Dear Glenn: I am building a new house that will be about 2,000 square feet. I am looking for a heating system to put in.

The house will have foam throughout the whole home. It also has a full walk-out basement that is not included in the square footage. I am only finishing the upper level.

I do have natural gas on site. I also want central air and a whole house exchange unit.

Terry, via e-mail

Dear Terry: Geothermal would be my first choice. You get heat, air conditioning and endless hot water.

Look into federal tax credits that cover the entire cost of installation.

Dear Glenn : I have researched gutter protection systems, and the Gutter Brush looks like a good system. I have requested and received a sample. It seems economical, and I can install it myself and remove it to clean gutters if needed. Do you have an opinion on this system? If so, I would appreciate your comments before I purchase. Thank you.

Glenn, via e-mail

Dear Glenn: I agree with you. But have someone familiar with climbing ladders remove and clean when necessary.

Dear Glenn: I want to insulate the ceiling in my house with blown-in insulation. Do you have a preference when using blown-in insulation between cellulose and fiberglass? I read the Colorado study, but that study was conducted in 1989 and used fiberglass bats rather than loose-fill fiberglass. Thanks for your help.

Jerry, via e-mail

Dear Jerry: Cellulose or foam are my top choices. There are overwhelming studies that make both of these insulation materials the big winners. Act soon for federal tax credits on the cost of insulation.

Dear Glenn: I have a three-bedroom ranch, and I am going to replace my furnace and air conditioner because they are very old. I need some help with choosing a good furnace/air conditioner brand. I also have birds, cats and a dog, so I will need a good air cleaner. I also will need a good humidifier for the birds.

I have no idea what is considered a good furnace/air conditioner. I was told to replace both at the same time because I would only have to pay once for the labor. Can you suggest some brand names that would be good? Thanks for your time.

Cindy, via e-mail

Dear Cindy: Start by asking friends and neighbors about their experience with the furnace/AC units that they have.

If both the heating and air conditioning units are the same age, then you can really save. Plus look into HEPA (High Efficiency Particulate Air) bypass air cleaning systems for filtered air 24/7.

Warranties -- on furnaces and air conditioners for 10 years on parts and labor -- should be addressed. They should be backed by the manufacturer of the furnace/AC units. Look for NATE (North American Technician Excellence)-certified installers to install your products.

If you act soon, and purchase the proper products, you may be eligible for tax credits and rebates from the federal government and from your state and local utility.

Dear Glenn: We have mold in the bathtub caulk in several spots along the tub. My husband has dug the caulk out and replaced it, but the mold keeps coming back. I have used Tilex and Dow mold removers, and it does disappear for a while, but keeps coming back.

There was an article in your column a while ago mentioning Concrobium Mold Control by Siamons. Is this safe to use on the tub? Or is there another product that will eliminate the mold? The caulk in these areas is just disappearing.

The bathroom was updated in 2003 with new fixtures and tile inside the tub. Thanks for any help you can give.

Karen, Sterling Heights

Dear Karen: First, you need to clean out the old caulk. To do this, fill the tub half full with cold water. Remove all caulk. Then wash down with the X-14, (888) 324-7596, www.x14brand.com. Rinse and let dry. Then wipe the area with rubbing alcohol. Now apply GE Silicone II, (866) 275-4372, www.caulkyourhome.com. Make sure that it is the one that cannot be painted. Smooth the caulk bead so it's not a speed bump. Drain the tub.

And yes, Concrobium Mold Control, (866) 811-4148, www.concrobium.com, is only for interior use and safe to use.