Q I've seen conflicting information about energy-efficient windows being worth the price. Do they do a good job or not?  

Energy-efficient windows do a great job of reducing drafts and increasing comfort. But the payback period, from energy savings, on the cost of new windows is long. So it's generally not advisable to replace old windows for energy-saving purposes alone.

The most cost-effective time to buy high-performance windows is when you're building a new space, putting on an addition, or replacing nonfunctional windows. If you've got windows that work, you're better off, cost-wise, improving them than replacing them.                                                                                             

And that's pretty easily done. Repair any cracked panes and glazing, run a bead of caulk around window frames, and use side-mount sash locks to hold windows firmly in place. Block drafts through sash-weight pulley openings by using pulley seals. Use inexpensive window weatherization kits, available at hardware stores. If you have storm windows, use them in the winter. If not, have them made - they're far less costly than new windows.

QOur condo association has voted against replacing our windows. The association has given us permission to buy our own but the price is daunting. Is it worth it?

Energy-efficient windows do a great job of reducing drafts and increasing comfort. But the payback period, from energy savings, on the cost of new windows is long. So it's generally not advisable to replace old windows for energy-saving purposes alone.

The most cost-effective time to buy high-performance windows is when you're building a new space, putting on an addition, or replacing nonfunctional windows. If you've got windows that work, you're better off, cost-wise, improving them than replacing them.

And that's fairly easily done. Repair any cracked glazing, run a bead of caulk around window frames, and use side-mount sash locks to hold windows firmly in place. Block drafts through sash-weight pulley openings by using pulley seals. Use inexpensive window weatherization kits, available at hardware stores. If the building has storm windows, use them. If not, have them made - they're far less costly than new windows.

QI have good quality, double-glass windows that have been in the house since before I bought it. A few of them have a patch of what looks like moisture between the two panes that obscures part of the view. Is this a sign that the windows no longer are energy-efficient and should be replaced?

That foggy patch indicates that the airtight seal between the panes has weakened and allowed moisture between the two layers of glass. This doesn't necessarily mean that the energy-saving performance of the windows has been significantly reduced. Even if this had been a sign of lowered efficiency, replacement wouldn't be recommended. Replacing a window for energy-saving reasons, alone, usually is not cost-effective.

Don't get me wrong; I'm all for energy-efficient windows. But they're an investment, and one that is unlikely to pay for the full replacement cost in energy savings. However, if you've got to replace a window that is non-functional or if you need one for a new space, by all means get the best, energy-efficient window you can afford. At that point, an energy-efficient window becomes cost-effective, because your energy savings will pay for the difference between the price of a basic window (an amount you're going to pay, regardless of what window you pick) and the higher price of an energy-efficient window.

If buying new windows, look for a U value of .32 or lower to keep heat in. And, unless you're installing east- or west-facing windows, which are most subject to overheating in the summer, look for a solar heat gain coefficient of at least 0.4 to allow in more heat from the sun.

QOur home was just built, so why do we have condensation on our windows?

A. Your home's newness may actually be the cause of the condensation you're seeing. Humidity in the air is caused by people, animals, plants, cooking and bathing. But in new homes, a great deal of moisture also comes from the construction materials, especially from the concrete foundation.

The condensation on your windows is a sign that the relative humidity in your house is too high and causing water vapor to collect on colder surfaces. It's a good idea to have a hygrometer in your home to keep track of indoor relative humidity. Generally, you want to keep it between 30 and 50 percent, lower in the winter to help reduce condensation potential.

Usually, new building components will have lost most of their moisture and the relative humidity levels will drop within a year of completion. In the meantime, you can reduce the humidity by adding more ventilation within the house, such as a bathroom exhaust fan or range hood. Due to potentially high power consumption, dehumidifiers should be the last resort.

QDoes Efficiency Vermont offer rebates on windows, doors or insulation?

 A. Efficiency Vermont offers incentives on certain energy efficiency improvements that are the most cost-effective when it comes to saving electricity. Since the savings from replacing windows and doors is usually small and very site specific, we don't offer rebates on these items.

If you're looking to save money by reducing heat loss around your home, look at reducing air leakage first. It's typically the greatest single source of heat loss in any house, and reducing it is one of the most cost-effective ways to lower your heating and cooling bill.

For other ways to save energy in your home, contact a certified Home Performance with ENERGY STAR contractor. These professionals can help you identify the best energy-saving opportunities, while also protecting health and safety and improving the comfort and durability of your home. You can find a list of certified contractors in your area at the Marketplace.

QAfter shelling out so much money for heat this winter, we're going to do something about it. Is it a good idea to replace our drafty windows with energy-efficient windows? They seem to be a good thing, but I want to be sure before we spend the money. 

A: Good-quality, energy-efficient windows do a great job of increasing comfort and lowering heat loss. But you're right to think before investing. It's generally not a good financial move to replace old windows for energy-saving purposes alone, because the high cost of the purchase is rarely paid back by energy savings.

The cost-effective time to buy high-performance windows is when you must buy new windows anyway. Like, when you're building a new home, putting on an addition, or replacing nonfunctional windows. Otherwise, it's possible to improve old windows to make them perform nearly as well as new ones but at a fraction of the cost.

Replace cracked panes and glazing and be sure that sashes close and latch properly. Use a window weatherization kit, available at hardware stores. Install storm windows. If you have space between the sash and the frame, ask at your hardware store for a flat spring called a V seal. See if you have functioning sash weights. If you don't, get a cap designed to close the opening where the weight used to hang. Use caulk to seal any gaps around window frames.

The best approach to reducing drafts is to take a look at your entire home. When air escapes to the outdoors through one area of a house, it can create incoming drafts elsewhere. The first place to look is anywhere air can escape to the attic. Likely places include attic hatches, pull-down attic stairs, the attic floor above pocket doors, plumbing, and wiring and more. Seal gaps and make sure that you've got at least 12 inches of well-installed insulation on the attic floor. A Home Performance with ENERGY STAR^® contractor can find and fix leaks and perform any necessary insulation work. You can find a certified contractor by calling Efficiency Vermont at 888-921-5990. Good luck and stay warm!