humidity/temp/dewpoint questions

[venting]

I noticed that some thermostats are now starting to include hygrometers and have the ability to dehumidify on demand. Can someone clarify setpoints for me? I have been searching other threads and noticed a lot of people state to keep RH at around 50. some people say to keep it at below 50. Shouldn't this always be stated with a temperature since they are related? For example, a temperature of 76 degrees with a 50 RH does not have the same water content as 73 at 50 RH. At 73/50, the rh would be around 44 at 76 degrees and 42 at 78 degrees if moisture content is held constant. Therefore, a person that keeps his house at 70 degrees and has a RH of 60 does not have a humidity problem. Is it better to look at dewpoint instead of temp/RH? Based on the numbers, it looks like a dewpoint below 59 should feel comfortable.

Would a temperature of 73 and RH of 55 be considered good considering the following factors?
OD temp 88 degrees
OD RH 71 percent
OD 77 Dewpoint

Does anyone have any literature that explains any of this well?

[ACFIXR]

Try this

[Shophound]

At normal room temperatures in the cooling season, keep the indoor dew point below 55 degrees.

This is easier than fretting about relative humidity. It has "relative" in the term for a reason.

[beenthere]

I don't.

But, a 59° dew point is too high for any indoor temp below 77°.

70°DB X 59°DP=68.1%RH
72°DB X 59°DP=63.6%RH
74°DB X 59°DP=59.5%RH
76°DB X 59°DP=55.6%RH

At 72°DB X 59°DP, it would feel more like it was at 79° at 43.1%RH.

[just_opinion]

I noticed that some thermostats are now starting to include hygrometers and have the ability to dehumidify on demand. Can someone clarify setpoints for me? I have been searching other threads and noticed a lot of people state to keep RH at around 50. some people say to keep it at below 50. Shouldn't this always be stated with a temperature since they are related? For example, a temperature of 76 degrees with a 50 RH does not have the same water content as 73 at 50 RH. At 73/50, the rh would be around 44 at 76 degrees and 42 at 78 degrees if moisture content is held constant. Therefore, a person that keeps his house at 70 degrees and has a RH of 60 does not have a humidity problem. Is it better to look at dewpoint instead of temp/RH? Based on the numbers, it looks like a dewpoint below 59 should feel comfortable.

Would a temperature of 73 and RH of 55 be considered good considering the following factors?
OD temp 88 degrees
OD RH 71 percent
OD 77 Dewpoint

Does anyone have any literature that explains any of this well?

Even the engineer uses RH to control the HVAC. So don't feel bad.

[teddy bear]

I don't.

But, a 59° dew point is too high for any indoor temp below 77°.

70°DB X 59°DP=68.1%RH
72°DB X 59°DP=63.6%RH
74°DB X 59°DP=59.5%RH
76°DB X 59°DP=55.6%RH

At 72°DB X 59°DP, it would feel more like it was at 79° at 43.1%RH.

Plus-- Consider some that 59^F dew point air gets into a 65^F crawlspace/basement, results in +80%RH space that grows mold. The 50%RH requirement has some meaning regarding moisture absorption by the materials in the home. Idealy, storage space in basements/crawls should be 50%RH. The dew point will depend on the temperature in the space. This is why dehumidifiers use %RH to for a dehumidistat.
Regards TB