HVAC Guide
Heat pump or furnace in this climate
By All Purpose Anytime Services LLC
Most of a winter around DC sits at temperatures where a heat pump runs efficiently, with a handful of nights where it needs help. That's the whole argument. The rest comes down to how the system is set up.
What a heat pump does differently
A heat pump moves heat from outside to inside instead of burning fuel to make it. In mild cold that's efficient. As the temperature outside drops it gets less efficient, until the backup heat costs less to run than the heat pump does.
That crossover is the balance point, and setting it properly is the difference between a sensible bill and a shocking one.
Why the air feels cooler
A heat pump sends out air at a lower temperature for longer stretches, where a furnace gives short blasts of hot air. The rooms reach the same setting. The air from the register feels cool on your hand, and that's normal.
Where a furnace still wins
A house with a gas line already in, poor insulation and undersized ducts often heats more comfortably and more cheaply on gas. The price of fuel matters too, and it moves.
The dual fuel option
A heat pump with a gas furnace as its backup runs the heat pump in mild weather and switches to the furnace when it gets cold enough for gas to be cheaper. It costs more to install, and it suits houses that already have gas.
Questions to answer before you choose
- Is there already a gas line to the house, and is it sized for a furnace?
- Are the ducts big enough to move the lower temperature air a heat pump delivers?
- How well is the attic insulated and how drafty are the windows?
- Is the AC also near the end of its life, so one heat pump could replace both?
A house that says yes to the last question and has decent ducts is usually the strongest case for a heat pump. A house with gas already piped in and small ducts usually points toward the furnace.
Weighing a heat pump against gas
Tell us what heats the house now and whether there's a gas line, and we'll price it both ways.