No, a heat pump does not draw in outside air on it’s own. So how does a heat pump bring in outside air? Outside or fresh air is a function of the duct work not the heat pump. You can add a duct to the return air of the system that penetrates an outside wall. That’s how to bring in fresh air from outside. You can have any type of forced air furnace with duct work that has a fresh air intake attached.

So when you’re wondering where’s the fresh air intake on an air conditioner, it’s simply a duct attached to the return air duct and piped to the outside so it can suck in outside air. Any time the fan is on, it draws air into the duct system and pressurizes the home with outside air.

The return duct is usually the larger single duct attached to the furnace and has the air filter incorporated in it somehow or somewhere. Filters are always in different places in furnace systems so it’s hard to explain in words where yours is located.

If you want to know how to bring in fresh air from outside you can cut a hole in a return duct. If the duct is sucking air with the fan on then you have the right duct. Next attach a duct to that hole and run a round duct to the outside of the house. You can finish it off with a screened vent that looks like a dryer vent.

What’s The Downside Of An Outside Air Duct?

A split AC with fresh air intake will pull or suck fresh air into your ductwork to be distributed by all the supply ducts that are in hopefully every room. Imagine that fresh air when it’s below freezing outside or a heat wave of 110 degrees.

In winter your furnace has to reheat that air and in summer the AC has to cool that incoming air, and at what cost? But, we have a solution. It’s called a fresh air damper. Motorized to open and close when needed.

Added energy cost can be quite high if a fresh air duct is left uncontrolled and open to the outdoor extremes of weather. With a fresh air damper such as this one available here on amazon can control the time open and closed to provide fresh air when it’s economical to do so.

Heat Recovery Ventilators Are The Next Best Thing To Motorized Fresh Air Intake Control

Heat Recovery Ventilators or HRV’s incorporate the use of a heat exchanger to temper the incoming air and deliver the air into your home in a very efficient manner. Heat exchangers keep the outside air and the inside air separated by walls inside the HRV and the temperature of the air is exchanged through the walls.

You can search for HRV’s here and get a good look at the various manufacturers and some cutaway drawings of what they look like inside. Or look at some prices on Amazon here. As you look around you will see HRV and ERV. The main difference is an HRV transfers heat and ERV’s transfer heat and humidity.


So do heat pumps bring in outside air? Only when a duct is added to the system that funnels outside air into the homes duct system. There is more than one solution to exchange the stale air in your home with fresh outside air. With the information you’ve gleamed from this article you can begin some in-depth research into finding which option fits your budget.

Personally I have serviced many of these systems and have installed several of the simple outside air ducts with dampers, but I’ve never installed an HRV or an ERV. Just wasn’t something that fit in my market.

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