 Welcome to Appliances Lesson. This lesson is really exciting, I tell you. This is the most important one for most of the students. Most important in the sense it can make difference in both energy consumption as well as environmental protection. Because we use a lot of appliances at home, we use a lot of energy for these appliances. In this chapter, we are going to learn the basic operating principles of most of the residential big ticketed items. For example, refrigerators or water heaters. Water heaters is one of the most energy consuming appliances. And we'll talk about clothes washers, dryers. We're not going to look at how to do the laundry, but we are going to look at the basic operating principles. In other words, how these things really operate. What are all the things that govern the energy consumption? And what are all the things that we need to look for when we buy some of these appliances? And how to do a cost benefit analysis? So to do that, we will learn how to read energy guide labels. Energy guide labels are one of those that stick out on most of these appliances. If you look at these yellow ugly looking kind of appliances, these give you the amount of energy that a model consumes. So when we go shopping, I'm sure you're all going to do that with your honeys in a few years. And when you do that, you're going to compare. You're going to look at a couple of models or three or four or five models and say, okay honey, this is better than this. This is worse than this and so on. What are the factors that go in just to compare different models and pick the right one both with respect to energy consumption as well as environmental protection? So you're going to learn actually what kind of information we're going to get from these energy guides and how this can be used to compare model A versus model B. For example, model A may cost $400 and model B, whatever that might be, may cost $500. What you are basically deciding is, is it worth to pay $100 extra to get the benefits that this $500 model would give? In other words, $500 model obviously should give you more features that you want or it should give you energy savings in a long run. For example, if your energy bill is cut, let's say by $10 every month. So it's going to take really about 10 months to recover the $100 that you're paying upfront. So this kind of analysis is basically called life cycle analysis. What it would cost to buy a piece of equipment and to operate that over its lifetime, and we do that calculation for two models and see, okay, in a long run, this model is going to be cheaper and environmentally friendlier than the other model. So we're going to learn that how to do. That discussion will be very common for all the appliances. So this calculation of payback period is the key for most of this lesson as well as the lessons to come. And we will have several calculations. One of these is this payback period, and we will also look at the refrigerators and calculate the efficiency of those refrigerators and using the efficiency we need to calculate how much energy these things consume. We will do that with clothes, washers and dryers, and from here on, you will also encounter some acronyms, energy efficiency terms. So acronyms, you will see some of those things in this chapter, so you need to pay attention to those things, all right? And as I told you, these calculations are important and use of energy guide is the most important concept in this chapter. Thank you.