This article series discusses finding and curing air leaks and heat losses in buildings, here focusing on the bottom line value of energy savings retrofits - where to spend your weatherization and insulation money. This detailed article accompanies a building weatherization and energy-savings company through a detailed building inspection for heat loss points and air leaks.
Our page top photo shows the risk of an insulation blow-in retrofit by an amateur. The heating cost reduction from adding cellulose to the attic floor may be offset by the installer's mistake of knocking down and failing to replace improperly-installed horizontal fiberglass batts on the attic side of a wall between the attic and heated space.
The net gain of this incomplete insulation retrofit may have been small. But properly performed, an energy retrofit that determines the main heat loss points in a building (or un-wanted heat gain during the cooling season) can pay for itself very quickly.
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As we introduced above, in this article the author, Steven Bliss, accompanies a building weatherization and energy-savings company through a detailed building inspection for heat loss points, convective loops, and air leaks.
The author accompanies Princeton Energy Partners as they use thermal imaging, smoke guns, and visual inspection to pinpoint building air leaks, heat loss points, air infiltration and air exfiltration on a building.
The importance of setting priorities for sealing these points of energy wasted is emphasized and discussed, and sketches as well as photographs of common points of building heat loss, or unwanted heat gain, and air leaks are provided.
The text below paraphrases, quotes-from, updates, and comments an original article, "House Doctors with Better Medicine, Princeton Energy Partners use the latest diagnostic tools to comb a house for the major causes of heat loss. Their findings are often astonishing. Their strong prescriptions bring results', Steven Bliss, (see links just above) from Solar Age Magazine and written by Steven Bliss.
Energy retrofitting reduces drafts and cold spots and, according to PEP, produces some unanticipated benefits such as fewer rodent problems and fewer frozen pipes. Still, to sell the service to big buyers - the developers, housing authorities, and government agencies - it has to show an attractive return on investment. Says Gadsby referring to conventional weathersealing treatments, "To do a job for $1200. that's going to save $50. a year is just not the way to do business."
In some cases the savings have been spectacular. For example in a 1982 retrofit, PEP spent three months retrofitting the 450-unit Glenhardie Condominium Comlex near Valley Forge, PA, for $62,000.
The 20-building development already had its insulation and heating system upgraded when it went condo four years earlier. After three months of house-doctoring, consisting solely of attic work, the annual heating bill was reduced from2093 to 1329 therms of natural gas, resulting in a first-year savings of $40,600, not including the $9,300. tax credit.
More typical was a proposal to the Baltimore Housing Authority, in which PEP agreed to treat apartments for $550. each while they were undergoing rehab. PEP's work was to be staged over two to three visits.
With annual heating bills in that housing stock running $1200 to $1300 (1984 costs), the simple payback would be under three years. In terms of air infiltration alone, said Gadsby, recently-built townhouses generally measure in at about 10 to 15 ach (1984 data) at 50 Pascals before house-doctoring and are sealed down to about 6 ach after.
Costs for weatherizing are held down by providing the service in a one-day blitz, or in new construction in a series of quick hits. In general, a weatherization company can do more effective work for less money during construction or rehab than with retrofitting, since the problems are more visible and accessible. The cost to the homeowner was estimated to be one half to two-thirds what it would cost to retrofit after construction, and you're probably going to save an extra 5 to 10 percent on energy costs as well.
See HEAT LOSS R U & K VALUE CALCULATION for additional details about calculating building heat losses.
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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