Questions - I've heard that harmful formaldehyde gas levels are highest during the summer in efficient houses like mine. How can I determine if my house has a problem and how can I lower the gas level energy efficiently? E.W.
Answer- Formaldehyde gas is given off by many common materials and products in every home. Symptoms of high formaldehyde gas levels are often similar to colds and allergies - headaches, burning eyes, coughing, runny nose, etc. It is also a suspected carcinogen.
Indoor formaldehyde levels are generally highest in the summertime. Both heat and humidity increase the release of formaldehyde from furniture, carpeting, drapes, kitchen and bathroom cabinets, many adhesives and many common household products.
If you have made energy improvements to your home, your central air conditioner may now be oversized for its cooling needs. The air conditioner runs less and does not dehumidify well, even though you may feel comfortable. This can increase the level of formaldehyde gas that gets trapped indoors. Typical central and room air cleaners do not effectively remove it.
Several laboratories offer inexpensive do-it-yourself home test kits (about $35 for three tests) to check the formaldehyde level inside your home. For one test, you just open a small bottle filled with a special water solution that absorbs formaldehyde gas.
After a day or two, you mix in a few drops of test liquid. The water solution changes color and you compare it to a color chart to determine the formaldehyde gas level inside your home.
For $20 more, you can send the sample to the lab for more accurate analysis. If your do-it-yourself test shows a higher than acceptable level of gas, you should consider having the lab analyze the next sample. Other seven-day-average-level home tests require laboratory analysis.
Natural ventilation is the most energy-efficient method to lower the formaldehyde gas level inside your home. Installing a heat-recovery whole-house fresh air ventilation system saves the energy from the stale air that it exhausts from your home. You can write to me for Utility Bills Update No. 473 listing laboratories that supply formaldehyde home test kits, prices, testing instructions, a chart showing typical household sources of formaldehyde gas and a list of do-it-yourself methods to reduce the formaldehyde gas level. Write to James Dulley, Deseret News, 6906 Royalgreen Drive, Cincinnati, OH 45244
Question - I want to add some more insulation to my walls and I can get a good buy on some 1-inch rigid foam insulation. Can I just glue it over the old drywall and glue new drywall to it? W.J.
Answer - This method works, but you should use foil-faced (on both sides) rigid foam insulation board. The foil provides a good surface for the adhesive and is a good vapor barrier to keep moisture out of the wall cavity.
Leave a narrow gap between the insulation boards. Fill that gap and the gaps around electrical conduit boxes with silicone caulk for an airtight wall. Silicone is effective because it adheres well, is elastic, and has a very long life.