COMPARE WATER HEATERS
When comparing hot water heaters, there are few things you need to keep an eye out. First of all, you need to check two important rating before you make your purchase. One of them is the energy factor (EF) and the other one is first-hour recovery (for storage tank heaters) or the flow rate (for tankless).
EF rating is the efficiency rating of your unit. Hence, understanding the EF rating is pretty easy - the higher the number, the more efficient the unit. Also, this helps interpreting the recovery time for the whole system. The higher the EF number, the more hot water you will receive in the first hour after you open the spigot. These changes when you are dealing with a tankless water heater. In the case of tankless water heater, you have to keep in mind that the lower groundwater temperature can cut the heater's flow rate by half. Therefore, when shopping for one, you have to make sure that the flow rate of the system is what you need based on the incoming winter water temperature.
TANKLESS HOT WATER HEATERS:
Tankless water heater, also known as instant water heaters are systems that heat water on demand, whenever needed. Instead of having a 40 to 50 gallon of hot water ready 24 hours a day, tankless water heating units only heat water whenever it’s needed. Hence there is no energy lost for keeping water hot all day long, even if it’s not being used. Instant hot water heaters come with a flow sensor that detects when the faucet is open. Once the sensor detects incoming cold water, it opens the valve for the gas valve and the burner fires up. Tankless hot water heaters have a specific temperature measuring unit that measures the temperature of the incoming water and calculates how quickly the water should flow past the burners. For example, if the incoming water temperature is 68 degrees F (usually summer), the heater will provide the maximum flow rate. But if the water is cold, as in 35 degrees, the heater will pull back the flow rate to almost 50 percent. You need to check with your local utility provider to find out the water temperature. The average price to get an instant water heater installed is about $1200, plus about $200 for a stainless vent.
Pros:
-Nothing beats a tankless heater for putting out lots of hot water—it never runs out.
-A tankless heater saves about 30 to 50 percent in energy costs over a conventional gas heater (minimum EF of .82 vs. .54 for conventional).
-A tankless heater usually a size of a suitcase, hence it can be virtually installed anywhere and won’t take up a lot of your valuable space.
Cons:
-With tankless heaters, there's a lag time of three to eight seconds to fire up the burners and heat the water to the set temperature.
-Installation can be a major project.
-Tankless heaters must be flushed annually with special chemicals to remove scale and maintain energy efficiency. You can easily do it yourself or hire a plumber (about $125).
What do you need to look for when buying-
You have to make sure to get the model with the highest EF and the best flow rate.
Can you do it yourself?
You can install it yourself—if you can run a new gas line, follow the venting installation instructions to the letter (and to your local code), install an electrical outlet, and reconfigure the water pipes. It's a big job.
So is this system the one you need?
If you want an endless supply of hot water for long showers or to fill a gazillion-gallon spa, this heater's for you. Just be aware that you may not be able to run several showers at the same time in winter. The payback on a professionally installed tankless heater is 16 to 22 years, or six years if you install it yourself.