Geothermal says they can save me 60% on heating colling bills at a cost of 12- 18k$.  Pex radiant says 50% savings at siimilar costs.  I can combine the two but at what savings over the extremily high cost?.  I can install a 96% furnace with 16seer air for $5000.  Sure ther is a 30% tax rebate on all systems; but ?  There must be a point of diminishing returns like the thickness of insulation,   Any opions??

Whether you use a heat pump or a furnace you still need to deliver the heat to the house. The pex radiant is the delviery system not the supply. You need to do the math and calculate all of the energy loads for the building and then firgure out which system will supply that and at what cost? Here are my reasons for opting for the heat pump. Stabilized cost of energy supply, Electrical rates do not jump 100% over the course of one year, as oil did last year. You also have the ability to put PV panels up to provide the electricity need. You have reduced the risk of fire, and eliminated deadly co2 from being produced in your home. Oh ya and saved a bunch of money, year, after year, after year. I tend to find ways to reduce the energy needs as a first step, every bit of energy you don't need will reduce the unit size and installation costs. I have done the calculations for 4 different homes and the return on investment is typically 8 years, maybe 6 with the new tax breaks. I personally like the idea of creating a home that is as efficient as you can afford and then make it apdaptable as technologies develop. This is my main reason for using a geothermal heat pump. If you want to be able to have a home, that is or can be, converted to an all renewable energy source, this is your best option.
Their is no diminishing retrun with a geothermal system over conventional heating it will continue to save you money as long as it runs. This system at todays energy costs will save the homeowner $650 this year, at last years cost it would have saved nearly $900. The additional costs for the system was basically the ground loop and that cost $6,000(closed horizontal slinky). The rest of the system ( heat pump and exchange tank) cost about the same as a good furnace, AC unit. Here is where it really gets interesting, this house has half the energy loss of most existing homes. So for a 2,000 sq/ft home here in New England you can easily double your energy savings but you will also increase the installation cost proportionally. Still making this an 8 year payback, after that it's all gravy. Now lets take into account the tax beaks. Total geothermal system costs installed $15,000, deduct $5,000 tax credit and the system cost $10,000. Now for conventional HVAC the system cost $9,000 deduct $1,500 tax credit a high efficiency unit now costs $7,500. A cost difference of $2,500 and will saved $650 this year, Just under a 4 year payback. Thanks for the question, I hadn't redone the payback with the new tax credits in place. We waited to finialize the installation until the new tax bill was signed, just to ensure that we weren't grandfather out.
Tese numbers are based on the energy needs for this house and every house will be different, but a great option if the numbers work. I have a great tool to help with heat loss calculations and energy cost. You can change the heating system and energy cost, do a rough heat loss calc and it gives you the annuall cost of energy based on the numbers you enter. It lets you do things like change the insulation vale of the walls an instantly see the how much money you can save by doing it. Increase insluation value of windows and see the results and then look at air infiltration which can easily be the biggest single heat loss in any house. Gives me design heat loss as well as annual heat lost and then the energy cost based on the cost of fuel and efficiency of the system used. When I do this I can quickly tell if the saving justify the costs. for instance upgrading insulation almost always has a 3-4 year payback of course this depends on how easy it is to install and the cost associated with this. Here is where Architects tend to fall off the deep end, They don't really have a grasp on how costly some of their designs are to install. Yea, it's great to increase the insulation and will save $500 in energy this year, but the materials the Architect spec'd cost $5,000 and twice as much to install, when it could have been done for $2,000 in a different way and resulted in the same level of efficiency. Either way first look to find way to redcue the need for energy and if you reduce this enough, it is tough to justify the costs. A minisplit air source pump may become a good option as energy demands are redcued and you live in a more temprate climate than Massachusetts.
video of ground loop installation. http://www.youtube.com/watch?v=way5AvYpnR4&feature=channel_page

Tom Pittsley
ecobuilder@aol.com
www.eebt.org

2 short answers
1) No way in floor radiant will save you 50%
2) My experience has been that most systems will pay you back in about the same amount of time or geo's quickest if that's true and you have a great ROI wouldn't you want to invest more not less?
J

600rmk;

Sip's and Geo are a perfect fit. The percentage of your savings with Geo versus whatever will not change. The size of your system will change. A smaller system costs less to install.

The tax credit should not affect your cost of the system. We are not jacking up the prices because of the tax credits. We welcome any local contractor that does because we will take the job from them.

Bergy

Bergy,

I guess the point I was trying to make was that if my geo quote was $52K and I am eliglble for a 30% tax credit, that doesn't mean that I will only have to pay $36,400 at the time of purchase. I will still have to pay the $52k for the system and roll it into my mortgage. I can then later take the 30% tax credit when I do my taxes. The 30% insn't an immediate reduction in the amount that it will cost for the system. I probably didn't explain that well enough in my ealier post. My intent wasn't to say that geo companies and/or contractors were hiking their prices to maintain the profit level.

I agree with you that no matter what type of HVAC system you use in conjunction with Sips, your system should be reduced based on the efficiency rating of the building envelope. If I build with Sips I can maybe get by with a 4 ton unit instead of a 6 ton unit. The same can be said for a propane furnace. I could get by with a smaller furnace. In that case I wouldn't really gain that much ground going with a geo system. I really want to go with geo because I think its the right thing to do in the long run but coming up with the up front costs is what would potentially steer me away from geo. I guess I will only really be able to answer that question after I have someone with knowledge of both systems do a manual j calculation for my home and give me the real numbers. My only other way of reducing this is by finding friends with the tools required to use geo (ie find a friend with a backhoe and a love for digging up the ground!).

I hope this makes sense and someone with a lot more experience than I have can show me how to make it a real possibility. I would appreciate any thoughts or comments from anyone if you're willing to share. If anyone would like to discuss this with me, please feel free to use the forum e-mail to contact me.

600rmk;

The cost difference between a slightly smaller furnace and A/C is not much. The cost difference between a four ton and a six ton Geo system is BIG. In eastern Iowa every ton saved will save you about $1K for the Geo and $1.5~3K for the loop. A two ton difference could be as much as $8K.

Bergy

For both of you (original thread offer and 600rmk), it is up to your perspective contractors to sell you on the system. If his op cost projections don't work for you then question answered.
I have to tell you though it's interesting to me that no one ever adds the interest on the mortgage to the pay back projections on their gas furnace....oh wait, it doesn't pay you back.
It might be a little bit of vodoo economy, but the lower your heating bills the more you can spend on the mortgage, so even if it's a wash (save 100 on the gas bill spend 100 on the mortgage), geo wins because the life of the mortgage is finite and the life of the geo is longer than a furnace.
Of course ther's those other sundries......safety and comfort and quiet operation.....
j