An important consideration for homes in cold climates is controlling heat flow, as well as getting maximum daylight, curbing air leaks, and managing condensation. The National Fenestration Rating Council and ENERGY STAR rate window products according to their energy performance – these measurements of performance are the benchmarks that are best used when selecting among the many window features and products available in the market today. Among the things homeowners should consider are:

U-FACTOR AND SHGC

U-factor measures the rate by which heat escapes through the windows, while SHGC or solar heat gain coefficient measures how much solar radiation is admitted and subsequently reradiated to your home’s interior. Windows with lower U-factors will allow less heat to escape from the home, while windows with higher SHGC values are likely to allow more heat to enter your home. These values can have a huge impact on your air conditioning bills during summer and your heating bills in winter; finding the right balance and installing the product that’s best suited to the changes in climate in your area is bound to bring you significant savings on your energy bills.

MULTIPLE GLAZING

Double or triple glazing means installing more than one pane of glass, separated by spacers, in your home’s windows. Multiple glazing helps limit the transfer of heat and can reduce the risk of condensation forming on the panes.

PART 1: COLD CLIMATE

FRAMING

Composites such as foam-filled fiberglass, vinyl, and engineered wood are materials that are good at preventing the transfer of heat, which can help you keep the warmth in your home during winter. Metal frames like stainless steel and aluminum, on the other hand, can be engineered for better energy performance with thermal breakers.

Aside from the window components themselves, how your windows are oriented is also important. South-facing windows are ideal for most climates, since an orientation towards the south is one of the easiest, more practical ways to better manage solar gain while admitting copious amounts of daylight into the home. Light-redirecting strategies – such as using light shelves – are also effective when approached from the south side. To maximize energy savings in winter, window insulation is critical. Likewise, the use of shading devices such as awnings, shutters, and drapes are the best way to cut down on the need for cooling energy during summer. If you’d like to have windows installed on the sides of your home facing the east and the west, shading devices can also help prevent overheating in summer.

What about if you live in an area with consistently high temperaturesduring the summer months? What kinds of windows are best? We discuss

that in the second part of our blog series.

PART 1: COLD CLIMATE

We examined which windows are best for cold climates in part one. Now, let’s take a look at the areas of the country where hottemperatures can put windows to the test. While heating is the primary energy consideration in cold climates, ventilation is critical in areas that enjoy high temperatures. To ensure that your windows can help you meet your home’s ventilation requirements, here are a few factors that you should bear in mind:

Passive cooling, for one thing, is a strategy which employs window placement and design to effectively keep the home cool. In hot weather areas, for instance, tall windows (in addition to high ceilings and wide porches) are great at allowing natural ventilation into the home. Orienting windows towards both the east and the west is also effective. By installing windows at opposite sides of the home, you can create cross-ventilation which helps improve air circulation and brings in more cooling breezes. Some window types – jalousies, casement, or awning windows, in particular – can act as air scoops, which can funnel breezes into your home.

WINDOW STYLE

Some types of windows are better at admitting ventilation than others. Casement windows, for instance, can be fully opened – while double hung windows and sliders have one or more movable sashes that can also facilitate the intake of breezes.

PART 2: HOT CLIMATE

ENERGY BENCHMARKS

When choosing your window products, make sure to check for the following:

Air leakage

Air leakage ratings should be 0.30 or less for maximum functionality.

Solar heat gain coefficient

Ventilation is not the only factor that can contribute towards proper energy management in hot regions. SHGC values of below 0.40 are also highly recommended; less heat trapped inside the home enables you to curb your expenses for air conditioning.

Visible transmittance

Visible transmittance is the measure of the amount of daylight a window lets into the home. Choose window products that have a VT values of between 60 to 80.

COATING AND GLAZING

Solar control low-emissivity or low-e coating is engineered to let daylight in while keeping the heat out. Low-e coatings have to be applied to the inner side of the outermost pane of glass.

WINDOW SHADING

Shading accessories are also vital in hot climates, especially during the summer. Invest in blinds, curtains, and other similar devices or accessories. Window film, too, is recommended.

Do you live in an area that allows you to enjoy the best of both worlds – a mix of both hot and cold? Part three of this series tells you how to handle

variable weather and climate conditions.

PART 2: HOT CLIMATE

In part one, we talked about window design considerations for cold climates, while part two took us through the best windows for hot climates. To wrap up this series, let’s talk about the kinds of windows you need if you live in a

mixed climate region.

Getting the right windows for mixed climate areas involves selecting windows and orienting them in such a way that can both: 1) curb solar heat gain during summer, and 2) make good use of passive solar heat gain during winter. You can successfully manage that with the following.

HOME ORIENTATION

Orienting your windows to the South is effective – provided there are overhangs to keep out too much direct sunlight during summer. West-facing windows are likely to receive the full force of the sun when it’s at its peak; east-facing windows are likewise bound to suffer the same issue in the mornings.

ENERGY BENCHMARKS

The lower the U-factor, the better; and SHGC should be less than or equal to 0.40. These two will contribute to overall comfort (especially during spring and fall), as well as reduce energy costs.

WINDOW GLAZING

Spectrally selective or low-e glass with moderate solar control works well for mixed climates, as it strikes the balance between the need for daylight while keeping out most of the radiant heat. In a study conducted by the Efficient Windows Collaborative, increasing the surface area of double clear glazing windows has resulted in bigger energy costs – so the smaller the window, the more energy efficient it can be (provided other requirements for energy performance are also met).

PART 3: MIXED CLIMATE

CHOOSING YOUR WINDOW CONTRACTOR

Choosing the right windows for your climate type is not going to make a difference if you choose the wrong window contractor. Look for the following before signing any contract:

Local knowledge

Oftentimes, the best contractors are local. They know what your weather patterns are like and, when they live in the same area as you do, they know what your home heating and cooling concerns are. Even more important, local contractors are informed of local or state building codes and regulations that have to be followed throughout the project.

Comprehensive experience

Working with more than one window type or manufacturer opens a contractor to the plethora of options in the market, which means he or she can help you find the best materials and design for your specific goals.

Strong warranty

In case you will need after-sales repairs or replacements, a strong warranty from a local-based contractor can save you a lot of money and trouble.

PART 3: MIXED CLIMATE

Nuss Construction

119 Church Road, Marlton, NJ 08053

(856) 452-0551

NussConstruction.com