Question: We are replacing the windows in our small office building and I’m curious about which kind would be the most energy efficient?

Answer: If you’re talking about framing materials, the vinyl option is very energy efficient and will result in some sweet savings on your energy bill!
Whether you’re battling cold in the winter or heat in the summer, your choice of window can have a serious impact on heating and cooling costs.

In today’s Ask an Expert, we are going to look at energy efficient framing materials, talk about what the U-value means and discover how to work in some savings on your energy bills when selecting a new window.

A beautiful view on energy efficient windows

Along with replacing old doors, replacing old windows will improve your building’s insulation — an energy efficient window will save you from drafts and keep your heat where you want it — inside — for the upcoming cold winter months.

The vinyl window option, fabricated from mainly polyvinyl chloride (PVC), is known to be energy efficient, condensation-free, reduces noise and requires zero to no maintenance, according to

While vinyl is a great thermal solution, with options of filling sections with foam insulation — there are other options to look at still.

Fiberglass windows are appealing because of their strong frames — they’re durable, also low maintenance and will hook your building up with good insulation.

For those who appreciate an older, traditional or ‘historical’ aesthetic, wood window frames are preferred. The thing about the wood option is you’ll need to keep in mind that the exterior surfaces will often require an aluminum or vinyl covering to reduce maintenance, according to Energy Star.

Of course, there are combination frames available that will allow your window to use different materials separately in different parts of your frame. This means you can opt for wood inside while you have vinyl on the outside. For some buildings, this option could be very convenient.

The low down on heat flow

When it comes to heating, a window provides buildings with an opening that allows warmth to come in and out. An energy efficient window will do the job best — avoiding things like air-leakage.

The uncontrolled heat transferred through windows can be expressed with U-values.

“U-values are the mathematical inverse of R-values,” says Fine Homebuilding, “So an R-value of 2 equals a U-value of 1/2 , or 0.5. Unlike R-values, lower U-value indicates higher insulating value.”

The U-value is the rate your window loses heat through a combination of these four ways: conduction, convection, radiation and air leakage.  When talking windows to the person installing your replacements, it’s important to keep the U-value low — and knowing that doing so will mean a more insulated window.

If you’re in the States, you can often receive energy credits for your energy efficient building while Canadians can receive sweet, sweet incentives.


Image credit: gotsetters