Just about everyone loves standing in the shower, basking in the warmth of hot water. Whether you spend your time daydreaming or methodically planning your day, a shower is a few minutes of calmness in what can otherwise be a modern hectic life. We take that time for granted, but that has not always been available to us. The modern tank water heater was invented in the late 19th century; prior to that most people heated water on the stove once a month or once a week to fill the family bathtub, and the last one in – typically the youngest – got some cold dirty water!
Water heaters are a quiet but key component of modern life, and as long as they work no one thinks about them. We just take them for granted. When they stop working… well… panic can set in. So best to think about water heaters before you need one.
Most people have and are familiar with the typical tank water heater. Another option is an on-demand heater. While tank heaters heat water to a preset temperature and then store it at that temperature for use when it is needed, on-demand heaters only heat water when it is being called for. They can certainly be more energy efficient, but be aware that in order to heat water when it is needed the appliance needs to be able to heat water quickly. That means much larger amounts of energy being consumed briefly, and since gas is likely your fuel of choice with an on-demand unit, you should be aware that most require at least a 3/4” gas line feeding it. Many people choose to replace their tank units with on-demand ones and then find out they need to upgrade their gas lines as well. Price just went up.
There are other options. Solar heating has been around for decades, but in the Northwest the direct heating of water by solar power tends to not be a very economical choice. Another technology, and one that is actually quite energy efficient, is a heat pump unit. Using electricity as an energy source and the same kind of technology seen in heating/cooling heat pumps and your refrigerator, heat pump water heaters capture heat from the surrounding air and concentrate it into your water. They are about 2 ½ times more efficient than an electric resistance water heater, but they should only be placed in certain locations. Ideally they are placed in an unconditioned area like an unheated garage, and they are specifically not recommended for placement inside the conditioned space of the home. Think about it… you are already spending money and energy to heat your home in the winter… paying to then take that heat out of the air and into your water is counterproductive and inefficient.
If you are tired of turning on your hot water and then waiting a minute or two for the cold to change to hot, you might want to consider a recirculating pump. When turned on they circulate hot water through your pipes and then back to the heater, making hot water available to you very quickly. They can actually save energy and a lot of water, but we do suggest you play a role in deciding when the pump is on. Just leaving it on 24 hours a day doesn’t make a lot of sense, but putting it on a timer or connecting it to the light switch in the bathroom might make good sense.
Safety is always a key issue in any home inspection and the temperature of your water can be an important consideration. We typically recommend water be set to deliver approximately 120 degree water at the tap. That is hot enough to actually feel quite hot while not so hot as to be unsafe. The hotter the water gets, the greater the risk of scalding, and young and old skin both scald quickly.
That said, one possible future change in the plumbing/mechanical code is an increase in the minimum heater settings to 140 degrees or more, with a tempering valve that then lowers the temperature to 120 degrees for actual use. Why? There are bacteria that are happy at 120 degrees but die at 140 degrees… such as the genus Legionella… a species of which can cause legionellosis (Legionnaires’ disease) and a flu-like illness called Pontiac fever. Does that mean you should rush to your heater and turn it up? No. The likelihood of a scalding accident is far greater than that of an aerosolized bacteria. But the next time you are replacing your heater, you might want to talk about this with your plumbing contractor.
And finally, as you plan for your next water heater and are getting caught up in all the technology available – from digital read-outs and direct internet connection and cell phone controls – consider whether you have power outages and/or back up sources of power. One of the beautiful things about a simple gas-fired tank heater with a pilot light is that it doesn’t notice or care if the electricity is out… and when your power/heat has been off for three days and the inside of your house is 50 degrees, the opportunity to take that hot shower is a real blessing. One we should not take for granted.