How to Choose an Under-Sink Water Heater
An under-sink water heater can save water and energy by bringing hot water closer to the point of use. This eliminates the annoyance of having to wait for hot water while it travels long distances in your house’s copper pipes.
A tank-type heater has a large insulated storage tank that holds hot water until it’s needed. Water enters the tank through a dip tube and passes by an adjustable thermostat and a pressure relief valve.
1. Energy Efficiency
Whether you are replacing your existing water heater or choosing one for a new home, consider the energy efficiency of each model you’re considering. Especially if you live in an area with high electricity costs, the right water heater can reduce your utility bills by eliminating waste.
Storage water heaters—which range in size from 20 to 80 gallons and are fueled by electricity, natural gas, propane or oil—warm water in an insulated tank until you turn on a hot-water tap. Then the heated water exits the tap and cold water flows into the tank to replace it. The energy factor (EF) of a storage water heater measures the amount of fuel or electricity it takes to heat the water to its rated temperature.
The most energy efficient model of a demand or instantaneous water heater may be the best choice for households that can dramatically reduce their hot-water use through water conservation (see “Conserve Water”) or by staging multiple uses. Look for models with modulating temperature controls to further reduce energy consumption. In addition, choose a gas-fired unit with either sealed combustion or power venting. Sealed combustion units use a two-pipe system to completely separate combustion air from house air. Power-vented units use a fan to assist in exhausting combustion gases.
Another option is a point-of-use water heater, which heats only the water that you need at any given time. These devices eliminate the waste associated with running a full load of hot water to and from a conventional whole-house water heater. However, point-of-use models don’t always provide enough hot water for large families and require a rethinking of your plumbing systems, including a return line, to prevent scalding.
2. Size
The size of your water heater is a key factor in meeting your household’s hot water needs. If it is too small, you will run out of hot water during peak times of use. If it Kitchen instant water heater is too large, you’ll spend money heating water that you don’t use.
Ideally, your water heater should have a First Hour Rating (FHR) that exceeds the total consumption of your household during its busiest hour of usage. Calculating the FHR of your current unit is easy by looking at the EnergyGuide label located on the unit.
A family of three will require a 50 – 60 gallon tank, while a two person household may be able to get by with a 30 gallon model. These sizes are only a rough estimate as the amount of hot water you consume will depend on your personal habits.
If you’re considering a tankless model, the sizing process is slightly different. You need to determine the maximum flow rate of each appliance and sink, as well as their corresponding temperature rise requirement. Using this information, you can calculate the FHR rating of your home and select the ideal model for your household. The free Pro-Size sizing and product selection tool is available to help you with this process from A. O. Smith.
3. Water Heater Type
Most kitchen water heaters are electric, but you’ll also find models that operate on natural gas or propane. Choose the one that matches your available fuel source and fits with your home’s existing plumbing.
The tank-style under sink water heater (also known as point-of-use or instantaneous heating) is smaller than whole-house models and sits beneath a sink. It preheats a set amount of water and then turns on when you need hot water. These units often run on 120 volts and can be plug-in or hardwired in place.
If you’re a frequent cook who needs a constant supply of hot water, this type of under-sink unit might work best for you. It’s small enough to fit under a sink and comes with a stainless-steel faucet that delivers up to three gallons per minute.
On the other hand, a tankless on-demand water heater heats water as it flows through your pipes, providing an endless supply of hot water. It uses less energy than a conventional tank model but may require more upfront investment.
4. Installation
The installation of a kitchen water heater should be done by a licensed plumber to ensure safety, avoid costly mistakes, and to comply with state regulations. Before beginning, check the manufacturer’s instructions and clear the area to prevent interference with the plumbing electric tankless boiler and electrical connections. The location must also be free from flammable materials and allow adequate ventilation.
Mini tank water heaters should be mounted close to the faucet they will serve. This helps to reduce energy consumption because the device will only work when water flows through it. It’s also important to make sure that the temperature of the incoming water is appropriate for the sink.
It’s essential to follow the water heater manufacturer’s instructions for securing it to the wall and connecting the hot and cold water lines. It’s also advisable to shut off the main water supply to avoid any leakage during the process.
It’s recommended to use pipe joint compound or plumber’s tape on the threaded connections to ensure they are watertight. Lastly, check that the combustion vent is properly installed to protect against carbon monoxide poisoning and other dangerous gasses. It’s worth mentioning that the installation of a point-of-use kitchen instant hot water system may be a better option for some homes. This method of heating provides quick, constant, and reliable hot water and can be cheaper in the long run compared to traditional tanks.
