Early water heaters all had tanks. Nowadays we can heat water without storing it, by using tankless water heaters.
You can install multiple tankless heaters at the fixtures (called point of use) or centrally to serve your entire house.
Three reasons to go tankless:
1. Tanked heaters use energy to maintain water storage temperature, even when not in use. This is essentially wasted heat. Having a tankless heater when your use is intermittent will save you energy, lowering your bills.
2. In order to decrease the amount of energy used and increase efficiency, new tanks require more insulation, making them bigger. With a tankless system, you get that space back.
3. If you’ve ever been the last person to take a shower, you know the frustration of having the water get colder as you use the last trickle of hot water. Depending on the size and type of tanked heater, it could take an hour or more to get the water hot enough for your bath. Tankless systems don’t have this problem. Water is heated as it flows through it so there’s no waiting.
Sizing your tankless heater
The benefits of a tankless water heater evaporate quickly if it’s sized incorrectly. Tankless heaters are sized according to maximum flow rates and temperature rise.
To get flow rate, add the flows of fixtures likely to run at the same time. Showers flow at approximately 3 gallons per minute (gpm), faucets at 1-2 gpm, washing machines at 2-3 gpm, dishwashers at 1-2 gpm. Check manufacturer information for accurate values.
The temperature rise is the difference between the temperature of incoming water and the desired hot water supply temperature. For safety, the supply temperature should not exceed 120oF (49oC) at the fixtures. The incoming water can be as low as 40oF (4oC). In that case, the heater would have to increase the temperature by 80oF (45°C).
Service requirements for installation
Since tankless heaters are instantaneous and must provide heat in a short time frame, they require larger electrical or gas services than tanked heaters, which heat the water more slowly.
If you’re replacing an electrical tanked water heater with a tankless device, you would need to upgrade the electrical service to the heater and possibly to your house. Replacing a gas-fired tank heater with tankless may require a gas supply upgrade as well as changes to the venting system.
For both gas and electric, the water pipe measurements are the same since they are both sized to provide hot water to the same home’s fixtures.
Even with its numerous advantages, making the decision to install a tankless heater requires thought and professional analysis.
Call us today to talk about your options for a tankless heater in your home.