HVAC in Washington has to cool a District rowhouse that stores heat in the brick, then heat it on a damp winter day when the rivers make the air feel colder than it is. The top floor over a flat roof is the complaint in summer. The English basement is clammy in every season. Radiators still heat a great many of these rows. Window units still fight bedrooms the radiators never reached. Say what is actually in the house.
The alley is a bad place for a condenser and it is where the condenser usually goes. Poor clearance, debris, and heat off the opposite brick wall are normal. A boiler low in the house can leave the third floor lukewarm. Ducts added later snake through closets and the ell. If you only have radiators, do not call it central air. The person on the phone needs the truth of the equipment, not the equipment you wish were there.
Give the symptom on the floor where it happens. The top will not cool after sunset. A rear bedroom smells at the first heat. Ice on the alley unit, a thermostat on a drafty stair, and a filter behind a panel you cannot open are all useful. These houses stay hot because the masonry is the battery. That is not a mystery and it changes what a new piece of equipment can do.
Fuel and location belong in the call: gas or electric, cellar, closet, or alley. Maintenance before the humid stretch is not a no-heat emergency, and both are legitimate calls if you say which. Do not invent the failed part. A blocked return can imitate a dead compressor. The party wall will not air-condition the house beside you, and it will not excuse a top floor that has no supply.
HVAC in Washington is District brick, flat-roof heat, basement damp, and alley equipment on a rowhouse. Call the number on this page.