Whats your guys opinions of them. I havent been able to find any real person thoughts on them, I only run across whats advertised by the company....The cheapest one I found was just under 500 bucks for what was equivalent to a 40 gallon tanked heater. Is that money justified with these things.... Any of you guys running these, if so can you see a difference on your bill???
I do not have one in my home, but I have installed them.
You must size it properly. That means pay attention to the temperature rise at the specified flow rate. Also note that some manufacturers claim a 40* rise at a much higher flow than the more meaningful 77*F rise flow rates. The higher flow numbers are usually in the bigger type on the box.
There is also a minimum flow rate that activates the burner, and another flow rate needed to keep the burner lit.
While showerheads (singly) and faucets are federally restricted to 2.5 GPM, a tub fixture is not. Tub faucet flow rates (and multiple showerhead installations) can easily exceed 6 GPM. This info is located in plumbing fixture spec catalogs. This means you could easily have warm, not hot, water for your bathtub/whirlpool/body spray. Several models can have two or more tankless units run in series to feed hungry tubs and whirlpools.
Newer top of the line water heaters with lots of tank insulation don't lose much heat. Using a PVC vented water heater tank eliminates most of the flue losses associated with a standard metal flue unit. Adding insulation to the tank will reduce energy consumption. I turned the burner off on mine on a 4 day trip, and the burner did not ignite when I turned the thermostat back to "normal".
People with multiple water heaters may see more of a savings through eliminating traditional water heaters.
Those that buy a tankless water heater and enjoy the "limitless hot water" will realize an energy consumption increase when their hot water usage habits change.
I doubt the energy savings claims made by tankless manufacturers. It is very easy for increased fuel usage to offset the savings gained from the elimination of standby losses.
The typical residential 40 or 50 gallon water heater has a 40k btu gas burner, while tankless units have a 25k to 199k btu burner. Remember, both appliances need combustion air (about 1 cubic foot of gas needs about 13 cubic feet of air to support combustion, and a cubic foot of gas has about 1000 btu's). Using combustion air from within the home creates drafts and will cost you money to send heated indoor air up the chimney (obviously those that can install their water heaters outside don't have this problem).
Tankless water heaters have a nice copper coil in them. Wait until the theives figure that one out... $1000.00+ heater turned to scrap for maybe $10 in copper....
Low end tankless water heaters will not have a modulating gas valve, but will be either single or two stage. Two stage units can supply warm (not hot) water easily if the flow threshold is just under the second stage level. This was common with the older Bosch $500 retail priced units.
Newer models require stainless steel venting material. This is serious money if you need it. Expect to pay in excess of $40 per lineal foot of straight pipe at retail pricing. Fittings such as elbows are also big bucks.
They can offer: longer service life, virtually unlimited hot water and a space savings in your home.
A traditional tank style water heater may have less of an environmental impact over the life cycle of the equipment (easier to make, more readily recycled).
