Hi, I’m Tristan, a home performance expert with Barron Home Services. In this video, I’ll walk you through how we add cooling to an existing down-flow gas furnace. A project we’re doing more and more often each year as western Washington homeowners want more choices for their home comfort. Today our Barron Heating an AC team is working at our Whole Home Academy: Barron’s in-house technician school, where our techs learn and practice installs like this before they ever step foot in your home. Now, if you live in western Washington, there’s a good chance you have a gas furnace like this one in your garage or utility room. These systems are very common here, but not in many other parts of the country. This furnace is called a down-flow furnace because air enters at the top, gets heated, and then gets pushed downward into the duct system to warm the home. So let’s say you want to add air conditioning. To make that happen, we install a new component onto the furnace called an evaporator coil. You can think of this as the part that allows your furnace to work with an air conditioner, almost like an AC adapter on a down-flow furnace. That coil must be installed underneath the furnace, on the warm air, or supply side. To install the coil, we first disconnect the gas line, the electrical connections, and the venting. Then we remove the furnace and filter and set them aside. With the furnace out of the way, we place the new evaporator coil, we reinstall the furnace on top, and modify the ductwork as needed so everything fits together properly. We also install a condensate drain line to carry away moisture that naturally forms when warm air meets the cold coil. Once the coil is in place, we reconnect everything so the system looks much like it did before. Here’s where the cooling happens... Outside your home, the air conditioner or heat pump connects to the indoor coil using refrigerant lines. When your thermostat calls for cooling, the refrigerant flows from the outdoor unit to the indoor evaporator coil. As the refrigerant absorbs heat, the coil becomes very cold. The furnace blower fan then pushes warm air from your home, across that cold coil. The heat is pulled out of the air, moisture is removed, and the cool, conditioned air is delivered through your existing ductwork to cool the home. Because adding cooling to a down-flow system requires removing the furnace, this is often the most practical time to consider replacing or upgrading an older unit. On the flip side, if your furnace is nearing the end of its life or if you’re planning to replace it in the next few years, adding cooling at the same time can save you money, reduce disruption, and avoid having to do this work twice. A new system can also improve efficiency, reliability, and comfort, and it’s a great opportunity to upgrade indoor air quality with better filtration or duct cleaning. If you’re thinking about adding cooling or wondering whether it’s time to replace an older furnace, talk with a Barron Home Performance Expert. We’ll evaluate your system and explain your options to help you choose the solution that best fits your home and your budget.