Published on September 29th, 2011 | by Jeff McIntire-Strasburg2
The Ductless Heat Pump: an Efficient Heating (and Cooling) Solution
UPDATE (2/3/12): NEEA has wrapped up their Going Ductless campaign, and drawn a name for the cash prize. Ross Daniel of Seattle will no doubt have a good weekend, as he’s the winner of the $10,000 grand prize. He’s also a big fan of ductless heating systems, which we describe in more detail below…
It’s starting to get cooler out, especially at night, and your thoughts may be turning to the pleasures of Fall: colorful trees, sweaters, and hot mugs of cider. Of course, you may also be dwelling on some less pleasant thoughts… namely, what it’s going to cost to heat your home this Winter. I don’t know if the almanac’s predicting as brutal a winter as last year, but we’ll definitely be running the heating system… and paying for the fuel to do it.
The Northwest Energy Efficiency Alliance (NEEA) has picked this appropriate time to start promoting a technology that was new to me: the ductless heat pump. Their argument: this heating (and cooling) system is much more efficient and cost-effective than some of the decades-old technologies many of us still use, like baseboard and wall heaters. They’re having fun with their Going Ductless campaign by letting people know that “the 70s are calling, and they want their heater back,” giving users some graphic tools that allow you to place your picture in 7os-style settings, and sharing their “King of HVAC” videos (that’s one above). They’re even offering a $10,000 cash prize to Northwestern residents. They’re very serious about the technology, though, claiming that ductless heat pumps can save consumers 25 – 50 percent on heating bills when compared to older systems.
Still, I didn’t know much about these systems, so I started digging…
What is a ductless heat pump?
Essentially, they’re smaller-scale versions of air-source heat pumps. Also known as “mini-splits,” they consist of “two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.”
They seem like a good alternative for new construction, for replacing a ducted system (if you need to do that… I don’t know that the costs line up for optional replacement), or for replacing non-ducted systems. They run on electricity.
What makes these systems so efficient?
The Oregon Department of Energy lists three advantage of ductless heat pumps:
- They’re ductless (duh!): Since they’re not feeding heated or cooled air through ducts, much more of that air makes it into the room – the US Deparment of Energy notes that losses of heated/cooled air through ducts can account for as much as 30% of the energy consumption of those systems.
- Inverter technology: “Variable speed compressor models, usually labeled “inverter technology,” avoid on-off cycling losses and are able to provide usable heat efficiency on all but very cold days.”
- Zoning: Ductless heat pumps work a bit like space heaters, it seems; that means you can warm/cool specific areas of your home that you’re using, rather focusing on the whole house.
Disadvantage of ductless heat pumps
The US DOE notes that these systems can cost more per ton of cooling capacity: about 30% more than a central (ducted) system (but that doesn’t count the cost of ductwork), and twice as much as window units. That appears to only take into account upfront costs. DOE also notes that these systems must be properly sized and sited in order to achieve maximum efficiency and cost savings (but that strikes me as a qualification that applies to nearly any heating/cooling system). Finally, because this technology is still relatively new to the US, you may have trouble finding an installer (though, if you live in the Northwest, NEEA has a tool for locating qualified installation professionals).