent Gas Fireplace / Heater

Gas fireplace exhaust too close to AC/heat pump compressor/condenser unit (C) InspectApedia AJ

The clearance distancess shown above and at the top of this page are between the vent termination cap of a gas fireplace and the air inlet side of an A/C or heat pump compressor/condenser.

At CLEARANCE DISTANCE, HVAC a reader commented that his building inspector did not accept the safety of this installation.

We agreed.

[Click to enlarge any image]

Reviewing manufacturer's installation instructions for a typical gas fireplace direct-vent exhaust termination cover or cap we find that the clearance distances to other building features or mechanical systems are similar but not necessarily identical to the Direct Vent Gas Appliance clearances given in the preceding table.

This may be because that a typical gas fireplace heater does not use a power-exhaust vent or also because of different BTUH ranges.


Minimum Clearance Distance Requirements for the Exterior Vent Termination of a Gas Fireplace Heater8

Direct vent gas fireplace exhaust termination item clearance distance Distance required (Canada)1 Distance required (USA)2
Clearance above paved sidewalk or a paved driveway located on public property 84" (2.1m)3 [Note 5]
Clearance above paved sidewalk or a paved driveway located on public property 84" (2.1m)3 [Note 5]
Clearance to a mechanical air supply inlet

3' (91cm) above if within 10' (3m) horizontally
72" (1.8m) 36" (90cm)5b
Clearance distance from gas vent termination cap to adjacent building   48" 8
Clearance distance from gas vent termination cap to any mechanical air-supply inlet   48" (Travis 2016)
Clearance to the side of any non-mechanical supply air inlet   36" (Travis 2016)
Clearance to each side of center line extended above [the gas] meter/regulator assembly 36" (90cm)5a [Note 5]
Clearance to gas service or gas meter regulator vent outlet 36 " (90cm) [Note 5]
Clearance above any non-mechanical supply air inlet   36 "(Travis 2016)
Clearance distance to bushes, garden sheds, fences, decks or utility buildings   24" (Majestic 2016)
Clearance distance horizontally to any surface such as exterior walls, for vertical terminations   24" (Travis 2016)
Clearance distance to any vinyl surface   24" (Travis 2016)
Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet (61cm)
from the center line of the terminal (check with the local code)
18" (46cm) 18" (46cm)
Clearance below a veranda, porch, deck or balcony (must have two open sides)   18" (Travis 2016)
Clearance below ventilated soffits   18" (Travis 2016)

Clearance to or below any unventilated soffit

or below any roof surface

15" (38cm)

15" (38cm)

11" (Travis 2016)

Clearance distance above the roof line (for above-roof vents)   12" (Travis 2016)
Clearance distance to vinyl surfaces such as vinyl siding or vinyl trim   12" 8
Clearance above any grade, veranda, porch, deck, or balcony 12" (30 cm) 12" (30 cm)
Clearance to window or door that may be opened 12" (30 cm) 9" (23 cm)8
Clearance to permanently closed window [Note 5] [Note 5]
Clearance to outside corner / corner walls: with approved Termination Caps 12" (30cm)

12" (30cm)

3" (Travis 2016)

Clearance to inside corner: with approved Termination Caps 12" (30cm) 12" (30cm)
Clearance to roof eaves   6" (Travis 2016)
Clearance to outside corner: with Manufacturer's Special Termination Cap 6 6" (15cm)6 1-6" (15cm)6, 8
Clearance to inside corner: with Manufacturer's Special Termination Cap 6 6" (15cm)6, 8 1-6" (15cm)6, 8
Clearance to non-mechanical air supply inlet to building or the combustion air inlet to any other appliance 12" (30cm) 9" (23 cm)
Clearance under balcony, porch, or veranda 12"(30cm)4 [Note 5]
Clearance from outside corner walls   3" (Travis 2016)

Opinions On Additional Recommended Cleareance Distances from a Direct Vent Gas Fireplace Exhaust Opening to other Building Features or Equipment

Distance to an air conditioner or heat pump compressor/condenser unit to the nearest point of a direct vent gas heater or gas fireplace exhaust 24 inches to 6 feet [Note 6]

The table of gas fireplace vent clearances above is derived from the codes, standards, and example gas fireplace installation manuals cited in this article.

Watch out: the final legal authorities for acceptable clearance distances from the direct vent opening/hood on a gas fireplace to building features are the manufacturer of the specific gas fireplace (see the I&O manual for your fireplace) and your local building code inspector.

Be sure to check the Installation & Operation manual for your fireplace as the manufacturer's specifications could differ from the gas fireplace vent opoening clearances table above.

Notes from the original source cited below:

1. CSA B149.1, Natural Gas and Propane Installation Code

2. ANSI Z223.1/NFPA 54, National Fuel Gas Code

3. A vent shall not terminate directly above a sidewalk or paved driveway which is located between two single family dwellings and serves both dwellings.

4. Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.

5. Clearance in accordance with local installation codes and the requirements of the gas supplier

5.a 3 feet (91cm) within a height of 15 feet (4.5m) above the meter / regulator assembly

5.b 3 feet (91cm) above - if within 10 feet (3m) horizontally

Additional Notes:

6. This is the author's OPINION considering that heat from the gas exhaust vent blowing onto an A/C compressor unit condensing coil could imact the coil's ability to condense refrigerant back to liquid form, affecting the condenser unit's efficiency and life. I'm considering the situation in which the hot gas exhaust blows onto the air intake side of a condensing coil.

(Most modern condenser units draw cooling air in from the unit sides and push it out the unit's top). Also see CLEARANCE DISTANCE, HVAC

7. This is a Regency Fireplace Producucts termination cap; other manufacturers may have similar options. See the additional sources below.

8. Watch out: check with the manufacturer of your heater and venting system for specific venting instructions and clearances to combustibles or to other features as these distances may vary from one appliance and manufacturer to another. For example the Travis Industries direct vent clearances include some distances that are different from the tables given above.

DuraVent (and other manufacturers) warn that if a gas appliance, fireplace heater or other heater is not properly installed the system may be unsafe.

A major cause of vent related fires is failure to maintain clearances (air spaces) to combustible materials. It is of utmost importance that double wall direct vent pro be installed only in accordance with these [the manufacturer's] instructions.

Additional sources of direct vent gas fireplace clearance information:

  • DuraVent, "Direct Vent Pro Venting System for Direct Vent Gas Stoves and Fireplaces", M&G Duravent, Inc., Tel: 800-835-4429, Website:, retrieved 2016/04/07, original source:
  • Mendota Fireplaces, MENDOTA FULL VIEW DIRECT VENT GAS FIREPLACE INSERT WITH PREMIUM TEXTURE FIBER LOGS COMBUSTION SYSTEM, INSTALLATION & OPERATING INSTRUCTIONS, [PDF] Johnson Gas Appliance Company, 520 E. Avenue N.W., Cedar Rapids, IA 52405, Website: or, retrieved 2016/04/07, original source:

    Note: This gas fireplace insert installation manual expects the fireplact to be vented vertically through an existing chimney.
    Venting system must be installed by a Mendota approved person according to Figure 3. pg. 8 with clamps securely in place and all joints leakproof.
  • MAJESTIC DVBL7 SERIES DIRECT VENT GAS FIREPLACE I&O MANUAL [PDF], retrieved 2018/06/26, original source:


    There must not be any obstruction such as bushes, garden sheds, fences, decks or utility buildings within 24” (610 mm) from the front of the termination hood.

    Do not locate termination hood where excessive snow or ice build up may occur. Be sure to check vent termination area after snow falls, and clear to prevent accidental blockage of venting system. When using snow blowers, make sure snow is not directed towards vent termination area.
  • NAPOLEON® GAS DIRECT-VENT MILLIVOLT SYSTEM INSTALLATION & OPERATION INSTRUCTIONS FOR VENTED GAS FIREPLACE [PDF] for natural gas models GD33NR, GD 24NT, BGD 33NR, BGD34NT, and propane gas models GD33PR, GD 34PT, BGD 33PR, BGD34PT gas fireplaces. (2005) Wolf Steel Ltd., 24 Napoleon Rd., Barrie ON L4M 4Y* Canada Tel: 705-721-1212 Website: Email:
  • Regency Fireplace Products, "P33-4 ZERO CLEARANCE DIRECT VENT GAS FIREPLACE OWNERS & INSTALLATION MANUALl", [PDF] , FPI Fireplace Products International Ltd., retrieved 2016/04/07, original source:
  • R.H. Peterson Co., "REALFYRE PREMIUM GAS LOGS OWNER'S MANUAL" [PDF] Robert H. Peterson Co. 14724 East Proctor Avenue, City of Industry, CA 91746 USA Website:, Tel: 800 332 3973
  • Travis Industries House of Fire, "4415 HO GSR2 (WITH SCREEN) INSTALLATION MANUAL", [PDF], Travis Industries, Inc., 12521 Harbour Reach Dr., Mukilteo WA 98275, USA (2014), retrieved 2016/04/07,original source:
  • Travis Industries, TRAVIS DVS EF FIREPLACE OWNERS MANUAL [PDF] Op. Cit., retrieved 2018/06/26, original source:

    This manual includes a detailed description of allowable vertical vent terminations using 0, or 2 45° or 2 90° Offsets in the flue vent piping as well as horizontal vent termination and routing restrictions.

    Excerpted additional clearance distances:
    Minimum 11" clearance below unventilated soffits or roof surfaces
    Minimum 18" clearance below ventilated soffits
    Minimum 6" clearance from roof eaves
    NOTE: Vinyl surfaces require 24"

Question: what is the required clearance between adjacent houses & a neighboring direct vent fireplace?

Is there a minimum distance between brick houses in Toronto for venting termination of a fireplace using direct vent? - A.W., 12/30/2012

Reply: 4 feet or local codes

I have not found building code citations that refer to nearby or adjacent buildings when specifying clearances for direct vent fireplaces, though some of the fireplace installation manuals we reviewed specified a minimum of four feet to the nearest separate building.

It seems likely that your local building code inspector would agree that the clearance requirements for the building in which the fireplace is installed would set the minimum acceptable clearances that would then apply also to a nearby or adjacent building.

In other words, if the fireplace vent distances and position relative to your own building windows or doors were LESS THAN those to the windows & doors on the building where the fireplace is installed, and presuming for a moment that the fireplace was installed properly, meeting local building permit and code requirements, then a violation probably exists.

If the fireplace vent distances and position relative to your own building windows and doors is GREATER THAN those to the windows and doors where the fireplace is installed, and presuming for a moment that the fireplace was installed properly, meeting local building permit and code requirements, then a violation probably does not exist.

Take some some sharp photos of the installation that concerns you, or make a sketch and send those along and we may be able to comment further.


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