Top positive review
58 people found this helpful
Great Water Heater
on June 6, 2011
After installing a new high efficiency gas furnace and central air conditioner, I discovered that my 15 year old gas tank water heater was leaking. I had a choice: either replace the tank heater with new one for about $500.00 or upgrade to a new high efficiency gas tankless water heater.
I wanted to go with the tankless choice to provide endless hot water, but I was concerned with the potential difficulty of the installation. There were three key issues with replacing a tank heater with a tankless water heater.
First, I wanted to keep the new water heater in the same central basement location as the old tank water heater. That necessitated the choice of a "Condensing" type tankless water heater because they vent the exhaust through standard 3 inch PVC drain pipe (about $1 per foot). The non-condensing type tankless water heaters have a higher exhaust temperature and require very expensive stainless steel exhaust piping. This type of heater are usually mounted on an outside wall to shorten the exhaust pipe length. So, I chose the Rheem condensing tankless water heater, but I still needed to run two 25 foot runs of PVC pipe to feed the intake combustion air and to exhaust the combustion gases. Since I had just done the same procedure when I installed the 95% efficient gas furnace, I knew that it was time consuming, but within my abilities.
The next issue was the water pipe plumbing. I have done a little copper pipe plumbing in the past, it was functional but not pretty. So, I knew I could get the job done. The key problem was that the old tank water heater had the cold inlet and the hot outlet pipes at the top of the tank and the tankless heater needed the connections at the bottom. I would guess that they use the bottom connection to eliminate the chance of water leaking on top of the heater. The heater has a very sophisticated computer control system that needs to be protected. I mounted the new heater on a 2x4 frame with a OSB sheathing and ran the water pipes behind the mounting between the exposed stud wall of the mechanical room. This also helped free up room to run the PVC piping up and through the exposed floor trusses in the ceiling.
The last issue was the natural gas supply. This tankless water heater requires a much higher gas flow supply as compared to the tank water heater it replaced. While this might seem counter intuitive; why should a more efficient appliance take more fuel than a less efficient appliance? The reason is that the tankless water heater must heat the cold water very quickly, in just the few seconds that the water is running through the heater on its way the the hot water tap in your house. This water heater needs 199,900 BTU of natural gas. My old tank water heater used 40,000 BTU. This large increase required two changes in the gas supply. First, I had the replace the 1/2 inch black pipe gas line that fed the old tank water heater with a 3/4 inch supply line. Second, I need to have the gas utility company replace the 240,000 BTU meter outside my house with a upgraded 400,000 BTU meter to accommodate the nearly 200,000 BTU tankless water heater, the 115,000 furnace, the 66,000 gas range and the 20,000 gas clothes dryer. Some utilities will do this for free, but in my area (near Chicago) they charge $220.00 minus what they "calculate" as increased revenue from additional gas usage. While there will probably be less overall gas usage, the utility just looks at the difference in the old gas appliance and the new gas appliance. They estimate the new meter will cost about $160.00 net. I don't need to get this completed until the winter heating season when the furnace needs to be run at the same time as the water heater.
I didn't have much problem installing the Rheem tankless water heater. But it did take two solid days of work. I was able to perform the whole install without any assistance. I am a pretty good DIYer, but I don't think that it took any great skill, just a thorough reading of the instructions (the Rheem instructions are very good and they are available on their web site), a little YouTube How-To video research and a written plan including how to mount the heater and making the connections. I watched the set of videos on the Rheem web site. While they cover the older non-condensing type heaters, they are a good starting point.
I don't know what it would cost to have a professional install this heater, I would guess that it would take 6 to 8 hours of labor plus supplies. I spent about $350.00 on copper piping and fittings, gas pipe and fittings, PVC pipe and fittings and various miscellaneous supplies. Also, don't forget to budget in a set of "Service Valves". They cost about $80.00 to $150.00 per set. They are needed to provide an easy way to periodically flush the heater to clean any hard water deposits.
The Rheem tankless water heater worked great right from the initial start-up. My family enjoys the endless supply of hot water and we don't have to plan our showers around each others schedule or the the use of the clothes washer.