home energy audits
 One of the first things you should
consider if you are serious about saving energy in your home is to do
a home energy audit. You can do some of this yourself but for
certain kinds of measurements you probably want to make use of a
professional energy contractor who has both the equipment to measure
things such as the air flow in your house as well as the software to
determine how this compares to energy norms in your area.
A home energy audit will give you a baseline of your energy
usage today so that you can then make comparisons once you have taken
steps to cut your energy use. One of the techniques used in an energy
audit is to use infrared still or movie cameras to conduct a
thermographic scan of your home. These
sophisticated cameras use infrared light which is in the heat spectrum, similar to that used in night
vision goggles, to view the heat signature of your home. They
can identify energy hot spots that otherwise might be invisible to
you. Depending upon the time of year you can use them to measure leaks of hot air during winter or leaks of cool
air during summer. The heat loss might be due to leaking air,
ineffective heating or cooling systems, or
insufficient insulation or all of the above.
The scans can be taken either inside or outside depending upon the
weather conditions at the time of the audit. Warm air scans are
probably the most common because warm air escaping from a building
does not always move through the walls in a straight line.
Because of this seeing the leak from the outside does not always tell
you where on the inside the original heat loss occurred.
Another tool that professional energy auditors use is what is known
as a calibrated blower door. It is used to measure how air tight
your home is. A blower door is an external door that has a
powerful fan built into it. To do the measurement the auditor will
place the door, which has an adjustable frame, into one of your
current door openings. The door, if it is calibrated,
usually has a set of gages attached to it that measure air pressure.
To test your homes air pressure the fan is used to increase the air
pressure in your home so that it is higher than the outside air.
The increased pressure will cause air to leak out through any unsealed
areas. One type of gage called an airflow manometer can measure
how quickly the air leaks out. In addition the auditor may use a
smoke pencil or even incense to trace the flow of air out of the home
once it is put under pressure.
A blower door test sounds complicated but is really a
straightforward process that usually takes less than an hour. It
provides a scientific measurement of the air tightness of your home as
opposed to just a guess. It is often useful to do the test before and
after you have taken measures to improve insulation and plug up air
leaks. By comparing the difference in the readings you can get a
real sense as to how much improvement has been made.
Many aspects of an energy audit you can do yourself. The
first place to begin is by checking all of your door and windows for
air leaks. Look for dried or broken caulking or incomplete
weather seals. Other areas to check are:
- Electrical outlets
- Switch plates
- Baseboards
- Fireplace dampers
- Attic hatches
- Wall- or window-mounted air conditioners.
If you have a good sized window fan you can to some extent emulate
the technique of a professional blower door test. First close
all windows, doors, vents, and the flu in your fireplace. Then
use a large window fan to suck all of the air out of a room. If you
have exhaust fans in your kitchen and bathrooms you can also turn
those on. As you are doing this you can use an incense stick to
visually monitor where the air is leaking out. This won't be as
precise a measurement as you can make with a blower door but it may
give you some sense as to where leaks are occurring.
You should also do a check of the exterior of your home. Look
for areas where two different building materials meet, including:
- All exterior corners
- Where the chimney connects to the house
- Areas where the foundation and the bottom of exterior brick or siding meet.
- Exterior of doors and windows
- Exterior vents such as a kitchen vent or a dryer vent
When you are doing your exterior inspection look for any cracks or
holes in the mortar or foundation. If you have siding look for
any areas where the siding may be loose or cracking. Always
check the exterior caulking around doors and windows and replace the
caulking if it is cracked or broken.
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