Absence makes the heart grow fonder. That’s how you may feel when you turn on your shower and realize there’s no hot water. Your water heater might not be something you think about every day, but most of us love – and often take for granted – the comfort and safety we get from our hot water. Once you’re reminded how much you love your water heater, you want the replacement process to be as quick and painless as possible.
Your water heater is more than 10 years old, and it needs replacing, so you call your local water heater company. They go over the size and fuel type of your water heater and then start talking about the efficiency of all of these options. When we talk about efficiency, we should also talk about cost, which is what’s really going to make a difference in your pocket at the end of the day.
To demystify energy efficiency and water heaters, let’s go over some basics.
If you take a look at any water heater, you’ll see a sticker on it that says “Energy Guide.” This sticker will provide you with the annual estimated operating cost for that unit, given on a scale. Where your unit’s rating ends up on that scale is going to tell you how energy efficient it is compared to other models.
If you’re shopping for a new water heater and want to make comparisons, you can often look up these ratings on the manufacturer’s website. When you find a unit that has a figure on the lower end of the scale, you may want to consider upgrading to one with a higher number because that means that it will use less energy.
Traditional water heaters that are more than 15 years old are likely to be much less efficient than new ones. A tank-type water heater has a useful life of about 10 to 15 years, and the unit’s efficiency is going to decline with time. This means that it is costing you more per month to heat the water in your home, often so much so that you’d be better off replacing your water heater to start getting some cost savings.
One of the things that can reduce the efficiency of a traditional water heater is sediment buildup. Hard water often contains sediments like iron, calcium carbonate, sand, magnesium, and grit. This sediment can settle at the bottom of your tank over time and reduce its efficiency. Likewise, that same sediment can creep into the mechanics of your unit and weaken the tank’s structure, both of which are likely to cause problems.
You may also be facing efficiency issues because your old tank simply doesn’t suit your family’s needs, causing it to work too hard. If you have a 40-gallon tank that is trying to serve a family of six people, everyone is going to suffer. When your tank isn’t big enough, no matter how old it is, it’s time to think about an upgrade.
Today’s consumers are more concerned than ever about the environment, and your choice in household appliances matters. There are two things to consider – industrial waste and greenhouse gas emissions.
First, if you opt for a traditional water heater, this is a large tank that is going to end up in a landfill in one to two decades. To avoid this, you can choose a tankless water heater instead, which lasts longer and has a smaller footprint.
When it comes to C02 emissions, a solar water heater is going to produce the least greenhouse gasses. However, these systems often require electrical backup, which is the least environmentally friendly option.
For the average homeowner that has this concern, a tankless system that runs on gas is likely the best choice, followed by a traditional water heater that is gas-powered. Here is some more information about those different types of systems and their levels of efficiency.
The primary consideration when replacing your water heater is the current fuel source of the unit. Most people heat their home’s water with natural gas, propane, or electricity. That’s in order of cost, not efficiency. Gas water heaters aren’t as efficient. But, because gas is cheap (and due in part to the design of a gas water heater and the laws of thermodynamics), it’s much more affordable to heat your water with gas than electricity. Consider this:
So if there’s one thing you take away from reading this, it’s this: if you have gas, stick with gas. If you don’t have gas, you can always convert, but there are also some newer options that you want might want to consider, like heat pump water heaters, but we’ll get to that later.
Not quite. Let’s think about three basic options to keep it simple: Standard, Energy Star, and Tankless.
Your main advantages with a tankless water heater are going to be energy efficiency, space savings, longer lifetime (up to 2x as long as a tank water heater), and unlimited hot water. Be careful with that last one – if you’re looking to use endless hot water, you can do this with a tankless water heater – often running multiple showers and your laundry machine simultaneously. But if you do this, it will eliminate the cost savings from a higher efficiency rating.
Assuming you continue to use your hot water as you do now, you have three options to consider:
The main obstacle for a tankless water heater conversion is retrofit costs – from gas line changes to venting changes – but most homes can still achieve a payback of around 10-15 years with these energy savings. After taking into account real estate savings due to a much smaller unit, the payback drops below 10 years.
We’ve estimated these savings based on replacing a standard tank water heater with an EF of .60, and chances are your old water heater isn’t exactly working like it used to, so that’s something to keep in mind. And with a longer lifetime, you won’t have to replace your tankless water heater for another 20 years (as opposed to about 10 years for a tank water heater).
“$500? No wonder my bills are so high each month!” is what you might have said to yourself when you first read that fact above. The truth is, heating your water with electricity just doesn’t make as much sense as heating it with gas.
From a big-picture perspective, the net efficiency of electric water heating is significantly reduced by the fact that power plants generating electricity and the transmission lines carrying that electricity to your home are terribly inefficient compared to the production efficiency and distribution of gas. Plant efficiency will vary widely, but most electricity generation in the US is 30-45% efficient, resulting in a large amount of wasted energy and negative environmental consequences from the burning of coal and other fossil fuels. In addition, the nature of power transmission is such that between 5-10% of power is lost during the transmission process. Because gas is delivered by pipeline, the losses are negligible.
However, you may be stuck with no gas in your home, so let’s consider the options.
Utility companies and other entities like to support this technology with rebates, so for some, a switch to a heat pump water heater is a no-brainer.
Heat pump water heaters have gone through some technological changes as well, which addresses concerns of minimum supported installation locations, sound levels, size, recovery rate, and efficiency. So make sure you check out the difference between brands when choosing a heat pump water heater. This is going to be especially important if you live in a northern state.
Learn more about heat pump water heaters in northern climates.
In short, no. Typically rebates won’t be available to you, and you’ll have to pay for modifications, which will make the switch no longer feasible.
Better education around energy efficiency is important because it helps us understand how the resources we use to generate energy are put to work and the proportion of those resources that we use effectively vs. the proportion that we waste. Heating water with electricity is a three-step process. First, we have to generate electricity using a fuel such as coal or oil. Then, we have to send that electricity over power lines to our homes. And finally, we have to use that electricity to allow an element to heat our water, with energy being wasted at each step of the process.
With natural gas, we simply transport the fuel directly to our homes and burn that fuel in the water heater to heat our water. From an environmental perspective, cleaner-burning natural gas is not only better for the planet, but the way in which it’s delivered to your home creates less opportunity for waste.
Water Heater Type
|
Efficiency Factor
|
Approximate Annual Cost
|
Estimated Lifetime Savings
|
GAS | |||
Standard Tank |
.58 – .60
|
$250
|
n/a
|
Energy Star Tank |
.67 – .70
|
$225
|
$250-$300***
|
Non-Condensing Tankless |
.82 – .85**
|
$175
|
$1,150-$1,500****
|
Condensing Tankless |
.92 – .94**
|
$150
|
$1,500-$2,000****
|
Hybrid Condensing Tankless |
.92 – .96
|
$130
|
$1,800-$2,400****
|
ELECTRIC | |||
Standard Tank |
.90 – .93
|
$500
|
n/a
|
High-Efficiency Tank |
.94 – .95
|
$485
|
$150
|
Hybrid Heat Pump |
2.0
|
$250
|
$2,500+*****
|
*These are estimates from extensive in-field testing and monitoring. Not all homes will see these precise savings.
** May experience lower efficiency due to short draws – using hot water for 1 minute at a time or less
***Over a 10-year estimated lifetime
****Over a 15-20 year estimated lifetime
*****Over a 10-year period. Some Hybrid heat pump water heaters have a lifetime warranty on the tank, so savings will be extended.
Armed with an arsenal of knowledge about energy efficiency and water heaters, you’ll be ready to take care of the source of that constant puddle in your garage…Good luck!