March 18th, 2009
Impact Calculator Upgrades - Solar Hot Water and Air-Dry Laundry
Stumble it!
We’re happy to announce that we’ve recently added two new projects to the Low Impact Living Environmental Impact Calculator that show the benefits of air-drying your laundry or installing a solar hot water heater.
First, we’ve added a project that shows how much money, energy and carbon dioxide you can cut by replacing a few dryer loads of laundry a week by air drying. Simply fill in your current number of dryer loads (and your dryer fuel) in the “calculate impacts” section of the calculator, and then go to the “select projects” page. There you’ll find a project titled “Air dry your laundry” (it’s about five or six rows down). Click the “Project Description” link to see all of the details on how much you’ll save. The calculations assume that you air dry 75% of your existing dryer loads. We also show a couple of great drying racks/lines if you’re looking for something a bit better than the standard clothesline.
Second, we’ve added a solar hot water heater option to our list of renewable energy projects. This project takes your estimated hot water use (calculated based on your specific inputs) and the solar resources in your area and estimates how much a solar hot water system would save and cost for your home. Right now it takes into account the recently improved 30% federal tax credit for SHW systems, but not your local or state incentives (we’ll be adding those soon). Our friends at Green Made Simple have an up-to-date listing of renewable energy incentives near you.
This project has also been built so that it is a special “cumulative” project, which means that the project details change as you select other projects on the list. Why is this useful? Because it can help you understand how much LESS you have to spend on a solar hot water system if you make less expensive upgrades such as installing low-flow showerheads or buying an Energy Star clotheswasher first.
As an example, the calculator shows that a solar hot water system would cost about $4,900 (payback period of 16 years) in our home assuming no water fixture improvements - pretty ugly! But if I check off the “low-flow showerheads” and “sink aerators” projects, the cost goes down to $2,500 (payback of 10 years). Our $40 worth of showerheads and $5 worth of sink aerators cut the estimated cost of a system by $2,400 by reducing our system size by one panel and reducing the storage tank size. By the way, the solar PV, graywater and total carbon offset projects work in the same way - they adjust each time you select a project that reduces electricity, wastewater or your carbon footprint respectively.
Last, we’ve made some additional improvements “under the hood.” One that you might notice is that we’ve modified the calculator so that you can’t enter overlapping projects. For example, once you select any one of the water heater insulation, tankless hot water heater, high efficiency hot water heater or solar hot water heater projects, the other three projects will be deactivated. This eliminates the double-counting that was possible by selecting overlapping projects before.
We’ll be making other additions soon (including wind power and using wood as heating fuel), so check back soon!
(Note: Our calculator is meant to be a preliminary planning tool for your green improvements. Before starting any of the more expensive projects, make sure you get a detailed estimate from your local green service providers … which you can easily find using LIL’s green services directory).
Popularity: 6% [?]
February 11th, 2009
At Last: Energy Star Water Heaters For Your Home
We’ve always found it a bit strange that one of the most energy-intensive systems in our homes wasn’t covered by the Energy Star program: water heaters. Water heaters are particularly challenging to select. They’re expensive, they employ several different technologies, and unlike many appliances you can’t just judge their merits based on what you see in a store.
Well, Energy Star has finally stepped up and given us some guidance. The standards for hot water heaters were released last year, and as of January 1 many different manufacturers now offer Energy Star models. So what does an Energy Star water heater mean for you? As you might expect, it differs by category, so we’ll run through them and list some good options for you below.
Storage Hot Water Heaters
Storage hot water heaters are the ones most of us have in our homes - a big tank with a burner at the bottom. They’re the least efficient type of hot water heater, for significant energy is lost as the hot water sits in the tank regardless of the insulation level. The new Energy Star standards say that a storage hot water heater must have an Energy Factor of at least 0.62, meaning that 62% of the energy in the fuel burned is converted into heat in hot water. This is about 7% more efficient than the current minimum federal standard for storage hot water heaters. If you’re on a budget, then these models are best.
Some options include:
Tankless Whole-House Hot Water Heaters
The new Energy Star standard for tankless hot water heaters is that they must have an Energy Factor of 0.82. This isn’t that stringent: most quality tankless units already meet or exceed this level. However, the Energy Star certification also specifies that the warranty be at least ten years on the heat exchanger and five years on parts. This is a major upgrade for some manufacturers. Tankless hot water heaters make sense if you don’t have huge hot water demands and if space is at a premium in your home.
Options include:
Gas Condensing Water Heaters
Gas condensing water heaters are very similar to the traditional storage hot water heaters from the outside. But inside, there’s a major difference: they have very efficient heat exchangers that capture much more of the heat from burning fuel than do traditional models. An Energy Star condensing model must achieve an Energy Factor of at least 0.8, which puts most of these models right up there with tankless versions. That efficient heat exchanger comes at a price, though, so they’ll be more expensive than your typical storage model. Condensing models are great if you have a large family with high hot water demands - the storage gives you a bit more capacity than a comparable tankless unit.
Heat Pump Water Heaters
The previous three hot water heaters all employ gas as a fuel. So what happens if you use electricity? Consider a heat pump hot water heater. Like a normal heat pump or air conditioner, a heat pump water heater uses a refrigerant to “move” heat from outdoors inside to heat your water. Because you’re moving rather than creating heat, the efficiencies are incredibly high: Energy Star heat pump water heaters have Energy Factors of > 2.0. Per unit of energy, though, electricity is often much more expensive than gas or propane, so this higher efficiency might not translate into higher savings.
Solar Hot Water Heaters
Solar hot water heaters convert the sun’s energy into hot water, so why isn’t every solar hot water an Energy Star? The answer is that if they’re too small then they won’t make much of a difference. Therefore, an Energy Star solar hot water heater must have a Solar Fraction of > 0.5, meaning that it provides at least 50% of your total hot water heating needs.
Options include:
Popularity: 6% [?]
