Waste Not, Want Not: Conserve Energy by Upgrading Your Hot Water Heater

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Hot water heaters may seem innocent enough, but they are actually silent energy hogs that should be updated to conserve energy and save you money on your bills.  Just one topic of many sustainable ideas and solutions for your living space covered in “Your Green Abode,” the options to improve your water heating’s energy use range from behavioral adaptations to purchasing an Energy Star recommended high-efficiency water heater to replace your current behemoth.   
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The following is an excerpt from Your Green Abode by Tara Rae Miner (Skipstone Books, 2010). Drawn from interviews with experts, intensive research and trial-and-error experiences, the author provides a wealth of information on how you can conserve energy, incorporate eco-friendly products and give your house an overall green makeover from the ground up. The following excerpt comes from Chapter 2, “Save Time, Use Less Energy.” 

Right after heating and cooling, hot water is a typical home’s biggest energy expense. The EPA reports that the average household spends $400 to $600 a year on it. And for all that money spent, you won’t get a lot of well-used energy in return. That old tank buried behind boxes in your basement is most likely losing a ton: only 43 percent of a water heater’s energy goes toward heating the water you actually use; 31 percent is lost to standby heating (keeping the water in the tank hot). I’m talking about a clunky, more-than-a-decade-old hot water heater, the kind many of us — 27 million households — own. Seeing as a water heater only lasts about 10 to 15 years, we’ll have no choice but to upgrade soon. Here’s an opportunity to start thinking about energy-efficient options now, before that hot water runs out.

Conserve Energy First

Before we get to the new showroom models, let’s return to our mantra of conservation. Maybe your budget won’t allow for a big piece of new hardware, or maybe your landlord won’t pony up for the building. There’s still a lot you and your fellow tenants can do. If you’re hardcore, shorten your showers. Or if you don’t have the self-control, reduce your use automatically, and thus your heater’s workload, by installing a low-flow showerhead.

Next, try turning down the temperature. This isn’t as scary as it sounds — you won’t be left with dirty dishes or suffer through washing your hair in lukewarm water. Many hot water heaters are preset to 140 degrees Fahrenheit, which is too hot for most domestic uses. Ever have to mix your hot water with cold to get just the right temperature? You’re wasting the electricity that was used to heat the hot water in the first place. You probably won’t even notice the difference if you turn down the thermostat to 120 degrees (115 degrees may feel just fine), and you’ll also save roughly 10 percent of the energy it takes to heat your water. Or to look at it from a financial perspective, for every 10 degrees you lower the temperature, you’ll save 3 to 5 percent on your water-heating costs. Don’t forget to turn your thermostat to the lowest possible setting when you’re away on vacation. There’s no sense in heating water for nobody to use.

Insulating your older water heater in a blanket (most newer heaters are already well clothed) is perhaps one of the easiest do-it-yourself energy saving actions you can perform. It’s cheap too: A home-improvement store will likely have one on the shelf for around $25. Swaddling your pipes in conjunction with the tank will save you roughly another 10 percent. This is easier said than done, because of the nature of pipes winding this way and that and disappearing into walls and crawl spaces, but at the very least you should insulate exposed pipes–they sell pipe-sleeve insulation, the thicker the better, just for this purpose.

About to Run Out of Hot Water? 

Let’s say you’ve been conserving and insulating for a few years, but recently your water heater started giving signs that it’s heading for the grave. Now’s your chance (or your landlord’s chance if you can convert her) to purchase a modern energy-efficient model. Energy Star recently gave its coveted blessing to five different types of water heaters; some only came on the market in 2009. There seems to be a model for everyone, in every situation. Four of the options are described below, and solar water heaters are also an option.  

High-Efficiency Gas Water Heater

First, a slight but significant shift up from the status quo. Do you or your landlord have a gas water heater? Are you pretty much satisfied with it, in terms of delivery of hot water and maintenance? Do you have a little extra cash to spend but not much? Then Energy Star recommends a high-efficiency gas storage water heater. You’ll trade a little money spent up front (recouped in about two and a half years) for an approximately 7.5 percent increase in efficiency and a 7 percent reduction in your water-heating bills — about $30 a year or $360 over the course of its 13 years of life. What’s more, the planet gets a break too.

If everyone who planned on purchasing a gas water heater in 2009 opted for a high-efficiency model, about 1 billion pounds of CO2 would be kept out of the atmosphere. All of this results from some simple improvements in the basic water heater design: better insulation, heat traps, and burners. 

Gas Condensing Water Heater

If you have a couple teenagers in the house and/or for other reasons often run out of hot water — and want to take advantage of newer technology — think about a gas condensing water heater. Yes, you’ll pay more up front, but you’ll decrease the money spent on hot water by about 30 percent, saving roughly $100 each year. That savings is compounded by regular federal tax credits (30 percent of the cost up to $1500 in 2010) as well as potential local rebates. Energy Star boasts that if only 5 percent of prospective gas water heater buyers purchased one of its qualified gas condensing models, consumers would save $25 million every year, and the effect would be equivalent to taking 17,000 cars off the road.

Plus you get lots and lots and lots of hot water — you won’t have to worry about running out in the morning if you’re the last person in the shower line. New technological design helps the tank heat up almost as quickly as it’s filled up. Like regular gas water heaters, condensing models produce waste combustion gasses. Unlike their conventional counterparts, they don’t vent them directly outside but capture them and use them to heat the water more before finally releasing them. 

Electric Heat Pump Water Heater

Many a homeowner or utility-paying renter has suffered through the high cost of running an electric hot water heater. Though a good electric tank is more efficient than a good gas tank (90 percent versus 60 percent; the remaining percentages are what’s wasted in the process of heating the water), electricity is much more expensive in most parts of the country and, more importantly when considering your energy budget, is a much less efficient form of energy because energy is lost when electricity is transmitted through the grid. So who among the electric water-heating crew wouldn’t jump at the chance to cut his or her bill by about 50 percent? Or to save roughly $300 a year?

Takers should consider an electric heat pump water heater. If all who were planning on buying a new electric water heater did, the planetary savings would be significant: Energy Star says that in 2009 buyers could have kept 19.6 billion pounds of CO2 out of the atmosphere by choosing an electric heat pump over a conventional tank — a feat equivalent to taking 1.6 million cars off the road.

Heat pumps operate using a technology that Energy Star describes as a “refrigerator working in reverse.” While your fridge expels hot air from its chilly interior to the outside, a heat pump takes warm air from outside the water tank and brings it inside to heat the water — essentially moving heat around instead of wasting more energy creating it. There are drawbacks to this more efficient method: heat pumps need to be housed indoors at a temperature between 40 degrees and 90 degrees (they don’t operate as well in the cold); they’re claustrophobic (requiring about 1,000 cubic feet of air space around them); and they’re a bit frigid themselves (they actually cool the air around them). Energy Star recommends putting them in a space with extra heat, like a furnace room — this seems like a good option for an apartment building. Electric heat pump water heaters are also more expensive up front, but their payback time is better than most — about three years — and they qualify for tax credits and rebates at all levels. 

Tankless Water Heater 

With water heaters, thinking outside the box means getting rid of the tank. This isn’t really revolutionary so much as it’s common sense. Do you use hot water all the time, every hour of the day? Of course not. So why feed energy to a standard tanked-up water heater so that it can keep water hot 24/7? Tankless water heaterspossess a logic that’s beautiful in its simplicity: they only heat water when you need it. This design can reduce your hot water energy consumption from 10 to 40 percent. The Department of Energy reports that for homes using 40 gallons or fewer of hot water daily, a tankless water heater can be 24 to 34 percent more efficient than a storage tank model. What’s more, the water’s always hot and continuously so.

You can get your tankless in electric or gas, but Energy Star only rates the gas models, which receive rave reviews. They will save an average family $100 per year on gas bills (or reduce them by 30 percent), last for two decades (far longer than their tank competitors), and are eligible for big tax federal credits (30 percent of the cost up to $1500 in 2010). All models eliminate the risk of tank leaks and water damage and save space, since they’re small and attach to a wall — some can even be mounted outdoors.

Here’s how gas models work in a nutshell: you turn on hot water to fill the tub; cold water flows to the water heater; the gas burner is activated, which heats a heat exchanger, which the cold water encircles, leaving to fill the tub at the determined warmed-up temperature. The leftover combustion gases are vented outside. Installing this system is trickier than just replacing one tank with another. You might need to beef up your natural gas line or install new venting or electrical service — professional installation is recommended. A professional will also give you advice on the best size for your home or building. This work and planning on the front end could be a little stressful, but I’d predict that that stress will melt like an ice cube as you’re enjoying your “on-demand,” almost guilt-free hot water. I say almost…please remember that the energy used to heat the water still likely comes from an environmentally insensitive source: coal, gas, nuclear (even hydroelectric in many situations).

So enjoy, but keep that shower as short as possible.

Reprinted with permission from Your Green Abode, published by Skipstone Books, 2010.