Mechanical ventilation is when a fan is used to draw air into the house. Passive ventilation is the same as opening a window. Air is free to enter as its required. Plusaire uses both methods to bring air into the house.
Firstly air is mechanically drawn into the house by the furnace fan during the heat cycle. This is the time when more oxygen is burnt and exhausted up the chimney than at any other time. Air is also mechanically exhausted by the various fans such as in the bathroom, clothes dryer, central vacuum, and kitchen causing outside air to be drawn into the house through Plusaire. Without an entry point for the replacement air it would have to find its way in through holes in the house structure, or depressurize the house.
Secondly, when the furnace fan is off, fresh air is drawn into the house through Plusaire by the combusting appliances such as a wood stove or fireplace. The air that is being combusted must be replaced and Plusaire does this in the most economical way.
Remember for every cubic foot of air that leaves a house a cubic foot must be brought in to replace it. The diagram shows the method of installation and the air flows.
For any of the models, the maximum length of ductwork between the PlusaireŽ and the furnace and the furnace and the outside wall should be twenty feet, (forty feet overall). For each of the models, a seven, eight or nine inch dia. hole must be cut in an outside wall to accommodate the fresh air hood and insulated flexible duct. If the wall is wood or siding, then the task is quite simple and fast. If however the wall is poured concrete or block you will need a hammer drill to cut the hole. Most heating contractors have these drills and would be able to cut the hole in about one hour.
Two rectangular holes must be cut into the furnace plenums to take the duct connections, but this is very thin metal and a pair of tin snips is all that is needed for the task. The PlusaireŽ module can be screwed directly to any convenient joist or rafter through the flange in each end. For convenience, model 1 will fit between 12" centre joists and model 2 will fit between 16" centre joists.
Once the plenum connectors and the fresh air hood are installed the only task left is to connect the flexible ducts.
You will notice immediately that the air feels different and you can feel confident that your house is now being automatically ventilated. For houses that have central air, a balancing damper, provided on all models, should be closed during the summer months so that the air conditioning system is not overloaded by pulling in hot humid air.
If a house is 1500 sq. ft. and the ceilings are 8.5ft. then it will have 12,750 cu. ft. of volume. To achieve the recommended comfort level the air must be replaced at a rate of 4207 cu. ft. per hour or 70.13 cu. ft. per minute. Use this formula to calculate your own house requirements.
Experts state that a bathroom fan of the required capacity (70 ft./min) running continuously will accomplish the ventilation requirements. No mention is made however as to where the air is coming from. Obviously air must be introduced into a house so that house air can be exhausted, otherwise depressurization will take place. For every cubic foot of air that leaves a house, a cubic foot is required to replace it. A device able to introduce warmed fresh air at the rate at which your house is using it and be able to add combustion air at a place and time when it is needed is therefore essential.
A PlusaireŽ ventilation system sized for the house will look after the fresh air and combustion requirements in the most cost efficient way. Go to the sizing page for more information about PLUSAIREŽ.
Phone: 1-519-458-4714
E-Mail:sales@plusaire.on.ca OR tech@plusaire.on.ca