Most tankless water heaters in Hampton Roads get installed on the day the old tank fails, in a garage that has just taken on forty gallons of water. That is not the best moment to weigh the decision. This post is for the homeowner who would rather think it through beforehand. It explains how a tankless heater works, what it saves and costs, and why the form suits a coastal home. It closes with the two questions about gas and electricity that decide how simple the switch will be.
How a tankless heater works
A conventional water heater keeps 40 or 50 gallons hot around the clock, reheating the tank every time it cools. A tankless heater holds no water at all, and when a hot tap opens, water flows through the unit, a gas burner or electric element heats it on the way, and it arrives at the tap a few seconds later; when the tap closes, the unit shuts off. The heater works only while hot water is being used, which is where the savings come from, and it never runs out, because it heats a flow rather than emptying a tank.
What it saves
The Department of Energy estimates that for homes using about 41 gallons of hot water a day or less, a tankless heater is 24 to 34 percent more energy efficient than a conventional storage tank, and 8 to 14 percent more efficient for homes using around 86 gallons a day. The savings come from eliminating standby loss, the heat a tank gives off to the garage around it day and night. The second saving is lifespan, since a tankless unit lasts about 20 years with maintenance, roughly twice a tank heater’s 8 to 12, so one unit serves the period in which a tank would be replaced twice. The third is space, since a tankless unit is about the size of a carry-on suitcase and hangs on a wall.
Why the form suits a coastal home
That last point matters more here than most places. In Hampton Roads, water heaters live in garages and crawl spaces, and both flood. A tank heater on a garage floor takes water in a nor’easter, and a tank that has stood in saltwater is a replacement. A tankless unit mounts on the wall, above the level that storm water usually reaches, and it can be placed higher still when the installation is planned with flooding in mind. The wall mount also frees the floor space a tank occupied, which in a garage that also holds the panel, the transfer switch, and everything else is not a small thing. For outdoor-mounted units, salt air is the consideration, and a unit rated for coastal installation or an indoor mount is the answer.
What it costs, and the winter question
A tankless heater costs more to buy and install than a tank heater, and the gap is largest when the switch requires new gas piping or venting. The premium is recovered through the lower operating cost and the longer life, and financing is available for the installation. One limitation belongs here: a tankless unit’s flow rate depends on how much it has to raise the water’s temperature, and incoming water in a Hampton Roads winter arrives colder than in summer. A unit sized for a July shower may run short when two showers and the dishwasher run together on a January morning, so the unit is sized for the cold-water season and the household’s peak use, and that sizing is part of the estimate.
The two questions that decide how simple the switch is
The first is gas. A gas tankless heater draws several times the gas a tank heater does while it runs, and it often needs a larger gas line and its own venting. Homes with natural gas service can usually be piped for it, and our gas line team does that work. The second is electricity, for homes without gas. An electric tankless heater draws a large amount of current when it fires, and it frequently needs new circuits and sometimes a panel with more capacity than a 100-amp service offers. Because Russell’s American Mechanical handles the electrical work as well as the plumbing, that evaluation happens on the same visit, and a panel upgrade, if one is needed, is quoted alongside the heater rather than discovered afterward.
When a tank still makes sense
Tankless is not the right answer for every home, and a technician should say so. A household with modest hot water use, a tank in a dry interior closet, and no gas service may find the premium hard to justify. A home with hard well water needs treatment before a tankless unit, since scale collects in the heat exchanger faster than in a tank, and our water filtration team can say whether that applies. A homeowner planning to sell within a few years may not recover the difference. In those cases a new tank heater, installed well, is the sensible choice.
Maintenance
A tankless heater asks for one thing a tank does not, which is a yearly flush with a descaling solution to clear minerals from the heat exchanger, along with a check of the inlet filter and the venting, and skipping it shortens the unit’s life and voids many warranties. Members of the Premium Home Care Agreement receive an annual plumbing inspection that covers the water heater, and our tankless water heater page describes the service.
Deciding before the tank decides for you
Russell’s American Mechanical has served Hampton Roads since 1977. If your tank heater is past ten years, or sits in a garage that has flooded, schedule a consultation online, through the website chat, or by phone. The technician will measure the household’s peak hot water use, check the gas line or the panel, and lay out the tankless and tank options side by side.