It is a commonly asked question: Why do on demand water heaters have to be on an exterior wall? Most people have no idea how these things work. And while there is a technical explanation for the design, it's the perception of the question that may cause someone to ask the question in the first place.
The reason that a water heater must be on an exterior wall is to keep it from accidentally leaking. One of the biggest reasons that you would need a heater on a wall would be if you were constructing a home, apartment, or office building. The building code, which will vary depending on the type of building that you are building, dictates the location of water heaters and fireplaces. If you have a major remodeling project to do, the plumbing or electrical contractor may recommend using a water heater that does not need to be installed on a wall, and a fire pit that can be located anywhere within the property that you have given him permission to use.
An exterior wall is also used to secure the heat distribution system to the foundation. The fireplace outlet for any type of gas system is best installed away from the foundation. If you have electric water heaters, they should not be near your foundations. The reason that a gas water heater, or a water heater that has an electric heat element, has to be installed on an exterior wall is because they produce hot gasses when you burn fuel. These gasses must be contained and directed away from your house.
The pipes of the heater must also be ventilated before they get too hot, so they don't emit dangerous gasses. A gas heat element needs to be installed in an outdoor location because the vents of an indoor unit do not allow the gasses to escape quickly enough, and you could overheat them.
It is also important that the pipe is covered when it is installed inside the house, so that no unwanted exterior debris can enter the home. Because of this, it is recommended that the heater be installed on a free standing structure, like a tree, pole, a wall, etc. In addition to this, because they are powered by fuel, the outdoor water heater has to be installed in an area where there is no risk of rain or snow causing the fuel source to stop working. While there are some models that can be installed on a home exterior wall, most are best installed on a structure. This way, if there is a storm or bad weather that causes a leak, it will only affect the exterior of the structure.
Here is another question that might be on your mind: Why do on demand water heaters have to be on an exterior wall? There are a number of reasons that they must be installed on a structure, but here are the main ones:
The primary reason is that there is no way for the heater to be turned off if there is no fuel to burn to heat it up. As long as there is a source of heat in the home, the heat source must be kept going in order to avoid a fire hazard.
You should also consider that since most heaters are outside, there is a potential that there will be either sand or grit from the construction site that might be deposited into the firebox, making it impossible to use. This would also be a safety hazard since it would be difficult or impossible to extinguish. It is important to consider installing a gas water heater that is a structure to be able to withstand the build up of dirt and other such debris.
Finally, because there is no way to get rid of the debris, there is also the danger of electrocution that would damage the unit. so installation on a structure is the safest choice.
If you really want to save money and the health of your family, a natural gas heat source is the best option. for your heating and cooling needs.