As for venting, a cheap option is Nikota programmable vents. They're battery powered devices designed to be hooked up to a duct as an indoor room vent. They allow you to customize the temperature inside a given room by opening and closing to the heating/cooling system (there's a winter mode and a summer mode). I got one on ebay for under $25. The batteries reportedly last for years; I haven't had mine long enough to find out. It's a true thermostat, not one of those "adjust up or down until you find the right temperature" things. Notes: 1) I made the mistake of insulating the vent blades themselves. Bad idea. The motor is very weak (to save power), and can't move much. Insulation should be above and/or below the vent. 2) They're not a perfect seal when closed -- but good enough. 3) They're quite easy to install in a thin film glazed greenhouse, but I imagine it would be tricky if you have polycarbonate panels and don't want to damage them (and near impossible with glass). So far, I'm pretty happy with my little greenhouse. I've got a 41 cfm DC computer case fan ($5) and four 1W solar panels ($25) to hook up (since a vent on its own isn't enough to do the trick), but I haven't had the time yet, and since it's an unseasonably cold October up zone 5a here (cloudy, daily highs 8-16C; normally are ~18C), it's not a high-priority task. ;) I'm kind of a "on the cheap gal". Occasionally things come back to bite me, but I'm usually pleasantly surprised.

Way overpriced. Just google 'water heater timers' and you can find lots of water heater timers, none as expensive as the DigaHot. Basic mechanical models run around $30, while electronic one are around $65.

suburbanmd: while i've had my Electrolux units just installed a week ago, i have not yet used them. they merely turned them on briefly to indicate that they are "turning" and "working", so to speak. i could get my washer to go through the set up cycle and complete it, so i felt good about it. for some reason, i could not get the dryer to display "set up cycle" despite following all the directions. i called their support number, of course, but received totally incompetent help from difficult, poorly trained staff. they were difficult to talk to, poorly informed, and merely reading off some script with practically zero knowledge of the issues, unwilling to go to the next step to ask a more senior "engineering type", or a more senior "tech" person. they just wanted to tell me that if it's turning, then ignore the fact that the set up cycle did not appear and just feel ok about it. plus, they were downright rude in the manner of talking to me as well. all that said, i was impressed in how the Electrolux machines look and feel - of course, this is based on purely superficial criteria and i have yet to make a judgment based on usage experience. i have also just received my Persil delivery so i'm ready to go. my new apartment is 2 months away from being ready to move in so i'm thinking of doing a wash this weekend at the apartment which is currently a construction site. at least if there are issues, i can get them resolved prior to my move in date. i'm not as sure as you are, "suburbanmd", that 78F is THE temperature that "warm wash" is at. i think it's more along the lines of: should the water temperature falls below 78F, then the water heater kicks in. this does NOT discuss what happens if the water temperature is above 78F to begin with! right?

Set them at the same temperature. Nothing at all is gained with any other plan. If hot water uasge in a household is moderate, the top element could fail and no one would ever know. The bottom element will heat all the water in the tank. The top element heats only about the top 1/3 of the water in the tank when the top thermostat is chilled, such as from cold starts or when the stored hot water is being used rapidly.