Connect a small gas vent to a larger one
New gas vent system
Install a reducer if you have to increase your vent size by 1-in.
Close-up of vent pipe reducer
A ‘reducer’ increases your vent diameter by 1-in.
If you find that your new gas water heater has a smaller vent than your existing gas vent, don’t assume that you have to completely replace the venting system. If you can’t find a unit that has the same size vent opening as your current water heater (or you just want a smaller unit), buy one with a vent opening that’s just 1 in. smaller, then use a “reducer” to connect to the vent as shown. Use clamps or sheet metal screws and aluminum tape to connect the reducer. Install it on the horizontal part of the vent, at least 12 in. away from the elbow. Reducers are available at home centers for about $5.
Be sure to check building codes (this project requires a permit) and manufacturer’s specifications for any additional venting requirements.
Required Tools for this Project
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
- 4-in-1 screwdriver
- Drill bit set
- Drill/driver - cordless
Required Materials for this Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
- Aluminum tape
- Reducer fitting
- Sheet metal screws