Low Impact Living Impact Calculator FAQs
- What is the purpose of this calculator?
- How is this different from other carbon footprint calculators I’ve seen?
- What is a LILI?
- How is the LILI score weighted?
- Where do you get the data to calculate all of these impacts?
- Where do all of the models you use come from?
- How customized are my project results?
- What are cumulative projects?
- Why do we look at the household and not the person?
- Can I compare these results to my utility bill?
- What if my scores don't match my utility bills?
- Can I use this calculator for my office, business, school or other institution?
- What is “runoff”?
- What is the unit referred to “MBTU”
- I don’t live in the United States…why can’t I use the calculator for my country?
What is the purpose of this calculator?
The Low Impact Living Environmental Impact Calculator is a tool that calculates the environmental impact of your household. You simply put in some basic information about your home and habits, and the calculator tells you how much energy you use, how much carbon you emit, how much water you use, how much trash you produce, etc. You get a snapshot of your household’s full impact on the environment. You also get a score, or LILI (Low Impact Living Index), that rates your household relative to the average household in your region. Finally this tool gives you a list of green projects you can undertake to reduce your environmental impact. You can see how much each of these projects will cost and save you, how much positive environmental impact they will have, and you can also find the products and local service providers to do the job by clicking on the resources links. You’ll be on your way to living a more low-impact life!
How is this different from other carbon footprint calculators I’ve seen?
There are several “carbon footprint” calculators online today. A carbon footprint refers to the amount of greenhouse gases we are personably accountable for, measured in units of CO2. Using electricity in our homes, burning natural gas to heat our water, driving cars to work, and flying in airplanes are all examples of ways in which we as individuals are responsible for the production of greenhouse gases — and thus for contributing to global warming. This calculator also gives you a view of your carbon footprint, but it goes far beyond that one type of environmental impact. This tool calculates your full set of environmental impacts — energy use, water use, sewage production, trash load, runoff production AND carbon emissions. It is the most comprehensive household environmental impact calculator online.
In addition, this calculator is much more customized to your regional situation. It takes into account local energy prices, how much carbon dioxide your utility emits per kilowatt-hour of electricity in your state, rainfall patterns and evaporation rates (for water calculations), recycling rates for your area, how much solar and wind energy is available in your area, and many more factors.
What is a LILI?
A LILI is a Low Impact Living Index, and it is our proprietary score for your household’s environmental impact. You receive a LILI score for your household and also a list of green projects by which you can lower your LILI. (For example if your starting LILI is 79 and you install a solar water heater, insulate your home and change your lighting to compact fluorescents, you might reduce your LILI by more than 10 points. (The goal is to get the lowest LILI possible — a low score means you have a below-average environmental impact.)
The average LILI is 100. This is based on the environmental impacts of a typical home in your region. If you score 100, you are doing no worse or no better than your regional impact. This does NOT mean that your environmental impact is low! Again, the goal is to get as close to 0 as possible. In general a LILI score in the 20-30 range is very low. On the other end of the scale, a LILI or 200+ means that your household is having an unusually negative impact on the environment. We encourage you to try to lower your score and help protect our planet!
You may have heard about other ratings systems for homes, such as the LEED for Homes standard from the US Green Building Council, the GreenPoint rating system from Built it Green, or the Energy Star home rating system from the US EPA. These are all very good tools for helping you build a new green home, or to pick materials and services for a major remodel, but they tell you little about how your impact is changing through time. They also don't help very much if you aren't doing a major project but instead are upgrading your house step by step. That's where the LILI comes in - it indicates your home's impact whether it is new or old, large or small, and it gives you a way to track through time where you started and where you are now. It also takes into account transportation impacts (and we hope some day food and other issues), so it is an indicator for not just your home but your lifestyle as well.
How is the LILI score weighted?
The LILI gives you one overall score for your environmental impact. It is a weighted composite of six different dimensions: energy use, carbon footprint, water use, wastewater production, stormwater runoff production, and trash production. We reviewed many different indexes and standards to come up with our weighting, which is now as follows:
- Energy Use: 30%
- Water Use: 30%
- Carbon Footprint: 20%
- Trash Production: 10%
- Wastewater Production: 5%
- Runoff Production: 5%
During our beta period, we will keep these values fixed and collect input from our users and the environmental community on any recommended changes. In the future, we may expand the index to account for other dimensions, or to add a "bonus" category for projects that are good for the environment but are very difficult to quantify. We also may develop regional weightings at some point. As an example, water use issues are much more important in the desert southwest than they are in other parts of the country, so it might make sense to give it a higher weighting in the index.
Where do you get the data to calculate all of these impacts?
We have compiled data from hundreds of different sources in order to build this calculator. The base calculations employ data such as temperatures, cooling degree days, energy and water prices, rainfall amounts and number of storms, soil types, average miles driven per year, typical home size, age and construction type in your area, and many more, sometimes down to the level of individual ZIP codes. Through time, we hope to continually refine our data so that it most closely reflects your area. For the projects, even more data is taken into account. As an example our solar and wind projects take into account the solar radiation, annual average windspeed and rebates from your specific region. We will provide much more information about these data sources in the near future.
Where do all of the models you use come from?
The Impact Calculator is a very complex system that employs many different models to produce its calculations. There are different models, for example, for energy, water use, landscape water use, carbon dioxide production, runoff production and many other areas. And, each project often employs its own model to produce results. All of our models are based on published, peer-reviewed equations and techniques, and many of them are based on government information and research. We will provide much more information about our models in the near future.
How customized are the project results?
Depending on how much detail you entered, they can be very customized. All of the project values - savings, resource savings, product and service links - are customized based on the inputs you entered and the region-specific data in our databases. These aren't national or even regional averages - they are all calculated on the fly based on the inputs you select and, in the case of our cumulative projects, on the other projects you have selected. Right now the project page might show some projects that either don't apply to your situation or have zero results, but we're working on filtering those out in advance.
What are cumulative projects?
Cumulative projects are projects that adjust based on the selection of other projects. For example, the 'Install solar PV system AFTER other projects' project shows how big and expensive a solar PV system will be AFTER you have done the other projects selected that affect electricity use. There are two other projects like it, one for installing a graywater system and one for purchasing carbon offsets for your remaining carbon footprint. Our goal is to show that, by doing simpler less expensive projects first you can drastically cut down on the cost of the big-ticket items. In the case of carbon offsets, we show how many offsets you need to exactly cancel out your carbon footprint, taking into account projects you've already done.
Why do we look at the household and not the person?
Many calculators look at the impact of one person. This makes sense if you are talking about transporation, or food, but when you look at a home it doesn't. We focus on the home, and so we want to make sure that we provide estimates and recommendations that make sense at that level. You can still use our calculator for personal consumption, though. As an example, if you just enter your car's type and mileage, and also your personal air travel profile, then the carbon offset projects on our projects page will be specific to your use. In the future, though, we hope to add a function that allows you to take either a whole household OR a per-capita view if you so desire.
Can I compare these results to my utility bill?
In some cases, yes. The fresh water bar can be compared directly to your bills (although you might have to divide by 748 if your water bills come in hundred cubic feet, or HCF). Some areas bill for sewage production too, and the wastewater bar can be compared to this. Although we do estimate your home's use of electricity, natural gas, or whatever other fuels you use for heating, cooking and hot water, right now we only display the aggregate energy use across all fuels as MBTU. If you are willing to do some math, you can convert your bills to MBTU using the conversions listed above. We hope to offer direct output of LIL Impact Calculator results soon. Oh, and one more thing: all of our projects show energy savings in units that CAN be compared directly to your bills.
What if my scores don't match my utility bills?
Estimating a household's energy or water use is very tricky business. First, to get a very accurate figure you'd have to enter far more inputs that we felt were feasible for a short web calculator. Second, we've found through visiting many different homes that consumption often depends as much on behavior as it does on construction techniques, appliances and equipment. An Energy Star washer will still use alot of energy if you do 12 loads of laundry a week using hot water!
If your scores don't match well, think about what elements of your home aren't considered that might be adding to your use. One good example is a pool - pool pumps and heaters use huge amounts of energy, and right now we don't have pool-related elements in the calculator (we will soon, though). Or perhaps you live on an open hilltop with direct sun all day - your house might be much warmer (or cooler) than homes in your region. Through testing, we've found our calculator to do very well at estimating average values, but when it misses it usually misses low. If it is low for your house, then you can consider the recommendations presented as worst-case scenarios for what you might expect from the recommended upgrades.
Can I use this calculator for my office, business, school or other institution?
This calculator is specifically set up to work for homes (including apartments). The main reason why it is not well suited for other uses is that the energy systems, lighting types, and usage patterns for schools/offices/etc. are very different than those of homes.
What is “runoff”?
Runoff is the water that flows off of your property every time it rains, when you wash your car, or when you overwater your lawn. Aside from the wasted water it is harmless to begin with, but as that water flows through your yard, down the street and into storm drains, it picks up animal wastes, trash, fertilizers and metals (from worn down car parts among other things) that poison our waterways when they are dumped there. In many parts of the country this is the single greatest threat to our oceans, rivers and lakes.
What is the unit referred to as an “MBTU”?
MBTUs are million British Thermal Units, or BTUs. It is a non-source-specific measure of the energy used when some kind of fuel is burned. We use MBTUs because it allows us to compare the energy that comes from natural gas, heating oil, propane, electricity and even gasoline or diesel fuel using one number. The positive of using MBTUs is that we can compare homes across the country regardless of what type of fuels they use. The downside is that it clearly makes it harder to compare our results to your electric bills. For reference, one BTU = 10 therms of natural gas, 10.9 gallons of propane, 7.2 gallons of heating oil, or 294 kilowatt-hours of electricity. In the near future we hope to add a tool that allows you to see units you can compare directly to your energy bills.
I don’t live in the United States…why can’t I use the calculator for my country?
We are sorry to say that we cannot at this time offer the calculator for countries beyond the United States. This is our first release of this calculator and, as you can imagine, the complexity of the data behind the calculations took us years to do for the United States alone. We aspire to make the calculator work for more countries in the future.