Richard, Some thoughts: * Cooling requirements can be adjusted based on how many machines are running at the same time and for how long. * Winter cooling needs may be nill, or even undesireable. * Dehumidification is probably more important to the collection than heating or cooling. My "machine room" is a section of the basement - a naturally cool place except during the hottest, most humid days of summer. I run a simple dehumidifier as needed during the summer and leave the door open to the upstairs to allow heat to rise. In winter the machines contribute to keeping the basement a little warmer. My running machines are 2-3 PC-based servers plus a microVax and occasionally 1-2 machines under test. This is closer to a "server garden" than what you want to run. But cooling may be less of a problem if continuous operation is not the goal. Jim Richard wrote:

On 9/3/07, scheefj at netscape.net <scheefj at netscape.net> wrote: Sure. I live in Central Ohio. Winter temps range from a typical low of -5F (it gets lower, but not every winter, and not for long), to a typical high around +20F, but we have had a number of "Green Christmases" over the years, and do exceed +60F in December and January on occasion. When working for employers with tons of AC cooling multi-hundred square-foot machine rooms, I have had to call for AC repair in the winter. We got the strangest reactions from the HVAC contractors, but we really did need to have our AC repaired. In Ohio, dehumidification is essential in summer, whereas humidification is frequently warranted in the winter, at least above ground. In my area, moisture in basements isn't normally too hard to achieve. In my area, natural gas is the most ordinary heating fuel. For those that live in areas where electric heat is common, an in-house machine room will add heat to the house "for free". Summertime, though, is a different matter. I have aspirations of building a new structure next to my 30'x50' quonset hut. I already have several hundred square feet of steel-backed raised tiles and all the pegs. Money, naturally, is the factor that's holding me back. At this point, my intention is to plan for a 40'x60' structure with straight walls, giving me substantially more usable space over what I have now. Depending on how well insulated the place would end up, from my prior experience in machine rooms, I'd say that 5 tons of AC wouldn't be oversized, and might be a bit small. Expensive to run, though, especially in July and August. -ethan