by Don Ames, www.detectenergy.com
Nothing worse than saving and planning for that energy efficiency project and then having the Contractor lose the potential savings because of poor quality work. Whether we're talking about attic insulation or new windows, the right contractor can make the difference between zero reduction in energy usage and a 40% reduction.
Before you head for the yellow pages and put your money on the dotted line, know that a job done well will result in energy savings and a job done poorly will not. To get your project headed in the right energy efficiency direction, ask your power company to recommend a contractor or two. Chances are they have already weeded out the bad ones.
If your not sure that you have prioritized your energy efficiency projects correctly, you may be ahead-of-the-game to have an Energy Pro check your home and your retrofit wish list. Trained energy auditors will be able to estimate a retrofits potential energy savings and help you prioritize the retrofits in descending order of cost effectiveness. Here again, your power provider or your State Dept. of Energy may be a good resource for identifying qualified Energy Auditors.
If the Energy Auditor shows up at your front door with a pickup load of impressive equipment, invite him or her in. If all they have is a company brochure and an invoice, tell them you have changed your mind and would like to reconsider. Please understand - a sloppy contractor can really short-sheet your potential energy savings, but an ill prepared energy auditor is even worse.
From all around the country, data from government weatherization programs has been pouring in for years. Some counties will do 200 weatherization retrofit's per year and are keeping up that hectic pace so they can whittle down their 600 home waiting list. If your driving down a narrow residential street and you see a small box truck with writing on the side that says "County Weatherization", you know somebody is being issued a smaller power bill through energy efficiency retrofits. Stop and give them a pat-on-the-back, both the contractor and the homeowner.
Some of this weatherization retrofit data has provided some surprising results. By analyzing the data, the true cost-effective retrofit has been identified and quantified. Some old beliefs as to what was saving energy had to be sent to the bottom of the list and some things had to be retrieved from the bottom and placed near the top.
When household energy education was added to a weatherization program, the weatherization retrofits produced additional energy savings. Data indicated that the lifestyle of the household and their awareness of potential energy waste impacted the effectiveness of the energy saving measures.
The more an Energy Auditor is prepared and managed, the more successful the retrofits. A really sharp auditor is able to identify the retrofits that lead to the most cost-effective energy measures. By effectively prioritizing energy efficiency measures, the auditor is able to increase energy savings.
Winter heat loss and summer heat gain are really different animals and require strangely different measures. Those retrofit projects that are so effective in Arizona did not fair too well in North Dakota. Research performed on the bungalow by the palm trees had to be thrown out the window when the house was moved to the rain forest of the Olympic Peninsula. Be careful reading that great article in the digest about double low-E glass for windows, might not be such a good idea in your neck-of-the-woods.
Data indicates that your best chance of finding significant energy saving opportunities in a large house will be found in the mechanical system. In a climate where degree heating days outnumber degree cooling days, look at the heating system to find areas where energy efficiency can be increased and energy savings can be realized. Cooling days outnumber heating days, look to your cooling system to find energy savings. Also, the bigger the house, the more energy is used by lighting. Power reduction can be realized with energy efficient lighting fixtures and bulbs.
During initial tests on homes and determining areas of energy waste, researchers were surprised to learn how much the duct system contributes to energy waste and the potential for energy savings. First of all, ducts have a lot of holes, more than one would think. Second, the air that leaks through those holes causes a lot of expensive trouble. With duct leakage, you end up paying for conditioned air you never get to use and the leaking creates air pressure differences that increases air leakage through the exterior walls. It's the double whammy.
Blown insulation that can be dense packed in a cavity will act as a poor mans air barrier. Cellulose is a type of insulation that can be packed in a wall cavity to a density that will reduce the transmittance of air through the wall. This takes a little practice, if your going to dense pack and do it yourself, better spend a little time with a pro first. If your going to have a contractor do it, don't assume they know what they are doing, like I said, dense packing is not for the dense.
The thermal resistance of insulation is greatly reduced if air is allowed to flow around it or through it. This is where your air barrier comes into play - insulation should be placed next to a sealed and continuous air barrier. Insulation, install it correctly or you might as well not install it at all. Insulation is one of the most cost effective, energy saving retrofits you have, unless you install it in a wind tunnel.
Too bad doors and windows cost so much - they look good, but they just cost a lot. If the window or door is secure, weatherstripped and in good working order, it is not a cost effective weatherization measure to replace it. The payback period on a window can be 30 years if you are just figuring energy savings - if you are figuring how they look from the street, the payback period is reduced to the eye-of-the-beholder. Too often doors and windows are replaced when they could be repaired. Door and window weatherstripping can be replaced.
As an example, a 900 square foot home with electrical usage of 800 kW/h per month has a potential energy savings of 10%. A 3,600 square foot home that uses 2,400 kW/h has a potential energy savings of 35%. This is simple math, the more you use - the more you can save. The general assumption of the family sleeping in a large home built in 1995, is that they have it made - big newer home, everything, energy-wise, is up-to-date and OK. Little-do-they-know, they maybe having breakfast in the worst energy hog on the block.
In all this energy efficiency and energy savings, computerized energy audits produce more energy savings than a pad of paper and a sharp pencil. Auditors and weatherization programs that use computerized modeling as a part of the audit process increased the percentage of effective energy savings at comparable homes. The modeling provided additional information concerning cost effectiveness and the retrofit project as a whole.
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