Tankless Water Heater Install

[MarkCO]

I've done 3 fires caused by standard water heaters, and a dozen caused by Tankless. When you run the math, in most cases, they are not worth the trouble. A good commercial high efficiency water heater will cost more, but the fuel costs will be less in the long run. For an average family in a normal sized home, a 90% to 96% efficient tank commercial grade water heater will cost the least over it's lifetime. I have an AOSmith Vertex (only HE choice when we built the house) and we never run out of hot water, but there are now others on the market as well. I have about 50 failed water heaters in my shop at any one time, so I see a lot of them.

You do NOT want your water heater set less than about 120F. Read up on Legionnaires disease before you go telling people to turn their water heaters down to 100F.

[dodgefreak8]

I've done 3 fires caused by standard water heaters, and a dozen caused by Tankless. When you run the math, in most cases, they are not worth the trouble. A good commercial high efficiency water heater will cost more, but the fuel costs will be less in the long run. For an average family in a normal sized home, a 90% to 96% efficient tank commercial grade water heater will cost the least over it's lifetime. I have an AOSmith Vertex (only HE choice when we built the house) and we never run out of hot water, but there are now others on the market as well. I have about 50 failed water heaters in my shop at any one time, so I see a lot of them.

You do NOT want your water heater set less than about 120F. Read up on Legionnaires disease before you go telling people to turn their water heaters down to 100F.

Legionnaires isn't "generally" considered a threat in a domestic drinking supply. It is more prevalent in situations such as cooling towers etc where open atmosphere is in contact with recycled water. If you are worried about legionnaires than simply adding cold water to the 120* hot water in a standard system to make 102* water would be just a much a threat to getting the disease.

Tankless water heaters are designed to run at temps around 105*. That is where the energy savings come from and the fact that you aren't maintaining 50 gals of water while not in use. The downsides to tankless are 1) you rarely recoup your installation costs in savings before you have to pay for repair parts. There are A TON of moving and expensive parts in a tankless heater. Also there is maintenance that should be done annually like descaling the heat exchanger. 2) the heater SHOULD give you whatever temp you ask of it but at a cost of flow. Internal valves reduce the flow through the heater in an attempt to reach the desired setting. 3) the savings calculations the manufacturers publish are given in an optimum environment with warmer incoming water temps and minimal usage. I've been a licensed plumber for over 10 years and I won't put one in my own home. There are better choices out there and better ways to improve efficiency within your home. All that being said, a lot of people enjoy them and in some cases like the OP where there are only a couple people in the home and minimal usage they are better than say a 50gal electric WH. But that depends on the cost of natural gas/propane at the time.