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Observational U.S. home energy assessment

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Observational Energy Assessment[edit]

Are you tired of throwing money away on high energy bills? This is your first step on cutting your electricity bill, saving you money, and helping protect the environment!

Purpose and Need[edit]

The purpose of an observational energy assessment is to determine what features in a home are consuming or wasting excess energy so that upgrades can be made to reduce the energy consumption of the home, and therefore save money. With the rising prices in energy rates, along with excessive rates of consumption there is a need to reduce the footprint that we all leave from our lifestyle choices. Whether you rent your living space or own it there are plentiful ways to reduce your energy impact and live at the same comfort level that you are accustomed to.

What is involved in the Energy Assessment?[edit]

The observational home energy assessment can be completed without any tools to make broad generalizations about the living space which will lead to informed knowledge about energy use. A few of the traits that will be examined are heat and cold loss, electric and water consumption, and resident behavior. The behavior of the residents will play the largest role in the energy trends, as use of lights, appliances, and heating/cooling usually has the most influence on energy consumption. There are five sectors that will be looked at when determining traits of the home; these sectors include: building envelope, water heating and usage, delivery usage, heating, and conditioned vs. non-conditioned space. The design of the living space will determine how to approach these sectors, due to the relationship of conditioned and non-conditioned spaces and how they are treated.

Performing Observational Energy Assessment[edit]

The five steps of the observational energy assessment are: building envelope, water heating and usage, delivery usage, heating, and conditioned vs. non-conditioned space. According to Heidi Benzonelli of the Redwood Coast Energy Authority, the single most important detail to notice when starting a home energy assessment is the ambient noise occurring. The subtle noises heard can indicate heating leaks, high energy consuming appliances, or phantom loads that are present in the home. This first step will help lead you through the actions that can be taken to assess the home energy use and take positive action towards energy reduction.

Building Envelope[edit]

Building envelope
Window caulking

The building envelope or outer shell of the house is the separator between the interior and exterior environments that is designed to preserve the inner environment & control the indoor climate. There are three functions the building envelope:

  • Structural Integrity - The transfer and enduring of mechanical loads.
  • Interior Flow - The advection of energy and matter throughout the house.
  • Finish - The final touches of human fashion on the exterior and interior home.
  • When examining heat and cold loss the common threats are unsealed cracks in the doors and windows, and simply leaving windows open while heating the home. To stop the loss of heat energy one can easily re-apply chalking to window frames, electrical outlets, and door frames to limit the exposure of unconditioned space to the interior of the home.

Water Heating & Usage[edit]

Pipe wrap aka Pipe insulation
  • Another energy consuming appliance that should be checked is the water heater, both for the temperature it is set to and the insulation surrounding it. The minimum temperature for the heater should be 120 degrees Fahrenheit to properly disinfect the water lines, but often the temperature is set far too high for the needs of the residents, and wastes excessive energy. If the water heater is in unconditioned space like a garage, then a water heater blanket and pipe wrapping should be used to reduce energy lost to heating the unconditioned space as well.
  • Water consumption rates in the home can be significantly reduced without any changes in personal behavior by installing low flow shower heads and faucet aerators. These aerators in the kitchen and bathroom sinks reduce flow by more than half while maintaining similar pressure and feel, saving money on water bills and living in a more sustainable manner. Low flow shower heads also have significant effects on the water used and can provide large reductions in amount of water used per shower.
  • Water pipe insulation is an easy fix to reduce the amount of energy consumed to heat the water.

Delivery Usage[edit]

  • Phantom loads are defined as the electric power consumed by electronic appliances while they are switched off or in a standby mode, and there are typically many of these devices in the common home. Devices like televisions, DVD players, video game consoles, and laptop chargers often have phantom loads that can be costing you money while they are not even on. The solution to this problem is to use a power strip for all of these devices and leave it exposed (not behind the tv) so you can easily turn the strip on and off whenever you use the system. By turning the power strip off you are actively eliminating all phantom loads to the devices, and saving yourself money in the process.
Power strip with multiple devices in use



Heating[edit]

  • Heat that is contained within the home can be lost and gained through window areas while natural sunlight and solar radiation are present and absent. The use of Thermal Curtains can trap heat within the home gained during the daylight, and maintain that energy through the night. By simply opening thermal curtains during the day, and closing them at night you can make use of natural heating sources and avoid unnecessary heating costs.


Conditioned vs. Non-conditioned Space[edit]

The middle layer blocks air from infiltrating to the conditioned spaced
Conditioned Space
  • Conditioned space is defined by the part of the building that is designed to be thermally conditioned for the comfort of occupants or for other occupancies or for other reasons. These rooms usually include living rooms, bedrooms, and kitchens. The non-conditioned spaces within a home are not meant for habitation and usually include garages, attics, basements, bathrooms, and utility closets. The relationship that these areas have to each other in terms of placement and connection will have implications on how you will treat them; in terms of energy retrofits, it is important that they are distinguished from one another.
  • To help separate the conditioned space, add insulation around your electrical outlets.

Tools[edit]

Thermographer photo style
Blower Door equipment in use

Though the home energy assessment can be done by simply observing the objectives listed above, there are a few tools that can be used to give even more in-depth idea of how your home's energy consumption. A Blowerdoor can be used to measure the airtightness of a home. By doing this one can find the air leaks throughout the house, and diagnose where heat is being lost. Another tool of the trade is called a Thermographerwhich is typically a camera with the ability to capture temperature differences and display them as images. The purpose of this device is to determine where heat is escaping from homes, or where areas of high energy use and heat are being created.