“There is nothing so horrible in nature as to see a beautiful theory murdered by an ugly gang of facts.” – Benjamin Franklin
How do you really save money on your utility bill? Americans have been trying to lower their energy consumptions for decades. Yet the data shows an average American spends 2.5 times more energy compare to a British. In the internet age people are reading and studying about this subject more than ever, but the results are getting worse by the day.
That’s why we decided to set the record straight about energy savings at home. We will talk about reality vs predictions, why models by scientist don’t work. Why people are not lowering their energy consumption when they follow advice. Who really needs more energy saving advice? We will give you some solid advice how to really save money on your electric bill.
Who needs more energy saving advice?
There are lots of advice out there, newspapers, utility bill staffers, magazines, and the internet. Green group websites and literature telling you about weatherstripping and caulking, the amazing savings from furnace tune-ups. Washington Post has an article saying “replacing filters monthly can each save $100/yr or more!”. If you google, “How to save energy”, the first result is a slide of bankrate.com and it tells you to “paint your roof white” on the first slide.
But it’s often bad advice, most of the information out there is myth and conjecture more than data. There not many studies of measured energy savings. The whole “Top 10 lists” craze lacks prioritization. The little data we have never gets cited or mentioned anywhere.
First of all, you have to qualify for energy saving advice. Do you really need energy saving advice?
Weatherization Program Evaluation Results
Here is some real data about weatherization programs evaluations. You can clearly see that Low Users are Low Savers. The bulk of the savings is from the High energy Users.
The more energy consumed, the more savings is possible. When you spend an average amount on your electric bill, your savings will be will lower as well.
This is why High users need more energy saving advice if we want to lower our energy spending. Nobody mentions this fact when giving advice about energy savings. Perhaps it won’t generate enough attention if the articles started with this fact.
But we don’t care if you stop reading here. We wanted to put the truth out there, if you are not a high user, energy saving advice has low savings for you.
Why did we fail saving energy?
More often than not, we end up doing something to lower our electric bill without tangible results. Why is that? How come the real saving we see on our electric bill is way off compare to predicted energy savings? Studies of actual energy use show retrofit savings are often 50%-70% of projections and sometimes much less.
Is it the occupant’s fault? Maybe a little, it’s an easy scapegoat, but there is not much evidence of big takeback. Is it the contractors? Again maybe a little, because the work quality can be a factor for skilled measures. But there is not much evidence of that either.
Are the models wrong? Yes, and by a lot. It starts with poor assumptions and biased inputs at first. It continues the trend with bad algorithms that never get tested or fixed ever.
Most common modeling flaw is assuming low existing efficiency, for example, the models assume that the current furnace is at 60% efficiency, therefore it should save you a lot by replacing it. But this is rarely true. Other wrong assumptions are R-3.5 walls and attics, 4 gal/min showers etc. the list goes on and on. Current models make biased simplifications, for example ignoring interactions and regain effects. They measure what’s easily measured (with too much detail).
The most important flaw is, they don’t bother with a “reality check”. They don’t look at actual usage, don’t make adjustments based on research and evaluation results.
Why are predictions are so wrong?
The main reason why models are wrong is because houses are complicated. There are a lot of variables that goes into calculating predictable energy savings you see on “Top 10” lists. When they tell you that you will save 100$ if you replaced your furnace filter every month, they have no idea what kinda house you have. This is the main reason why these predictions are wrong.
Models collect data on what’s easy to measure and model, but key factors often unknown. The key factors are the most important part for calculating the real savings.
Some of these unknown key factors are:
- Foundation heat loss: How is the soil conductivity; what is the waste heat from ducts, appliances, etc; What’s the stack effect?; How is crawlspace ventilation?
- Air Leakage: Known errors remain from foundation heat loss; the wind speeds unknown; Are all homes “well shielded”?; What is the leak distribution?
- Wall and Attic Heat Loss: framing factors; insulation quality; air leakage interactions
- Window Loss/Gain: shading, screens; old storm windows, air film R values?
- HVAC Performance: duct efficiency and regain, AC charge and air flow impacts
If you have no idea about these factors, your predictions will be way off.
How to really save energy?
Here is a list real recipe for energy savings at home.
- First of all, if your house lack efficiency measures, install them. Insulate your attics and walls. This will save you the most energy in the real world.
- Second, if you have inefficient stuff at home, replace or improve them. Old furnaces, refrigerators, washers and lights.
- Third, unplug/remove/turn off/control extra stuff at home, 2nd fridges, freezers, 24×7 computers, TVs, stereos; all night security lighting
- Fourth, if you have defects at home find and fix them. Air seal, dense-pack cellulose, hot water leaks.
- And lastly, change your behavior, learn and educate. Prioritize this after dealing with “Extra Stuff” at home.
- Stay away from bad advice.
How much are the real savings?
The following data is for Boston weather, we modeled an old house with gas heat and hot water.
We used the following data to calculate the energy savings and CO2 savings.
Boston energy prices/costs: single family home
- Gas ~ $1.90/therm (current prices are lower)
- Heating 400-1200 th/yr, average ~$1500/yr, annual use typically 0.20–0.60 th/ft²
- Hot water, dryer, stove 150-250 th/yr, $400/yr, monthly use ~5 + 3-6 therms/person (compare to summer bills)
- Electric ~ $0.20 /kWh monthly use 300–900 kWh for lights, appliances, etc $1500/yr
- Approximate CO2: 1.3 lbs/kWh, 12 lbs/therm
No Cost Actions that works
Here is a list of actions you can take in order to save energy at home.
Bad advice about energy savings
Here are some of the bad advice about saving money an on electric bill we found during our modeling. These actions will save you little or no money in the process. Do not waste time doing these.
At the end, you should be very skeptical about free energy saving advice you get off the internet. We can only win the fight against climate change, and save money on the electric bill if we work together. Please share this article with your friends. Help them better understand how to save energy at home.
What is life after all? A global unity movement.
Here is a list Energy savings $/yr, it was asked by a commenter on our Most efficient way to save energy and money article.
- EPA’s Energy Star site http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_index
- Affordable Comfort Inc. national & regional conferences for efficiency contractors, researchers, and policymakers
www.affordablecomfort.org many handouts from conferences available free
- Home Energy Magazine www.homeenergy.org good archive of older articles on wide variety of topics
look up your refrigerator’s rated usage at http://www.homeenergy.org/consumerinfo/refrigeration2/refmods.php
- ACEEE (American Council for an Energy-Efficient Economy) Technical resource and advocacy group
- Advanced Energy (North Carolina) good building science knowledge library, but the southern orientation
- Building Science Corporation (Westford, MA) Extensive info about how houses work, how they fail, how they should be built, etc..
Berkeley CoolClimate Calculator – CoolClimate Network http://coolclimate.berkeley.edu/calculator
- Lawrence Berkeley National Laboratory https://emp.lbl.gov