On-demand water heaters aren’t new, but modern tankless systems have become a popular home improvement. The latest innovations have delivered higher flow rates, greater energy efficiency, and longer equipment lifespans. How practical is it to convert from a standard water heater, such as a 40-gallon tank, to this newer approach? Let’s explore everything you need to know before making a decision for your home in San Jose, CA.
Does a Tankless Water Heater Provide Enough Hot Water?
The average water heater tank size in the United States is between 40 and 50 gallons. If a 40-gallon tank is enough for your household, your hot water needs are modest. The industry measures on-demand systems in flow rate or gallons per minute (GPM). The approximate equivalent of a 40-gallon tank is a 5-GPM tankless water heater. Some on-demand water heaters on the market provide 10 GPM and more.
Energy Efficiency
Tank water heaters store and heat water in a tank in advance. Tankless water heaters, on the other hand, heat water upon request. That approach is inherently more efficient, but how much more efficient is it? The answer depends on how much hot water the household uses. The U.S. Department of Energy (DOE) estimates 24% to 34% improved energy efficiency for the average household.
The average in this case is using 41 gallons of hot water or less daily. The energy savings decrease the more water you use. They can fall to as low as 8% to 14% at around 86 gallons daily. But that’s still a significant reduction.
Electric or Fuel
About 40% of Americans have electric water heaters, while the other 60% have fuel-burning models. Electric water heaters are less expensive and highly efficient. The downside to them is the cost of electricity, which adds up over the system’s life. If you have an electric water heater, consider switching to a gas-powered model. You’ll save money even if you stick with a tank water heater. You’ll save even more money if you choose a tankless water heater instead.
There are oil-fired water heaters, but they’re not common in California. Most homes in the state have gas water heaters. Natural gas is convenient and relatively cheap, and most homes have access. If you can’t use natural gas, you can opt for liquid propane (LP) and use a tank on your property to store the LP that will be delivered.
Compatibility and Conversion
Most homes in the U.S. already have the electrical and plumbing hookups for a tank water heater. You may not have them for a tankless water heater. If not, you’ll require conversion. This is usually worth it in the end, but it can make budgeting more difficult now. Our plumbing services team can help you understand the pros and cons.
Electrical System Considerations
All tankless water heaters require electricity. That’s true of fuel-burning models, too, and it is becoming more common with tank water heaters as well. On-demand systems have electric igniters rather than pilot lights. They also need electricity for displays, indicator lights, smart features, and so forth.
Most modern electrical codes require a 240-outlet and a dedicated circuit for a water heater. You probably already have that unless you live in an older home. If you don’t have those features, upgrades will be necessary if you go tankless. The building code may require it even if you don’t. If there’s no ground-fault circuit interrupter (GFCI), your electrician will have to add that as well.
The other consideration with on-demand systems is that they require a greater burst of electricity due to the way they function. For homes built before 2023, you may need whole-house surge protection. Your electrician may recommend the upgrade even if it’s not a code requirement. If you have an outdated electrical panel, or it lacks the necessary amp coverage, you may need to replace it.
Plumbing System Considerations
Plumbing codes have changed over the years. Modern homes will generally have everything a tankless system needs for water lines. Homeowners with older households may need to increase the size of some pipes and add pipes and valves. If you need such upgrades, you may be able to circumvent the need for this equipment with an outdoor installation. Outside installations are an option in regions with mild winters.
Even if you already have a gas water heater, your home may need upgrades. Tankless water heaters often require a larger diameter gas line than their tank counterparts. Your plumber may need to upgrade the exhaust system as well. That includes installing a stainless-steel exhaust flue and vent pipes. The plumber may also need to add a direct drip leg to the gas line.
Sizing a Tankless Water Heater
Sizing a tank water heater is relatively simple. You get an initial estimate based on the number of people in the home. The plumber can then adjust it as needed for certain appliances and the number of bathrooms.
Tankless water heating sizing is more involved. Every fixture and water-using appliance has a flow rate requirement. A plumber must add the flow rate for every fixture and appliance you want to use simultaneously. In other words, the water heater must deliver a flow rate that meets or exceeds your household’s peak demand. If it doesn’t, you’ll experience low hot water pressure and other issues.
Your installer must also factor in temperature rise, the difference between the temperature of your water supply and the temperature you desire for your hot water. Manufacturers rate their on-demand systems for flow rate at a particular rise. If your rise is above or below that number, your plumber will adjust for it.
Another consideration is oversizing your tankless water heater installation. Wouldn’t it be nice if you had added capacity when hosting guests for the holidays? Oversizing isn’t practical with tank systems. That’s because you’d pay for that added capacity day in and day out. That isn’t the case with tankless systems. You’d pay initially and when you used the added capacity. It wouldn’t cost you anything extra the rest of the time.
Hard Water
Many homes have hard water. That means that it has a high content of calcium and magnesium that can become limescale. Limescale is bad for all water heaters. It decreases efficiency, increases operating costs, and may lead to premature component and system failure. Still, traditional water heaters deal with it better due to their tanks and sacrificial anode rods.
If you have moderately hard water, consider adding an anti-scale device to your tankless water heater. It will prevent scale from forming in the system. If you have very hard water, consider a whole-house water softener instead. It will protect not only your water heater but also your pipes, fixtures, and other appliances.
Tankless Water Heater Installation in San Jose and the Silicon Valley
Plumbtree Plumbing & Rooter is a Diamond Certified plumbing contractor based in San Jose, CA. Our licensed plumbers travel throughout Silicon Valley. We install all types of electric and fuel-burning tank and tankless water heaters. You can also count on us for plumbing inspections, maintenance, upgrades, and emergency repairs.
To schedule an installation consultation or get answers to your questions about our products and services, contact us at Plumbtree Plumbing & Rooter today.
