As a committed TreeHugger, one of the most important goals of my recent house renovation was to reduce energy consumption per person. The first thing many people do in a renovation is replace all the windows, even though study after study have shown that it has just about the worst bang for the buck of anything you can do. It also doesn't even make that much difference; a single paned window has an R value of perhaps 1, a new double glazed window between 2 and 4 unless you go very, very expensive.Then there is the issue of character and appearance. My 100 year old house has beautiful 100 year old windows, with divided lights at the top that give the house its charm. They will also last as long as the house; double glazed units will not, as they lose their seal and the argon leaks out, as the vinyl or finger-jointed wood deteriorates.The salesmen keep pitching the energy savings of replacement windows; It's a huge problem for those of us concerned about preservation and conservation, where replacement windows ruin heritage houses, at great cost to owners and for very little long term gain.
But double hung windows are very hard to seal, the spaces where the counterweights go are big empty wind tunnels. Air leakage becomes a far bigger problem with them than heat loss through the glass.One solution that has been around for a while is the window insert, an acrylic window that fits inside your existing windows, often held in place with snap fittings or magnetic strips. I have been considering them for years, but worried about the fit (thanks to settlement over the years, all these windows are parallelograms, not rectangles) and the look of the strips that held the windows in.Then there is the Indow window. It has a compression tube around the edge that holds it in place so that nothing needs to be fastened to the window frame. This also seals it really tightly to the frame so that there is no air leakage around it. But what I found most impressive in discussions with Indow was their measuring system, where they promised that they could deal with parallelogram or trapezoid windows.
In their literature, Indow promises an almost doubling of the R value of my single glazed windows, from R-1 to R-1.87. That's not a lot, but not much worse that replacement windows that cost a whole lot more. But as I mentioned earlier, that is only one of a number of factors that affect comfort, which is really a misunderstood concept. Engineer Robert Bean explains that your body absorbs or radiates heat from the surrounding surfaces:The less efficient a building, the greater the temperature difference between your skin and the temperatures of the walls, windows, doors, floors and ceilings. It is the temperature differences between you and the building which causes discomfort.These walls and windows are COLD, as seen in this thermal image taken last January, pre-construction. It was always uncomfortable in this bay window. Even the piano was suffering.However the Indow insert promised to significantly reduce draftiness, to well below even what new windows would deliver. And although noise from the street is not a problem where we live, even the standard inserts offer significant noise reduction.
They don't feel cold, because acrylic is not as good a conductor as glass.Michael Ruehle, an Indow authorized dealer with GREENheart Buildings Inc, arrived with a little laser measuring device and a netbook running an online program, and measured the length and width of the windows. Then he used the clever little device to measure the diagonals, and entered all the data into the program. Voila: a trapezoid is on the screen.A few days ago he returned with the inserts. They are delivered with a protective coating on the acrylic which is peeled off; then the window is pushed into place.You can see here how seriously distorted the window frame is, compared to the window itself. Yet each of these three inserts fit perfectly, sealing tight to the frame. The difference in comfort was immediate and palpable, and within half an hour the temperature on the floor rose 3 degrees. (The hot water rads have a lot of thermal inertia, so it takes a while for thermostat to cope).As for comfort, the best judge of the subject in our house also noticed the change.
I must disclose that Indow provided these window inserts for my review, but I am seriously impressed at how accurately they fit and how much of a difference they made. I have ordered them for the other existing old windows on the front of the house, and expect that they will make a huge difference in the apartment upstairs- saving energy, increasing comfort and preserving the historic character of my home.Get more information at Indow.Now that the hot and humid weather of summer is giving way to the cooler temperatures of the coming season, it's time prepare your home for the seasonal change. Sealing the air leaks around your home windows and doors is a simple chore that can help prevent drafty cold spots in your house, which means you can save money on your monthly utility bills. The key to success when tackling this home maintenance project is knowing how best to discover all of those tiny air leaks that prevent your house from being the cozy, energy-efficient home you want. When checking your home windows and doors for air leaks, start with a detailed visual inspection from both the interior and exterior of your home.
On the outside you should look for areas where the old caulking has failed, revealing the gap between the window or door frame and your home's siding. If your home has old single-paned windows, be on the lookout for damaged glazing, which is the hard putty that holds the individual panes of glass in place. If the entire perimeter of each window and door is not sealed tight against water and air infiltration, then your home is vulnerable to expensive heat loss.From the inside of your home, you should inspect the threshold under each door, looking for daylight or other obvious signs of an opening that is too big and needs to be sealed shut. Make sure that the weather stripping around the windows and doors is in good condition, making note of any damaged weather stripping that needs to be replaced.Although many problem areas are obvious enough, keep in mind that some air leaks are not easily seen. One way to detect these air leaks is to conduct a "smoke test." To do this, you will need to close all the windows and doors in your home and turn off any combustion appliances, such as a furnace or water heater.
Next you will need to turn on the kitchen and bathroom exhaust vents, which will create a negative pressure in your house that sucks outside air into your home through any crack or opening. Now you can check for air leaks by holding a lit incense stick close to the spaces around the edges of your home windows and doors, looking for a noticeable change in the smoke rising from the lit incense stick. If there is a air leak, the smoke will waiver and be drawn inwards by the outside air that is finding its way into your home. If the smoke remains undisturbed, then you can assume that there are no air leaks in that specific area.Another option for detecting air leaks is using an infrared thermometer, which is a non-contact thermometer that can measure the ambient air temperatures around window and door frames. In areas where cold outside air is leaking into your home, the thermometer will register a colder temperature, indicating a vulnerable area that could be wasting energy and costing you money.
If you don't want to discover your home's air leaks on your own, then you always have the option to hire a professional energy auditor to conduct a "blower-door" test on your home. Similar to the smoke test, a blower door test can assess the air tightness of your home and detect air leaks. During this test a specialized fan is attached to your home's door frame, which then pulls air out of your home, resulting in a lower interior air pressure. Once the fan is stopped, the higher air pressure outside the home tries to find its way back into your home through any cracks or crevices. A smoke stick is then used to locate those areas that are leaking and vulnerable to heat loss. These test are usually not very expensive, and in many areas you can apply for a free energy audit from your local utility company. Once you've discovered the air leaks in your home, you can set about sealing them up. More often then not, a fresh layer of exterior-grade caulking will adequately seal shut any gap or crack that is causing you problems.