Blackflag,
I do this kind of stuff for a living and have a certificate of wonderfullness that says I am qualified to voice an opinion.

Geo thermal heat pumps are the most effective heating and cooling systems you can buy.  The higher the SEER number the more they cost and the loss they cost to run.  Over a five year period they are the most cost effective units.  The humidity in your house is a result of a faulty heating and cooling system.  The heat pump will eliminate that problem unless it is oversized.  And it probably will be.  Make sure that your heating contractor does a "MANUAL J"  evaluation of the heating and cooling loads of YOUR house.  Even then he will try to oversize the unit by adding 15% to the calculations.  This is good for heating but bad for cooling.  It is better to have the cooling unit a little undersized than oversized.  If it is oversized it will cool very quickly and shut off before it can take the humidity out of the air and you will feel clammy and condensation will be all over the place.

There are a large number of things that you can do to cut your utility bills.  Air leaks or infiltration is the biggest thief of your heating and cooling dollars.  I lived in Delaware during Carters make believe oil shortage and know what you are going through.  Look for dust tracks around the edges of doors and windows.  A dirt smudge indicates air is moving through the crack.  Use foam gaskets behind the electrical outlets and switches to cut down on drafts. 
Switch out ordinary light bulbs for compact flouresents.  They cost more to buy but save you a lot more over a years time as 95% of the electricity in a bulb goes to heat and you have to pay to get rid of the heat in the summer.
The duct work in your house leaks.  I can tell that from Florida without ever crawling around your attic.  I have been in the construction business for over 50 years and know from experience the quality of workmanship.  A very small leak in a duct or around a register will cost you many dollars a month. 
The crawl space under the house should be insulated and it sounds like it is not.  Fiberglass insulation has value only if it is installed correctly and maintained that way.  It never is.  If there is any gap between the fiberglass and the studs or rafters the insulation value is reduced by 45 to 70%.  Fiberglass and cellulose  settle and lose 60 to 75% of their value over a few years.
Sprayed on styrofoam is the best bang for your buck over the long term.  It costs more but then cars cost  more than motor scooters.  Conventional wisdom will tell you to put vents in the soffits and even in the ridge line of the attic so the natural convection can help heat and cool the house.  WRONG.   Attics with vents have temperatures of 120*+ in the summer and this heat load is transferred into the house.  the reverse happen in the winter.  Here in Florida I build houses with the underside of the raters sprayed with closed cell foam to a depth of 6 ".  The soffits are sealed.
I do not insulate the ceilings.  The temperature in the attics varies from 75* in the winter to 85* in the summer.  The foam acts as a glue that holds the roof plywood to the rafters in 180MPH winds.  The rafters are metal strapped to the ICF walls and I have hurricane "proof" house that is also the most economicial house on the market.
Hope this helps.
Joe Redburn
LEED AP
E3 Buildi0ng Sciences

> Geo thermal heat pump ...Over a five year period they are the most cost effective units.

This is highly dependent on circumstances and if I heard a potential geo vendor say it, that would be the end of the conversation.

There are three primary methods of heat transfer, conduction, convection, and radiation. In layman's terms, conduction is the heat moving through the particles in your wall. This is the heat transfer method that "R" value refers to. It has absolutely nothing to do with air leaks, that is the second method, convection. Basically, it is the air that blows in/out of your house. This is rated in air changes per hour, which is what a blower door test will determine. This value, you are actually looking for a number about 0.3, not zero. Having 0 air changes would make for a very unhealthy house. If you do too much air sealing, you will have to install mechanical ventilation, such as an ERV or HRV to bring in fresh air. The last method of heat transfer is radiation. The simplest way to picture this is the UV rays coming from the sun. Basically being in PA, I don't see a huge benefit, but if you have it, it can't hurt anything.

Your first post said you were looking for inexpensive ways to reduce heating and cooling loss. Blowing in more attic insulation is the best bang/buck, but air sealing is another great option, just be sure not to go to low on your air changes. The cheapest way to get an air seal in your current situation would be to go for an airtight drywall system, which would entail accepting the field of drywall as airtight, and then sealing any penetrations. The only problem will be digging up all the fiberglass to expose any can lights and the tops of all the walls, where lots of wires and pipes run through. From there, you can use cans of foam or caulk to seal up all the penetrations. Then you can replace all the fiberglass and go over the top of it with even more blown insulation of your choice. Based on my personal experiences, I would suggest fiberglass over cellulose but it creates so much argument on the forums that now I just suggest you use whatever you like the most.

Posted By aardvarcus on 18 Apr 2010 05:06 PM

There are three primary methods of heat transfer, conduction, convection, and radiation. In layman's terms, conduction is the heat moving through the particles in your wall. This is the heat transfer method that "R" value refers to. It has absolutely nothing to do with air leaks, that is the second method, convection. Basically, it is the air that blows in/out of your house. This is rated in air changes per hour, which is what a blower door test will determine. This value, you are actually looking for a number about 0.3, not zero. Having 0 air changes would make for a very unhealthy house. If you do too much air sealing, you will have to install mechanical ventilation, such as an ERV or HRV to bring in fresh air. The last method of heat transfer is radiation. The simplest way to picture this is the UV rays coming from the sun. Basically being in PA, I don't see a huge benefit, but if you have it, it can't hurt anything.

Your first post said you were looking for inexpensive ways to reduce heating and cooling loss. Blowing in more attic insulation is the best bang/buck, but air sealing is another great option, just be sure not to go to low on your air changes. The cheapest way to get an air seal in your current situation would be to go for an airtight drywall system, which would entail accepting the field of drywall as airtight, and then sealing any penetrations. The only problem will be digging up all the fiberglass to expose any can lights and the tops of all the walls, where lots of wires and pipes run through. From there, you can use cans of foam or caulk to seal up all the penetrations. Then you can replace all the fiberglass and go over the top of it with even more blown insulation of your choice. Based on my personal experiences, I would suggest fiberglass over cellulose but it creates so much argument on the forums that now I just suggest you use whatever you like the most.

The house already has an ERV system, if I've read his posts correctly, in which case the zero IS the number he's looking for, and properly controlling the ERV should make it both energy-efficient & quite healthy.

But if it's already in the 1-ish range on ACH it may not be good bang for buck going for sub-0.3 unless the air leaks are obvious & easy to fix.

Blowing more insulation is only the best bang for buck if it's already well under 2 ACH natural, but more insulation is still more bang for buck than the high-efficiency heating system he's committed to.  It's dead-obvious low-hanging fruit, but it may not be the only dead-obvious low hanging fruit.  From a cost-effectiveness point of view air infiltration under control tends to be job-1, then insulation, then heating system efficiency.  Since he's going for the latter two, it's useful to at least check on #1.