Consider planting a Hornbeam tree. they are durable and long lived trees with roots that will not damage your sidewalk. Just do web searches on the American hornbeam and the European Hornbeam trees. Of the European Hornbeams, the Carpinus betulus 'Frans Fontaine' is a narrow less formal looking tree which grows tall but continues to stay narrow even after reaching maturity. The Carpinus betulus 'Fastigiata' grows into a more formal, narrow, oval to vase shaped form. Near maturity it will begin to spread wider into a more oval canopy form than the 'Frans Fontaine' Mature height is 40-50 feet. The tree does not drop litter other than leaf litter when it enters its winter dormancy. The tree grows fine in shade or sun exposure. Hornbeams do well in alkaline soils especially where the soil becomes more alkaline due to leaching from cement sidewalks and foundations. It is considered a good street tree, provides good shade, and can be very effective when planted in a group to create a screen. They have crisp, green summer foliage and smooth gray bark. They do not suffer from common insect or disease problems. They grow best in well draining soil, but will tolerate a wide range of soil conditions; even in clay soils. They are hardy down to USDA Zone 5 and do fine growing in my local 6b/7a zone.

That makes sense. I wondered about the venting. Your poor mom, LOL she'll never hear the end of it!

Wow!! How simple is that?! GREAT idea, Westelle, and thanks for sharing. Brenda

Audible alarms are one option. Another is a cellular connection to the monitoring company. Even the big boys (Brinks, ADT, etc.) sell cellular backups on their alarm systems. Frankly, your best bet on home security is a local shop that partners with a national monitoring outfit. They'll be more willing to meet your needs and you'll probably find them price-competitive or better.