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Heating & Air Conditioning Vent Safety

Heating & Air Conditioning Vent Safety

High CFM Range Hood | Heating and Air Conditioning

The current trend of installing powerful commercial style range hoods in newer homes is creating an air balance problem that may affect not only the heating and air conditioning system, but may also potentially pull dangerous carbon monoxide gases back into the home through gas exhaust vents in a process called backdrafting.

The problem with these powerful fans is providing them with incoming fresh air to equal the air they exhaust. If air is not provided by a clean source, they may pull air from unclean sources, and even worse they may pull dangerous exhaust gases/air in from the exhaust vents of gas fired appliances into homes!

Homes are becoming tighter with better insulation, and while this is good for reducing the cost of heating and air conditioning it may be bad from a ventilation viewpoint, especially when the kitchen fan is pulling 1200 CFM.

With newer homes so tight, the air being pulled by a ventilation fan must come from somewhere. If it can’t draw clean air in a well-insulated home from the outside it will come from any available source such as chimneys and gas fired appliance exhaust vents. Gas fired appliances may be the hot water heater or the gas furnace portion of your heating and air conditioning system for example.

Nationwide, building code changes are beginning to call for Make Up Air when the kitchen range fan exceeds 300-400 CFM. If you live in an area where cold weather is not a problem the simplest means of providing the air required is to open a window. Otherwise, mechanical ventilation is a requirement.

Let’s look at some of the solutions for providing the air the new commercial style kitchen range hood requires.

  • Good- An opening to the outside can provide the required ventilation; this can be either by manual operation or electric. It is optional for air to be filtered but filtering may reduce performance as well as the amount of air provided. If you are located in a colder climate you may want to choose preheated incoming air.
  • Better- A power operated exterior opening with booster fan providing incoming air of an equal amount to the range hood fans exhaust of air, providing filtered and optional preheated incoming air.
  • Best- A self-contained filtered and heated make-up air fan. These are similar to the systems used by restaurants but on a smaller scale. They are large and costly but are a worry free way to go.

The means of concealing these fans in the kitchen is the use of grills or to locate them out of sight. Typical locations are cabinet bases, behind refrigerators, and installed in ceilings. Some locations will require a duct to provide the outside air a means of entry. If your make up air supplier has a filter you must consider access to the filter, access to an optional multispeed fan switch and access for providing a duct if necessary.

Cypress Heating and Air Conditioning serves the Katy/Fort Worth regions. Our certified technicians provide for expert air conditioning installation and for all of your heating and air conditioning needs.