Home Efficiency 101

Home efficiency is one of those things you may think has been done already — building code improvements surely must’ve accounted for what we’ve known about home energy use for decades now, right? And all the technology has been integrated, right? Not so fast, my friend. There is so much work to be done.

Home efficiency is one of those things that has few barriers to market implementation. First, unlike solar and battery systems, there is generally no permit required for home efficiency work. Second, the cost per kWh is absurdly low, meaning payback periods are very short. Third, unlike the first generation “low flow” and CFL options for greening a home, the new technologies of heat pumps or solar water heaters, “high efficiency” fixtures, and LED lighting make it sexy, fun, practical (still), and chic.

The impacts are strong, too. Many home efficiency projects pay for themselves in a year or a few years. Many also make the home a lot cozier and warmer, so there are additional benefits beyond the financial. On Project Drawdown’s list of the top 100 solutions to the climate challenge, a half dozen technologies/solutions are listed that include things most homeowners can act on today.

Home Efficiency Summary

Where does one begin when thinking about doing some home efficiency work? The first thing is to understand the basics. Electric bills are based on kilowatt-hours (kWh). A 100 watt lightbulb running for one hour would use 100 watts for an hour, or 100 watt-hours. If it runs for ten hours, it uses 1,000 watt-hours, which is a kilowatt-hour. Easy. Water heaters and fridges are a bit more complex, but basically the same. With these appliances, the device powers on for a short period, and then goes into other cycles, which often use little or no energy. But otherwise, it’s still watts × hours = kilowatt-hours, more or less. (See “how to read an electric bill” for more info.)

Water is a bit different. Water is typically billed to you in 1,000 gallon increments. Your cost per kilogallon is usually on your water bill. The tricky part is that water that goes into your house also mostly leaves your house, and therefore you’re also charged for that. Lumped under the term “sewer charges,” this is usually a % estimate of the water in. So, in essence, if 1000 gallons go in, the utility estimates whether 700 gallons need to be disposed of, or 300, or some other amount. It is largely dependent on how much irrigation is needed, and how much the utility believes the water is used for discrete purposes (watering plants, washing your car, etc. … anything where the water doesn’t go down a drain in your home after use). So, kilogallons in, kilogallons out, plus some surcharges, and you have your water bill. (See “how to read your water bill” for more info.)

Once you have a basic understanding of what you’re paying for, it’s time to do some research. A home energy monitoring device would be very helpful in determining which of your appliances uses the most electricity. Lacking that, there are some good common rules of thumb. Water heating, refrigeration, and HVAC (heating, ventilation, and air conditioning) tend to be the consistent top 3 energy users in most homes. This chart is a general purpose visual to showcase what a typical home’s energy use might look like:


This will obviously change quite a bit depending on the circumstances and use profile of the people living in the home, but serves to showcase the big picture. We’re not going to solve climate change by focusing our energy on the 2% of “other,” right? And if your situation is different, the solutions will also be different (e.g., a larger family in a home would have much more energy used by a clothes dryer, whereas the amount of heating and cooling wouldn’t change that much with more people).

What Are Our Home Efficiency Options?

These days, cleantech rules, of course. And cleantech in the home means energy efficient and high functioning. The days of dysfunctional water heaters, wimpy showerheads, and squiggly bulbs that took a few minutes to get to full brightness and then killed your eyes with flicker are LONG GONE. The good news is that, right now, today, there are fantastic options to green your home that are high performance, often pay for themselves quickly through lower bills, and represent an improvement over older tech.

HVAC — Sure, you can change out the HVAC system, but that’s really pricy. It makes sense to start with a look at insulation here. Properly sealing the home will go a long way toward keeping the expensive (conditioned) air in the home, and not let it leak out. You can do some small things to help (later in this series we’ll go over some of these), but in general, this is best left to the pros, who use expensive testing equipment and understand the issues of air quality, backdrafts/negative pressure, and the like. If you have gas appliances, sealing your home too tight could be deadly. So, it might then make sense to start with a smart (learning) thermostat, which can help in most cases to lower the energy used in HVAC systems, without other major changes.

Fridge — This one is pretty clean. Upgrading to a new Energy Star fridge is a great way to get an upgrade that pays for itself. Here’s a great article about how to establish whether an upgrade makes sense. The other main thing to think about is that second fridge in your garage. Often, these are donated fridges — someone’s getting rid of one and someone else says, “Sure, I’ll take it.” It then goes into the garage, where it holds a six pack and a half package of cheese and crackers, and uses 3× as much electricity as the newer, more efficient fridge in the house that people are actually using. If you have a second one, strongly reconsider it, especially if it’s sitting in the hot garage.

Water heater — The first thing to do is upgrade your showers and faucets with high-efficiency fixtures. Note: these are not your grandma’s low-flow options. These are high-efficiency, high-pressure, high-performance options. If you’re going to upgrade your water heater, too, a good rule of thumb is that if you have 3 or fewer people in the home, a heat pump water heater is a great option for an upgrade. These use heat exchange technology to reduce the amount of electricity needed to change the water’s temperature. Solar water heaters tend to work better for larger families, with electrical backup systems. Whatever you do, steer clear of gas! Having gas appliances in the home creates air quality and fire issues. So … just say no to gas.

Lighting — Another easy one: switch to LEDs. They now come in all shapes, colors, configurations, etc. They even have decorative options with little filaments, beautiful and use 90% less electricity than incandescents.

Pool — Heating a pool uses a TREMENDOUS amount of energy. If you’re heating a pool, cover it. Otherwise, the heat is lost, and in addition, the water evaporates off faster than ambient-temp water will. When you lose a gallon of water through evaporation, you have to refill the pool, and often the water coming out of the hose is from a mountain reservoir or groundwater, often very cold, which is similar to the effect of tossing an ice cube into your coffee. So, the more water you lose to evaporation, the more ice (cold water) you’re tossing into your coffee (heated pool).

Pool pump — The next thing is the pool pump. Check the gallons of the pool and the horsepower of the pump and you should get an estimate of how many hours are needed to keep the pool clean. Any extra and you’re just wasting energy. The next thing is to think about an upgrade to a variable-frequency drive pump. Switching to these as standard across the U.S. would be equal to putting $770 million back in Americans’ pockets every year and taking 1 million gas mobiles off the road. Here’s a post about VFD pool pump upgrades, if you’re curious.

Laundry — The clothes dryer would be one of the biggest energy hogs in the house in the above graph, except for the fact that it’s not used as often as other appliances. But consider that a clothes dryer requires a 220V line, and you then understand it uses a ton of power. Not just that — it burns fossils that someone had to remove from the ground, which itself burned fossils, and someone else had to burn fossils to transport it, just to produce … hot air. That’s not just climate-trapping gases, but thermodynamics at play too. There are not a ton of great options for clothes dryers — they’re just energy hogs. But air plus time does the job too. I’ve been without a clothes dryer for more than a decade. Took a little adjustment, but between a retractable clothesline and a foldable drying rack, I’ve been saving my clothes while saving money while saving the planet for more than 10 years, and have probably saved enough money to buy myself a full wardrobe at this point.

from cleantechnica.com