| Plan to purchase a tankless hot water heater? If | | | | Heating the water to full temperature requires |
| so, and if you aren’t familiar with how a | | | | that the cold water entering the heater travel all |
| tankless water heater operates, then there are | | | | the way through the heater. This will causes a |
| some things you should know about before you | | | | longer delay in getting the hot water to the |
| make that purchase. | | | | fixture, and results in running more water down |
| | | | | the drain while waiting than with a tank type |
| There are some big differences between the | | | | heater. |
| way tank type water heaters and tankless hot | | | | |
| water heaters interact with you the user as you | | | | An easy way to visualize the workings of a |
| operate your hot water system. With a tank | | | | tankless hot water heater is to picture a coil of |
| type hot water heater, when you turn on the | | | | copper pipe with a fire in the middle of it. As the |
| faucet and the hot water begins flowing through | | | | water travels through the tubing it absorbs heat |
| the hot water piping on its way to your faucet. | | | | from the flames and gets hotter and hotter. An |
| Since the piping is cold, it absorbs a portion of the | | | | electric heater is similar but instead of fire the |
| heat in the water, gradually warming up to the | | | | water flows over heating elements. |
| temperature of the water. | | | | |
| | | | | The maximum temperature of the water coming |
| This is why your hot water gradually goes from | | | | out of the water heater depends on flow rate |
| cold to hot if you leave your hand under the | | | | and what the incoming cold water temperature |
| running water. If your pipe run is short, the | | | | is. If your flow rate is too high, or your incoming |
| warm-up will be faster. The longer the pipes and | | | | cold water is too cold, you could exceed the |
| the heavier the piping material, the more gradual | | | | ability of the water heater to keep up. |
| will be the warm-up because the pipes will absorb | | | | To make things even more interesting, a tankless |
| more heat from the flowing water. | | | | hot water heater does not turn on until a |
| | | | | sufficient flow of water occurs in the hot water |
| Another significant variable in the warm-up time is | | | | pipe. Tankless hot water heaters typically |
| the velocity at which the water is traveling. The | | | | require between ½ gpm and ¾ gpm to turn |
| more quickly the water flows, the quicker the | | | | on. |
| warm-up. The higher the water velocity, the less | | | | |
| time it is exposed to the cold piping material. | | | | If you like to run the hot water tap full-on to get |
| The ambient temperature is also a big factor. If | | | | the hot water to the sink quickly, and then |
| your pipes are in the attic, and you are in | | | | throttling it back to a small stream while you |
| Bakersfield California, in mid summer, your pipes | | | | brush your teeth or wash your hands, then the |
| will be so warm that they won’t absorb any | | | | tankless water heater will change your behavior. |
| heat from the water. | | | | With a tankless water heater, if you reduce the |
| | | | | flow to a small stream, the water heater shuts |
| However, if you are in Truckee California in | | | | off, and cold water is on its way. No more using |
| January, your pipes will take far longer to warm | | | | a tiny trickle of hot water. |
| up, and with very long pipe runs with un-insulated | | | | |
| pipes, the high temperature might never be | | | | Tankless water heaters don’t work with |
| reached since the heat loss from the pipes to the | | | | most traditional water circulating systems. If the |
| surrounding air might be quite high. | | | | circulating pump produces enough flow to turn on |
| | | | | the water heater, it will cause the water heater |
| Within a short time the hot water the | | | | to run continuously until a safety mechanism |
| temperature stabilizes. Since you have a tank | | | | shuts it off. Most pumps don’t produce |
| filled with plenty of hot water that is at one | | | | enough flow to turn on the heater and will just |
| temperature, the temperature at your faucet | | | | circulate cold water. |
| vary very little, even when you change the flow | | | | |
| rate with the faucet. A tiny stream of water is | | | | There is a type of hot water pump that will work |
| basically the same temperature as with the | | | | with the tankless heaters. The pump will get the |
| faucet flowing at full stream. | | | | hot water to the fixture more quickly and without |
| | | | | running any water down the drain. You activate |
| Now let’s see how things change with a | | | | the pump with a push button and it automatically |
| tankless hot water heater. The previous | | | | turns off when the hot water reaches it. Two |
| warming-up factors apply and there are a few | | | | such pumps are the Metlund D’mand pump |
| more things that come into play. When you | | | | and the Chilipepper CP6000. Unfortunately they |
| turn on the hot water faucet there is no big tank | | | | don’t solve the other problems. |
| of hot water to start flowing to the fixture. | | | | |
| There is, however, a tankless heater full of cold | | | | Tankless water heaters do have their place. |
| water that begins passing through the hot water | | | | They do eliminate standby and they do provide |
| piping on its way to your sink. | | | | unlimited amounts of hot water. |
| | | | | |