Heat Pump Efficiency: Two Zones vs. One
LESLIE: Bud in Virginia’s got a problem. You’ve got some heat pumps. What’s going on?
BUD: Yeah, I have two heat pumps on my house. It’s a single-family home. It’s 2,500-square-foot all on one level. And it has two heat pumps and one of them is really starting to make a lot of noise and we’re going to have that replaced. But I was wondering if we can just get one whole system to replace both units with one.
TOM: Well, it’s separated now into two zones, I presume. Correct?
BUD: That’s correct, yes. There’s two thermostats and two …
TOM: Yeah. No. So you will always need two heat pumps.
BUD: OK. There’s no way to put that all into one? I’ve … my only reason for that is the cost of one is substantially cheaper than buying two and they’re both about 20 years old.
TOM: Yeah, but then you would have to run … let’s say … let’s say you could conceivably do that. You would be running a much larger unit and spending a lot more money to run it more hours of the day. With two zones, you know, you run the different zones when you need them. So, a two-zone system is always more efficient than a one-zone system; even though the equipment cost is a little bit higher.
TOM: If you have a one-zone system, you can divide it up further by the use of zoning dampers that close off different parts of the duct system. But you generally can’t take a two-zone HVAC system and turn it into one; nor would you want to.
TOM: Alright, Bud?
BUD: Alright. Thank you very much.