Tankless Water Heater?

Question

How does a tankless water heater work? Can it be used for multiple items at the same time? (ie. laundry, dishwashing, 2 showers). Do you install one unit that heats water to every appliance in the house? How long do they generally last? What should I expect cost-wise?

Answer 1

They work on the principal of heating what you will use. When the unit calls for hot water, the burner lights and heats the water that go through coils, cold water in - hot water out.

If you have high water use (2 or more people) don't install a tankless. The demand will never keep up. There is a common fallacy with tankless heaters being an endless supply. Sure you are only heating the water when you need it, but if you are doing laundry and washing dishes at the same time, it's not for you and will cost more in the long run.

Cost wise, they are 2-3 time more than conventional tank heaters and cost more to install, especially if you get a plumber not familiar with a tankless. Additionally, you will find that most plumbers are not in agreement with the "endless" theory. Hope this helps.

Answer 2

Cost to purchase a unit will vary from about $600 to $1200. I have one in my house a 3 bed 2 bath with 3 kids and 2 adults. Never had an issue with hot water yet (1.5 years). In a larger house you may want to install 2 units as it can take a bit of time for the water to arrive at a distant faucet as these systems do not have a recirculation loop. Check on the web but I have seen estimates that claim you will save about 30% of your energy bill So in California a typical energy bill is $250 to $300 per month in the winter so you save $75 to $90 per month so the pay back time is quicker than you might think. Be sure to get a unit that will heat water to 120 deg F and at a minimum 110F.

Oh the way it works is that it is a very efficient heat exchanger and only heats the water you have demand for. Savings result because you arent constantly heating a big tank of water all day when noone is using it.

Answer 3

1) They work with a natural gas burner and a water coil right in the heat area. They have a flow sensor, that turns the burner on when ever you turn the hot water on, and off when you turn off. The water is heated in the coil as it flows to you; there is no stored reserve of heated water.

2) Capacity depends on what you install, just as a tank type heater does. Buy a large capacity tankless and it can supply several fixtures. Buy a small one, and it can't keep up. Capacity is a specification provided with every model.

3) Life is better than tank water heaters, but varies with the water quality it works in. It's a good idea to have particle filters in your feed line.

4) Cost depends on model and installation issues, of course. Basic models equivalent to a 30 gal tank capacity have a street price (like at Lowe's) of around $600 for the unit. Installation requires modification of water, gas and flue connections (assuming you are using your old tank location) and also requires an electrical connection. Installation cost would vary widely with the conditions.

Answer 4

They heat water on demand only. When you turn a faucet on and water flow is detected the burner kicks in and the water is heated as it passes through a heat exchanger. One correctly sized water heater will take care of all your needs- showers, laundry, dishwasher. Newer models last up to 20 years and require very little maintenance which you can do yourself.

Answer 5

The cost is very high, rangers from $2,000 and up, depending on the size of the unit. It's one main unit and it delivers the hot water on demand. There is a heating element in the unit and that's what heats up the water. Supposedly it will last about 10-15 years, but heating element requires maintenance every 5.