Yes you can vent a gas fired water heater out of the wall if it is either a power vent unit.
Can i vent my gas water heater through the wall.
Be sure to check your gas water heater annually for cracks or leaks in the flue.
Direct venting or side wall vent chimney and flue systems are a method of venting the exhaust gases from a heating appliance directly out through the side wall of a building while eliminating the need for a vertical chimney of any sort.
They do make two models of power vent units one is called a direct vent power vent as bob harper pointed out it draws its combustion air from outside unlike a standard power vent unit which burns its combustion air from the dwelling.
Direct vent water heaters with a direct vent system air for combustion is drawn from a vent pipe that runs through an exterior wall or the roof.
They depend on draft which you won t have.
Single wall natural draft gas water heater vent pipe cannot be used in unheated areas like attic or garage even if only partially penetrating that space because such vent pipe installation will cause excessive condensation on vent pipe walls and compromise proper drafting double wall pipe b vent type is required.
What your doing can be very dangerous.
Here s how to vent a water heater to a chimney.
If your water heater is near an outside wall you can go with a direct vent water heater.
The difference is that a power vent water heater pulls in combustion air from the space.
Gas or oil fired side wall power vents are provided by several manufacturers listed at the end of this article.
Venting a conventional or typical gas fired water heater straight out through a sidewall using plastic pipe would be failure to follow the manufacturer s instructions and most likely would be unsafe.
To avert this problem you can vent the water heater to the largest hole in the chimney and cap the remaining holes.
The only other option is an electric water heater which requires no vent.
They are a bit more expensive but do not require electricity to run a power vent.
On 2019 11 11 by mod vent gas water heater out through side wall with pvc.
You can t vent a standard gas heater like that.
Exhaust gases are vented outdoors through a separate vent duct or through a separate chamber of the same pipe this requires a double wall vent duct.
Instead both systems typically expel exhaust through a pipe that runs outside through an exterior wall.
Most building codes require 4 inch flue pipes on water heaters.