Is geothermal good for my community?
It's news to no one that construction for senior living is strong, in no small part because large investment dollars are flowing into the space. But those investors, and even mission-driven nonprofits, are looking harder at each dollar spent on construction to make sure it is used as wisely as possible. As builders, our charge is to help those teams invest those dollars however it best serves the goals or business case of any specific project.
Beginning with the energy crisis of the 1970s and elevated by the LEED (Leadership in Energy and Environmental Design) guidelines first published in 1994, project teams regularly evaluate geothermal heating and cooling as an energy-saving option. Depending on the myriad variables of a given project, geothermal may or may not be the right choice.
Here are a few ideas to help you evaluate this technology.
First, let me explain the basics of the system. Geothermal takes advantage of the fact that at a relatively shallow depth, below-ground temperatures remain essentially unchanged all year. So in the coldest of winters or the hottest of summers we can move heat to or from the ground into our buildings with essentially the same science that traditional heating and cooling systems use.
Geothermal's advantage is that those traditional systems use expensive mechanical machinery (a chiller, a boiler, a compressor, etc.) and a lot of energy to generate that heat transfer, whereas the Earth is free (or at least paid for). The system pumps a liquid (usually water) down into wells deep enough and long enough for it to assume the proper temperature and then returns it to the terminal unit in the resident room where the heat transfers to or from the loop depending on whether there is demand for heating or cooling.
There are also “open” loop systems that simply draw water from the ground (or a deep lake) and reject water from the terminal units in a balanced quantity but these are rarer. So instead of large central plant, the community runs a series of small water pumps and energy bills drop significantly.
The first consideration for most systems – and even more so for geothermal — is the cost to install it (so called “first costs”). Geothermal, justifiably, has a reputation for being expensive to install. It is. However, at a per-resident-unit level, geothermal may carry a first cost premium of $10,000 or more (sometimes quite a bit more) over traditional systems. In a long-term care or assisted living unit, the energy usage is probably less than $100 per month, so the payback on that first cost is exceptionally long, much longer than most providers or investors would consider prudent.
So why is geothermal done anywhere, ever? One reason is definitely marketing. In the communities for whom we have installed geothermal, there is a "sustainability theme" running through the entire brand and the communities show potential residents and their families how much energy geothermal saves as an explicit demonstration of their commitment. With these communities, being green is much more than lip service and recycling bins.
Another reason is architectural. Especially in long-term care, regulatory bodies often require each resident unit to have an independent (not shared with another resident) HVAC system. Generally, this is a through-wall unit that sits under the window so it can draw fresh air from the outside.
The grille or louver that allows that air to pass through is a potential source of leaks and generally considered to be an eyesore when viewed from the outside. With a geothermal unit, we can bring fresh air in through a rooftop unit (where it can be preconditioned enhancing comfort) and the wall penetration eliminated. Hotel brands think similarly. Hilton's limited service Hampton Inn will usually have these grilles below the windows whereas Hilton's luxury line, Conrad, almost never will.
Lastly, we encourage clients to consider geothermal systems when renovating landlocked buildings or spaces where reclaiming rooms for revenue-producing activities or care is needed. Because geothermal systems don't require that boiler or chiller (a central plant), we can often reclaim some or all of the mechanical room space and repurpose it to the betterment of the community.
Similarly, in a new construction project with a limited footprint, we can reduce building square footage (also an economic enhancement), particularly if your local jurisdiction allows for the geothermal wells to be installed directly under the building.
There are a few operating issues geothermal raises (the wells can be a path to ground for lightning, the terminal units are technologically complex so servicing is usually outsourced, they run constantly so residents don't hear that on/off cycle they're used to). But first costs are always the reason the system isn't chosen.
In 50-plus years of building senior living communities, we've done geothermal less than a dozen times. But as competition increases and differentiation becomes critical, this is one way to set a community apart and drive down operating costs.
It won't make sense for everyone, but it's worth evaluating to make sure.
Michael Hass, LEED AP, is the director of senior living at The Weitz Company in Florida.