Jim Rooney On The Level

Q. We will be gone for the summer--June, July, August and half of September. I am coming back for a week in July. My wife thinks we should leave the AC on which I think is crazy. My inclination is to turn off the water-- we always do that-- and leave an upstairs window open with the ceiling fan on. She is worried about mildew. Thanks.

 

A. Leaving a modern house empty for an extended period of time is not like it was years ago before such things as insulated walls and tight windows and doors. Both winter and summer present challenges that must be anticipated or expensive trouble can set in. It mostly has to do with temperature and humidity.

What happens to homes now is a thing called natural air change which in times passed occurred rather rapidly such as several complete air changes per hour, especially with the wind blowing. In modern houses there is a time lag between the air changes so the interior air temperature and humidity-- which will mimic the outside air if the HVAC system is shut off-- will lag the outside temperature and humidity by a factor of hours.

During our very warm summers when the dew point gets to a level that it nearly is equal to the outside temperature, the air is very moist-- cool it down and it wants to condense. I’ve been in a closed up modern house where the air was left off and the hot humid air found its way inside and started to condense on the upper ceilings and walls late in the night when things cooled down. The home owner called me thinking the roof went bad while they were gone. It hadn’t. The mold was bad.

I agree with your bride-- leave the air set at 78º. That is for whole house dehumidification. Make sure the filter is clean before you go and replace upon your return home. Leaving a window open with a ceiling fan might help that room only. What if one of our intense summer thunderstorms blows a ton of water in through that window? The room might dry out but if the storm is bad enough water will leak further down into the house and now you’ve got a recipe for real trouble.

If you’ve got a sump pit and a pump make sure it’s in working condition and if your area is prone to power outages consider a battery back up system. Power outages usually accompany those sever thunderstorms and if the power goes out and sky keeps dumping rain, water may find its way into your sump and you’ll want to get it out.

If you’ve got a sump pit and a pump make sure it’s in working condition and if your area is prone to power outages consider a battery back up system. Power outages usually accompany those sever thunderstorms and if the power goes out and sky keeps dumping rain, water may find its way into your sump and you’ll want to get it out.

If you have a security system-- which I would recommend-- give them your cell phone number. It has to be a monitored system which is cheap insurance in my opinion not so much for break in but for fire.

Leave a light on a timer switch that shuts off during the day and maybe again in the middle of the night so it looks like someone is home. Unplug appliances such as TVs, microwaves, toasters, coffee makers etc., just to be on the safe side.

You can go to the main electric panel and turn off power to the electric stove and the dryer. I testified in a case once where a control on a high-end electric stove began arcing while the owners where gone and when they came back the house had burned. If you have gas, shut the gas off. If you don’t know how to do that call a plumber.

If you are on well water I’d leave the water heater on to discourage microbial growth but city or county water is good enough to shut the water heater off for three months without it turning sour and smell like rotten eggs in September.

If you have a friend close by have them park a car in the driveway that moves from time to time.

If you have a trusted neighbor or friend leave a house key with them. If the alarm goes off and it’s not a fire the police will not enter the house unless they actually see someone inside or find broken door wide open.

Do all or most of the above to ensure that you don’t come home to unpleasant surprises.

Keep the mail coming. If you've got a question, tip, or comment let me know. Write "On The Level," c/o The Capital, P.O. Box 3407, Annapolis, MD 21403 or e-mail me at jimrooney@jimrooneyonthelevel.com or inspektor@aol.com.