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ENERGY SAVINGS in buildings
AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
APPLIANCE EFFICIENCY RATINGS
BASEMENT HEAT LOSS
BLOWER DOORS & AIR INFILTRATION
CATHEDRAL CEILING INSULATION
COMBUSTION AIR for TIGHT buildings
DEW POINT CALCULATION for WALLS
DEFINITION of HEATING & COOLING TERMS
DUCT SYSTEM & DUCT DEFECTS
ENERGY STAR PROGRAM
FLOOR RADIANT HEAT Mistakes to Avoid
FRAMING DETAILS for BETTER INSULATION
FREEZE-PROOF A BUILDING
GREEN BUILDING CONSTRUCTION
HEAT LOSS in BUILDINGS
HEATING COST SAVINGS METHODS
HOUSE DOCTOR, how-to be
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION INSPECTION & IMPROVEMENT
LEED GREEN BUILDING CERTIFICATION
SOLAR ENERGY SYSTEMS
THERMAL IMAGING, THERMOGRAPHY
THERMAL MASS in BUILDINGS
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
WINDOWS & DOORS
WINTERIZE A BUILDING
This article explains the priorities for preventing heat loss in a building.
We also discuss how to measure or calculate heat loss in a building, defines thermal terms like BTU and calorie, provides measures of heat transmission in materials, gives desired building insulation design data, and shows how to calculate the heat loss in a building with R values or U values.
Our page top photo illustrates a large insulation void in the walls of a building renovated by the author (DF). The seller had informed us that the house was "fully insulated". Our repair of this area is shown below.
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If we had not had other reasons to strop the walls in this room (loose falling plaster) we'd have considered blowing-in cellulose insluation - leaving the walls more nearly intact.
Watch out: on this and other older homes we renovated I often found voids in "blown-in" insulated walls where installers had not anticipated wall cavity blockages formed by diagonal bracing or fire stopping.
When the object is to make a building more energy efficient, and before any more sophisticated analyses are performed using thermography, insulation evaluations, or even calculations of areas, "R" values, "K" values, or "U" values (defined below), remember this order of concerns when working for building efficiency.
The order of magnitude of sources of un-wanted heat loss in a building are pretty much this:
1 - Close open windows or doors when a building is being heated or cooled by other than "natural means" (like using fans, summer breezes or evaporative coolers in windows). Where older windows are leaking air but are otherwise in good condition, it may be most-economical to install a high quality, well-installed, storm window.
2 - Investigate and cure leaky windows or doors or other openings that are producing drafts; also check for drafty wall or ceiling vent fan openings such as kitchen fans and whole house ceiling exhaust fans that have been left un-covered during the heating season. See BLOWER DOORS & AIR INFILTRATION - how to measure air leaks, equivalent leakage area (ELA), and air changes per hour (ACH) in a building.
3 - Top Floor Priorities of placing or improving building insulation: Investigate and make sure that the top floor ceiling or attic floor (or cathedral ceilings) have been insulated, with no insulation voids or areas where insulation was removed or omitted. See INSULATION INSPECTION & IMPROVEMENT
4 - Wall insulation priority: Investigate and consider installing or adding wall insulation.
5 - Building perimeter insulation: investigate and insulate any other un-insulated building perimeter areas such as the building rim joist or band joist accessed from a basement or crawl space.
6 - Insulate under floors over un insulated crawl spaces (we prefer to make the whole crawl space an enclosed and conditioned space).
7 - Insulate building foundation walls below grade in basements or in conditioned-space crawlspaces.
8 - Investigate the efficiency and state of tune of the building's heating or cooling equipment, including boiler or furnace and the condition of the heating or cooling delivery system (baseboards or ductwork, for example). (Warning: have heating systems cleaned and tuned by an expert before accepting a measurement of the system's efficiency.)
The full text version of this article has been relocated to RADIANT HEAT FLOOR MISTAKES where we describe installation specifications for radiant heat flooring in a poured concrete slab along with a detailed report of just how bad a radiant heat floor slab installation can be. The article's conclusions include this insulation advice:
Continue reading at HEAT LOSS R U & K VALUE CALCULATION or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs) about the priority of steps to take to stop building heat losses and reduce building energy costs
Questions & answers or comments about the priority of steps to take when cutting heating bills by reducing building heat loss - priority of fixing air leaks, sealing, caulking, insulating, etc. .
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