Here's three options I found on the internet:
1. "It's been over a month since you have been able to visit your property. How do you know if your pipes are freezing or if your electricity has been interrupted?"
http://www.virtualtechnologiesltd.com/Water_Watcher.htm
2. Home Guard (SM-VM-500-2):
Basic Temperature Monitor and Power Alarm.
Protect Against Power Damage or Furnace Failure
"This simple and inexpensive home temperature monitor/home alarm meets basic needs for most homes. Plug in, set dial-out numbers and PIN and the HomeGuard home monitor is on duty.
Power monitor feature alerts for power outages (more than five minutes).
Temperature sensor prompts temperature monitor feature to sound home alarm alerts for temperature drops below 45 degrees. (Note: Temperature for alerts CANNOT be changed).
Dials out to two (2) 20 digit phone numbers. CANNOT dial out to a pager.
Power Alert: Stops calling out when power comes back on.
Remote access: Check temperature and power any time.
Plug-in wall transformer, splitter and telephone extension cable included.
4 hour battery back-up.
FCC Approved and Registered.
Enclosure Dimensions 5 1/2" x 5" x 2 1/2".
Click here for Home Guard Manual and Installation Instructions.
Part Number Description Price
SM-VM-500-2 Home Guard Monitor, Spring Special, Reg. 195.95
Currently In Stock - (8/15/2004) Suggested Retail:
$209.95
US $185.95
http://www.safehomeproducts.com/SHP/SM/Home_Guard.asp#input_guard
3. This would be the best one I think:
http://www.e2di.com/Who-uses-it.html
The ThermaViewer™ is a new type of dynamic thermometer that can display weeks and months of temperature history of the refrigerator and freezer .
The ThermaViewer™ is powered by a 120vac power supply with a 9vdc battery backup. It enters battery mode and the display 'sleeps' if the 120vac power is interrupted. While the display is asleep, the probes continue to collect temperatures for a few days. In the event that power is not restored before the 9vdc battery is depleted, the stored data will still be retained, although the unit will not collect new data. Once power is restored, the display wakes up and the power light comes on.