Q. My daughter will be away for the month of September and is thinking of turning off the air conditioner completely while she is away. She lives here in Anne Arundel County. I am concerned that humidity and heat could do some damage if the house is sh ut up for a month with no climate control. Is it okay to close up a house with no A/C in September? Thanks for your advice.

A. If she does it will be at her peril. You are correct in worrying about potential condensation that will surely lead to mold, mildew etc. I have entered houses left unconditioned for a few weeks during summer, and it doesn’t matter if it’s late spring or early fall either, that looked like there had been water streaming down upper walls (owners suspected a roof leak) and the walls and furniture were mottled with green, white and black mold. It was very expensive to clean up.

Sure, folks closed up houses in days past with no-- or little-- problem. A musty smell perhaps might be all they’d encounter upon return. Our old summer cottage on Saratoga Lake in upstate New York had a very familiar musty wood smell when we’d open it up in spring but those leaky old cottages were just sticks and siding built in the 1920’s. They weren't the tight, well insulated houses like today's and it's a whole different set of circumstances. Insulated houses with modern windows and doors reduce s omething called the natural air change that takes place in buildings. Over the day, and for lots of atmospheric reasons, buildings exchange inside air with outside at varying but measurable rates. It’s called unscheduled venting. Outside air enters the house from tiny openings and through existing but unoperating vents like bath vents, chimneys, dryer vents, attic hatches, door sills-- the list goes on.

A modern, tight house will experience on average from about .25 to maybe .45 natural air changes per hour. Really tight houses qualify for the Energy Star Program. Compare that to the 1932 Four-Square that I grew in that was easily 4.0 air-changes per ho ur. The reason housing tried to lower natural air changes is obvious. If you heated or cooled a quantity of air it only made sense to try to hang onto it and not let it waft out of the building to be replaced with air that needed either heating or coolin g and dehumidification, as ours does through mid-October.

In an unconditioned closed up modern house in a hot humid environment, warm moist air very slowly migrates into the house-- it takes a while to be sure. But then it cools. Either at night or from a cool front moving through or both. The air inside the h ouse is still holding all the moisture it had when it worked its way in and now it’s cooling down. It naturally must lose the moisture it can no longer hold at the lower temperature and it condenses and there’s where trouble starts.

Advise your daughter to set the thermostat at 78º and leave it and don't worry about what the BGE bill will be because the clean up bill will be hundreds times more whatever her BGE usage will be. If she’s hard-headed and doesn’t take the warning, rest a ssured she’ll only do it once.

Q. Were building permits required for indoor work like paneling basements in the 1967-1970 period.

A. Technically, yes. The building permitting process with the codes and "inspections" began under County Exec Joe Alton (the first CE in AACo) in 1966. As I recall, the law read that if you did a $100 or more of work that was not regular maintenance you were to get a permit. Especially if the work included structural, electrical work or plumbing. Almost no one did that. Builders back then hated the permitting and inspection process as intrusive, slowing them down (while waiting for inspectors to show up on the job) and petty. Homeowners thought that since it was their house they could (and did and still) do whatever they wanted, whenever they wanted, especially if the work could not be seen from the street.

I'd say 95% of the "after market" work I see done on the interiors of homes in this state was not "permitted" And 95% might be too optimistic of a number-- it could even be higher.

So I bet your problem is probably things like electrical outlets (not enough or improperly spaced) and lighting and/or distribution of HVAC registers (few to none) etc-- that's what I usually find and it tells me no permit was pulled. I’m not a code insp ector but I am code certified so I know what to look for.