Autodesk has just released a clever little game called RETROFITS "to help educate everyone from industry professionals to teachers, parents and students about green building issues."
It is fun and and full of good information. But it certainly starts off on the wrong foot....
The very first thing you do in the game is tear out the existing double-hung windows, even though study after study show that this is just about the last thing you should do in terms of bang for your buck. Payback time estimates in energy savings vary between 40 and 400 years, and it can destroy the character of the building. One Vermont study concluded:
Our study of old windows showed that the energy savings are similar for a variety of retrofit and replacement strategies. Rates of return on investment for energy improvements are quite low when starting with typical or tight windows with storms in place, but are significantly higher when renovating loose windows with no storm.
The difference in annual energy savings between renovating an old sash and replacing it with a new one was very small--retrofits saved only a few dollars.
For preservations, the good news is that with a proper choice of renovation strategy and good workmanship, historic sashes can be almost as energy-efficient as replacements. Window renovators and homeowners can give more weight to comfort, maintenance, lead abatement, egress requirements, durability, ease of operation--and historical value--without sacrificing energy savings. For those of us who work with old windows, this is very good news indeed."
Donovan Rypkema has come to much the same conclusions:
- Properly repaired historic windows have an R factor nearly indistinguishable from new, so-called, "weatherized" windows.
- Regardless of the manufacturers' "lifetime warranties", thirty percent of the windows being replaced each year are less than 10 years old.
- One Indiana study showed that the payback period through energy savings by replacing historic wood windows is 400 years.
- These houses were built hundreds of years ago, meaning those windows were built from hardwood timber from old growth forests. Environmentalists go nuts about cutting trees in old growth forests, but what's the difference? Destroying those windows represents the destruction of the same scarce resource.
Another point about double hung windows is that they work better; you can tune them to get better air circulation.
I know, it's just a game. And it makes some very good points in between the window replacement and attachment of green gizmos:
There is no question that we have to fix our existing buildings, including our older, historic ones. But tearing out old windows is not where you should start, in a game or in reality.
Get more information at the National Trust for Historic Preservation.
Autodesk discusses the game. Their heart is certainly in the right place.