The Solar heater has been running for about 1 month now and I have a few updates to make on it's performance:
- Maximum observed temperature in room ... ~74 degrees
- Out of the last 30 days in my office I've only had the heater on 2 times.
- It's been a bit warmer and sunnier than usual (2 F greater average temp in Feb in 2009 than 2008)
- Estimated energy savings on electric heating bill in February, March (and by inference Oct and November) ~50-75% of total bill.
- Number of hours of heat delivered per day ~8
- Time when maximal temperature is reached ~3 pm
- Time when temperature in room drops below 65 F after a full day of heating- ~10 pm-1am.
- Maximum temperature inside heater ~110-130 F (even when it's 30 F outside)
- Possible efficiency improvements:
- glass on front of box instead of polycarbonate, with better sealing to minimize convective heat loss and maximize solar gain.
- air must be collected from bottom of room for optimal heat exchangement
- neighbor's tree and house must be removed for more direct sunlight.
But overall I'm quite happy with the project. It has practically already paid for itself and best of all... my wife thinks that it's an acceptabley asthetic project completed on a nice timeline to warrant further tinkering in the garage