Atlanta Inspection News! Consumer information: Cutting Cost with Older Homes

It's usually considered an advantage to have a tight home; limiting air movement through the building envelope means you don't lose the air you've paid to heat, right?But what about all those sweaty, smelly bodies, human and dog, especially wet dog? Easy answer! Just take a shower/put him out ‘til he's dry,
Jeez, some people! But wait... people, showers, dish and clothes washers and cooking put moisture into the air and a number of activities put odors into the air. This means for the home to have clean, comfortable air, stale air must be ventilated to the outside and be replaced with clean air.

There are different methods used to recover the heat from the stale home air before it's ventilated to the outside. One way is with a Heat Recovery Ventilator (HRV). Wherever did they get that name? HRV's work by passing outgoing warm air past incoming cold air. A good portion of the heat is transferred to the incoming cold air, which means you heat less air and save more money.                                                     

Inadequate number of air exchanges per hour can result in...

Excessive humidity
unpleasant odors
Increase in mold spore concentrations
Control of moisture around the home increases efficiency and comfort.Consistent moisture levels are more easily maintained inside the conditioned space when surrounding areas are dry.
Crawl spaces may be susceptible to bulk moisture in part because there are no waterproofing requirements for "uninhabitable" under-floor areas.                                                                                            Crawl vents allow airborne moisture air contact with framing, pipes and ducts.

Basements require deeper excavation than crawl spaces. Their floors are "closer" to seasonal high water tables and are subject to higher soil and moisture loads. Measures to reduce bulk moisture around the perimeter of the home include:
1) Maintain roof drainage: Keep gutters clean and properly pitched, pipe downspouts away from foundation walls.                                                                                                                                                           2) Create a positive slope away from foundation walls. Install drains, swales, or retaining walls, add soil where backfill has settled. Fill voids under walks, stoops and patios.

If bulk moisture (visible signe of water) is controlled airborne moisture can be reduced by closing crawl or basement vents.