Abby Normal wrote:

Try this scenario, almost up your alley. Home without AC.

If you must have weather data, pick Duluth Minnesota...

Ah yes... 66.1 F in July, with 55.1 and 77.1 average daily min and max
and w = 0.010 (not very humid.)

It can get hot there, well above averages.

A 30-year record max of 97.0...

Basement walls, 10 inch poured concrete, no insulation added.

Windows upgraded to double pane low e. Natural infiltration sufficient
to avoid winter condensation, not high enough to warrant use of humidifier.

Large picture window facing east, perhaps 8'x5', two at 3x3 windows west.

Unshaded...

Curtains drawn to keep sun out as best it can...

...basement tends to be cool, like 66F in summer, will get warm upstairs.

Average yearly air (and deep ground) temp: 38.5 F.

Run dehumidifier in basement.

For heat :-)

Imagine access door on return air drop, open the access door. Run
furnace fan, most return gets drawn from basement, cool thermal storage
of air in basement gets re-distributed upstairs.

Upstairs will cool off a couple degrees, below grade effect takes the
air from upstairs and sensible heat rejected by dehumidifier, basement
temp stabalizes at 68.

End up typically with 78F upstairs humidity less than 60%.

Warming outdoor air to 78 would make the RH 48%...

I lived it for a couple summers, dehumidifier made a big difference.

You mighta froze without it.

Nick