Heat Pump or Not

dougrainer wrote:

The Heat Pump is an electric source for heat. It will supply and maintain heat assuming the
outside (ambient) temperature is above 40 degrees.

Just a slight clarification: Both use electric for power but in very different ways.
- A heat strip converts electrical power to heat power. It's basically like a toaster with a fan blowing across the coils. The total electrical power that goes in will roughly equal the heat power out. Very similar to a small electric space heater but built into the air/con unit. It will put out the same amount of heat energy regardless of the interior or exterior temperature.
- A heat pump, uses electricity to run a "pump" to push heat from outside to inside (or vice versa when cooling). As a result it tends to be more efficient than a heat strip at moderate temps but as it gets colder outside, it takes more electrical power to push across the larger temperature difference (similar to pumping water to a greater height). (A traditional roof air/con unit is basically a one way heat pump that can only pump heat from inside to outside).

An analogy: Moving a wheeled cart.
- Heat Strip is like lifting cart off the ground. You might be able to lift a 200lb cart by yourself but quickly you will reach your limit. (this is also equivalent to a propane furnace where chemical energy stored in the propane is converted to heat energy). If it's within your lifting ability, the slope of the hill you are standing on doesn't make much difference so long as you can stand securely.
- Heat pump is like pushing the cart forward on the wheels. I can push a 3000lb compact car on level pavement by myself. I can push a 500-600lb cart up a 2-4% slope (far more than I could lift). But as you increase the slope, it gets harder and harder and the cart moves slower and slower. A steep hill is equivalent to heating in cold weather...eventually, the pump simply can't overcome the temperature difference.