Spot ventilation can help to remove heat at the source, lowering the load on your air conditioning system. Use of bath exhausts, laundry room exhaust and kitchen cooktop exhaust also help to manage moisture at its more noticeable sources, helping to keep indoor moisture and humidity levels in check. Unfortunately, most people do not understand the effective use of these appliances.
Oversized kitchen cooktop vents (400 CFM or larger) create negative pressure that can literally make a house suck in pollutants. The makeup air will follow the path of least resistance and that often means from the least desirable sources. How many of you have turned on the cooktop vent only to have the fireplace not draft properly, filling your house with smoke? This is because the fireplace offers the closest source for makeup air for that large volume of conditioned air leaving your home every minute through the exhaust fan vent pipe. If you don’t have a fireplace or if it is sealed with tight-fitting glass doors, the next path of least resistance is probably any unsealed gas appliance vents. If your home has unsealed gas appliances, your best solution is to seal up any closets housing the appliances with weatherstripping and ensure that they have access to combustion air from outside.
Many bathroom exhaust vents are not used correctly. Although most can exhaust 50-100 cubic feet per minute of source-point moisture created during showering or bathing (if they are properly vented to the outdoors), most people do not run them long enough to remove that moisture. Or, you might do the opposite, turn it on and then forget that it is running. These appliances should be run 20-60 minutes (depending on the length of their duct run) after each bathing event to effective do their job.
Today we have some great new options for bathroom ventilation. First, there is a new generation of bathroom vent fan. It has a permanent magnet motor so it runs on far less electricity and runs far more quietly, too. In fact these new vent fans make less than ten percent of the noise of the fans of just a few years ago and are therefore virtually silent. The controls available today also make the proper use of these fans almost foolproof. There are now wall switches available that contain relative humidity or condensing sensors. They can be programmed by simply turning a set screw to come on whenever the humidity in the room exceeds 50 percent or condensation occurs. Others have occupancy sensors that turn the fan on when the bathroom is occupied and off when you leave (of course there may be times that you visit the bathroom without needing to operate the fan). If you specify the use of only ENERGY STAR-certified exhaust fans that meet ASHRAE 62.2 standards, you can ensure that your new fans will be both quiet and energy efficient.
Interior Finish Products
Many adhesives used to glue wood together, install floors and countertops and bind product components together have formaldehyde and other chemical compounds in them. So ask questions about the products and the materials that will be used to install them. There are formaldehyde-free and low-VOC options available for all of these products, and many carry no additional cost.
- Cabinets, Countertops and Trim:
Many cabinet materials are made using urea-formaldehyde binders, as are subfloors, decking under countertops and some interior trim products. Most cabinet vendors purchase the components from production sources, especially the boxes, drawer assemblies and doors, which can be made from MDF (medium density fiberboard), particle board, or OSB (oriented strand board that may contain these binders. These products release toxic VOCs into the indoor air that your family will be breathing for years. Alternative binders with much less harmful ingredients can be used. MDF that is certified to meet certain standards is available for both cabinetry and millwork. Look for cabinetry carrying either the CARB (California Air Resource Board) or E-1 (European Standard) certification.
- Flooring:
The key considerations for flooring products are that they be hard surfaces. Stay away from carpet and sheet vinyl, even those products certified as green off-gas toxic chemicals for years, and carpets trap pollutants that have been tracked into homes and shed from our clothing and shoes. Some of those pollutants are organic, meaning that they are a food source for organisms higher up on the food chain and therefore attract these pests into the home. All of these organisms create waste products as they go through their entire life cycle-breeding, pooping and dying-in the carpet or other crevices of your home. Carpet is virtually impossible to keep clean.
Choose materials that are prefinished or finished offsite with low-VOC finishes and are installed onsite using minimum adhesives (i.e., floating floors). Engineered wood floors (not solid wood, but wood flooring manufactured through a layering process) may also use formaldehyde binders and glues. So, again, check for products made with non-urea-formaldehyde binders and finishes, choose low-VOC adhesives, stain the concrete foundation or use natural solid wood, tile, linoleum, cork or bamboo.
- Finishes/Adhesives:
Paints and stains, varnishes, solvents, binders, caulks and sealants are big sources of VOCs. VOC content is usually listed on packaging as grams per liter. Safe limits vary per product type and are defined by the Green Seal GS-11 and GS-4718 and other reputable standards. There are many products available on the market that are within the recommended VOC levels published by Green Seal, some at little or no additional cost.
When you think about sources of VOC off-gassing in materials, do not forget about the floor adhesives, floor finishes, countertop adhesives and wood trim finishes. Also, think about how the product fits into your long-range needs. Moisture-cured urethane finishes are durable but too toxic. You might find penetrating oils not durable enough or requiring too frequent maintenance. Contemporary waterborne finishes can provide the same durability as tough oil-based products with much lower environmental consequences.
