Nevertheless, Rosenbaum’s preference for ASHPs in highly insulated buildings does nothing to explain GHPs’ low market share growth rate. Net Zero buildings are the exception, not the rule, and have a far lower market share than geothermal heat pumps. When the heating load is very low, the operating cost advantage from the greater efficiency of GHPs is not enough to repay the additional installation costs. That is not the case in 99.9% of new and existing buildings today.
GHPs Almost Everywhere Else
My own home, a farmhouse built in 1930, is much less efficient and requires a lot more heat than a Net Zero home, despite my own significant improvements. I don’t have enough suitable roof space for photovoltaics to make up for the extra energy ASHPs would require, even if that could be done economically. I opted for four ductless minisplit ASHPs rather than a GHP system, but it was because the minisplits allowed me to do the install without adding air ducts. Adding air ducts to my 85 year old home would have significantly increased the cost and disruption of installing a GHP system.
ClimateMaster, a division of LSB Industries (NYSE:LXU), makes a ductless split system called the Tranquility Console Series which probably would have been suitable for my needs, but I did not know about it until I received comments on an earlier version of this article telling me about it, nor did any of the geothermal installers I spoke to. Unfortunately, the efficiency ratings are low for GHPs with a COP of 3.3 in the ground loop configuration. This is not much better than the Mitsubishi air source units I had installed, which operate at a COP of around 2 from around -10° to 20°F outdoor temperatures, and exceed 3.3 COP when the ambient temperature is 35°F or more. The added efficiency at low temperatures would probably not have been sufficient to pay for the ground loop, but I would have been interested to get a quote. Waterfurnace Renewable Energy (TSX:WFI, OTC:WFIFF) offers the Envision Series Consoles with slightly higher heating efficiency (up to 3.5 COP) for certain models.
Since GHPs are economic in most situations, other factors must be holding them back.
The relative complexity of a geothermal system is one likely suspect. As Rosenbaum says about ASHP minisplits,
“[O]ne thing I really like about the minisplits is how they are packaged systems from a single supplier, and are highly engineered as a system and therefore very reliable. GSHP systems are, at least where I have practiced, essentially custom engineered and installed, usually by several entities who have a shared responsibility to make sure the systems perform.”
Given the large up-front cost of a GHP system, the risk of a poor installation is likely to deter nonprofessionals from using GHPs even more than it deters experienced professionals like Rosenbaum.
The Curse of Complexity
The cure for installation risk would be a way to validate the performance of GHPs in the field, and track problems back to their source. When contractors lose the ability to blame others for their mistakes, they quickly stop making those mistakes or they go
out of business. Without such monitoring, it’s nearly impossible to track increased electricity use back to the source.
I recently spoke to Matt Davis, the co-founder of Ground Energy Support and a professor of hydrology at the University of New Hampshire. Ground Energy Support provides GHP monitoring to GHP owners and contractors, as well as data and analysis to support the development of the industry.
Ground Energy Support recently published a 14 page Homeowner Guide to Geothermal Heat Pump Systems. While I found the guide easy to understand, it makes clear that GHPs are not for everyone. The start of the guide directly helps homeowners decide if they and homes are suitable for a GHP, while its length indirectly makes the point that GHPs are not always “plug and play.” The six pages dedicated to finding and selecting a suitable GHP installer indirectly makes clear that the process is not for anyone with only casual interest in GHPs and their savings they bring.
If GHPs are to become commonplace, the process of financing and purchasing a reliable GHP system have to be simplified to the point where it becomes a matter of calling a name in the phone book. The success of SolarCity Corporation (NASD:SCTY) in providing solar to homeowners who are more interested in the green in their checking account than the green of their electricity shows the potential. That success is based on SolarCity’s ability to provide financing, installation, maintenance, and performance verification services internally. All the homeowner needs to do is pay the monthly bill for electricity production. The value proposition is simple: a hassle-free installation and savings from day one.