Not as Expensive as Oil

Here in Florida very few homes have double pane. Why bother? I imagine many southern homes in other US states are single pane, so maybe just a few of those 64% of 110 million home would really reap a benefit from double pane.

For us double pane is an issue with moisture and heat breaking the seal and fogging the inside panes.

Double pane really works when you have sub freezing weather where the inside and outside temperature delta is large. Even when we get 95° days here the inside-outside delta is only 20°. When i lived up north a relatively balmy 30° outside was a 50° delta, more than twice what we get here.

I do not agree with your comments at all, sorry.

I fail to understand why you have problems with condensation, unless your air conditioner is really out of whack.....

If you do not have A/C, then I still do not understand the problem, something is wrong in your house....

Reducing the need to burn electricity by good insulation is a must today, otherwise you have a large CO2 footprint and that is unforgivable.

Hi, Andy.

This is what I was told by an informed realtor when I asked the question. My best guess is the extreme heat cycling we get here is probably the problem along with high humidity. The result is moisture that seeps into the inner layer of the window.

My girlfriend says that newer windows are much better than the older ones which had a higher failure rate.

Double panes also help keep the heat out so the air conditioning does not have to run as much.

I do agree about the propensity of double-pane windows to fog, but generally the ones that suffer this are on the western side of a dwelling. Modern windows are an important part of a dwelling, however there are other things to consider when making a home energy efficient.

I just designed my next two-story 3,000 ft2 dwelling for construction at 36.5 degrees latitude north. Double-pane Low E windows are a small part of the solution as the new dwelling is a passive solar design with 2" x 6" stud wall construction on all outside walls. I will also place two (2) split HVAC systems in the home-one for the upstairs section and one for the lower section.

The passive solar design can be used for single-level dwellings. The degree of efficiency impact is determined by the delta of the sun angles from the lowest sun elevation of winter to the highest sun elevation of summer as related to the depth of roof overhangs, window size and placement, etc.

Interesting though. I submitted all of my CAD drawings to an architect for final approvals and stamps, and we discussed the design and layout of the dwelling. I made a statement that in essence said that I had to design my own dwelling, as no homes of this design were available for purchase. He stated to the effect that the intitial cost of course was an architect's and builder's reasoning to build conventional dwellings with efficient windows and doors, yet not apply thicker walls because of the cost issue. The basic reason was that most people who buy a home plan to stay there but a few years before buying something larger, better, etc..

The cost of 2" x 6" construction is of course approximately 60% greater than that of 2" x 4" construction, yet this cost is a very small portion of the final cost to build a dwelling. The essential problem is marketing, as most people compare prices ft2 to ft2 rather than the long-term cost of using the dwelling. I know that I went off the subject a bit here but I think I had a reason to do so. I do plan to stay in this new dwelling for many years, hence my justification for building a passive solar home with high-efficiency features.

So, in my opinion the efficiency gained by double-pane Low E windows is a very small part of overall energy effciency. They do help=no doubt about that, but are they the best "bang for the buck?" I do not think so if we are discussing new construction. For a remodelling project-now that is a different story.

Best Regards,

Ing. Robert Forbus

One advantage of 2 x 6 construction is that the studs do not have to be 16" on center. 24" works just fine so the added cost is not that great. The added and the advantage of 24" stud spacing is more insulation and envelope sealing. While a fir 2 X provides insulation, it is not as efficient as fiberglass, or better yet, isonene or other foam-type insulation. Super insulated construction significantly reduces operating costs. If finance the additional expense, payback is pretty quick (monthly interest on marginal cost increase is usually less than monthly energy cost savings - heating and cooling.)

Double pane or triple pane windows have come a long way. Location and size is one consideration. Multi-glazed windows come in a variety of configurations. The type of film applied, where applied, and the gas fill effect transmission and reflectivity of light and heat. Consider that the windows on the south side of the house may require different properties than those on the north. Since your building new, you can spec out each window. Just be sure the builder installs them in the right place.

Solar influx during the summer contributes to cooling loads. There's no reason significant energy savings can be achieved in hot climates with double pane windows with the proper coatings.

My last house was 2X6 construction in Ohio. Down here in Florida they won't let you do that due to hurricanes. I favor the 2X6 construction (for non-hurricane requirements) as it is sturdier and a better insulator.

In florida the hot (no pun intended) technology is poured concrete walls with the insulation on the outside. The concrete acts as a giant heat sink. Once the house is cool the concrete tends to keep it cooler as daytime temperatures fluctuate. We have drywall lined walls, so everything looks normal.

The real weak spot is roofs. Most are lumber frame with asphalt shingle. Steel roofs are also popular as are tile. Both are pretty resistant to hurricanes.

This sounds like a very american discussion of energy efficiency. It is out of date by a decade or so. Modern european double glazing panels do not suffer fogging. It was a problem with those installed 20 or 30 years ago, but is very rare now. Double glazing has a number of benefits besides heat insulation. It insulates noise, and the windows are nearly unbreakable. In England building standards dictate the use of double glazing, and everybody has benefitted from an increased quality of life.

And that sounds like a very narrow view of American discussions. Virtually all modern American domestically-manufactured windows also suffer no fogging. They did 20 or 30 years ago, and improved their products. A cheap window is just that, no matter where it's built. The biggest problem now in the USA is being flooded with cheap crappy imports. I sure don't blame the Europeans for that.

We'll see who's out of date twenty years down the road. It will be interesting. Best regards.

J

I have given you a point for a good post. I did not understand what he was on about either, but cheap crappy windows could explain it completely.....

I agree, but I think Florida is a bit outside the norm compared to European climates. However, I think you are right that things have improved dramatically.

That leaves us with the actual delta temperatures between inside and outside. Double pane windows provide a better payback for cold climates than warm ones because the delta temperatures inside and outside are much greater in winter than summer in Europe and northern US.

When I went to Sweden I was amazed at the windows there. There were a lot of triple glazed windows that were so well designed that they looked like the original single pane windows that were installed hundreds of years ago.

In Switzerland, triple-glazing with low-emissivity glass is not unknown.

Alternative transportion is not just a good idea its a matter of national security since the greatest transfer of wealth in the history of mankind has / is taking place. OPEC makes enough in 6 days to buy GM and enough in 3 years to buy 20% of S&P 500. Our government has let us down by letting big oil suppress the electric car in america. In 1998 oil was $8 /barrel now its $100. WE NEED THE ELECTRIC CAR AND NOW! I.E. The www.TripleBatteryLife.com patent makes a 50 Mile range into 100 miles for electrics, more than enough to eliminate 90% of america's oil needs. Imagine 50 cent gasoline and never having to stop at gas stations unless you are going more than 100 miles !

A whole lot of older homes in the USA could be made much more energy efficient by just sealing up the air leaks. I have seen too many projects to add insulation or double windows to a home when there are air leaks. There is a real problem in the USA in building modest houses instead of McMansions. The old inefficient homes continue to be lived in by people who cannot afford the huge new homes.

in the 70's we sealed up our houses to save energy. We saved energy buy we got "sick" houses. colds and flus were rampant.