How Combustion Appliances Complicate Crawl Space Encapsulation
Encapsulating your home's crawl space can reduce moisture problems, keep your home warmer in the winter, and prevent mold from settling in. However, many homeowners also use their crawl spaces for storing their gas powered furnaces and other similar combustion-producing appliances. If your crawl space has a furnace or gas water heater sitting in it, you'll need to plan the encapsulation carefully to avoid serious hazards.
An Airtight Seal
Crawl space encapsulation is a process that leaves the area as air tight as possible. This creates a buffer of stable air you can heat or cool along with the rest of the house, as well as keeping out mold spores and moisture. It's fine to make the crawl space this air tight when it's empty, but it becomes dangerous when there's an appliance in it that needs fresh air and produces dangerous fumes.
Fresh Air Supply
Electric water heaters and furnaces work normally in an airtight crawl space, but gas or oil fired units work differently. The combustion process requires a source of fresh air, and encapsulation blocks all the possible sources of that air flow. You can work around this limitation by adding a duct or sealed vent that connects directly to the appliance so it gets plenty of air. Keep in mind that your furnace is likely a model based on open draft technology, which is not automatically suited to attaching a duct. You may need a new furnace, known as a sealed combustion unit, that is designed for using in an enclosed space to make your crawl space improvement plans work.
Dangerous Gases
Aside from incoming fresh air, combustion appliances also need to send the carbon monoxide gases and other emissions they produce. At least with this part of the combustion process, all gas and oil fired appliances include vents for directing these fumes out of the house. However, you'll need to check the venting equipment regularly to make sure there are no leaks and install carbon monoxide detectors so that the invisible gases don't end up forced into the rest of the home.
Most crawl space encapsulation contractors won't agree to seal in an area with a combustion appliance unless it's a sealed unit. If your home has serious mold and moisture problems that only sealing can fix, it's probably worth the cost to switch to electric appliances, invest in sealed combustion chamber models, or move your heating equipment into another part of the house. For more information, contact companies like Atlantic Heating and Cooling.
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