I would go heat pump with gas secondary. If your used to gas or your like my dad who thinks heat pumps run continuously and just blow cold air, you can flip to emergency heat and hp switches to nice warm gas. The heat pump will save you money if you allow it to run.
What I've learned?
Dual stage furnace with heat pump is probably overkill, since the heat pump will meet the heating requirements down to the balance point of approximately 30 degrees F. Below that point, or at a temperature pre-determined, the heat pump shuts off and the gas furnace takes over. With a two-stage furnace, chances are at those temperatures the furnace will operate on high-heat and on low-heat very seldom. So in the dual-fuel application, I would rather see you with a single-stage high-efficiency furnace and perhaps a two-stage heat pump.
Manufacturers provide COP for 47 and 17 degrees at http://www.ahridirectory.org/ahriDir...ultSearch.aspx.
Its a heat pump vs. gas calculator.: http://www.energyright.com/cgi-bin/dtc?tvaparms
Break even point (economic balance point) is a function of the heat loss of your home, the cost of fuels and the efficiencies of the systems. Most economic balance points in our area are well below 30 degrees. Just have to set to consumption equations equal to each other.
(-b-probably want 35 degrees for comfort, IF get a heat pump.)
(Not sure it will pay for itself in ten years.)
Comfort Balance Point is a matter of personal preference. I had my balance point set at 20 or 25 in the my old home. I'm currently all electric and have electric heat off until 30. New heat pump is sized tight on cooling. Therefore, don't have the extra capacity in heat mode. So, must use electric heat sooner.
Proper installation has way too many aspects to try to explain over an email. But the basic theory is that your system must be balanced, properly sized, and installed according to the manuals and codes that we as contractors follow.
A system that is too large could have major complications. The AC will not run long enough, short cycling, etc... As far as heat, a 100K puts out more heat than an 80K, but only in volume. The actual temp. of the heat will remain generally the same. Not to mention, if you enlarge your unit, you need to enlarge some ductwork.
I would strongly recommend spending some money and get your house insulated very well. If you are planning to live there for a long time, then take the time now to get it right. At the rate this world is going, your better off to spend the money now and avoid major costs later.
Get the most efficient system that you can afford. I work for a Trane dealer. And as far as Trane, I recommend a 15 or 16 seer. I don't recommend you get the 13. They will be surpassed here in the near future. Energy Efficiency is a big thing now and I wouldn't be surprised if in 3 years, the 13 Seer will be no longer available.
Also, with a full system change-out, go with the new R-410A freon. The R-22 is being phased out and in the near future, no more R-22. Which means the R-22 prices will skyrocket while the R-410A prices slowly fall and steady out.
I would be willing to bet the thermostat is not correctly wired or programmed. But it could be several things.
A heat pump isn't always more efficient. Temp ranges are not accurate to determine because of several options that are available. i.e. low ambient temp controls, low temp cutout, outdoor thermostat, etc.....
No CO with heat pump!!
Gas is 3$ more than electric per One million BTU. 2007-2008
How many Million do I use in a winter?
Say winter is 5 months and I go to 4 month heat pump and 1 month gas...
use say 25% less gass and it costs 1/3 more how many dollars have I saved?
.064$/KWhr + 5$
To convert therms to KWHs multiply them by 29;
to convert KWHs to Therms multiply them by .034.
.90$/CCF + 20$ (1 CcF = 1 Therm)
1 cubic foot = 1050 Btu
Therm = 100,000 Btu
Ccf = 100 cubic foot, or 1 therm
Mcf = 1000 cubic feet = 10.20 therms
MMcf = 1 million cubic feet
Bcf = 1 billion cubic feet
Decatherm (Dth) = 10 therms = 1 million Btu
Mmbtu = 1 million but = 10 therms
one SEER is one extra btu per watt
1KW = 1000 Watts is 1000 BTU extra
100KW is one extra therm. is 7$
at .07$ per kw.
Therm = 100,000 Btu
KWHs to Therms multiply them by .034.
therms to KWHs multiply them by 29;
Doesn’t make sense to turn of the back up electric unless you have a set back thermostat that doesn’t ramp up in the morning.
Because your heat pump is sized for cooling isn’t why the heat pump alone won’t keep the house warm. It’s because your heat loss is way more than your heat gain.
Go Dual Fuel
100k BTU seems kinda high, but I don't know the heat loss number. Yes, put in a heat pump with a Vision Pro t-stat and outside temperature sensor. It will work great. If you go all electric, then size the strips according to the load and make sure your ductwork is 10% or less leakage with 0% Return leaks.