I have two 1000 watt HID metal halide set ups and prefer them to the HO fluorescent for mature plants. I still use the fluorescent tubes for starting seedlings but once the seedlings have a couple sets of true leaves I put them under the HID lights. I didn't invest in the HPS bulbs but did buy the switchable ballast just in case I want to use them at some point. I was really more interested in just keeping the plants growing over the winter and wasn't that concerned with promoting flowering but I get loads of blooms with the MH bulbs. A 400 watt system isn't going to cover 12 sq ft. Here's a chart that shows the area covered: HID Light Output *Primary Growing Area Supplemental Growing Area 100 watts *2' x 2' 3' x 3' 250 watts *3' x 3' 5' x 5' 400 watts *5' x 5' 8' x 8' 600 watts *6' x 6' 10' x 10' 1000 watts *8' x 8' 12' x 12' There's quite a bit of info about different types of lighting systems on this site. I don't know how their prices compare. http://www.littlegreenhouse.com/guide3.shtml

You've already answered our own question. Get an 8 bulb T5HO fixture. I use a combination of T5HO and LED for mature plants, but you've already ruled out LED and HID. An 8 bulb T5HO fixture will put out significant heat though. Less then HID, much more then LED. It will also use more electricity then either HID or LED. You really need to narrow down your requirements, as there is no one technology that meets all your needs. LED does sound like it meets the most criteria, but has the highest initial cost.

It boggles my mind that people think 10 years is a long time. After installation, you pay each month (including financing) about what you were already paying anyway (probably less). You do it for 10 years, (especially with all the new government incentives, rebates, and low-interest financing now available) and after 10 years you're paying a ridiculously paltry amount for heat. Of course it makes sense. Think of the payback over 20 years once that loan is paid off! Even if you only end up paying even 1/2 of the normal cost over that period (including the cost of your system and electric), you're still saving substantially. I know not everyone lives in a home for that long, but seeing low energy bills does increase home values. I've seen homes sold almost immediately with their main advertising point being their geothermal system even in our horrible present climate while others still linger on the market. Not only that, but why not decrease your monthly bills slightly (before the loan is paid off)? Slightly lower bills, a higher sales price which will pay off the rest of that loan - still makes sense. We had someone come out to our house and they specifically calculated everything from current estimated heating costs, heating/cooling with geo, then savings/payback period. This was a full service option, including thermostats, etc. Finding that should not be difficult. One argument I saw above made no sense. If it really is worth insulating your home to use a normal system, it is a no-brainer to insulate your home using geo. Whether you decide to use geo or not, you can't say, "Well, normal is better, because we insulated, too." That makes no sense. Insulate either way. Then compare. The financial analysis does not make much sense, either. Yes, it would be wonderful if we could just stop paying the oil company, live without heat, and invest that money! Realistically, while you could want to put away the whole $25,000, you really are still using it for heat either way over those 14 years as projected. Geo, with the loan, electric, etc, will cost about the same each month as heat before the loan is paid off, so you can't just pretend that money could be invested elsewhere. Use it upfront with geo, use it over several years with oil, it makes no difference. That money is being spent on heat. Should it be spent on something worthwhile, or just, at the end of 10 years, have you still spending the same amount on more heat with oil? Geo will typically initially cost you a little less (including the loan and electricity) per month than you would be paying otherwise, then suddenly drop dramatically to only the cost of using the system as soon as that loan is paid off. That's money you would have spent anyway each month with your normal system (even though some of it went to financing, it is still less that what you would have paid for oil). Then suddenly, once the loan is gone, you actually DO have perhaps $1,000 a year in money saved that you can invest if you wish over 10 years. If, with financing costs, it does cost more per month than your normal heating system, that's one thing; but if not, the argument that it is wasting money is not valid. You're spending it anyway. Might as well spend it on something that will, in the future, save you tons of money. (Not just a little, a lot.)

A properly sized unit should be able to maintain reasonable humidity levels (though maybe not at 78 degrees without a dehumidification mode). The dual-stage unit will help control humidity. The only way of extra dehumidification with the XL16i that I know of is with the TCONT803/Honeywell TH8321 thermostat, which will overcool to control humidity. Ask your contractor why he proposed the VisionPRO IAQ when the BK terminal is already in use by the XL16i, thus not allowing the dehumidification feature of the VisionPRO IAQ (which is great as it actually slows down the blower). If you want an alternative that can make use of the VisionPRO IAQ, I'd go with the XL15i. It's a single-stage unit, but sized properly it should control humidity fine with the added advantage of the VisionPRO IAQ. Here are possible setups (ask your contractor what size he would recommend--I would NOT go with a 3 ton for your size home). Now, there are different air handlers that can go with these units, but the 4TEE3F39 air handler is tall due to the Vortica blower. The 4TWX5024A1000A (2-ton XL15i) with the 4TEE3F31B1000A yields 13.00 EER, 15.25 SEER and 8.60 HSPF. The 4TWX5024A1000A (2-ton XL15i) with the 4TEE3F39A1000A yields 13.00 EER, 16.00 SEER, and 9.00 HSPF. The 4TWX5018A1000A (1.5-ton XL15i) with the 4TEE3F31B1000A (only rated match with the 1.5-ton outdoor unit) yields 13.00 EER, 15.00 HSPF, and 8.50 HSPF. Feel free to print out my responses if it will be easier for you to go over these possible issues with your contractor. Good luck.