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

If you must have weather data, pick Duluth Minnesota. It can get hot
there, well above averages. Assume a somewhat inland from Lake
Superior.

Small place, 900 square foot main floor, 900 square foot basement,
undisturbed R40 blown into ceiling, walls poorly insulated, lathe and
plaster, recovered with vinyl siding, similar to 2x4 framed walls.
67,000 Btu/hr 80% AFUE furnace more than adequate for heat loss, no
cooling load ever sized but would be no bigger than 1.5 ton.

Basement floor 5.5 ft below grade, 8 foot to under side of joists, main
floor 9 foot ceilings.

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.

North and south walls, two at 3x3 windows. Guessing that eaves overhang
by 2 feet and were typically 2 feet above top of windows

Curtains drawn to keep sun out as best it can.

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

Run dehumidifier in basement.

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%.

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

Also helped to have spare bed down in basement.

Need airflow take 67,000 input, 80% afue, 60 degree ATR

wrote:
Anyone else notice the ad for dehumidifiers on Bob Vila's web site,
which says "Stay a bit cooler with a dehumidifier"?

If it's 75 F and 80% RH indoors and outdoors, 11.8% of people would find
that "too warm," according to the ASHRAE 55-2004 comfort standard.

Dehumidifiers add about 1600 Btu/pint. An average house with 400 Btu/h-F
of conductance and 200 cfm of air leakage would be 79 F with 65% RH with
a dehum removing 1 lb/h of water, and 27.3% would find that "too warm."

OTOH, an AC using the same electricity and removing 1500 Btu/h of heat
and 1.5 lb/h of water would leave the house 71.3 F and 82% RH indoors,
and only 5.1% would find that "too warm." (We can't please everyone--
about 5% of the population will always be dissatisfied.)

Clicking on "How to contact Bob Vila" brings a message saying you can't :-)

Nick