|Affordable Cooling with Window Air Conditioners|
|Radiant barrier installations averaged $394 per house, including an estimated $250 for material donated by the Reflective Insulation Manufacturers Association. Air conditioner installation (materials and labor) was $811-$1,487, averaging $947.3
Rather, it probably reflects tight financial situations and use of air conditioning to cool only a portion of each home. Occupants in many houses may have accepted discomfort knowing that operating the units would be costly. In some parts of the houses and especially the kitchen, elevated indoor temperatures may have been even more severe than those measured; window units by design only cool limited areas.
The only two houses with savings greater than 1,500 kWh per year were both in the air conditioner replacement group which also had the fewest houses with negative savings and only one with large negative savings (consumption increases greater than 500 kWh per year).
For example, houses with high consumption had higher savings while houses with low consumption had lower savings. The average savings for four houses with pre-weatherization consumptions greater than 2,750 kWh per year was 1,503 kWh per year (41% of their average pre-weatherization consumption), nearly three times that observed for the group as a whole.
We monitored indoor temperatures in each of the houses in the rooms with the window air conditioners. If two air conditioners were in a house, we monitored the indoor temperature in the room with the air conditioner operated most (as reported by the occupants). Summer indoor temperatures often were far above the 72-81deg.F comfort zone (at 50% relative humidity) prescribed by ASHRAE. It's likely that some indoor temperatures approached heat stroke thresholds (95deg.F at 50% relative humidity) as identified by ASHRAE's Handbook of Fundamentals.
Outdoor temperatures rarely dropped below 80deg.F on these 41 days. In contrast, indoor temperatures fluctuated between 77deg.F and 82deg.F in 19 houses that consistently used their air conditioners (with pre-weatherization consumption greater than 2,500 kWh per year).
Comfort zone temperatures inside the house were achieved from this approach only for summer days when the average outdoor temperature was less than 78deg.F. For hotter days (82 such days occurred during the pre-weatherization summer), average indoor temperatures remained above 85deg.F at midnight.