New Homes, Tight Homes: Why Indoor Air Can Get Trapped

Quick answer: Newer homes are sealed tight to save energy, so cooking smells, shower moisture and fumes from new materials have fewer ways out. The fix is fresh air on purpose (a fresh-air intake or an ERV), exhaust fans that vent outside, and indoor humidity kept between 40 and 50 percent.

Why do newer homes hold in stale air?

Homes built in Central Texas over the last 15 years or so are much tighter than older ones. Better windows, spray foam, house wrap and sealed ducts keep cool air in and cut electric bills during our long summers. That's a real win.

The trade-off: a home that holds in cool air also holds in everything else, from cooking smells and shower moisture to gases from new furniture and the everyday bio-load of dust, microbes and allergens. Older homes have nearly the opposite problem. Here's what to know about both.

Less air exchange

Older homes "breathe" through gaps around windows, doors and outlets. It's wasteful, but it swaps stale air for outdoor air all day long. A tight home swaps much less. Without a planned way to bring in fresh air, odors, moisture and particles have nowhere to go.

More synthetic materials and VOCs

New homes are full of fresh paint, engineered wood floors, cabinets, carpet, caulk and adhesives, and new furniture and mattresses add more. Many of these give off volatile organic compounds (VOCs), especially in the first year or two, and heat speeds that up. In a tight home in a Texas summer, those gases build up, which is why a new house often has that strong "new home smell."

Oversized air conditioning

Many homes, new and old, have AC systems larger than they need, and a tight, well-insulated home needs even less cooling. An oversized system cools the house fast, then shuts off before it has run long enough to pull moisture out. The result is a home that feels cool but clammy, with humidity sitting above 55 percent. Damp air feeds dust mites and microbes and holds onto odors.

Moisture from daily life

Cooking, showers, laundry, plants, pets and even breathing add several pints of water to the air every day. In a leaky home, some of it escapes. In a tight home, it stays unless your exhaust fans and AC carry it out.

What problems do older Austin homes have?

If you live in a 1950s ranch in Allandale or a 1980s home in Round Rock, your challenges look different.

• Air leaks pull in outdoor air you didn't choose. That can mean humid air in summer, pollen during cedar season and dusty air from the attic.
• Leaky ductwork in hot attics often has gaps that pull in attic dust and insulation fibers, and it can sweat in humid weather.
• Older AC equipment may not control humidity well.
• Aging bathroom fans may be weak, noisy or vented into the attic instead of outside.
• Years of buildup collect in ducts, carpet and closets.

Many older homes sit on slabs, but some have pier-and-beam floors, where a damp space under the house can add moisture and odors to the rooms above.

What helps in any home?

Use your exhaust fans

• Run the bathroom fan during every shower and for 20 minutes after.
• Use the range hood every time you cook, especially with gas. A hood that vents outside works far better than one that just recirculates.
• Make sure fans actually vent to the outdoors, not into the attic.

Bring in fresh air on purpose

In a tight home, the best answer is controlled fresh air. Options include:

• A fresh-air intake tied to your HVAC system, which brings in a measured amount of outdoor air.
• An ERV (energy recovery ventilator), which swaps stale indoor air for fresh outdoor air while trading heat and some moisture between the two streams. It's a good fit for humid climates like ours.
• A whole-home dehumidifier, often paired with fresh-air ventilation, to keep humidity in check.

Some newer homes already have a fresh-air intake or ventilation fan. Make sure yours is working and hasn't been switched off. Our sister company, Gold Eagle Services, can look at your home and HVAC system and recommend the right fresh-air and humidity options. They can also check your AC sizing and look for duct leaks.

Good habits

• Keep indoor humidity between 40 and 50 percent. An inexpensive hygrometer tells you where you stand, and our Central Texas humidity guide covers the rest.
• Change your HVAC filter on schedule. Consider MERV 8 to 13, based on what your system can handle.
• Open windows on mild, low-pollen days to air the house out, especially after painting or bringing in new furniture.
• Let new furniture and mattresses air out in a garage or open room before moving them in, when you can.
• Choose low-VOC paints, finishes and cleaners.
• Skip heavy air fresheners and scented candles. They cover odors instead of clearing them.
• Vacuum with a HEPA vacuum and wash bedding weekly.

If you notice a leak, water stains or visible growth, deal with that first, starting with an independent state-licensed professional. We don't measure or analyze indoor air.

Can a whole-home treatment help new and older homes?

Whether you just moved into a new build in Pflugerville or have lived in your Austin home for decades, dust, microbes and odors build up over time. Pure Maintenance Austin's whole-home dry fog treatment reaches every room, closet, crack and crevice and your HVAC ductwork without getting things wet, then adds a surface protectant. On treated hard, non-porous surfaces it helps neutralize odors. The dry fog treatment is done in one day.

Dry fog isn't a fix for new-material fumes. It doesn't remove VOCs, so ventilation and time come first. Our guide to a fresh start in a new home covers move-in timing.

What to do next

1. Check that your bath fans and range hood vent outside.
2. Put a hygrometer in your main living area and aim for 40 to 50 percent.
3. Once the basics are in place, book a free phone consultation about a whole-home fresh start.

Call 512-904-4646 to book a free phone consultation. A Comfort Advisor calls you, learns what's going on in your home and sends a written quote based on square footage. We serve all of Central Texas, out to College Station (about 2.5 hours), including Round Rock, Georgetown, San Marcos, Bastrop and Marble Falls.