A direct furnace vent features two pipes of different sizes in the heating system. One pipe draws in air from outside the house to bring it to the combustion chamber, and the other pipe lets the gas escape once it is used. It can be installed either vertically or horizontally.

Direct vent (two-pipe) vent system – This system uses one pipe to bring in outside air for combustion and another to remove exhaust gases. Non-direct (single-pipe) vent system – This system uses only one pipe to remove exhaust gases.

Direct-vent technology describes a gas-burning appliance that uses two pipes – often one smaller pipe within another larger pipe – to both exhaust the flue gases and bring in fresh air for combustion.

When a direct-vent system has its air intake and exhaust vents improperly installed on the outside of the home, it can create a problem of “short-circuiting,” which allows exhaust gases to flow back into the combustion air intake pipe.

Proper sidewall venting requires installing separate vent pipes horizontally so that they vent to the outdoors through a wall of your home. These ventilation pipes should be isolated from the furnace combustion chamber and made airtight to eliminate the possibility of combustion gas leakage.

The Direct Vent series is ideal for applications where a conventional chimney is unavailable, nor easily installed; an electrically heated home being retro-fit for oil forced air heating for example. The term Direct Vent refers to a sealed combustion system.

Most high-efficiency (condensing) oil furnaces vent their exhaust gases through a single plastic flue pipe extending from the furnace through a nearby sidewall. The flue vent pipe in these installations is not connected to the chimney. In some condensing furnace installations, two vents are used.

The answer is YES and NO! An 80% efficient furnace CAN be side wall vented per National Fuel as Code 7.3. 4 with the use of a “mechanical draft system of either forced or induced draft design”. You CANNOT just take the vent off an 80% efficient furnace and run it out a side wall.

The maximum vertical distance you can run a furnace exhaust vent is about 15 feet. If there is a forced air inlet within 10 feet of the exhaust vent, the exhaust gas ventilation terminal should be positioned at least 3 feet above it.

You CANNOT just take the vent off an 80% efficient furnace and run it out a side wall. You need to use an auxiliary power inducer. The combustion air flow through the furnace must be controlled or its efficiency will decline.

Yes, a furnace needs to be vented. A furnace vent allows for any gases and exhaust created by combustion to be removed from the home. If your furnace is not vented, it can lead to dangerous conditions, like carbon monoxide building up within your home.

Most direct vent gas fireplaces are vented to the outdoors horizontally (through the wall), but they can also be routed vertically (through the roof). Direct vent gas fireplaces, stoves and inserts produce highly efficient heat in a broad range of sizes and can be installed almost anywhere in the home.

A gas fireplace might require a one-inch combustible clearance behind it, six inches at the sides, 36 inches out in front and 36 inches above. A typical clearance to a six-inch wide mantel shelf above the fireplace is four inches.

But here’s a piece of interesting news: you may not need a chimney at all. Today’s gas furnaces operate super-efficiently, so they use an entirely different type of furnace venting system. Here’s how it works and what options you have if you choose to forego chimney repairs.

Direct Vents These furnace vents can be installed horizontally through an exterior wall, or vertically so exhaust fumes go out through the roof. Although more costly than a natural vent, a direct vent is also a more efficient and safer option.

Why do gas furnace efficiencies jump from 80% to 90%? Efficiencies over 80% cause condensation but the flue gas is still too hot for PVC vent pipe until the efficiency reaches 90%.