So, all of a sudden it's summer, with a vengeance. The official thermometer at BWI-Marshall has already reached 94 degrees - 3 degrees above the earlier forecast, but not yet a record for the date. The hottest May 30 was 98 degrees, set in 1991.

The heat and humidity on Memorial Day finally penetrated our upstairs enough to push me to turn on the air conditioning for the first time this season. But by the time it dragged the indoor temperature back down out of the 80s, to the 75-degree setting we use in summer, it was already cooler than that outdoors. Whatever happened to whole-house fans - the big attic fans that used to drag cool, nighttime air in through every window in the house, and push it out through the attic?

I grew up in New Jersey, in a little Cape Cod without air conditioning. The whole-house fan would cool the house at night, and in the morning we would close the windows and blinds. That would keep the house relatively cool all day. By nightfall, when the outdoor temperatures would drop again, we'd open the house again and switch on the whole-house fan. It worked fine. And the drone of that fan would sing us to sleep each night.

When I moved my family to Baltimore in 1980 - into another Cape Cod - the first investment we made in the place was a whole-house fan. It drew cool night air in all the windows, and blew it into the attic and out the attic vents. Until we finally broke down and installed central air in 1987, my kids fell asleep every summer night with the big fan whirring at the top of the stairs, just as I did as a kid.

With electric rates about to spike in Central Maryland, I'm thinking once again about a whole-house fan for the townhouse we inhabit now. Fans draw much less juice than air conditioners and heat pumps. Maybe, before the summer is over, we'll be nodding off once more to the old summer song of the attic fan.

Any memories of keeping cool in summer before air conditioners? Leave a comment.

Some power companies offer substantial rebates to customers who install whole-house fans. Here's an example. BGE, it turns out, does not.

BGE does, however, offer its customers "time-of-use" meters. These devices meter not just how much electricity you use, but when you use it. The company charges TOU customers lower-than-market rates for electricity used in off-peak hours. But it also charges higher-than-market rate for power used during peak hours. The object is to shift demand load to off-peak hours. In periods of very hot or very cold weather, that helps the utility limit peak demand loads on the generating system.

Customers moving to TOU meters have to pay attention to when they use their power. A programmable set-back thermostat helps to reduce consumption during peak rate periods. It's also important to delay using appliances such as electric dryers until off-peak hours. But it can work, especially if everyone in the household is gone during the heat of the day, when power demands - and TOU rates - are highest.

We have had a TOU meter for nine years. We delay clothes drying until late evenings or weekends (when the TOU rates are low all day). And we have a dishwasher with a time-delay feature that allows us to delay starting the load until after the low-rate period begins. We also have a programmable thermostat, and try to run the AC hardest at night, when it's cool outside and rates are lowest, and let it stay idle during the peak-rate period. Ususally the house stays comfortable enough during the day.

And it works for us. The meter broke down for five months last fall, and BGE inadevertantly charged us peak rates all the time. I didn't notice until after BGE spotted the problem and replaced the meter in December. I had to ask for a rebate of the five months of overpayments, but in the end the company credited my bill for $79. That suggests the TOU meter was saving me almost $16 a month on average. Then BGE threw in another $25 for the inconvenience of having to ask for my money back.

All told, the credit was more than enough to bring my subsequent BGE bill to zero for the month, a one-time budget bonanza. Now all I have to do is remember to set aside the money I WOULD have paid, and hold it for the big bills coming after the rate BGE increase this summer. It's nice to spend a little more time with my money.