Heat pump noisy?

I upgraded to a '14 from my '11 a little more than a week ago. Walked out to my car while it was pre-cooling, and noticed that the heat pump is pretty loud, definitely louder than the non-HP climate control in my '11. I shut off the A/C, leaving just the fan, and it got quiet, so it isn't the blower.

I'm used to heat pumps being a bit noisy, but hearing it in a car is a bit startling. Is this level of noise normal?

I don't notice it from within the car, but when I'm outside, the humming is definitely distinct. Compared to a normal window mounted AC, it's pretty dang quiet.

The heat pump is definitely improved over the '11, but I don't know what that entails. It's likely a larger/stronger compressor, which is what makes that sound.

If you're worried about something malfunctioning, take it to the dealer to look at. Otherwise, I wouldn't worry about it.

My 2013 has the same characteristic sound and volume as my home's central air compressor. I think it's kind of funny. At 3KW, it might have the same power as my home's A/C!! I turn it off when I'm bragging about how quiet the car is.

Never thought about how quiet the resistive (old) heater is, but I guess it is.

Staque said:

My 2013 has the same characteristic sound and volume as my home's central air compressor. I think it's kind of funny. At 3KW, it might have the same power as my home's A/C!! I turn it off when I'm bragging about how quiet the car is.

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Unless you have a very small unit for your home, your AC is probably rated closer to 6kW. Larger units can be 10kW. A small window unit is usually rated around 800W, with ~3000 BTU of cooling. Central air units are generally around 25,000 BTU.

I don't know the cooling or heating capacity of the Leaf, but based off wattage, it should be around 10,000 BTU.

Thanks, all! I wasn't too concerned, seeing as I know heat pumps are noisy! Having graduated from an '11, I'm used to silence, but I'll gladly take a little noise in exchange for better heater efficiency come winter time. That PTC heater was a killer!

I happen to have a service appointment tomorrow for an unrelated issue (auto headlight sensor not working), so I'll ask about it then, just in case.

I wonder what is it about a heat pump that would be louder than just a straight AC compressor? I thought the difference was mainly how the refrigerant was being routed to switch the roles of evaporator/condenser.

I think there are extra coolant pumps and lines involved.

Nubo said:

I wonder what is it about a heat pump that would be louder than just a straight AC compressor? I thought the difference was mainly how the refrigerant was being routed to switch the roles of evaporator/condenser.

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It's effectively the same thing. The only significant difference is the way it's hooked up allows it to function in reverse.
With the "AC" on, it's using outside air to cool the condenser, which reduces the cabin temperature. This is how a normal air conditioner works.

With the "heater" on, it's using inside air to cool the condenser, which increases the cabin temperature. Believe it or not, this is actually more efficient than a regular resistive heater. This is one reason why the winter range went up with newer models.