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A few things: 1. I'm not sure what "if you hit rock" means there. In general, you want to hit rock, and should hopefully hit it very quickly (40-50ft), becaus

A few things: 1. I'm not sure what "if you hit rock" means there. In general, you want to hit rock, and should hopefully hit it very quickly (40-50ft), because rock generally has much better thermal conductivity than stuff like clay. 2. You hopefully got a loop design report that has real details on the load of your house and the design of the loop and how it meets them. The loop design should hopefully tell you they are mostly drilling in rock :) Hopefully it all does not look like nonsense (I'm happy to look at it if you like, as are the folks over at forums like geoexchange) 3. The only units you should consider are waterfurnace, climatemaster, and maybe bosch. Trane, for years, was using rebadged waterfurnace units At least browsing, it looks like they still are. In any case, you want someone who does this for real, and Trane ain't it. Bosch is an okay unit, but they are newer at this, and not obviously better in any meaningful way. 4. The price for single family residential drilling is high in part because it's not what the drillers want to be doing. The rig setup takes them quite a while, the actual drilling is not that bad. For multi-family residential (or commercial), where they are drilling 100 holes, it's much more cost effective. So you are right in that sense - the current way of drilling is not going to bring the cost down. On top of that, keep in mind you are probably paying significant markup on the drilling because it's being subcontracted.

SEJeff 5y ago
By "hit rock" I mean the 3 hvac firms I spoke with didn't want to dig through rock, but couldn't nail down a cost if they hit it, which is basically a certainty. Bosch as a general rule has pretty solid engineering. I've used their kitchen appliances for years and am quite happy with them. Unlike some of the korean vendors (I'm looking at you Samsung and LG, it is easy and fast to get parts when things break). You're right that they're new at this, but all of the existing major appliances in the home are Bosch. If you buy more than three major Bosch appliances, they'll give you a fairly sizable discount. When I said American Standard/Trane, I meant for the Central Heating and Air, not for the Geothermal. They're the same hardware and come off of the same assembly line with different stickers on them.
- DannyBee 5y ago
  Honestly - you had the conversations and i didn't, but if they really said they don't want to dig through rock, i'd probably run away. I've got a lot of experience in this, and what you are being given sounds like a bunch of nonsense, and yes sometimes you will get a bunch of nonsense from more than 1 HVAC firm. Lots do not specialize in geothermal, and see it as a way they can make additional profit off some people. Concretely: At the price you are being given, the drill price should be fixed and included, excepting them hitting lots of water. The driller certainly gave a fixed price, based on the local geography and what they are gonna hit. The know exactly what they will hit in terms of rock/etc. The variable cost thing is not drilling rock or whatever, it's controlling water and sediment. If they hit lots of water (IE 100+gallons a minute), controlling and remove it can be expensive and unexpected - most cities/etc have strict rules on this (so they can't just run it into the street). This is the thing that is hard to tell for them - it's rare to have good enough data to know exactly whether and where you will hit water, and it can even vary from hole to hole in the same job. Otherwise, be careful - unlike regular HVAC, Geothermal requires people who really know what they are doing, and not just doing the kind of "finger in the wind" HVAC you can often find for folks doing heat pumps/furnaces. At a minimum, make sure you are using IGHSPA/etc certified folks. If you want to get more into this, there are lots of knowledgable drillers and installers over in places like the geoexchange forums, and they won't steer you wrong. As for Bosch, the units they are offering in residential are super basic units last i looked. They are neither variable-speed pump or variable speed compressor. They are simply 1-2 stage geothermal units. They appear to at least offer variable speed blowers on some of them, but that's very basic stuff. This is the kind of unit you would have seen 20 years ago. I would not pay what you are paying for them. Nice geothermal units (say, the waterfurnace 7-series) these days have variable speed pumps and compressors. They match themselves exactly to the load needed by the house over time, and run continuously at part-load, modulating up and down as they day goes on, and end up being both silent and very high efficiency. They are also much longer life - parts like scroll compressors (and most forms of rotary compressors) are much happier if you modulate load rather than start/stop.
  - SEJeff 5y ago
    I basically followed your advice and ran far away. That's why I'm getting Central HVAC, which I'm sad about as I like the idea of Geothermal, but it is what it is.

SEJeff 5y ago

By "hit rock" I mean the 3 hvac firms I spoke with didn't want to dig through rock, but couldn't nail down a cost if they hit it, which is basically a certainty. Bosch as a general rule has pretty solid engineering. I've used their kitchen appliances for years and am quite happy with them. Unlike some of the korean vendors (I'm looking at you Samsung and LG, it is easy and fast to get parts when things break). You're right that they're new at this, but all of the existing major appliances in the home are Bosch. If you buy more than three major Bosch appliances, they'll give you a fairly sizable discount. When I said American Standard/Trane, I meant for the Central Heating and Air, not for the Geothermal. They're the same hardware and come off of the same assembly line with different stickers on them.

DannyBee 5y ago
Honestly - you had the conversations and i didn't, but if they really said they don't want to dig through rock, i'd probably run away. I've got a lot of experience in this, and what you are being given sounds like a bunch of nonsense, and yes sometimes you will get a bunch of nonsense from more than 1 HVAC firm. Lots do not specialize in geothermal, and see it as a way they can make additional profit off some people. Concretely: At the price you are being given, the drill price should be fixed and included, excepting them hitting lots of water. The driller certainly gave a fixed price, based on the local geography and what they are gonna hit. The know exactly what they will hit in terms of rock/etc. The variable cost thing is not drilling rock or whatever, it's controlling water and sediment. If they hit lots of water (IE 100+gallons a minute), controlling and remove it can be expensive and unexpected - most cities/etc have strict rules on this (so they can't just run it into the street). This is the thing that is hard to tell for them - it's rare to have good enough data to know exactly whether and where you will hit water, and it can even vary from hole to hole in the same job. Otherwise, be careful - unlike regular HVAC, Geothermal requires people who really know what they are doing, and not just doing the kind of "finger in the wind" HVAC you can often find for folks doing heat pumps/furnaces. At a minimum, make sure you are using IGHSPA/etc certified folks. If you want to get more into this, there are lots of knowledgable drillers and installers over in places like the geoexchange forums, and they won't steer you wrong. As for Bosch, the units they are offering in residential are super basic units last i looked. They are neither variable-speed pump or variable speed compressor. They are simply 1-2 stage geothermal units. They appear to at least offer variable speed blowers on some of them, but that's very basic stuff. This is the kind of unit you would have seen 20 years ago. I would not pay what you are paying for them. Nice geothermal units (say, the waterfurnace 7-series) these days have variable speed pumps and compressors. They match themselves exactly to the load needed by the house over time, and run continuously at part-load, modulating up and down as they day goes on, and end up being both silent and very high efficiency. They are also much longer life - parts like scroll compressors (and most forms of rotary compressors) are much happier if you modulate load rather than start/stop.
- SEJeff 5y ago
  I basically followed your advice and ran far away. That's why I'm getting Central HVAC, which I'm sad about as I like the idea of Geothermal, but it is what it is.