Manual J design temperatures for Detroit, MI

Winter 10.4 °F, summer 87.8 °F / 71.4 °F wet bulb, daily range M: the outdoor design conditions for a residential load calculation in Detroit, with a free lookup for any address.

Detroit, MI: Manual J outdoor design conditions

Winter design dry bulb (99 %)10.4 °F
Summer design dry bulb (1 %)87.8 °F
Coincident wet bulb (1 %)71.4 °F
Daily range classM
Grains difference (75 °F, 50 % RH indoor)+26 gr/lb
Elevation626 ft

ASHRAE Handbook method (2025 edition) at Detroit-Young Intl Ap (WMO 725375), the nearest station with a recent record to the city centre. A different address in the area can use a different station: look it up below.

What these numbers mean for a house in Detroit

Heating equipment and heat pumps in Detroit are sized for an outdoor temperature of 10.4 °F: colder than that for only about 88 hours in a typical year. Cooling is sized for 87.8 °F with a coincident wet bulb of 71.4 °F. The daily range is medium (15 to 25 °F), which sets the Manual J cooling-load factors, and a grains difference of +26 gr/lb drives the latent (moisture) load. With indoor design temperatures of 70 °F heating and 75 °F cooling, the design temperature differences are 59.6 °F and 12.8 °F.

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For a whole-building energy model, the same site gets hourly EnergyPlus weather files (EPW) with design days: typical year, actual years and future climate.

Frequently asked questions

What is the Manual J winter design temperature for Detroit, MI?

10.4 °F: the 99 % heating dry bulb by the ASHRAE method at Detroit-Young Intl Ap.

What is the Manual J summer design temperature for Detroit, MI?

87.8 °F dry bulb (1 %) with a coincident wet bulb of 71.4 °F.

Which daily range class does Detroit use?

Class M: medium (15 to 25 °F).

Can I get the values for my exact address?

Yes: type the address in the lookup on this page. A one-page PDF for the permit or rebate file costs 1 credit.

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