SOLON — As utility bills for natural gas, propane, and electricity continue to increase homeowners may not be aware that the very ground their home sits on may be an option
for their heating and cooling needs.
Geothermal energy is a more efficient way of exchanging heat for your home or office
building, said Tom Rutkowski, General Manager for E&J in Solon as well as President of the Iowa
Geothermal Association.
“We use the ground as a thermal battery. We send a water and antifreeze mixture down, and that is what is transferring heat into and out of the ground. That water flows inside and hits a ground source heat pump. That’s where the water will interact with the refrigerant system and that will produce hot or cold air for the house, or depending on what type of geothermal system, it will also produce hot or cold water.” Geothermal systems can also provide in-floor heat or traditional forced air heating and cooling and while these systems are ideal for new construction they can also be retrofitted into existing homes. “About half of our business now is retrofit,” said Rutkowski.
Geothermal vs. traditional heating and cooling
“Geothermal is just a more efficient way of doing your heating and cooling,” Rutkowski said. “You can have electric backup, you can have gas backup. Either way the geothermal portion, that heat pump portion, is there to do the majority of your heating and cooling. How you back it up with a redundancy is based on the type of house and what the homeowner’s preference is.”
So for example, if a homeowner wants to keep their reliable gas water heater, E&J can install a geothermal system that utilizes a furnace. One advantage to this system is in the event of a power failure, the furnace will take less power (once restored) to restore heat. And if a homeowner wanted to go 100% electric Rutkowski said they can accommodate that too.
“We have units that do that as well. It can be tailored to each person, and some of that has to do with what power company you have, what the utility rates are, and what their structure is. Then,
we can pair that with the energy load of the house and design a system that is going to be the most efficient and the most comfortable for you. You’ve got every option available. It’s a very redundant system so it’s very similar to conventional heating and cooling. The only difference is we’re using a ground loop as a more efficient means of heat exchange.”
It’s simple physics, explained Rutkowski. “BTUs want to move. Your heat wants to move so hot wants to move to cold.”
A conventional air conditioner takes heat from the house and kicks it to a hotter environment
outside, which necessitates larger and larger units with bigger and bigger coils inside to raise the efficiency and force the heat to move.
“When you’re rejecting that heat into a 55-degree ground loop, it wants to move that much easier. Those BTUs will flow easier when there is a liquid or a solid instead of air. “Because we’re flowing liquid its going to transfer the heat easier.”
The bottom line, he said, is that “you’re moving more heat at less amps, and you’re having a more efficient heat exchange.”
Geothermal systems are also less impacted by the outside temperatures, he said. “If its minus-40 out in the dead of winter, it doesn’t matter because the ground is always going to be a consistent 50-55 degrees. Yes the house is going to lose more heat, but that’s where that backup comes in.” E&J designs for the average temperature range in east central Iowa, which typically goes from minus-five for heating and 92 for cooling.
“The reality is it gets colder. So having a good system in place for that backup is a good idea, but geothermal doesn’t react to it as fast.” He explained it could take up to several days or even a week (during a prolonged extreme cold spell) to fully adjust because of the 50-55-degree ground loop, which does not adjust on a dime. “If somebody wanted to have that gas backup, that’s not a problem, we have that system. We put them in all the time. If they want to go full-electric (as with the REC) because they have a reduced rate for geothermal, we can put in an electric backup.”
Rutkowski noted even straight-resistance heat on REC’s rate is less expensive than gas. On the flip side, Alliant Energy’s electric rates tend to be higher, which could make a gas backup system more desirable.
“Mid-American has a decent electric rate, REC has an awesome electric rate. I would typically guide somebody toward an electric backup system in those locations unless they
really wanted to have gas, and then we’ll make it work for them.”
The installation process
A typical retrofit project takes a couple of days to execute once all utilities have been located, permits secured, and the plans marked out. Geothermal systems utilize a “loop”
buried in the ground and Rutkowski explained that once you get below the frostline the next 40-feet or so is pretty consistently 50-55 degrees, the ideal.
“When we do our loops, we primarily use horizontal loops where we stay 19-feet down or shallower.” The depth is in part due to DNR regulations as well as industry standard installation process. For a ‘Slinky’ style loop a pit contains what looks like a giant Slinky toy, but only goes down six-to-seven feet, which puts it a couple of feet below the frostline. “But we’re still in that range where we have plenty of buffer. If we are doing a retrofit application or if it’s a really tight lot or there’s a lot of trees to where we can’t dig, we’ll bring in our horizontal boring machine
and directional borer.”
In such instances the loop is typically placed 12-15 feet down coming up to the six-to-seven foot level on the ends. For an extremely tight and limited lot, a vertical loop option exists as well. E&J’s screws, with the horizontal boring, are even able to run the loops underneath a house, if
needed. “Even on really, really tight lots, we can still get geothermal in.”
“To get into the house we’ll go into the basement and cut about a foot-and-a-half- square hole in the floor near the furnace, dig down a few feet, pull the pipe back, then we’ll put in bentonite and re-concrete it, and it will look like the pipe has been there since day one.”
The boring and other exterior work typically takes a day or a day-and-a-half to complete followed by a pressure test and back-fill (usually the second day).
“Once the pressure test has been inspected and released, the ground portion is more or less complete,” he said.
Next is the interior work led off by the HVAC (Heating, Ventilation, and Air Conditioning) crew replacing the furnace with a geothermal unit and connecting the piping to it. Electrical work is coordinated with the utility company.
“The interior process takes about two-to-three days. We’ll set up your thermostat, do a walk-through with you, and go over your paperwork.” Rutkowski noted there are many different rebates and tax incentives and credits available for geothermal systems.
Overall, “It’s a relatively painless process and we do 50-100 retrofits per year. It’s a very tried-and-true technology, it’s very robust, and it’s just a better and more efficient way to do your heating and cooling. It’s definitely a technology that you want somebody who knows what they’re doing. You can have the best unit in the world but if its not installed properly its not going to
give you the desired results. Having it done with a quality installation by somebody who knows what they’re doing is very important.”
Starting the process
For more information go to www.ejgeothermal.com or call 319-624-2065 (office) or Rutkowski direct at 319-538-7440.