Not sure what you are asking?

If you live in a heating climate, then don't lose the storm windows - refurbish them, replace them, whatever, but bronze weatherstrip or not you are not going to want to use only single pane glass.

The eight over eight configuration is not going to help either.

Understand you don't want to obscure architectural expression, but I agree with Oberon...if you in a heating climate, you need the storms during heating months (you could take them out during the warm months.

In addition to replacing the seals, upgrade the storms by going with low-e glass...you'd cut heat loss significantly.

If you live in the far south, disregard....

The reason your 1950 wooden windows have survived this long is due to the storms taking the beating in winter. Condensation on the inside of the glass is a bad thing, it dampens the wood for months at a time, keeping it soggy through spring, when it is is warm enough to start rot, and at the same time the water getting under the glazing putty makes a very short lifespan for that material.

So my advice is to _treasure_ those wooden storms. A competent woodworker can modify them to take an interchangeable lower section with a screen for summer and glass for winter; the very best possible outcome.
Casey

+1 to the advice above.

Single pane, regardless of tightness, is not going to cut it in about 95% of the applications.

Storm windows cut infiltration loss, they have essentially zero R value.

Glass conducts heat way to well to have a significant temperature difference across a thin section.

Bronze weatherstripping does the same thing, reduces infiltration.

The R-Value improvement as a result of the storm is not due to any thermal resistance in the single lite of glass but in the dead air space (assuming that the storm window is functionally tight) that it creates.

A properly functioning single pane storm window can yield an overall R-Value of about R-2.5 whereas the R-Value of the single pane glass is going to be 1 or less.

Measured performance (multiple sources):

Outside temp 0F and indoor temp 70F with no direct solar gain.

Single pane interior glass temp ~16F

Clear dual pane (no LowE coating) or single pane with storm window ~43F

"but in the dead air space"

The space is normally to large to be effective.

Convection sets up.

Wood storms can have a small value, but metal storms are always zero.

I will have to respectfully disagree with you on this one brickeyee.

Can you cite what source you are using to determine that too large a space makes the storm window and trapped air ineffective?

Absolutely still air (zero movement) has a hypothetical R value of 6. Some folks will use that idea to suggest that a single pane with storm is actually better than a sealed dual pane because of the wider airspace.

However those folks fail to take into account the convection currents in the airspace that very significantly affect the performance of the single pane and storm. So much so that the R-value performance of a single pane with storm and a wider airspace isn't any better and may be a bit worse than a clear glass, air-filled, sealed dual pane with a 1/2" airspace.

However, the other side of the coin is that the single pane with storm is going to have energy performance numbers comparable to the clear glass, air-filled, sealed dual pane with a 1/2" airspace.

Calling the area between the inner and outer lites - be it a 3" gap between a single pane and storm or a 1/2" gap of an IG unit a "dead air space" may not be scientifically precise, but it is very common and it works for the general idea.

Adding a second lite does improve R-value performance - there is a measureable improvement. As typically simplified, one lite equals R-1 and two lites equals R-2.

And as I mentioned earlier, and using the same set-up, one lite equals interior glass temp of ~16F and two lites improves that performance to ~43F. That improvement is absolutely measureable and is so well known that it is considered axiomatic in the glass and window industries.

Oberon,

Thanks for the follow up and technical clarification on that. That was my understanding (minus the specifics).

Convection happens in any air space and hence the reason that denser than air fills contribute to additional efficiency improvements over a sealed IGU with air fill.

Storms are a great idea and can wood but most of the ones that are out there are so horribly sealed that they are likely operating at 50% of their potential, however, they are certainly a vast improvement over single pane as you have clearly illustrated.

Thanks...as always....for the clarification.

By the way...great word (axiomatic). I will have to use that one again.

"Can you cite what source you are using to determine that too large a space makes the storm window and trapped air ineffective? "

ASHRAE Fundamentals Handbook.

Glass is a good heat conductor, and you will not get any appreciable rise over its thickness except for surface film affects.

The large gap also is more than adequate to set up convection if there IS and temperature difference from inside to outside.

While I ASHRAE and they do have a bunch of good standards (thankfully BPI is adopting some of the newer ones too), I have seen more than enough thermal testing that indicates just what Oberon is referencing.

The idea of a storm window not having and impactful difference on the R-Value of that opening is simply not true.

Glass is a great conductor but window manufacturers are still getting R-3+ out of windows with no low-e coatings.

Convection sets up regardless of air space and even happens inside of insulation materials and other tight gaps.

A well sealed storm window will function at or near R-2.

Yes, as others have mentioned, you'll get appreciable convection in a very large air space (such as what you'll find with storm windows), but it's still a much better barrier to heat transfer than a single pain of glass. As Oberon mentioned, you'll take the R-value from 1 all the way to 2 with a storm window. (and putting using low-e glass on the storm will take the R value to close to 3).

The biggest issue with the performance of most storms is poor fitment/condition and not creating that trapped and static air space.

If they are tight and functional, they can work pretty darn good. Put low-e on them as Trapper and Oberon said and they can be just as good as most of the newer Low-e equip double pane windows.

3bean3,
Just now our 100 year old house is without its nasty white proud-sitting triple track aluminum storms for the first time since we moved in 11 years ago. It is lovely to see the original 6x6 and 6x9 windows unobstructed, until they are repainted and new storms are installed, design yet to be determined. But suddenly we are very aware of street noises, while before our house was very quiet. Also, we have one less layer of security in our northeastern urban neighborhood. I'll be very glad when we have settled on a design for storm windows and they are installed. In our neighborhood, a number of house-proud neighbors have chosen those wooden storms with fixed upper panels and interchangeable storm/screens below. I am torn about losing the ability to open window sashes at the top to exhaust hot air near the ceiling.

Have you thought about installing nice full-length screens on the outside, and magnetic interior storms? Some on the Home Forum say that this will make your original windows deteriorate faster, since they will remain exposed to the elements. Others say that condensation is actually a greater threat to your windows and that interior storms do a better job of protecting them from condensation. I'd be interested in hearing what Oberon, WoW, Trapper, brickeyee, xoldtimecarpenter and sombreuil have to say to that. Apparently many historic preservation districts require this solution. But somewhere in my research I remember someone -- Mr Yapp? -- pointing out that our old houses never were meant to be without storm windows -- people just rotated full-length storm and screen panels twice a year. And my friends who live in a meticulously restored 1740s farmhouse in Connecticut do just that -- they are the most historically correct homeowners that I know.

This question makes a small bungalow seem mighty appealing about now: possibly the best solution!

Your thread has attracted the great wizards of the Home Forum: their guidance is invaluable -- I just wanted to add a couple of less technical points that I think you might want to consider.
Lynn