One question that we are often asked is how to tell what size PVC vents a customer has so they may purchase the correct vent screen. Since high efficiency boilers, furnaces and hot water heaters come in many different styles and BTU ratings, the PVC vent pipe can often vary in diameter. Though it is quite common for 2″ and 3″ diameter pipe to be used for venting, 4″ and 6″ pipe may be used for larger appliances and those units operating in a commercial environment. Fortunately, for most home owners, it is easy to determine what size PVC pipe they have and which of our vent screens will work for them. Please click here for detailed dimensional vent size information or continue reading to visually determine the size of your ventilation system.

Most HVAC technicians and plumbers terminate intake and exhaust vents with a PVC elbow. Elbows are often molded in 45° or 90° styles, which allow installing technicians to have directional control over the air intake and exhaust discharge. By pointing the PVC vents at a downward angle, it also reduces the risk of lawn debris (leaves, grass, etc.) from inadvertently entering the ventilation system. Since our PVC vent screens are designed to fit inside their equivalent sized hub or coupling, determining the size of your PVC vents is important.

The good news is that most PVC elbows have their size molded right on them. If you inspect your PVC elbow(s), you can usually find the size rather quickly. In the image to the left you will find a photograph of a Charlotte Pipe 3″ PVC hub, which our 3″ rodent vent screen and 3″ insect screen are designed to fit into. As you can see by the image, the 3″ size is molded directly into the hub for easy identification. If your PVC vents terminate with a PVC hub, you should be able to easily locate the size. Please note that some hubs lack much in wording but will have their diameter molded at multiple points on the ends.

Though looking at the PVC hub on the outside of your home or business is the best way to determine what size PVC vent screen you will need, you may also determine the diameter of the PVC vent terminations by looking directly at the lengths of PVC pipe leading to the exterior of your home. In the picture to the right you will see that the Cresline Plastic Pipe Company brand PVC pipe has the size printed on the pipe itself. As you can see by this image, the vent pipe is 2″ in diameter. Our 2″ insect screen and 2″ rodent screen models are designed to fit inside vents that terminate with 2″ hubs or couplings.

As you can tell, we have made it easy to match our PVC vent screens to the exhaust and intake vents that your high efficiency appliance uses. If your vents are two inches in diameter, select a two inch screen from our store. The same ease in selection applies to our three inch models. What can complicate sizing is when a HVAC technician or plumber has installed a reducer or adapter at the end of the vent pipes. In these situations you will want to measure the inside diameter of the reducer and adapter and compare it to the outside diameter of our vent screens. If you look to our individual product pages, please click on the “additional information” tab to find critical dimensions and other specifications exclusive to each vent screen model we sell.

If your high efficiency boiler, condensing furnace or power vented hot water heater vents without a hub or coupling, you will need to add one for our vent screens to fit inside of. Both hubs and couplings have a lip on the inside that our vent screens press up against. When used with our internal wire clips, the vent screens will remain secured in a position that provides maximum protection against insects and/or rodents.

It is our hope that this page helps you to determine the size of your PVC vent pipes. If you have additional questions about our screens, please visit our FAQ page for additional compatibility information and other important considerations that you should be made prior to purchasing any vent screen product.