I'm lost here. Are you saying that's $347/mo * 12 mo/yr * 20 yrs = $83,280????!!!!
Originally Posted by Frostie
Sounds like a heating scenario. Here in NW Arkansas, I had a geo contractor say that the geo well temp can get into the 90's, as I recall, during the cooling season. Does this sound right? If that's right, isn't it kind of hard to cool against that well temp?
Originally Posted by geodude
Originally Posted by sbe
SBE, your posts are pretty old, but I hope that you are still around. I would like to give you a very high compliment for your logic and clarity. Your advice is tremendous.
Originally Posted by sbe
Too many HVAC customers are fixated on a particular solution for a complex situation, whether it be geo, HP, or whatever. As you point out, all cost effective solutions are LOCAL. You have to decide on your priorities and preferences and run the numbers so that you have the real facts in front of you before you decide on a very expensive solution.
SBE, maybe I have worked with too many engineers when trying to design an effective solution, but I appreciate your engineering mentality when it comes to acquiring one of the most expensive systems that a HO will attempt.
THUMBS UP, SBE!
Your comment about high first cost is an often heard complaint - do you know there are three methods of earth coupling for geothermal? Closed Loop, Standing Column Wells and Open-diffusion wells - Closed Loop will be the highest first cost for the earth side of the system by a factor of three or four. alway get a clear definiton of these three earth coupling options, each have advantages and disadvantages. With the 30% Federal tax credit your pay back should be very quick - with a positive cash flwo from day one.
Carl, not sure I know exactly what you are talking about. Here in NW AR from my experience they propose vertical closed loop almost exclusively. Have heard of horizontal closed loop but it messes up the yard and you need a lot of acres. Using running water or ponds or other water isn't a very likely scenario for most HO's as I see it.
Originally Posted by Carl Orio
PS: I was reviewing some of the previous posts and find such scenarios as 10 tons needed and $900/month "power bills" a bit off the wall. If I needed or had either, I would freak. Sounds like that person should invest a lot of money on the house envelope before proceeding with any HVAC upgrades.
Standing Column is hardly a viable option for a residential installation. You did not to mention DX.
Originally Posted by Carl Orio
Since you don't have a real summer (what 800 cooling degree days? compare with Miami 3500) and are drilling in rock, it is not surprising your simple straight line payback looks so bad. The numbers don't lie, your right! Good for you that you did your homework.
Best payback is going to be to insulate and tighten your home and use less of what you are using. Use that same approach to review that and other equipment choices.
You are a good customer to deal with. The numbers will sell you if the approach is right.
What's the sense of being a New England Yankee without that common sense.
Too bad you have that unfortunate association with a team called the Patriots or Parrots or something
PS do a blower door test to see how much infiltration you have. The sealing and extra insulation should be available through a good insulation contractor.
Be sure to have an HVAC guy who understands ducts engaged as well. The insulation guys only understand duct leakage and not airflow. Two different things
Yep still around. Glad you found the advice useful. BTW I am an engineer.
Originally Posted by jerryd_2008
The "problem" is as you note that determining the lowest cost system is quite simple, IF you just run the numbers. Of course very few people actually do that and most suppliers won't volunteer them either (for a whole host of reasons).
My own experience highlights the problem. I determined the a ground sourced heat pump didn't make sense in the Portland OR climate so I decided to go with air sourced.
One of the hidden costs in any niche technology (which ground source heat pumps certainly are) is market inefficiency. They just don't have the volume to drive costs down the way a more mainstream product does. Another is installation cost inefficiency. I'm not talking about the additional cost of additional work, like the buried lines, but costs associated with the low volume of work which means less money to focus on driving down costs.
Well if ground source heats pump are niche, the air sourced (to water) are a niche on that niche. I went in with my eyes open and because I was getting the equipment for a fraction of the retail prices I figured that would leave some room for more labor and still come out Ok.
Wrong. Everything begins to change once you leave the mainstream. Manufacturers with low volumes don't have the resources that larger companies building hundreds of thousands of units have to pour into design, testing, support and that allow them to get all the details right. At low volumes you may get a solid product, but it isn't going to be plug and play.
While I don't regret the decision and I'm having fun this kind of system is not for the faint of heart. Even the best installer is not equipped to engineer a design and it is my experience that this can become necessary since each of these is a one off due to difference in the installation.
This is not to say its a bad thing only something to be aware of. Everyone knows how to install a furnace or an air to air heat pump. If it croaks, anyone can fix it. A ground source heat pump is a whole different animal. You need to get it right and doing so exacts a cost.
Ideally I'd like to see a mainstream system that is as plug and play as a air to air heat pump in air to water but there isn't really anything like here in the US yet.
So if you are looking at a ground source heat pump and you want to run the numbers it shouldn't be that hard, except for one little problem. You can look up the cost of natural gas vs electricity. You can estimate the heating days. But you never really know what the COP is going to be. You know what the manufacturer tells you it will be, but I've yet to see any supplier that will guarantee a figure for an installation. Few people if any instrument their system so they don't know how well its really performing so any payback calculation is almost certainly fatally flawed because everything hinges on that COP being what it needs to be.
Just so you don't think this issue is merely theoretical I spent a fair bit of time researching what measured COPs were for actual systems and, surprise, they are significantly lower than what suppliers tout. This isn't surprising marketing being what it is, but it points out once again the absolute necessity of running the calculation and doing so with actual verifiable numbers for COP that one can expect for your installation. Since this requires one to figure in the size of the system, length of loops, depth, type of material, DX vs water, number of heating/cooling days, type of soil, wetness of the soil among other variables it will, it has to be performed by a competent unbiased person skilled in the art. That rarely happens.
One final note and remember this comes from someone who has just spent an enormous amount of time and energy putting in a heat pump system. I wouldn't bet on ground source paybacks getting better but rather that they get worse. There is growing glut of natural gas and there isn't the political will to tax it so I'd venture there is a higher chance that gas prices will stay stable or head down over the next 5-10 years. Electricity is the opposite. There is resistance to new plants especially nuclear and coal so prices are likely to head up. Within reason, this is politically acceptable as it is supposed to encourage conservation (which it does for lighting, but not for heat in that it discourages a move from gas furnaces to air sourced heat pumps even in the south where they are a screaming good idea). What this means is that for better or worse to the country as a whole the lowest cost fully loaded for those in a heating dominated climate with access to natural gas other than people with very cheap electricity is almost certainly going to gas. I know I said you have to run the numbers and you should but don't be surprised if this is the way they come out.
Like I always say...this is directly from the mouth of a WaterFurnace rep,
"If natural gas is there, we do not target that area"
Reverse Cycle Heat Pumps
ALL this discussion AND NOBODY has brought up Reverse Cycle . . using heat pump - compressor technoplogy AND a heat exchanger coil to give COP's of 2 @ zero degrees. Check out The Aqua Products Co. on line I think they Build the ORIGINAL one!
I think if you check my posts you will see that I am talking about exactly that. My installation is two heat pumps each with its own reverse cycle chiller...from Aqua Products.
BTW I'd like to see test results validating the whole system COP at zero degrees (or any other temperature for that matter). Is this something the company is publishing now?
Personally, I'm with SBE.
Getting a professional to setup & service these systems is critical!
One service call could wipe out a lot of savings.
I see a lot of high SEER equipment running by the skin of it's teeth! Savings???