What are the black stains on my roof, and how do I get rid of them?
The black streaks that appear on your roof are not caused by mold, but blue - green algae called Gloeocapsa magma. It is a result of algae spores being carried to the roof by a combination of wind, birds, and squirrels. The spores stick to the roof and multiply, encouraged by warm humid weather. Roofs in the shade that do not receive direct sunlight are more susceptible, as they tend not to dry out completely. Other things that may appear on your roof are moss and lichen. Moss is a thick, green grass like growth, and lichen are light blue-green circles that can grow up to 5” in diameter
To eliminate these unattractive stains is a fairly simple process, and if your roof is not too steep for you to walk on safely, you should be able to do it yourself. First, purchase a 2 gallon garden sprayer tank. These usually cost less than $20 and are available at places like Sears, Wal-Mart or Lowes. Fill it with a solution of 1 gallon bleach and 1 gallon water. Choose a cloudy but not rainy day and saturate the entire roof. Next, take the nozzle off your garden hose and rinse the solution off. You may have to repeat this several times to remove all the stains. Do not use a power washer, as the force of the water may damage your shingles.
To prevent the stains from reappearing, purchase a 6 inch wide strip of copper or zinc and insert it under the row of shingles closest to the top of your roof. Leave about 2” exposed to the rain. When rain falls on this strip, it will become “ionized” and prevent any growth of lichen, moss or algae.
Why do I need a furnace filter, and which one is best?
If your heating system uses forced air to heat or cool your home, you probably need a filter. The first reason to use one is to keep the inside of your furnace clean. The entire system, from the fan compartment to the a-coils of the air conditioner, and even the inside of the air ducts needs to be as dust-free as possible for maximum heating and cooling efficiency of your furnace. If the A-coils in the air conditioner get clogged, no air will be able to pass over them, and your furnace will have to run longer and work harder in both summer and winter, raising your heating and cooling bills as the furnace tries to reach the temperature you set on the thermostat.
A filter also helps to keep the air in your home cleaner, and create a healthier environment for you and your family. The air in every home contains many pollutants. Not only things like pet dander and dust are in the air, but also pollen, plant spores, discarded human skin cells, lint, bacteria, candle soot and mold are waiting for you to breathe them in. No filter can get rid of 100% of these contaminants, but modern technology has made it possible to get rid of over 99%!
When choosing a filter, there are some things you should know. The cheap fiberglass filters that most people buy for about $1.00 screen only about 10% of the pollution form the air. Slightly better results are gained from the frameless plastic mesh filter that is held in place by a rod in the filter compartment. The problem with this type of filter is that it has no frame and tends to get deformed by the suction created when the furnace is running. This type often comes with a new furnace, and needs to be washed every 30 days. Many people just keep this without realizing they can upgrade.
A better quality filter is the "electrostatic" filter that comes in a black plastic or metal frame. These filters must be washed in the dishwasher or hosed off every two or three months. They are specially treated to create a magnet effect that snatches particles out of the air. They are about 80% effective. Over time, however, dirt builds up on the inside and they will still need to be replaced. The cost for this type of filter is between $40-$70 depending on whether they have a five or seven stage filter.
There are several other options, but the one of the most efficient types of filter is the pleated paper filter. This type has a zig-zag pattern which increases the area of the filter. The "Filtrete" filter by 3M is one example of this type. They cost about $13-$19 and come in several electrostatically charged versions. It is important to realize that while these are the best at trapping particles in the air, they still need to be changed regularly. Otherwise, they will become blocked and create a barrier rather than a filter. This can increase your bills, put a strain on your fan motor, and cause your air conditioner to freeze up, all things that I'm sure you would want to avoid.
There are also HEPA filters available for those who need to block nearly 100% of the allergens from their home. These are 4" thick filters that fit into a special compartment that is constructed at the factory. These filters will catch nearly all the particles that are in the air.
To keep the air in your home clean, avoid smoking or burning candles inside the home, vacuum regularly, and remove your shoes at the door. And make sure you change that furnace filter!