So far there’s nothing posted in this thread that’s hard to disagree with. It’s all basically valid advice. But we still need put some meat o the bones.
Re: Elmer J Fudd
Could be all true, I don’t live in Texas. It comes down to personal philosophy and choices we make in life. Not everything is about money.
When’s the payback on a Tesla? People still choose to buy them for reasons other than the ‘bottom line’.
Personally for myself I would not choose natural gas or propane for reasons relating to the environment, safety, IAQ & paying for yet another utility hookup for an energy source that might not even be used for months on end during the year.
EJF - This is not a personal attack so please don’t take it that way.
I often hear about Solar Panels when geothermal is mentioned, as an alternative way to save money by creating energy.
Again, I’m speaking for myself. Rather than spending perhaps tens of thousands of dollars on a Solar Array, I would sooner invest that same money, hopefully less, in a ground loop for a Geothermal system.
Why? Geothermal too is a form of Solar Energy. The Sun heats the earth; we extract that energy or reject into it and with it we cool, dehumidify and heat our homes & DHW at a rate that can be up to ⅕th the cost of resistance electricity alone. It’s a far less complicated system, it’s not subjected environmental damage such as wind, hail, etc and unlike virtually any other form of Solar Energy, Geothermal works when the Sun doesn’t shine & the Wind doesn’t blow! Unlike PV Solar, energy storage is already ‘Built In’ - It’s call The Planet Earth. It’s never going to require servicing.
Everybody makes their own choices based on what’s best for them.
Re: Seabornman
There is no ‘Rule of Thumb’ only mathematical formulae to be followed that would determine the length of a horizontal trench. It is based on linear feet required and configuration.
The volume of air supplied by duct work is determined by its size and is the same regardless of what energy source a Heat Pump uses, Air-Source or Ground Source. The same is true for temperature. Air temperature supplied will essential be the same regardless of source for heating and cooling if talking about a heat pump. Only a Fossil Fuel or Electric Resistance source is capable of suppling a substantially higher air temperature, which is why older homes build before the advent of the modern heat pump have smaller ducts that are not well suited to modern HP heating or AC. Smaller ducts delivering higher temperatures at lower volumes can deliver the same Btu as a HP that must use larger ducts to deliver higher volumes due to lower temperature, to be equivalent to their fossil fuel or all electric cousins.
You are right (IMO) regarding set backs. We almost never use setbacks at our home - even when going on vacation for weeks on end with no one home, our geothermal just runs. I personally do not believe in setbacks with any kind of HP - particularly for severe weather, that is our case. Others might feel differently and that’s fine. ‘Everyone does what’s best for them’.
Re: sandk
There is no Electric rate ‘gotcha’. Comparatively you’ll always be doing better with a HP - any HP as long as it can be run up to ‘Design Conditions’ and not beyond! Longer run time do help keep room temperatures more stable and don’t seem to dry out the air as much, as higher temperature sources of heat, as you have mentioned.
A desuperheater is a great way to increase the value of a geothermal installation by at least preheating DHW. Depending on the type and configuration of a geothermal heat pump, you can also produce all your DHW at a greatly reduced price.
Re: Austin Air Companie & sandk
Again regarding trench length for horizontal ground loops, that is dependant on what you install and how. Furthermore, the trench does not have to be straight. It can be ‘L’ shape and be on 2 or more sides of your home. The total length of pipe can be 1-long run but buried at different depths within the same trench separated by as little as 1-foot of earth vertically. This would shorten the total length of trench. Beware - this technique has risks! The risks are to the installers working on the project. The deeper the trench the greater the risk of wall collapse and death. The slope of the trench wall must be of a gentler angle or the walls have to be supported to prevent collapse or cave in. Consult with Geothermal Professionals, State & Local Officials!
Another method of horizontal loop installation the ‘Slinky’ where the loops are configured just like a Slinky that is spread out horizontally. Trench length can be greatly shortened with this method - particularly with greater loop overlap, shorter ‘On-Centre’ loop distancing.
Both linear pipe installation and Slinky can also be installed vertically by digging a narrow trench with a ‘Chain Trencher’ that is like a giant Chain Saw. Again this is something that requires professional expertise. Imagine the installation of the vertical Slinky that is a series of many vertical loops. There can easily be - and there will likely be trapped air at the top of some, most or all these vertical loops that might be spread out over hundreds of feet. You might need to rent a Fire Truck to purge, flush and pump out all the air and debris from this type of configuration!
As I have already gone on way to long, the last thing to mention regarding ground loops, deep, shallow, horizontal or vertical - is to not install them where you or a subsequent owner of your property might want to install an in-ground swimming pool at a future date!
IMPO
SR
Q
This is an example of it not done right
Q