Affordable Geothermal | Future House | Ask This Old House

[Music] when you're looking for renewable ways to fuel your home it's hard to beat geothermal heat pumps at least in theory just below our feet the earth is always at a consistent temperature of about 50 degrees fahrenheit using a looped pipe filled with water or antifreeze you can tap into that constant temperature in the summer that wall can be a place to dump excess heat and in the winter he can be pulled out of the ground that same system can also provide hot water for your showers and your dishes it's incredibly efficient and requires no fossil fuels so why isn't geothermal as common as solar or wind for one thing drilling a well can get very expensive some of it's because you don't know what's below your feet when you start drilling could be soft like this or it could be hard as a rock it's also typically a messy process that involves big equipment that doesn't fit in every yard here on future house we've been exploring ways that geothermal has been getting more accessible i toured a community in texas that installed geothermal wells before any houses were built every home in that neighborhood was connected to the geothermal system and each house only paid a small portion of the overall costs but what if you're not moving or you like the house you live in today i'm headed to albany new york to see the evolution of geothermal that may allow it to get deployed to many many more houses ross welcome to our drill site thomas thanks for having me when i think of geothermal though i am not thinking about established neighborhoods with small lot lines i mean i'm thinking usually major renovations new construction large projects this is unique this used to be the case up until now what we're trying to do is bring geothermal to residential neighborhoods and to be able to do that we have to design for modularity and be able to squeeze into really tight spaces yeah when i think of a traditional geothermal rig i'm not thinking if this is something this small i mean it's it's fitting between a tree and the house and a small lot like this this is this is compact correct we tried to design to be able to squeeze into really tight spaces and to be able to do that we designed uh the undercarriages to have rubber tracks to be able to rotate 360 degrees without churning up the yard and it also distributes the load so that you don't damage driveways that's great all right so this is the rig let me see it yeah so you see how the drill is in place now the casing is vertical so we're about to commence with sonic drilling right and what sonic drilling does is oscillate that casing vertically at up to 150 hertz and that is 9 000 vertical beats per minute so if i get a recap here you're basically hammering the ground at 9 000 times a minute which allows the ground to actually vibrate so fast that it actually becomes like a jello which allows you guys to drill through the earth so quickly correct and that lets you get in and out of the job much faster yes right now and we are adding an additional 10 foot of casing okay to the drill string and you'll see that we are running 10 foot casing lengths as opposed to 20 foot casing lengths and that's going to help us make the entire system more compact got it so if you're using 24 casings this truck would be a lot larger exactly gotcha okay with this sonic system we are able to install the casing all the way down to bedrock in 30 minutes a conventional system could take up to seven hours to install the same diameter casing to the same depth wow that is a significant difference and they will not be able to extract that casing every piece of casing that you see on our pipe handler right now has been used on previous projects we have not replaced a single set of casing yeah it's really unique because most installations that i see the casing stays in forever right and the purpose of that casing is to prevent collapse of the hole and to retain all of our drilling fluids which will increase the rate of penetration as a whole for the entire project this allows us to bring down the cost even further for the ground loop installation so six education has made its way down 82 feet lodged itself into bedrock and now they're switching to another drill rig exactly and that's going to have a down the hole hammer which we call the dth and it's going to be drilling through the center of this six-inch casing all the way to bedrock and then from bedrock all the way through to the total depth which is the design depth for this well this well is going to be a 300 foot well and this project will have two of those 300 foot wells gotcha while we are drilling you'll see that all of the rock chippings and mud and swale that is excavated from this hole will have to come up the hole and instead of dumping it all on the customer's yard we are transferring that to our mud processing unit and our mud processing unit will be able to separate the solids from the liquids and this enables us to recycle the water and reuse this same water over and over again and clean that water to within 30 microns which is about a thousandth of an inch so i can see the loop rig coming in i see the high density polyethylene pipe being lowered into the into the borehole i also see another pipe coming in at the same time what's that pipe for that is the coil tubing pipe and that's going to enable us to grout from the bottom up which is an underwater grouting technique that will become a column that will have really good contact with the earth for really good efficiency correct and this grouting or concreting layer around it has two purposes the first purpose is to conduct heat from the soil to the ground loop and the second purpose is to ensure that no pollution or impurities can actually penetrate the soil towards the aquifers all right so now we have completed our drilling looping and grouting which means the geothermal loop has been installed right and this will be linked towards the inside of the house and brian zumerly is inside working on that system right now and he'll be able to show you all the magic inside so brian i design a lot of geothermal systems and they typically require a custom solution right high-end residential it's you know it's a different market so tell me about the innovation what you guys are working on here absolutely yeah so one of the steps that we've done right off the bat is standardize a lot of the way that we design and engineer the systems so we use design software to properly size the unit to make sure the geothermal well is properly sized and that just helps the overall efficiency of the project gotcha what we've also done is that we're reusing any existing infrastructure that we can so in this case the existing air ducts gotcha okay and so you can see here we've cut off the existing ducts and added our new system in and just added these flexible ducts plug and play right plugging it in here connecting between the supply and return exactly so the home used to have an air conditioner outside natural gas furnace inside what we've done is pulled that old unit out coil condenser furnace and we've capped the natural gas lines and now we've got one single geothermal unitary system so no more outdoor condenser no more outdoor condenser which is great yeah and you'll notice too that one of the things you'll typically see in a geothermal system is a separate pump box that has your pumps and some of the flushing ports in it we've put all of that into one unit to make the the installation process that much faster and smoother and installing things in a factory is much faster than doing it in the field sure and so what you'll see here what we've got is two pumps that pump uh through this piping and out to our geothermal well and it's pumping a mixture of water and a little bit of glycol just to account for any possible freezing conditions okay and so that water then is moving through a heat exchanger inside the tank or inside the unit that uh exchanges with the refrigerant that's all self-contained inside the box gotcha so on the air side i see the return duct coming in here exactly what happens next yeah so this is just like any typical uh system where you you're pulling uh return air across a refrigerant coil that the fan is pulling and pushing out through the rest of your existing duct work got it so in the you know winter time when the air is cold it's coming in right across that coil warming up and then being delivered to the supply duct into the space exactly and then it's just a continuous cycle where we're then going back and getting more heat from the ground and pulling it back to your exchangers that's great awesome what about the blue piping yeah you'll notice that we've got this extra piping here that this is going over to heat your hot water for things like showers or dishwashing so domestic water exactly okay so in cases for example like the the summer time where you've got extra heat from the heat pump before we send that out to the geothermal well we can send it into a preheat tank so this tank here is just like any other water heater but we've just not connected it to any power right okay so the cold water comes in here and we can heat it with that excess geothermal before it goes into your traditional water here got it that's commonly called the superheater preheat tank exactly connection got it and so your electric water heater doesn't have to work as hard because it's got preheated water exactly yeah and it's basically this you know can heat anywhere from 20 to 30 percent of the home's annual domestic hot water use it just makes the the primary water heater have to work a little less hard yeah so it's all electric the whole system the system is all electric now which is really great if you can then pair it up with something like solar on your rooftop then your home becomes a lot more sustainable really exciting it is exciting so how many systems have you installed to date we've installed a couple of hundred all the way from here in albany south along the hotend river valley to just north of new york city gotcha now why new york yeah new york for a few reasons one is there are a few million homes that heat with fuel oil and propane today and they're going to see the most savings from geothermal on top of that new york has generally high energy prices and the state provides good incentives for homeowners to choose geothermal today gotcha now in a house like the one we just installed in what's the out-of-pocket expense for that homeowner yeah average out of pocket for a home like that would be anywhere from 18 000 to 22 000 that home coming in around 19 000. okay yeah that's less expensive than a traditional geothermal system but it's still really expensive yeah so we're taking a play out of the book of solar and you know a decade or so ago solar on rooftops was really expensive and what we're doing is providing financing similar to what solar did where we take away that upfront cost so the homeowner has zero out of pocket on day one and you replace that with a fixed monthly fee so they start seeing savings from day one and what that means is that now they get heating cooling and some of their domestic hot water with it for a fixed monthly rate that's lower than what they would be paying for their utilities otherwise gotcha and it should be added that the homeowner owns the geothermal system it's an asset they can amortize over the lifetime and that adds value to their real estate yeah that's a great point i'm a big fan of geothermal and i'm glad you guys are making it more accessible thank you yeah thanks thank you wow that is encouraging and interesting to see is it possible that this is the breakout moment for geothermal the one will make it go mainstream i mean it's a huge step in the right direction you know historically you had you know a driller you had a hvc contract you might have a controls contractor that you know team had to be assembled with them they're trying to bring it all together into one right and then of course the drilling costs which is always the biggest hurdle they're starting to attack that so it's promising well i've been advocating geothermal for a long time 25 30 years but it's been an uphill climb particularly in new england by the time you drill down into that granite it gets really expensive and painful you know and what's also happened in the marketplace is these cold weather heat pumps have come along you know we know that you have a single box outside it can find enough heat even on a zero degree day to heat the building it's hard to argue with that so it's true we see these mini splits all over the place these days i mean what do you say to that yeah but you think about ground source heat pumps inherently are always going to be more efficient than an airsoft airsource counterpart because if you think about it the house wants to be 70 degrees and the ground temperature is about 50 degrees so when i'm heating and cooling i'm bringing it from 50 to 70. that's a 20 degree winter or summer just 20 degrees doesn't matter but with the airsource heat pump the outdoor temperature when it's really cold out could be zero degrees and i have to bring that up to 70 or on a hot summer day it could be 95 or 100 degrees so the delta t is a lot wider with an air source heat pump so it has to work a lot harder yeah he's got you there the other thing that's pretty good on the geothermal is it's invisible you know you don't see it you don't hear anything there's nothing outside just like wc feels said about kids don't see them don't hear them did you feel it did you feel it you guys should resolve this over thanksgiving and report back to us thanks for watching this whole house has got a video for just about every home improvement project so be sure to check out the others and if you like what you see click on the subscribe button to make sure that you get our newest videos right in your feed

Channel: This Old House

Views: 388,335

Keywords: This Old House, Ask This Old House, DIY, Home Improvement, DIY Ideas, Renovation, Renovation Ideas, How To Fix, How To Install, How To Build, Future House, Ross Trethewey, geothermal heat, 7-10 minutes, Affordable Geothermal, geothermal heat pumps, home renovation ideas, home renovation ideas on a budget, house plumbing system, plumbing basics, renovation ideas for home, general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor

Id: IMO9jvwlHFg

Length: 13min 28sec (808 seconds)

Published: Tue Nov 19 2019