Tankless water heaters are commonly found in European and Asian homes where space is a premium. However, tankless water heaters are quickly becoming a popular choice in new and remodeled homes especially in the Bay Area. I had always wanted to install a tankless water heater in my home just to learn how they work and perform. Finally, the day arrived when my tank water heater had broken. Instead of replacing my tank water heater, I decided to convert to a tankless water heater.
Rinnai V Series HE Tankless Hot Water Heater: Outdoor Installation
What are the advantages and disadvantages of a tankless water heater?
There are many ADVANTAGES to a tankless water heater that I was excited about.
- Endless supply of hot water. No more having to wait 30 minutes between showers between my wife and me.
- Minimal space needed. The closet dedicated for a tank water heater now gets repurposed to a much-needed laundry room or pantry.
- Energy used only when in use. A tankless water heater only uses energy when in use, unlike a tank water heater which heats up periodically when the water cools off inside.
- Longer warranty. A tankless water heater can last up to 10 years and typically have longer manufacturer’s warranty, while a tank water heater typically lasts 6 years.
- Outdoor installation. Some tankless water heaters can be installed outdoors taking up no space inside the home.
Some DISADVANTAGES of a tankless water heater would be:
- Expensive. A tankless water heater (8.0 gallons/minute) by Rinnai RUC80iN Ultra Series Natural Gas Tankless Water Heater, Concentric or Twin Pipe Installation costs about $1,300. While a 40-gallon tank water heater by Bradford White 40 Gallon Natural Gas Water Heater RG240T6N costs about $700.
- Installation costs. If you have a gas water heater, the gas pipe requires 3/4″ to 1.0″ diameter and proper air venting. If you have an electric water heater, the electric power requires 240 volts drawing 115 amps.
- Soft water only. If your home has hard water, a water softener system will need to be installed (costs about $1,300). Tankless water heater malfunctions caused by hard water such as lime and mineral build-up in the pipes or heating system are not covered by the manufacturer’s warranty.
- Power outage cold showers. The water flow sensor needs electricity to detect water flow which ignites the burner to heat the water inside a tankless water heater. You will have to take a cold shower during power outages with a tankless water heater.
- 30-seconds of cold before hot water. It takes about 30-seconds for my tankless water heater to heat the water so my wife and I have to remember to turn on the shower before getting in.
How much does it cost to replace a hot water heater with a tankless?
My father’s water heater had finally broken down after 12 years of good service. The contractor not only replaced the old unit with a much better water heater but also added straps around the water heater for earthquake safety, ground wire around the copper pipes, and drain pipe with a drip pan. I immediately saved this contractor’s number to my phonebook. A few months later, I had him install a tankless water heater inside my own home.
The cost of replacing a traditional tank water heater is about $1,700 (labor + tank). The cost of switching to a tankless water heater is about $4,000 (labor + tank). Switching from a traditional tank water heater to a tankless water heater requires some modifications of the plumbing and space. My contractor provided all the following services with his estimate.
- The contractor increased my gas pipe size from 1/2″ to 3/4″ diameter.
- The contractor replaced the air vent on my roof because the original vent was not installed to code.
- The contractor installed valves to my hot and cold water pipes.
- My old tank water heater was placed on a pedestal. We were very happy to get rid of it and reclaim that space in our laundry room. My wife and I did this work ourselves so we told the contractor to exclude it from his cost.
Please note that the cost of replacing a broken tankless water heater could be cheaper if all the plumbing and air vent work is already in place.
Which is better gas or electric tankless water heater?
Most traditional 40-gallon tank water heaters run on natural gas. Therefore getting a tankless water heater that also runs on natural gas would be the most logical solution in terms of minimizing costs. However, if the space for the water heater has no ventilation and your electric panel can dedicate circuit breakers for about 115 amps, an electric tankless water heater could be a viable option.
- A natural gas tankless water heater requires the gas pipe size to be 3/4″ to 1.0″ diameter. It requires ventilation for combustion and exhaust.
- An electric tankless water heater requires 240 volts drawing about 115 amps. However, ventilation not necessary.
Do tankless water heaters run out of hot water?
A major advantage of getting a tankless water heater is that it will provide unlimited hot water. Just make sure to invest in a properly sized tankless water heater in terms of Gallons Per Minute to ensure that your water fixture simultaneous usage can be accommodated for.
How big of a tankless hot water heater do I need?
Most water fixtures in your home will have a Gallons Per Minute (GPM) rating. This means how many gallons of water this fixture can fill in 1 minute. For example, my shower rates at 2.5 GPM which means its water flow rate can fill 2.5 gallons of water in 1 minute. Now when sizing for a tankless water heater, you need to think about how many of these water fixtures will be running simultaneously. You need to ask yourself some questions:
- Would you take a shower (1.75 GPM) while running the washing machine (2.5 GPM)? Therefore you need a size minimum of 4.25 GPM for a tankless water heater.
- Do my kids take a bath (4 GPM) while my wife runs the dishwasher (1.5 GPM)? Therefore you need a size minimum of 5.5 GPM for a tankless water heater.
In my two bathroom home, my tankless water heater rating is 3.35 GPM. I made sure to get water-efficient fixture showerheads (1.75 GPM each) and bathroom faucets (0.75 GPM each). Below is a chart that I created to help you properly size a tankless water heater for your home.
| Water Fixture | Gallons Per Minute (GPM) |
|---|---|
| Bathroom Faucet | 0.5 – 1.5 |
| Dishwasher | 1.0 – 1.5 |
| Kitchen Faucet | 1.0 – 2.0 |
| Shower | 1.5 – 3.0 |
| Toilet (Flush) | 1.5 – 2.5 (Gallons Per Flush) |
| Tub | 3.0 – 4.0 |
| Washing Machine (Clothes) | 1.5 – 3.0 |
How long do tankless water heaters last?
A traditional tank water heater typically lasts 10 years. A tankless water heater typically lasts 20 years or longer. Also, manufacturer replaceable parts are easily found on Amazon that can extend the life of your tankless water heater for many more years. Just make sure the water in your home is soft water that contains low concentrations of calcium ions and magnesium. Tankless water heater malfunctions caused by hard water such as lime and mineral build-up in the pipes or heating system are not covered by the manufacturer’s warranty. Otherwise, expect to spend about $1,300 to install a water softener to filter out the calcium ions and magnesium from the water.
Does tankless water heater increase home value?
A recent Zillow home listing analysis found that these products may be worth the initial investment, however. The real estate marketplace searched through listing descriptions from over 2 million U.S. homes sold between January 2014 and March 2016, and then examined how certain keyword features impacted a home’s sale price and speed of sale. They found that homes with tankless water heaters sold for 4 percent more than their expected value. These homes also sold 43 days faster than expected.
https://www.digitaltrends.com/home/smart-home-renovations-that-can-increase-your-homes-resale-value/
Can I install a tankless water heater myself?
Installing a tankless water heater will require some knowledge of plumbing for water lines and gas with service shutoff valves. If you purchased an electric tankless water heater, you will need properly sized electrical wire(s), either three AWG 6 for 55 amps each or one AWG 1 for 125 amps to draw approximately 115 amps necessary to heat the water. If all of this sounds foreign to you then I would recommend hiring a good contractor.
One of my favorite shows called “This Old House” dedicated an episode where the contractor, Richard Trethewey, installs an indoor tankless water heater.
Did you install a tankless water heater in your home? What kinds of modifications to the plumbing or space did you have to make? I would love to hear about it in the comments.
