When it's time to add or replace a water heater in the home, there are several key factors which should be considered because water heaters vary in capacity, efficiency and cost.
The most commonly used units are storage water heaters.
These range in size from 20 to 80 gallons and are fueled by electricity, natural gas, oil, or propane.
When a faucet is turned on, hot water flows out from the top and cold water replaces it by flowing into the bottom.
For someone who is single, another option would be a demand water heater.
These do not contain a storage tank, but heat up water on demand.
Cold water passes through the unit where it is heated either through a gas burner or electric element.
However, they have a limited flow rate which is between two to four gallons a minute.
This can be a problem when hot water is being required from more than one source at a time.
Determine Capacity In order to choose a unit that has the correct capacity for your needs, calculate the First Hour Rating (FHR) and compare it to the FHR on the Energy Guide label.
The first hour rating is the amount of hot water that is produced when demand is made on a fully heated tank of water.
You can make a calculation by estimating the amount of water that is used by your household at its peak time.
Determine Efficiency Each unit should have an Energy Factor (EF) listed in its reference material which shows the energy efficiency of the unit.
The EF is determined by recovery efficiency, standby loss and cycling loss.
More efficient units will have a higher EF rating.
You will also want to only consider tanks which have at least 1.
5 inches of foam insulation.
Comparing Cost Total cost of a unit should be calculated based on the lifetime maintenance and operating cost, as well as the actual unit cost.
The rule of thumb is that heating units with a longer warranty will usually have a higher price, so a longer warranty may not necessarily be the best choice.
Bottom line is to calculate the overall expense of that unit based on the approximate length of its service time.
The most commonly used units are storage water heaters.
These range in size from 20 to 80 gallons and are fueled by electricity, natural gas, oil, or propane.
When a faucet is turned on, hot water flows out from the top and cold water replaces it by flowing into the bottom.
For someone who is single, another option would be a demand water heater.
These do not contain a storage tank, but heat up water on demand.
Cold water passes through the unit where it is heated either through a gas burner or electric element.
However, they have a limited flow rate which is between two to four gallons a minute.
This can be a problem when hot water is being required from more than one source at a time.
Determine Capacity In order to choose a unit that has the correct capacity for your needs, calculate the First Hour Rating (FHR) and compare it to the FHR on the Energy Guide label.
The first hour rating is the amount of hot water that is produced when demand is made on a fully heated tank of water.
You can make a calculation by estimating the amount of water that is used by your household at its peak time.
Determine Efficiency Each unit should have an Energy Factor (EF) listed in its reference material which shows the energy efficiency of the unit.
The EF is determined by recovery efficiency, standby loss and cycling loss.
More efficient units will have a higher EF rating.
You will also want to only consider tanks which have at least 1.
5 inches of foam insulation.
Comparing Cost Total cost of a unit should be calculated based on the lifetime maintenance and operating cost, as well as the actual unit cost.
The rule of thumb is that heating units with a longer warranty will usually have a higher price, so a longer warranty may not necessarily be the best choice.
Bottom line is to calculate the overall expense of that unit based on the approximate length of its service time.
Source...