Dad, when was the last time you had to yell, “turn off the lights - your wasting electricity!” I am sure even the non-dads remember having this told to them! You don't hear this as often in my house as it's not entirely true anymore! You see, I upgraded to LED lights throughout the house, and I use 1/5 the energy I did before. My math says I will save between $70-100 in lighting costs each year - and the electricity meter is agreeing with me!
The switch wasn’t cheap, let me tell you! Retail, all the LED “bulbs” were about $100. Luckily, I had a coupon and bought bulk so I spent only $50ish out of pocket. Still, the switch will save me money, even if I paid full retail. How? LED bulbs are so much more efficient than incandescent, halogen, or even fluorescent lighting. Remember those complaints about LED lighting being so “bright and cold”? How you can only get that “warm” color from incandescent or halogen? That is no longer the case at all… in fact you can choose different light warm depending on your needs.
Should You Switch to LED?
Short answer, yes. As in all things, the devil is in the details though! When should you switch, how much should you replace, and is it a cost-effective choice? Let's dive into these using my house as an example.
An LED Analysis:
I recently moved into a new rental property. The house had a mix of incandescent and halogen bulbs - no LED lamps at all. My kitchen and bathrooms had twelve 34 watt halogen spotlight fixtures alone! The two hallways had a 60w incandescent each, the living room has six 40w halogen dimmables , the dining room is two 60w dimmable incandescents, four bedrooms with a 40w halogen in each, and a 100w incandescent in the garage! If by some unholy event every light in the house was on at once - if we hosted a party, for example - that's a 1.1 kilowatts:
What is 1.1 kilowatts?
Let's go over some electrical terms - a kilowatt is a way of measuring the amount of electricity used. Each electrical device you own has a wattage rating -your cellphone charger, your computer, every light in your home. A 100 watt light bulb uses 100 watts of electricity to work. Your cell phone charger is likely 5 watts. A common laptop might be 35-60 watts while a full gaming computer with multiple screens and sound system could run 400-600 watts or more!
Your electrical company charges you by the kilowatt-hour - kWh. A kilowatt-hour means using 1000 watts for one our of time. If you have 1000 watts of electrical devices running for 1 hour, you use 1 kWh of energy. You can also use 1 kWh by using a100 watt device for 10 hours. Take a 100 watt incandescent light bulb; if you left one on in the garage overnight (let's say 10 hours) that light would use 1 kilowatt-hour of electricity!
How expensive if a kilowatt hour?
The cost of electricity is dependent on where you live. The average in the United States is about 13 cents per kilowatt-hour. Where I live it is 17 cents per hour. Hawaii is the most expensive at 26 cents per kWh and Louisiana is the cheapest at 8 cents per kWh. Check your local costs when you decide if LED makes sense for you! For this post, we will go with 17 cents an hour for my house.
In the case of leaving a 100 watt light on overnight, it would cost me 17 cents on my electricity bill. 17 cents doesn’t seem like much, but what if it is a front entrance light? That could run every night for 10 hours - $5.10 out of my pocket to keep that lamp running for a month, or $62 bucks for the year. The question is - should I replace the light bulb?
Costs of LED Replacement
LED lamps are not cheap - at least not compared to buying an incandescent light bulb. You can purchase a 100w incandescent light bulb for a dollar. An equivalent LED can be between $3 - $10! We need to consider lifespan, though! The dollar store bulb might last +/- 2000 hours. If the outdoor lamp we mentioned lasts for 3000 hours, it will need replacing once a year. LED Bulbs are often rated at 35,000 to 50,000 hours!
To be fair, LED is a newer technology, but reports so far are indicating that even the early LED bulbs sold a few years ago would reach 20 thousand hours of life. Based on this, it is reasonable to say an LED will last 10 times as long as the incandescent lamp. If we look at the replacement costs alone, the LED is at least as cost-effective compared to the incandescent - $1 a year for incandescent and $1 a year for the LED!
The real savings (aka: the place where you will notice it the most) is potential electrical savings. Let's look at that!
“Watts” up with Lumens?
Incandescent light bulbs became so universal that many people refer to “brightness” or “amount of light” by the wattage rating of an incandescent light bulb. If I ask you to imagine a room lit by a 100 w bulb and them imagine that same room lit by a 40 watt bulb, you probably can do that easily. What if I asked you to imagine a room lit by 1100 lumens? That would be like a 75w incandescent light bulb - and suddenly you can see that room, can’t you?
Lumens is a rating for the amount of illumination a device provides allowing comparison between different technologies. Compact fluorescents, halogens, incandescents, and LEDs all have different wattages to create 1000 lumens of illumination. It is helpful to know what “lumen” you have in a room if you want to replace the bulbs and keep the same illumination. When shopping for an LED bulb, they often put the “wattage replacement” on the box, but all should have a lumens rating. Here is a chart to help you choose the right LED replacement for an incandescent bulb:
How many watts does a similar lumen LED use? That's the question - and the answer is 1/6 to 1/5 of the incandescent.
Back to that entrance light - Remember how it runs for 10 hours a day, for 17 cents a day, for $62 a year? If I switch to an LED of similar illumination the electricity would cost me just $9.30.
(warning - math!)
(15w light * 10 hours a day * 365 days a year = 54.75 kWh * 17 cents per kWh = $9.3075)
Even if the bulb cost me $10 to replace, I would save nearly $43! I would save $54 the next year (as the LED would still be working and I didn’t have to buy a new incandescent bulb). If the LED only last 5 years (and it seems likely the bulb should last 10 years!) that one LED replacement would save approximately $250 in electricity.
Math in Real Life
For those who hate math, use this map - find your state and assume your lighting requirements are the ones listed here.
For those who like math (or can at least stomach it), we need to do an energy inventory! In short, you need to estimate how many hours a day the light in your house are on. For a better estimate, you need to figure it out for each room. The basic equation is this: wattage of the lamps turned on * number of hours the light are on = kilowatt hours used. We need to know how many kilowatt hours we use in each room. We can then add them together for the whole house or whatever we need to do. For these estimates, I am going to guess that the lights are on a shorter time that may actually occur. Why? If I guess low and the math says switch lamps, I know I will see savings. If I guess high, the math may say “buy” but I will see no savings…
As an example: In my house, the kitchen is used for making breakfast and dinner at least 5 days a week (approx 260 days a year). Breakfast takes about 30 minutes and dinner takes about an hour and then another 30 minutes for washing dishes or whatever. So each day the kitchen has its lights on for 2 hours. It has six 34 watt halogen spotlights. That room will use 0.4 kilowatts (~7 cents a day) each day based on my estimate. If I switch to LEDs, each lamp will be 6watts - 0.07 kilowatts (~1 cent a day). I could save about $15 a year by switching the kitchen to LED spotlights. Beware! Math!
.4 kWh * 260 days = 104 kWh * 17 cents per kWh = $17.68 vs. $3.10 = .07 * 260 *.17. $14.58 savings per year.
If I can find replacement bulbs for about $15 (which I was able to do!) I will see the money back in a year then save $30 over the next two years. If we use the kitchen lights more than 2 hours a day (and I suspect we do… turn the light off, kids!)then the savings are even more.
Repeat the math for each room to get a handle on your energy usage.
How much can you save?
Easy - take the number of kilowatt hours you use on lighting and divide by 5 - that is what you would use if you had all LED lamps. Multiply your kilowatt-hour usage buy you cost per kilowatt to see your cost - compare the two to see your savings!
All at once or once for all?
Should you replace all your lights for LEDs today? The long-term answer is yes! Switching now will reap the biggest rewards over time. Yet, the long answer is most likely not, as replace every bulb in your house today will cost a significant chunk of cash up front. If you are not convinced to replace EVERY bulb, I would suggest identifying the most used and highest wattage lamps and replacing those first. Also, consider replacing in batches - replace all the 100W incandescents first and buy a pack of those LED replacements. The bulk purchase will help save you money, and getting rid of the 100w energy suckers will reap the largest rewards. Then find the lights used most often - in my home it is the living room, the office, the kitchen, the kids' room, and the main bathroom. Replace those as you can when you can. Finally, replace the less used places when (and if) the bulbs burn out. This would allow you to find savings early and spread out the cost over time.
When should I replace my bulbs?
Good news, everyone! The cost for LED bulbs is continuing to decrease, so for many of you, just wait until the bulb you have dies - then replace it with an LED equivalent - and the price of the LED replacement will most likely have dropped a little bit more. When you do buy, I would recommend you buy in bulk - you can get significant savings buying a pack of LEDs vs. buying each replacement separately. I save 50% buying in bulk and that is why I did the whole house in one fell swoop. Also, consider that electrical prices tend to rise over time. As the price of electricity goes up the cost savings for LEDs does too. So watch your bill and that might tell you when to switch!
But wait, there's more!
A few quick considerations: When you buy LED bulbs consider the “warmth” of light. Incandescent and halogen lights are known for their “warm” light - it has a lot of red and orange hues. Florescent light is often called “cold” - it has a lot of “blue” and appears very “white.” Early LED bulbs were VERY “white” and this could make a room feel “wrong.” I purchased “warm” LED lamps and they emit a light that matches an incandescent bulb. You cannot tell that I switched the bulbs when I used the “warm” LEDs.
If you are replacing lights that are attached to a dimmer, you will need dimmable LEDs, which are generally a little more expensive than a non-dimmable version; an extra dollar or two per bulb. By dimming a light, you use less energy. If you are using a dimmer to keep the lights low, you may consider delaying replacing those with LEDs as dimmed lights are costing you less making the cost vs benefit less favorable for the replacement.
Finally, test out an LED bulb in a reading lamp for a few days before you go and replace everything in the house. Some LED designs can flicker. This flicker is “imperceptible” to most people, but through one of my lines of work, we discovered that certain brands of LED and most types of fluorescent lamps induced headaches or migraines in military veterans with traumatic brain injuries. Other people may be susceptible as well. So try out a bulb first to see if it works for you, and then you can buy with confidence!
Lights on? No worries!
How did it work out in my house? Well, I switched everything out! I was able to find bulk packs for each of the types I needed - two six packs for the halogen spotlights, two five packs for the 40 halogens, and a five pack for the 60w bulbs. I took the 5th bulb from that last pack and used it in place of the 100w in my garage. If my kids decided to turn on every lamp in the house I no longer use 1.1 kilowatts - now my whole house lighting system draws only ~ 200w! In the end, I should see between $70 and $100 dollars less in electricity over a year. It’s not huge - but it will pay for the bulbs in one year, and then save me money the next two; plus I have a little insurance in case the electrical rates go up, as well!
All in all, I feel good about moving from the old way to the new way. I know that I am saving money, I was able to teach my kids about energy usage and a little science while I was at it, and the idea of not changing another light bulb for 3-5 years (maybe 10 years!) is quite nice!