There are a couple of reasons why your hot water heater would groan. The valves may not be opened correctly. Or there could be a build up of dirt on the bottom of the tank. Clean out the sediment by letting the water run out until it is clear and this should help.
It is a water heater, not a hot water heater. There would be little point in using a hot water heater. I assume that is your point.
form_title= Tankless Hot Water Heater form_header= Save money with a tankless hot water heater. Do you need to remove an old water heater?*= () Yes () No Do you want an energy efficient water heater?*= () Yes () No Where will you be installing the hot water heater?*= _ 
THERE IS NO SUCH THING AS A HOT WATER HEATER.
It's called water heater. There isn't a reason to heat hot water
It's because "hot-water" is a compound adjective, modifying "heater". It's not for heating water, it's for heating a house with hot water. There are many types of heaters that heat water, but only a hot-water heater is used for providing heated water for domestic use. A hydronic boiler also heats water, but it's only for use in radiators.The name "Hot Water Heater" is completely wrong for any use. There is no need to heat hot water. IT has always been "water heater". The term hot water heater has just been used for years because people don't realize the difference. It has always been WATER HEATER.The first answer is jibberish and makes no practical sense at all.
new boiler and hot water heater
form_title= Electric Hot Water Heater form_header= Install an electric hot water heater. Is your current water heater electric?*= () Yes () No How old is your home?*= _  What is your current monthly electric bill?*= _ 
Hot water in homes is produced by a device called a water heater. A water heater can be compared to a pot of boiling water. The enclosure keeps water hot throughout the day so that when the faucet is turned on, there will be an immediate flow of hot water. The people who have hot water have invested in a water heater.
The plumbing in my house needs replacing. Which is the best hot water heater on the market?
If the tub is not getting hot water the issue is probably with the hot water heater. The hot water heater may have tripped a breaker or the pilot light went out.
Because hot water heater breaker has tripped, or hot water heater has failed.
When you want to know when your hot water heater is broken, simply run your faucet and test the water. If it's cold, the heater is broken.