My first Energy Geek video! This is the companion video for the recent article on Sun tubes.
Don’t expect much production quality. These videos will be like this blog – unedited, not politically correct, lots of opinions. So if you’re expecting “This Old House” you better look elsewhere!
——
What’s better than a sunny day? A sunny day that helps illuminate the normally dark recesses of your home!
Normally, people install skylights – basically just windows built into the roof. But skylights have several problems:
A sun tube works differently than a skylight. Instead of being large windows in the roof, they’re typically smaller, about one foot to sixteen inches in diameter. Right away, this is beneficial because energy loss is directly related to the area of the opening. So a 16″ sun tube has an area about one third to one fifth of a typical skylight.
Sun tubes are built with reflectors so that they bring light into the house even as the sun moves to a variety of different locations. Usually, they are set up to reflect the Winter sun optimally but they can work well year round. I’ve installed several in my own home and really like them. One is in my office, which is on the north side of the house and never gets direct sun through the windows. However, the slope of the roof is such that for most of the year, the reflectors on the sun tube can capture sunlight and direct it into the normally gloomy room. Here’s a cheesy video demonstrating how these products work.
During the summer, sun tubes brighten rooms without heating them up like conventional skylights. If you’ve ever stood under a skylight during the summer, you know what a problem this can be. You can get a tan under some skylights! That definitely doesn’t help your air conditioning bill. Solatubes bring in the light, but due to their relatively small size and the way they work, the amount of heat that they bring into this house is very low.
Installation of sun tubes is easy. I installed one myself, and I’m no carpenter. I just followed the directions and it went in easily. Granted, I am pretty good with a saw and don’t mind crawling around the attic. However, if you’re not up to it, there are usually “factory certified” contractors who have been trained to do the installation.
There are a variety of manufacturers of sun tubes, but my favorite is Solatube. They have residential and commercial versions are well made and easy to install. Please note – I have no business relationship with them. I’m just a happy customer!
Another nice feature of sun tubes is that they can act like light fixtures when you need electrical lighting. A simple bulb holder can be installed into the tube. Yes, it blocks a little of the light, but I’ve found this to be well worth it in the rooms where I’ve installed them.
Are they perfect? No. If you don’t like white, round plastic portholes in your ceiling, you’re out of luck. Additionally, the tubes are fairly cheap and easily damaged if you’re not careful. However, you only handle them during installation, so that’s not a big deal. They also need to be installed in rooms directly below the attic or roof because it’s a sun tube! It only directs light a few feet from the roof into the room. So they’re ideal for ranch houses or upstairs rooms but of no use on the first floor of two or three floor homes.
Other than that, I love these things. There are some rooms in my house where I almost never have to turn on the lights. If I could have, I would have installed several in my kitchen and living room.
We’ve all heard the hype – buy new windows and save 35% on your next heating bill. To put it politely, that’s a bunch of hooey. Unless your windows are old, poorly installed, leaky and missing half the glass, you are not going to save 35% on your heating bills. In fact, there are numerous studies showing that replacing windows is among the least cost effective measures for improving your home’s energy efficiency!
That said, windows are among the worst performing parts of your home when it comes to energy efficiency. Did you know that a single, 3 by 5 foot window can double the energy loss for the wall in which it’s mounted? This is why manufacturers often make such outrageous claims about energy savings. But a home loses energy through more places than its walls. It loses energy through air infiltration, walls, windows, doors, ceilings, the foundation and the slab.
Let’s compare a variety of window styles and their relative energy loss. But first, a definition:
U-value: is a measure of the energy transfer through a window. The higher the U-value, the greater the energy transfer and the worse the insulating ability of the window.
Comparing U-values, we can directly compare the relative energy efficiencies of these different styles of window. For example, if you install a super insulating, triple glazed window with a U-value of 0.20, this will lose 20%-25% as much energy as an old single glazed clear glass window. That is truly substantial. In fact, when I renovated my own home, I went this route. Not because I knew the energy savings will pay off (they won’t) but I was trying to optimize my entire home’s energy efficiency and comfort.
Suppose you have a moderately old wood frame, single glazed window with a tight fitting storm window. This might have a U-value of around 0.50. If you were upgrading to a double-glazed, low-e window, which typically has a U-value of about 0.35, then the new windows would only reduce the energy loss through the window by 30%. Not bad, but not great and probably not worth the investment.
In addition, most new windows are installed poorly. I have seen many instances where a house was less comfortable after installing new windows. Why? Because the installers did not seal around the windows properly and air infiltration is much worse for energy loss than is poor insulation.
If you remove the trim from around a window, you would see something like this. The window unit would be shimmed out and nailed into place. Around the perimeter are big air gaps. Sometimes, you can even see right outdoors.
The problem is, most installers just shove fiberglass in these cracks. Fiberglass is not an air barrier. In fact, when compressed like this, it isn’t even a good insulator!
Please see my website for more detailed information on proper window installation.
For all these reasons, if your windows are in good shape and don’t seem drafty now, then I usually don’t recommend replacing them. Instead, start with some high-quality window treatments.
It’s amazing how much of a difference cellular shades or window quilts can make. At a fraction of the cost and disturbance of new windows, properly installed shades or window quilts can reduce energy loss by anywhere from 50% to 80%, making your home more comfortable and energy efficient.
Practically speaking, usually I recommend that people outfit one room with these initially to see if they yield the desired improvement. However, you really can’t go wrong with these unless you’re planning on renovating anyway and will be upgrading the windows. In that case, I suggest holding off on the window treatments until you get the new windows because often the new windows will be a different size and the treatments might not fit then ew windows.
For more detailed information, please see the links below.
Other links:
Dept. of Energy – Energy Performance ratings for Windows
Dept. of Energy – Energy Saver Tips for Windows
Efficient Windows Collaborative for more technical information on windows.
Florida Solar Energy Center – Windows
Grace-Vycor – Contractor’s Guide to Window Installation
National Fenestration Rating Council – General website
Ted's Energy Tips 