Under sink water heater is a perfect option for those who have limited space either on their bathroom or kitchen. They are normally small in size and can be installed in a cramped place like under the sink. The main advantage of using under sink water heater is the compact feature which will make your kitchen and bathroom clutter free and well organized.
The first consideration before buying a under sink water heater is the space available. To accommodate the limited space, normally under sink water heater are designed in a small size. To give you a rough idea, a common 2KW water heater has a dimension of around 450H x 300W x 260D (mm) which is perfect to be installed under your sink.
The limited space also determines whether the under sink water heater will be powered by gas or electricity. Gas powered water heater normally needs a bigger space to accommodate the gas regulator and piping, and this type of water heater also needs proper ventilation for the gas to escape in case there is a leakage. Looking at this fact, the recommended under sink water heater to choose is the one powered by electricity.
As electrical under sink water heater may differ in size and capacity, you need to choose the power rating carefully. In general the bigger the power rating the bigger the capacity is, resulting in a faster heating time. Unless you are planning use under sink water heater to heat two faucets, there is no need to buy a big powered water heater. A 2KW water heater is normally adequate for a single point of use.
However if you are planning to use single under sink water heater to accommodate more than one faucet which probabilities to be ON at the same time is high, a bigger under sink water heater power rating of more than 3KW may be needed.
Another important factor in choosing the most appropriate under sink water heater is the temperature of the incoming water. The colder it is the bigger heater it needs. If you live in a colder place, it is better to invest on a bigger power under sink water heater. This is to accommodate the low incoming water temperature during the winter. However if the incoming water is already warmed by the public facilities, a normal capacity heater is more than enough.
An under sink water heater is normally free in maintenance, provided that the incoming water is free from dirt and have a low conductivity. The lower the conductivity the lesser mineral it contains which may corrode the system and creates encrustation inside the heater piping. Therefore depending on where you live it might be necessary to install a good water filter in the incoming pipe of your under sink water heater.
The life expectancy of a good under sink water heater can reach up to fifteen years depending on the usage and quality of the incoming water. However some small parts may tear after some time and need a regular replacement. If you can keep the under sink water heater away from rats and moisture, they will normally last more than 15 years.