Furnace vs. Heat Pump: What’s the Difference?
LESLIE: Tim in Indiana, you are on The Money Pit. What can we do for you?
TIM: Hi, I’m trying to figure out what the difference between a furnace and a heat pump is and which one’s better to replace a furnace with.
TOM: Well, what do you have now? Do you have gas heat?
TIM: I have gas heat and I had some – it’s a – the house was built in the 60s and it’s an existing furnace.
TOM: If you have gas heat then there’s no reason to put in a heat pump. If you have electric heat, then putting in a heat pump is a viable option. What a heat pump is – just for those that are not familiar with it – is basically an air conditioner that runs backwards. It has a reversing valve as part of the refrigeration cycle. Think of a wall …
LESLIE: But they can’t do both. It’s strictly a heat pump if it’s a heat pump.
TOM: No, it goes – well, a heat pump also supplies cold air or hot air. It basically reverses the refrigeration system.
TOM: In the summer the refrigeration runs one way. In the winter it runs a different way. But it uses the principles of refrigeration to basically either cool or heat your air.
TOM: Think of a window air unit; a portable. You know how it blows hot air out of the back side?
LESLIE: Turning it inside out.
TOM: Yeah, it’s like turning it inside out is all a heat pump is. And the way a heat pump works is it maintains the temperature in your home as long as the difference between what you set it at and what it is, is two degrees. So if you set the thermostat at 74 but it falls to 73, the heat pump comes on. If it falls to 72 the heat pump stays on. If it falls to 71, the heat pump says, “I can no longer keep up with your demand for heat” and brings on another part of the heat pump which is called the backup heat. And that’s straight electric resistance heat. Now it gets warm quick when that happens but it makes your electrical cost about triple.
LESLIE: Yeah, but imagine just trying to maintain the standard heat if it’s kicking on all the time. It’s expensive.
TOM: Yeah, it can be. You know, I was down in Florida not too long ago and I had to actually adjust the thermostat for my mom and dad. They have an electric heat pump in their house. And I instructed them to not move the thermostat up and down quickly. Because if you have a heat pump, you have to have a special heat pump thermostat that moves it up and down slowly because it doesn’t trigger that backup resistance heat from coming on.
TOM: But you know what? Hands down, if you’ve got gas I would never replace a good gas system with an electric heat pump because it’s going to be much more expensive to run.
TIM: OK, thank you.
TOM: You’re welcome, Tim. Thanks so much for calling us at 888-MONEY-PIT.