All about the Noritz Model 531 tankless hot water heater.
The Noritz Model 631 is an ideal water heater for a point of use water heater installation. It comes in two types, indoor and outdoor. The outdoor unit is nice if you have a bathroom, kitchen, or laundry room with an exterior wall. That way you don’t have to worry about venting it.
According to the owners manual, the 632 will produce 3.8 gallons per minute with a temperature rise of 60 degrees, 4.6 gallons per minute with a 50 degree rise, and 5.7 gallons per minute with a 40 degree temperature rise.
For bathrooms, I would think that a temperature of 105 to 110 degrees would be sufficient. 110 degrees is hot for a shower, and you probably don’t have a dishwasher in your bathroom.
You need to know what your incoming water temperature is at the coldest time of year to determine what temperature rise you will require. My water temperature doesn’t go below about 50 degrees, so to get a nice 105 degree shower I would need a temperature rise of 55 degrees. So the Noritz 531 can easily supply over 4 gallons a minute in my situation.
Tankless Water Heater Savings
The big difference between tankless hot water heaters and tank type water heaters is the tank type water heater loses a substantial amount of heat that leaks out of the tank full of hot water. Since the tankless water heater does not use any energy unless hot water is being used it’s more efficient.
Oddly enough, the less hot water you use the higher percentage of savings you will see. Think about it, if you never use any hot water your energy consumption from your tankless water heater will be zero, and the tank type heater will have used a considerable amount of energy keeping the hot water in the tank hot.
You can figure with a tankless heater you can probably save 15 to 20 percent of your total hot water heating energy compared to a storage water heater. Typically $5 to $10 dollars a month. That would however, be for an entire home, not a single installation for a point of use system.
Tankless Water Heater Costs
I looked around on the internet in the usual places, and the Model 531 and its variations are available for less than $700. That is of course, just the cost of the heater and does not include the installation cost. Installation could cost over $1000 so get a couple of quotes from installers. You may have to re-route gas lines or something which isn’t inexpensive.
Another often overlooked tankless water heater cost is that you have to pay for heating water, and if you used to run out, and you purchases a tankless water heater so you wouldn’t run out, you may see a substantial increase in your water heating bill as a result of just plain old using a lot more hot water.
Tankless water heater costs can be reduced via the tax incentives now being offered. Apparently you can get up to $1,500 in tax credits, but I did not check out the details.
Tankless Water Heater Operation
There is a little more to operating a tankless water heater than with a traditional storage tank type water heater. The tank heater just sits there and does its job. In some cases homeowners flush the water heater to get rid of accumulations of sediment. Most people don’t do that. There are areas where the mineral content is quite high and in those areas its much more of a problem and you may need to flush your water heater on a yearly basis.
Tankless water heaters don’t like hard water either. Quoting from the owner’s manual for the Noritz Model 0531 series… “If the water supply is in excess of 12 grains per gallon (200 mg/L) of hardness, acidic or otherwise impure, treat the water with approved methods in order to ensure full warranty coverage.”
The output temperature of the hot water can be set to several temperatures ranging from 120 degrees to 160 degrees, and you may want to change the settings once in a while. For instance, you may need to raise the temperature in the winter and lower it in the summer. Or use a lower temperature for taking a shower and a higher one for the dishwasher.
Since the tankless water heater won’t turn on unless you are using at least one half gallon per minute, you won’t be able to get a “trickle” of hot water like you can with a tank water heater.
Tankless Water Heater Pump with a Noritz Tankless Water Heater
If the tankless water heater is located a long distance from the fixture (not a point of use system) you might want to consider using a tankless water heater pump with your new Noritz water heater. A tankless water heater pump, or demand system as it is more commonly called is a small pump that mounts under the fixture.
When you need hot water you push a button to start the pump, which pumps the hot water from the water heater to the fixture, while returning the cooled off hot water to the water heater through the cold water pipes. When the hot water reaches the pump it shuts off to prevent hot water from entering the cold water lines. When you open the tap you have nearly instant hot water.
You get your hot water faster and you don’t run any water down the drain. Some hot water demand systems are less than $200 and they typically use less than $2.00 per year in electricity making them and your hot water plumbing green.
Installing a Noritz tankless water heater and a hot water demand pump (tankless water heater pump) you will reduce your carbon footprint, save water and energy, and have more convenience all at the same time. Your hot water plumbing will be about as green as it can get. Demand hot water pumps are water conservation products. Especially if you are looking for a drought solution… it won’t stop the drought but it will help save water.
An even greener hot water plumbing system would be using the Noritz water heater with a point-of-use type of installation.