Behind heating & cooling, water heating is the next biggest energy consumer in the typical home, about 20%. Being such a sizable portion of a home’s total, there is plenty of room for savings. If your water heater is less than 15 years old you will probably be better off by utilizing water saving technologies and behaviors.
Low-flow showerheads, faucet aerators, shorter showers and washing clothes in cold water will cost very little to implement, but save hundreds of dollars each year on your water and energy bills. Since that is not the emphasis of this guide, we'll write about that in another paper to be published soon.
Buying Criteria / Research
If your water heater is over 15 years old, then it’s a good bet that you would benefit greatly from replacing it. When I’m helping someone look for a new water heater, here is what I look for:
0) Geography: If you live in the Southern portion of the US or somewhere similar that gets copious amounts of sunshine, you may be able to get all or most of your hot water provided for you by the sun. Even if you live somewhere a little less sunny… like Seattle a solar hot water heater can provide a significant portion. Last September, it was gray, rainy and cold in Seattle, but the water inside a solar hot water tank that I was inspecting was 95 degrees F. That’s not hot enough for a shower, but the electric hot water tank now only had to raise that water 25 degrees instead of the full 70, saving 64%.
1) Fuel Type: This is the energy source for the water heater. The most common are electricity and natural gas, but it can also be oil or propane. *If you have an electric water heater, see below about super efficient heat-pump water heaters that can cut energy use in half!
2) First Hour Rating (FHR) / Gallons per Minute (GPM): This is the amount of hot water that you will get during that first hour (your shower’s not that long is it..?) for a storage tank system or how much you will get each minute with an on-demand system. This is the most important criterion because these numbers must meet or exceed your demand in order to not run out of hot water. Showers/baths, sinks, clothes washers and dishwashers all need to be taken in to account in this equation. If you can make it a rule to not run the dishwasher or clothes washer while you are taking a shower you can cut down dramatically on how much water you need to produce. TIP: Before looking to get a new water heater, install efficient showerheads, faucet aerators and EnergyStar qualified dishwashers and clotheswasher to bring your water demand down.
3) Capacity: This measure is only for storage type tanks, not on-demand water heaters. This is the amount of water that the tank holds in gallons. This number is also used to calculate the FHR, because the tank will hold the water at the set temperature and then heat up more water for you to use.
4) Energy Factor (EF): This is essentially the annual energy efficiency of the water heater. The higher the EF, the less energy it takes to provide you with the hot water you need. This number includes both the actual heating demand and any heat loss during storage. For example a water heater with an EF of 0.92 will have an efficiency of 92%. Usually, a water heater with a higher EF will also have a longer warranty because it will have more insulation, special heat trap fittings and will wear out less quickly.
Types
Storage
These are your traditional water heaters, tall cylinders, usually in the basement somewhere and with a big yellow “Energy Guide” Label on them, telling you their estimated cost per year.
On-Demand/Tankless
These units are common throughout Europe and Asia where space is limited, but are starting to make a strong incursion in to the US market. These units are much smaller than the tank styles and will often be mounted on the wall, being the size of a couple of shoeboxes. They are more efficient than the storage models because they do not store the hot water, but simply make it as you need it.
Heat Pump Water Heaters
Rather than using a fuel like gas or electricity to create heat, a heat pump transfers heat from one area to another. Your refrigerator takes heat from inside and dumps it in to your kitchen. The heat pump water heater takes the heat from whichever room it is located in and transfers that to the water in its tank. They work best in a room with excess heat, like a furnace room (40 – 90 degrees F year round) and need at least 1,000 cubic feet of air around them as well.
If you are in the market for a new electric water heater, spending the extra money on a heat pump water heater can help you to save more than 50% on your energy costs. New hyper efficient technology gives these water heaters an EF near 2! The most efficient tankless systems are around 0.95 EF. Depending on usage and rates this can pay for itself in as little as five years.
Financing
There is a 30% Federal tax credit available for the gas tankless and high-efficiency storage type heaters, electric heat pump water heaters and solar water heaters. Check with your utility provider and local government to see if they are offering any rebates or price assistance as well.
Installation
Before you buy a new water heater, talk to a few installers and have them calculate what your actual savings will be and return will be for the best water heaters for your situation. This way you can make the best decision for both your hot water needs and your finances.
When the hot water heater is being installed, (if it is a storage type) make sure it sits upon a two inch thick piece of rigid foam (R-10) and (any type) that the hot water pipes are insulated using pipe sleeves or wraps to within 12 inches of the water heater. This helps to keep the water hot both while it is in the tank and while it is traveling through the house.
