People are under the impression that installing a tankless water heater is no different then that of the standard tank water heater. They could not be more wrong. There is a lot that goes into the installation of a tankless water heater and one must take everything into account. No matter what you do you should always be in the loop. You must follow all the instructions to the letter to make sure that your tankless water heater installation goes off with safety and security for your home.
The first order of business is to ensure that you are setting aside the necessary room for the tankless water heater. While it is true that they take up a lot less room then the tank style of water heater, there is still an issue of clearance that needs to be taken into account. For one thing the unit cannot be touching any of the walls in the area where you are putting it. The outside of the tankless water heater will become very hot and that will cause a serious problem if you have it touching any kind of flammable surface.
Then you need to make sure that you are switching to the same kind of system that you are removing. So if you are currently running a system that is gas then you need to ensure that you are replacing it with a gas tankless water heater. If you do not then this will require you to get into some kind of wiring or pipe running that is not for the common person. If you switch from one to the other of the same kind of tankless water heater installation then you will need to do nothing more then a couple of fittings or electrical connections.
Lastly you will need to take on the issue of venting. Unlike the tank water heater systems, tankless water heater systems require proper venting, which is very much like a clothes dryer. The heated air needs to escape some where and you will need to make sure that you have the unit properly vented to prevent any kind of build up of moist heated air. If this were to happen it can cause danger to the residents of the home and also cause the tankless water heater to stop working.