Marvin Ultimate double hung, with storms, is our window of choice.

Depends on whether you want aluminum, vinyl, fiberglass, wood or a composite and your budget.

I put Great Lakes in a four season room and we really like the way they look. They seem to be a very solid window.

Why would you recommend a storm window with a Marvin Ultimate Double-Hung? Just curious.

Storm windows can provide the following benefits.

1. Increases insulation quality/energy perfomance by creating an additional warm-air space between the interior and exterior of a building structure.

2. Reduces air-infiltration by adding another seal between the exterior and interior of the building structure.

3. Adds protection to the basic window by shielding the window from the exterior elements.

I commend any manufacturer that has an optional storm window designed for their products. It should not be considered a detriment to have such an option, as it is obviously a beneficial component that can enhance a window's performance, if required. How many modern window manufacturers have provided the efforts and foresight to design their products to offer an optional storm panel?

Sorry to disagree with you mcbuilder but, most manufacturers of high energy efficient windows do not recommend the use of a storm window with their products. Not only does the use of storm windows increase the likelyhood of a glass seal failure due to heat build up between the window and the storm but, it will also void your warranty.

In response to the above post, if a manufacturer specifically designs a storm panel for their product/s, like Marvin appears to have done, how would it then void the manufacturer's warranty? Obviously, it would not. I've seen a variety of different storm panel types that have been designed for use by specific window manufacturers within their low-e glass products. Some examples include between-the-glass blind systems (Pella), and decorative glass products sandwiched between two panes of flat glass (Andersen). These glass products are offered by the specific manufacturers and are warranted.

The reason for a lack of concern for storm panels may be that the heat build-up that causes seal failures is generally associated with applying plastics directly to an insulated glass surface. However, a storm panel may provide a sufficient amount of air space between the insulated glass and the storm panel glass to allow for air circulation, thereby preventing the heat build-up noted above. However, it may simply be the different in utilizing glass instead of plastic, whereby the latter does not allow sufficient heat transfer through the substrate.

Additionally, a storm panel adds an additional layer of glass where the reflected heat from a low-e coating must pass. How is this diffusion of heat different from a triple insulated glass unit that also adds the additional layer of glass? I've never seen a window manufacturer's warranty exclude storm window applications, but have often witnessed exclusions for plastic film applications.

I am inquisitive on this subject only due to my personal preference in opting for a storm panel in lieu of a second hermetic seal (as found in a triple insulated glass unit), based on the detrimental aspects of increasing the likelihood of seal failure by multiplying the amount of seals within an insulated glass unit. I'd gladly forego the miniscule energy performance gain that a triple sealed glass unit would provide over a double sealed glass with a storm panel, if I don't have to double my probability for seal failures (as is found in triple glass).

Lastly, a typical double hung window maintains a fairly narrow jamb profile, as many manufacturers design their products to fit within a traditional 4 9/16" wall depth. If a company were to design a truly energy efficient triple insulated glass DH product, they would also be required to redesign the depth of their jamb. Since there is an optimal air space dimension associated with energy performance, many manufacturers are building double hung windows that do not allow for the use of optimal-performance air spaces within the triple insulated glass units. If they were to do so, they would likely have to redesign their double hung products to allow an additional 5/8" or more to their jamb depths, or otherwise compromise the structural integrity of their sashes. Therefore, I commend any double hung manufacturer that has made the effort to provide an option for an external storm panel in lieu of (or in combination with) triple glass, as it simply inserts in place of the standard screen (an assumption is made here), and does not require manipulating a standard product line.

*Disclaimer: I have no association with Andersen, Marvin or Pella, and the information noted above is in specific reference to wood and clad wood windows. I have little to no experience with aluminum, fiberglass, plastic or steel windows, as we have never installed these or reviewed specifications on these types of windows.