Furnace Air Intake Requirements

The pvc pipes are used for air intake exhaust gas and to remove the corrosive condensation resulting from the combustion process.

Furnace air intake requirements.

There are two types of airflow furnaces a downdraft or downflow furnace and an updraft or. Your home furnace air intake location depends on where the furnace is. A recent study on furnace installation quality completed for fortisbc indicated that on average only. A gas furnaceneeds approximately thirty feet of air for every foot of gas used.

Unfortunately the fresh air intake you have described is the second type and does not provide direct combustion air to the furnace room as it is directly connected to the return air plenum for the furnace. If the furnace is putting out 1 000 cubic feet per minute of air flow the return system must collect 1 000 cubic feet and take it back to the unit. This fresh air will enter the air circulation system of the heating system which is separate from the combustion chamber on your furnace. Hi efficient furnaces will still require them if drawing combustion air for the burner from inside the building other wise they would have a 2 pipe system.

This high efficiency venting system must be installed when you install the new furnace. This is a requirement by code for all mid efficient furnaces. Other aspects of high efficiency furnace venting. The furnace lifespans specified by many manufacturers.

An insufficient return system or one too large will reduce the efficiency of the heating and increase energy bills. Since there is really no specific requirement that states the exact amount of fresh air necessary a rule of thumb which says that it s generally accepted that a person needs 15 cfm cubic feet of air per minute of fresh air applies. You want to see at least one sq. Of open fresh air intake per 1000 btuh.

There are several other important aspects of high efficiency furnace venting. For heating equipment installed in confined spaces an old timer s rule of thumb is to add up the total input btuh numbers from all of the data tags on all of the heating equipment installed. In the case of residential applications though things are somewhat different. Furnace fresh air intake general discussion.

This is roughly the equivalent of running a bathroom exhaust fan into your furnace s combustion chamber. Square inches of combustion air intake.