Edwin Pawlowski wrote:

"Bill" wrote in message

Well if venting the dryer indoors, how much would it raise the indoor
relative humidity? Only from 40% to 60%? I should think it would be more
than that...

Based on what? The depends on the number of loads of laundry...

1 load.

wetness of hte laundry,

12 pounds of water.

size of hte house, etc.

A 2400 ft^2 average US house with 0.7 ACH, dried in H hours,
with a 0.0025 outdoor humidity ratio.

10 WO=.0025'outdoor humidity ratio (Phila in January)
20 TR=70'room temp (F)
30 CFM=.7*2400*8/60'airflow through house (cfm)
40 W=12'pounds of water per load
50 FOR H=2 TO 12 STEP 2'drying time (hours)
60 P=W/H'water vapor supply rate (lb/h)
70 WI=WO+P/(60*CFM*.075)'indoor humidity ratio
80 PA=29.921/(1+.62198/WI)'vapor pressure of room air ("Hg)
90 PS=EXP(17.863-9621/(460+TR))'vapor pressure at Tr and 100% RH ("Hg)
100 RH=100*PA/PS'relative humidity in house (%)
110 PRINT H,RH
120 NEXT H

Time (H) RH (%)

2 53.60285
4 34.89333
6 28.61733
8 25.47186
10 23.58219
12 22.32141

Nick