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February 7, 2022
A high efficiency furnace & water heater

Whether you use a boiler or furnace to heat your home, it’s important to make sure your heating system runs as efficiently as possible while keeping your home safe and healthy. One way we help ensure heating systems hit all these targets is by installing them with a second pipe to supply the outside air that is necessary for combustion.

“What is combustion, and why does it require a supply of air from the outdoors?” We’re glad you asked. Here’s a brief overview of combustion as it pertains to heating systems, and why ensuring an adequate air supply is essential for keeping your home safe, healthy, and energy efficient.

Heating Systems Need Air for Combustion

Most boilers and furnaces are combustion appliances, meaning they burn fuel like natural gas, oil, or propane in order to generate heat. But the combustion process also requires air. Depending on how your heating system was installed, it may draw air from inside your home for combustion, or it may use outside air.

One Pipe Heating Systems Use Indoor Air

“One pipe” heating system installations feature a pipe that safely vents combustion byproducts like carbon monoxide out of the home. There is no pipe to bring outside air in for combustion. Instead, the boiler or furnace draws air from inside the home.

Two Pipe Heating Systems Use Outdoor Air

“Two pipe” installations have a pipe for ventilation and a pipe that brings outside air in for combustion (a “combustion air intake.”) Sometimes these pipes are installed concentrically, referred to as a concentric pipe system, giving the appearance that there is only one pipe.

The Benefits of Using Outside Air for Combustion

Having a combustion air intake is preferable for a number of reasons.

Greater energy efficiency

When your heating system has a steady supply of outside air, you avoid using valuable conditioned air for combustion, helping to avoid energy waste and keep your bills low. 

Safer combustion

If your boiler or furnace is in an enclosed space and relies on indoor air for combustion, you run the risk of incomplete combustion, which produces toxic byproducts like carbon monoxide. Bringing in air from outside helps ensure complete combustion, keeping your family safe.

Less risk of back-drafting

When your heating unit does not have an adequate air supply, it will consume the surrounding air very quickly, creating negative pressure. This negative pressure can cause back-drafting, which is when combustion products like carbon monoxide spill back into the home. Obviously, this can undermine your indoor air quality (IAQ) and even put your family at risk. Having a reliable supply of outside air for combustion helps prevent back-drafting. 

Increased comfort

When inadequate air supply creates a negative pressure inside your home, you could also see an impact on your home comfort. This is because negative pressure creates a vacuum effect that pulls outside air in through any air leaks in your home’s exterior. As a result, you could experience more indoor drafts while your heating system is running. Having a reliable supply of outside air helps avoid this issue, so your home stays more comfortable. 

Trust CARJON for Safe Heating System Installation 

The expert HVAC team at CARJON knows how to install heating systems properly to keep your home and family safe. We have decades of experience installing HVAC systems and are committed to providing the best possible service for our customers. If you’re worried about your combustion heating system, call us today. We would be happy to inspect your furnace or boiler and make any necessary adjustments to protect your home and family. 

Need to replace your heating system? We’ll provide an installation that keeps your home as safe, healthy, and energy efficient as possible. Call at 401-232-9400 or contact us to schedule boiler or furnace replacement!

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