Heating and cooling in Dover
Dover has been Delaware's capital since 1777, when the seat of the new state's government moved here from New Castle. The town grew outward from The Green, and its houses come from many periods. Whatever the age of the house, the heating and cooling system has two jobs that pull in different directions: drying out heavy summer air and keeping up on the coldest winter nights.
What the weather station says
Dover has its own NOAA engineering weather station, at Dover Air Force Base (elevation 30 feet), so the figures below are local rather than borrowed from another city. Its figures:
- a 1% summer design temperature of 89°F, with a mean coincident wet-bulb temperature of 75°F;
- a 99% winter design temperature of 17°F;
- about 612 hours in an average year with the wet-bulb temperature above 73°F;
- about 1,723 hours a year above a 67°F wet-bulb.
A 75°F wet-bulb on a design day is muggy air. A good share of an air conditioner's effort in Dover goes into pulling water out of the air, not just lowering the temperature, and a system that cools well but dehumidifies poorly leaves a house cool and clammy.
Moisture is part of the sizing
In humid weather, a frequent comfort complaint isn't a broken system; it's one that's too big. An oversized unit reaches the thermostat setting fast, shuts off and never runs long enough to wring moisture out. Ask each contractor:
- whether they'll do a room-by-room load calculation, and which design temperatures they'll use;
- how the proposed system handles latent load, the moisture side of cooling;
- whether a variable-speed or two-stage system makes sense for your house;
- what fan settings they recommend for humid weather, and why.
Heat pump or furnace
A 17°F winter design temperature is well within reach of a modern heat pump, but backup heat still matters for the coldest stretches. Ask:
- at what outdoor temperature the heat pump will need help, and what supplies it;
- whether a dual-fuel setup, heat pump plus gas furnace, fits your house and fuel prices;
- what the yearly operating cost of each option looks like, not just the installed price.
Efficiency rules
Delaware is in the Department of Energy's hot-humid Southeast region. Split-system central air conditioners installed on or after January 1, 2023 must be rated at least 14.3 SEER2 (13.8 SEER2 for 45,000 Btu/h and larger), and split-system heat pumps must meet 14.3 SEER2 and 7.5 HSPF2 nationwide. Treat those as floors. Ask what a higher-rated unit would save in your house before you pay for it.
Ducts in older and newer homes
Older houses often have ducts squeezed in long after construction, and newer ones may run ducts through hot attics or damp crawlspaces. Ask the contractor to inspect and test the ducts, seal leaks and add insulation where ducts pass through unconditioned space. New equipment on leaky ducts underperforms.
Checking the company
Delaware law requires construction service businesses to register with the Office of Contractor Registration at the Delaware Department of Labor before beginning work in the state, in addition to registering with the Division of Revenue, and the department publishes a lookup of registered contractors. The Division of Revenue requires any contractor doing business in Delaware to hold a business license.
Those two checks tell you the company is on the state's books. They don't tell you how good its work is. Look the company up, then ask whether any separate state license applies to heating and cooling work and which one the technician holds, and ask for recent local references.
Comparing quotes
Line the quotes up item by item: equipment make and model numbers, SEER2 and HSPF2 ratings, the load calculation, how humidity will be handled, backup heat, duct repairs, thermostat and controls, removal of the old equipment, the permit, start-up checks and both the parts and labor warranties. A quote that shows only tonnage and a total is missing most of what you need to compare.