After our first window-buying experience, we decided to do a bit more research and go into our next purchases with some vocabulary. I never realized how little attention I’d paid to windows before. Here is some basic information we’ve picked up since our first uneducated window purchase. This is by no means an exhaustive list, just things we’ve learned along the way.
Vinyl. These are the (usually) white windows you see in many houses. They are the cheapest option and seem to be the most readily available for those looking to use salvaged or heavily discounted materials. We have found many to choose from in the Habitat for Humanity ReStores and most windows offered for sale on Craigslist are also vinyl. If white isn’t the look you’re going for, vinyl windows often come in an almond color as well. If we had known how common they were, we probably would have gone with almond rather than white, though it may have taken us a little longer.
Pros: cheap, readily available new or used for discounted prices, energy efficient models, low maintenance, rot resistant
Cons: limited color options, can’t be painted, can crack in very cold weather, frame can break with sharp impact
Wood. Wood windows are a bit higher priced but in my opinion look very classy. In our experience they are not as readily available in the ReStores or on Craigslist, at least not in sizes applicable for our tiny house and many of those available were old and rotting.
Pros: Wood detail, paintable/stainable to match decor, durable, better insulator than vinyl
Cons: more expensive, less available for reclaiming, more maintenance work, (painting/staining every few years), can rot
Aluminum. The aluminum windows we’ve found are on par with vinyl price wise or even cheaper, but are usually older and look far less appealing. I don’t recall seeing any new aluminum windows in the Habitat stores or on Craigslist. For this reason, and because they tend to have condensation problems, we didn’t really consider them as an option.
Pros: light weight, stronger than vinyl and rot-resistant
Cons: less available for reclaiming and what’s available is older, terrible insulator, can actually cause moisture issues due to condensation forming
Composite. Windows also come in a combination of materials, for instance, wood clad windows are mostly wood with an aluminum outer layer. Steel and fiberglass are also common window materials used alone or in composite. We didn’t look too much into these options as, again, they were scarce in the Habitat and Craigslist scenes and we are on a timeline. I suppose if you have a while to collect materials, you know a good source, or you’re ordering your windows new, these would be worth looking into. The combinations of materials seem to address the weaknesses of each individual window material.
Single Hung. Has one sash that you lift vertically to open. These seem to be the most common orientation of window we’ve found.
Double Hung. Has two sashes that move, so you can open the window from the bottom or the top, or both if you were so inclined.
Slider. Slides open horizontally rather than vertically.
Casement. Swings open like a door, and most modern versions are operated by twisting a handle.
Awning. Swings open like a casement window, but hinges at the top rather than the side.
Picture, fixed or architectural. No moving parts, just used to add light. Architectural windows in particular are odd shaped to add character or interest to the overall design.
Panes. The number of glass panes a window has effects the energy efficiency. There used to be only single pane windows, which kept out wind and weather, but still allowed for considerable heat transfer. Fortunately for our comfort and our energy bills, double-pane windows are more common today and I have even heard of triple-pane windows advertised.
Why are two or three panes better than one? The panes create a sandwich with dead air in the middle and glass on either side. This dead air, or in some cases a denser inert gas, acts as an insulator between inside and outside. Many manufacturers today use argon or krypton gas between the panes which are very poor conductors that help reduce heat transfer even more between inside and outside.
Glazing. In order to further increase the energy efficiency of windows, manufacturers have developed low-emissivity (low-e) glazing, which limits the amount of ultraviolet and infrared light wavelengths allowed through without limiting the visible light spectrum too much. Essentially, the glazing acts like a reflector to keep warm or cold air inside (whether you’re heating or cooling) and solar radiation and outside temperatures outside while still allowing enough light for us to see. Check out this awesome link for a more detailed description. This link and this link will also help you understand all the important looking numbers on the window stickers if you’re lucky enough to find new windows for your tiny house.
Tempering. Tempered glass, also known as safety glass, is specially treated so that when broken, it shatters into small blocky chunks rather than large shards. If you are concerned with building codes for your tiny house, certain windows are required to be made of tempered glass. For example, if you have a door with a glass insert, it should be tempered glass. See this link from Milgard Windows for more code information regarding tempered windows. Also consider how much you plan to move your tiny home. If it’s on the road often, the vibration and pressures from road travel may warrant tempered glass windows.
Sizing and other lingo. We didn’t learn until about a month ago that in the construction business, windows are standardly referred to by the length then height, and often in shorthand, but the dimensions are interchangable. So a window 3 ft long by 2 feet high would be referred to as a 3-0 by 2-0 window or 36 inch by 24 inch. It is handy to have that standard if you are talking to a contractor over the phone and need to be certain of the window size before you buy.
Sliding windows also have their own lingo to denote the window’s orientation. X represents the moving sash and O represents the stationary portion as viewed from the exterior of the building. For example, the window would be considered an OX slider because the right side moves and the left is stationary. If the dimensions were 3.5 ft by 4 ft, the window would be referred to as a 3-5 by 4-0 OX slider.
As I said, it’s not an exhaustive list, but it’s a start, and it’s far more than we knew when we first walked into the world of windows.