Thanks Tigerdunes. I stopped by the distributor of Heil today and he said this was a great combo as far as efficiency and said he would not recommend a higer SEER or 2 stage compressor, even from Heil as you would never recoup the costs. Also said to get the VS air handler as this combo will qualify for the $300 energy rebate due to the good efficiency ratings. Surprising but since the Trance XL15i does not get 13 EER it does not qualify for the $300 so that makes my difference $2100. At this point the Heil is the clear winner. not sure why what you have says discontinued but the dealers sells these all day long and I assume he would have told me this since I know them. Thanks for your input. We are actually going to add 3 registers in the lower level to help with heating this space. We have1 return that is in between both floors. Another contrator came out today and said I needed 38000 for cooling and 48000 for heating. In between a 3.5 and 4 ton which is consistent with the others. We have a lot of glass, face south, 7 skylights and avg ceiling height of 12'. He thinks 3.5 in/out was best solution especially since I told him I shut off most of the lower level registers in the summer as it is always cooler. Thanks

Thanks for the input. The builders were cheap. There were a number of problems we discovered after moving in. Most of it is detail stuff, but they cut corners where ever they could. It's a 4 story building. We own the bottom two floors, and our neighbors own the top 2. We have insulation in most of the exposed walls, but that's it. There's no insulation separating our unit from the neighbors, and I'm not sure there is insulation on top of the building the way a usual home would have in the attack because of the roof top deck. Not only this year, but the past two years their power bills in the winter are SEVERAL hundred dollars per month. Ours aren't quite that bad, but that's because we keep it as cold as an ice box and they're still higher than anything my friends in the area pay for similar square footage. Also, we can hear everything in the building. It's like the neighbors are in the next room. I've lived in multi-unit buildings before, but this one is the least sound proof of them all. I can only assume it's because there is no insulation in the interior walls and our ceiling. I don't know what else it could be? I'm admittedly fairly ignorant on building matters, but these power bills are far from normal, and it's senseless that we have to freeze in order not to pay $500+/mo for power in the winter. I don't know what else it could be if not the heat pump/insulation. Thanks.

Define very cold. It sounds like you may not be a candidate for a heat pump, unless you can afford a ground source heat pump. I replaced a propane furnace with an air source (convnentional) heat pump when propane hit $3.00/per gallon. But I am in Tennessee, and our electric rates are dirt cheap compared to most places. Check into ground source heat pumps, which is the more accurate name. Most people call them geothermal heat pumps. They extract heat from the ground and aren't bothered of affected by outside air temperatures. Beware, they aren't cheap, but with escalating energy prices, they are worth considering.

"I would like to know where the ground temp is around freezing in a geothermal loop Tedsan?" Good question! It's quite non-intuitive, but explicable, and quite common, for closed loop systems. Here's what happens... During the course of the heating season, energy is drawn from the ground around the loops. The energy gets replenished from ground further away from the loop. Depending on the thermal contact of the loops with the ground, the length of the loops and the conductivity of the surrounding earth, the rate of inflow of energy varies considerably. In the ideal case, when the loops have been off for a long time, or been used extensively for cooling during the summer, the "near field" around the loops is typically 50+ F or warmer, giving a large amount of energy to extract for the heat pump's operation. During the winter, the longer the on-time of the heating system, the more heat is drawn from the ground. So the loops "see" lower and lower temperatures. If the system only runs an hour or two per day, and the factors above are sufficient, then the ground recharges back to the ambient ground temperature. However, the further into the season you get, the longer the on-time, and the less opportunity for the ground temperatures to recharge. If the thermal conductivity of the ground is very high and you have lots of loop contact with the ground, then the recharge rate is fast, and the loop may never see ground temperatures of less than 40F. However, in most cases, a decision is made to balance the cost of many deep boreholes with the performance. You'll hear values from 100-250 ft per ton of capacity as typical ranges. The lower the number, the less the volume of ground to recharge the areas around the loops and the more the ground temperature will fall. To further complicate matters, you have to space the boreholes far enough apart or they will start interacting. The cold from one bore reduces the heat available to recharge the volume around its neighbor. The wider the spacing the better, but typically 12-15 feet is seen as a reasonable compromise. For all these reasons, if you look at the entering water temperature of most closed loop systems (that is, the temperature of the anti-freeze solution circulating through the closed loops) it will drop through the season, often down to freezing. The experienced geo installers I've worked with size their systems based on a 32F EWT to ensure that the system will still have adequate capacity at the end of winter. These issues become progressively worse for larger installations, like institutional settings where you have several hundred bores under a parking lot, spaced on a 10-15 foot grid. Thermal modeling shows that bores on the inside of the grid show these seasonal heating/cooling problems progressively worse, the further from the edge of the grid. At a recent training session I attended by one of the leading geo consultants and college, they showed that their actual ground temperatures over a period of years were reaching 90-100F and increasing yearly because in institutional settings, usually there's a larger cooling load than heating. In this case, it's like having an air conditioner running all summer in 90-100F temperatures! It's great for the heating season, but lousy for cooling. Sorry to be so verbose, I hope this description is useful. On to your other questions. At 0F, that same system has a COP of 2.42. The problem is, the heat output has dropped from 46.7kBTU/hr at 50F to 17.8kBTU/hr at 0F, so you have to turn on your heat strips, say 15kw worth (about 51kBTU/hr). Since that's at a COP of 1, your effective COP drops substantially, to only a shade above 1. In the mid-atlantic region, only a few percent of our days are below 15F, so that doesn't too adversely affect the overall system performance. If you can get the balance point down to 25-30F, you can handle 80+% of the heating hours with only the heat pump, so your "seasonal COP" for these systems remains well above 2. The colder the climate, the worse, so I wouldn't recommend a conventional air source system where the heating degree days goes much above, say, 6000. The same arguments apply to the 100F side. In this climate zone, the vast majority of the air conditioning is done at 75-85F, with maybe 10-20% above this. In very hot climates, the AC SEER definitely drops and the geothermal performs relatively better. For all these reasons, I greatly prefer open-loop geothermal, where you get a relatively constant 50-60F water, year round. In my area, they don't like using them due to maintenance issues with mineral laden water, but if you don't mind the maintenance, you absolutely can't beat an open loop system and all the ground source heat pump sales info is right on. The "BS" comment was about the "orders of magnitude" performance note. An order of magnitude is a factor of 10x. Orders of magnitude means hundreds, thousands or more times more. "If you could keep the outside temp the same range as the geothermal operates at we wouldn't need a heat pump or air conditioner." - For open loop at 50-60F, definitely true. For closed loop, where the loops "see" ground temperatures in the low 30's most of winter and 70-80 during the summer, the air source heat pump does see these temperatures for the majority of the year. The GSHP is definitely more efficient when the outside temperatures drop below the 30's and above the mid 70's. Actually, in my GSHP system, the installer f'd up and my temperature loggers show ground temperatures in the low 20's by the time I'm in January, which really sucks. So for my system, I'd be better off a lot of the time with an air source system. "If that xp19 will perform the same as a 3 ton geothermal with 4 150' holes when its between 0-30 and 80-100+ PLEASE SOMEONE let me know before I drop the money on a ground loop. It would save me a bunch of money!!" 600' of holes for a 3-ton system is great and your loops are likely to stay within 10F of the static ground temperature if the conductivity of the ground is reasonable. Few people around here are lucky enough to have that much. At $16-$20/foot for bores in my neighborhood, that's $12,000 just for the bores for a 3-ton system. I actually did a bunch of cost analysis for people around here who have houses that would be satisfied by a 3-ton system and the GSHP would have saved them maybe $500/year under good conditions. The installed costs were then about $10k for a top of the line air source and $24k for a mid-range GSHP. $14k delta is 28 years to make up the cost difference. Again, this is my climate, with about 5000 HDDs. The harsher your climate, the better the equation becomes for GSHPs. All that said, the GSHP will be more comfortable during the winter because of no defrost cycles. This is a big pet peeve for air source systems. People hate the hourly blast of cold air while the system defrosts and I consider this one of the major stumbling blocks to their widespread adoption in moderate climates.