Manual J design temperatures for Philadelphia, PA
Winter 19.0 °F, summer 90.9 °F / 73.8 °F wet bulb, daily range M: the outdoor design conditions for a residential load calculation in Philadelphia, with a free lookup for any address.
Philadelphia, PA: Manual J outdoor design conditions
| Winter design dry bulb (99 %) | 19.0 °F |
| Summer design dry bulb (1 %) | 90.9 °F |
| Coincident wet bulb (1 %) | 73.8 °F |
| Daily range class | M |
| Grains difference (75 °F, 50 % RH indoor) | +33 gr/lb |
| Elevation | 10 ft |
ASHRAE Handbook method (2025 edition) at Philadelphia Intl Ap (WMO 724080), 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 Philadelphia
Heating equipment and heat pumps in Philadelphia are sized for an outdoor temperature of 19.0 °F: colder than that for only about 88 hours in a typical year. Cooling is sized for 90.9 °F with a coincident wet bulb of 73.8 °F. The daily range is medium (15 to 25 °F), which sets the Manual J cooling-load factors, and a grains difference of +33 gr/lb drives the latent (moisture) load. With indoor design temperatures of 70 °F heating and 75 °F cooling, the design temperature differences are 51.0 °F and 15.9 °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 Philadelphia, PA?
19.0 °F: the 99 % heating dry bulb by the ASHRAE method at Philadelphia Intl Ap.
What is the Manual J summer design temperature for Philadelphia, PA?
90.9 °F dry bulb (1 %) with a coincident wet bulb of 73.8 °F.
Which daily range class does Philadelphia 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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