Fresh Air Mix Boxes – Barrie Home Inspections
During my inspections of Barrie’s many new homes I have come across many furnaces with a Fresh Air Mix Box installed. I always point this feature out to my clients but as many of them are totally unaware of the purpose of this feature I decide to give a brief explanation for those home owners who wondered what the purpose was.
The Fresh Air Mix Box is designed to allow your HVAC system to introduce air from the outside into your house. The difference in air temperature can vary radically so this is where the mix box does its work. Air from your furnace is mixed with outside air combining the two to create warm air.
The Fresh Air Mix Box should be designed to properly mix these two different temperature air flows. Temperature differences can cause stratification of air and thus prevent proper mixing of the two. Creating turbulence is one patented method that forces combining of the two thus ensuring a good mix.
Custom HRV units are much more complex and are designed to mix two
different sources of air at differing temperatures in a highly space
efficient and energy efficient manner without having to depend upon air
flow volume to create turbulence. This units are approximately $2,500.00 and up and are becoming more common and in some jurisdictions are required by code.
An interesting way of supplying combustion air is what I call the “Poor Man’s HRV and consists of a couple of 3 or 4 inch vents cut through the basement wall and a small electric baseboard heater installed below. The theory behind this is that the cold air enters the basement, drops down and is heated by the baseboard heater. Functional but highly inefficient.
Discuss your HRV unit or lack of one with your Professional home inspector and ensure you understand how your HVAC system works before you purchase your next home.
This article is brought to you by The Barrie Home Inspector and is for your information only. Always check with your local building department regarding bylaws and local requirements.