Tag Archives: energy efficiency

the Great Window Debate

Since M started the blasphemous discussion of tear-downs and window replacement in my house the other night I have been lying awake thinking about it. I can see that double-paned glass is more energy efficient than single-paned, I know you can feel the difference. I know energy efficiency is environmentally friendly, in fact I hope that environmental friendliness will save the world, but I also know the enormous environmental costs of demo and new materials, that any salesman will inflate energy loss/efficiency numbers to their advantage, and I have seen how very restorable older windows are vs. the short life span of replacement windows.

I know Preservationists’ biggest argument is often about “the historic character” of something but we have to acknowledge that many people just don’t give a damn, and that’s, well, that’s fine.

While preservationists protested, a few other people were doing their homework and refuting window replacement with valid arguments. The following articles cite findings that the time it would actually take to save $$ on this big investment (replacement windows) was consistently around 30 years, more than twice as long as the time it would take to recoup the investment in repairing and restoring existing windows. Read these (non-pres) articles on the pros and cons:
The Great Window Debate
Update Historic Windows

Energy efficiency, the environment and historic preservation are all important to me, and in my world they go hand in hand. In light of that, I’ve done my best here to be a good journalist. I’ve been honing my argument and this time I won’t even mention the aesthetic appeal:

  • Yes, double-pane glass is more efficient—it was a pretty great invention in fact.
    • Before double-pane glass came around people used storm windows to achieve that insulating layer of air. Storm windows (I prefer exterior and operable for use with double-hung windows) are still a brilliant retrofit option.
    • double-pane glass has gases between it that help filter UV and provide insulation, unluckily these can and almost always will eventually leak, leaving you with permanent condensation in the middle – yuck!
  • New windows require less maintenance
    • But the material is significantly lesser quality and unless you pay for custom built, high-quality wooden windows (an option many homeowners do, one at a time, when an old window really DOES get beyond repair), you will be replacing those windows wholesale in 20-30 years. Oh nevermind, leave that to the next homeowner.
  • Exterior storm windows also offer protection from the elements.
Operable metal storm windows at our house have been in place, I'm guessing, since at least the early '90s and though the wood windows are in need of paint at this point, they are far from deteriorating despite having not been touched in at LEAST 25 years.

Operable metal storm windows at our house have been in place, I’m guessing, since at least the early ’90s and though the wood windows are in need of paint at this point, they are far from deteriorating despite having not been touched in at LEAST 25 years. This winter, the wind rattled the windows but a little piece of cardboard fixed that and the storms kept the drafts at bay.

  • Most of the heat loss in your home is through the ceiling and walls, followed by the floor, windows and doors. Percentages range from 25-42% energy loss through the ceiling, 24-35% lost through uninsulated walls and 5-15% through windows. Hence, replacing your windows might feel warmer at the window but make little difference in the room’s ability to retain warm or cool air if the ceiling, walls, and floor are not properly insulated.
  • Speaking of which, old wooden windows SHOULD NOT be drafty! if you are feeling a draft around your window, it’s not because it has single-pane glass, it’s because it’s not sealed well which is infinitely fixable! Panes may need re-glazing (the putty that holds the glass in from the exterior), weather-stripping updated and/or caulk may be needed around the frame where it fits into the wall. Weather-stripping is the easiest of DIY fixes.
  • The replacement window industry wants us to buy new windows (duh), they’ve concocted all sorts of statistics and claims to make it seem like a no brainer. But even though their best claims were exaggerated, the damage was done, much of the general public was convinced that replacement windows would solve all their problems, and also:
    • Driven by consumer demand, the Real Estate industry lapped it up and preached the replacement window gospel.
    • Contractors will probably encourage you to get new windows too whether they believe in them or not because it SO easy to demo the old and install new and less time-consuming than restoring old windows.
  • Additionally, sending all your old windows to the landfill in favor of all new material that will go to the landfill in another 20-30 years (because they can’t be restored thanks to the low quality) wins some major negative environmental points.

In short, replacing your old windows is not a pat answer to the problem of heating and cooling efficiency in homes, and it is certainly NOT the first thing you should do to improve efficiency. Although houses will be different, air leaks should be sealed (windows and doors as well as outlets, baseboards, can lights and other problem areas) and insulation added before anything else is done.

Industry jargon needs to be analyzed, whether it’s from a Realtor, the Window Industry, OR a Preservationist.

If I’m trying to improve my comfort and save $$, I would restore my wood windows hands down, seal drafts and make sure I have sufficient insulation in the attic and floor which will have a greater effect on the comfort level of the whole room. I might even install storm windows if I wanted to spend a little more money and really reap the efficiency benefits. If a window was so far gone it had to be replaced, I would certainly take advantage of double-paned glass, but get a good quality wood window custom built to match the others so that I wouldn’t need to replace all the windows in my house for aesthetic reasons.

What about metal window frames??
I don’t know much about restoring metal windows in mid-century homes, although it can be done. I do know the frame gets quite cold. So I’m not surprised that you’d feel a huge difference once the metal windows in a ranch house were replaced with new ones. In this instance replacement seems reasonable, though I’d still be sure to choose quality windows without plastic bits that break.


green trials: lighting

After yesterday, I feel like I should put in a positive word for this green rehab project at RH. saving energy through lighting.

According to internet sources, lighting can consume 20% of your total energy use, and incandescent bulbs convert only 10% of the energy used into light! the rest is emitted as heat which makes them both super inefficient and dangerous as well if left on (if you’re the worried type). Switching to CFLs or LEDs is an easy and significant change, but I’m preaching to choir here right? Here at RH we replaced every bulb in the building with LED lights, (except for the bulbs dotting the reception room ceiling, which are relatively little used, low wattage, and we were hard-pressed to find an appropriate-looking replacement).

DSCN0268
We even found decent LED “candle” bulbs!

note: these too are MOST efficient if you don’t turn them on though.


going green: climate control

To some, energy efficiency and older buildings do not go together, but here at Rhodes Hall we are trying to prove you wrong. We have teamed up with Southface (or they with us rather) to create guidelines and a point system for LEED-like certification of the energy efficient rehab of historic buildings. The starting point of that being the inherent greenness of reusing an existing building to begin with.

Demolishing one building to build new and “more energy efficient” is like flaunting your choice of compostable paper plates and then throwing them away. YOU’VE MISSED 3/4 OF THE POINT!!

So, RH is serving as a pilot project to this green-rehab initiative. As we make necessary repairs to our building this year we are also making energy efficient upgrades, the biggest issue of course being climate control in the building.

While RH was formerly heated fairly efficiently by radiators (gas boiler in basement), the AC in the summer was another matter. Window units chugged noisily in all the downstairs and 2nd floor rooms while on the 3rd floor a central HVAC system kept us mostly cool but also cooled the uninsulated attic through leaks in the ducts. After much research and debate on the part of the Southface and The Georgia Trust and more debate before approval by the Board, we installed a central HVAC system (heat inverter?) downstairs zoned so that C’s office and the kitchen can be blocked off and controlled separately from the rest of the main floor which is often not “in use.” This was ideal for the museum/events space of our building, the least visible system we could install, but there is nowhere for ducts to run on the 2nd floor so up there, where most of our offices are, we installed top of the line split system electric units which are minimally invasive (least damage to the building itself and most removable), very efficient, and don’t block windows.

The basement ceiling and the attic were insulated with spray foam which has made the attic remarkably temperate year-round.

So how is it all working out?

Well, this is still a big building with high ceilings (for hot air to rise) and opulently expansive single-paned windows. On the first floor, the central heating does an excellent job of warming the entire area*, but on the 2nd and, subsequently the 3rd floors where we put in our 9-5, we are sorely missing the radiators. Here’s what seems to be the problem:

  • the individual room units are operated on a room by room basis, meaning the entire floor (notably the center hall and large bedroom opening onto that) are rarely heated. These large spaces of cold air make it harder to heat up our offices and, even if we close the door, we must pass through these unconditioned spaces to get to the bathroom, the copier, or any other room.
  • speaking of the bathroom, they did not receive any climate control at all and, since the 1st and 2nd floor bathrooms open onto unoccupied (and thus unconditioned) rooms, they are even colder, not an ideal place to pull your pants down. We got space heaters which take the edge off but the heat unfortunately is also rising into that 12 foot ceiling space!
  • there is no heat from the 2nd floor to rise up and warm the 3rd floor as there once was, so that by midday it is colder upstairs than ever (if the central air up here was actually warming that might help but i can’t say that it is)
  • we won’t even go into the aesthetics of the things.

center upstairs hall electric split system hvac

We have miles to go before our work here is done. Work on the windows for instance—fixing drafts, adding storm windows—may help heat retention throughout the building but we still have to turn on the heat and I don’t expect to come to love these Mitsubishi split system units.

I say, if you’ve got radiators then by all means maintain them and if at all possible find a way to install central air on all levels for the summer months. save the split system hvac units for hotel rooms or other closed off and smaller spaces. Despite the selling points of the Mitsubishi units (they ARE quiet and good air conditioners and efficient) I’m not sure they were ideal for us here, then again, anything is efficient if you don’t turn it on.

honestly, this is how energy efficiency looks at RH these days

honestly, this is how energy efficiency looks at RH these days

—-
ARGUMENT UPDATE:
I just ran across something on ZONE CONTROL on the US Dept of Energy website that better says I was trying to say about heating the whole house vs. just the rooms you are sitting in and something in between.

They write that “one way to save energy.. is to retrofit systems to provide separate control for different areas of large homes (RH). Zone control is most effective when large areas of the home are not used often or are used on a different schedule than other parts of the home.”—At RH this would definitely be the main floor/event space, and possibly the central areas of the 2nd floor, although… “Zone control works best in homes designed to operate in different heating zones, with each zone insulated from the others. In homes not designed for zone control (RH), leaving one section at a lower temperature could cause comfort problems in adjacent rooms because they will lose heat to the cooler parts of the home (unconditioned spaces).”

It goes on to say that you can of course enforce zone control/”insulation” by closing doors which we reluctantly do at RH right now though it shuts us off from each other. However, social/work interaction aside this is also not an entirely effective solution as everyone’s office opens onto the cooler central space and thus there is a lot of opening and closing doors. It would probably be advantageous to heat the central spaces daily in conjunction with our offices, thus providing a more reasonable level of comfort all around. let’s put these energy efficient units to work! sigh.

—-
* update in January: The HVAC system downstairs is failing miserable due to several likely factors: the basement now has NO heat where it was once quite toasty thanks to the boiler, this makes it harder for the heat inverter system to warm up and provide properly warm air to the 1st floor, it also means there is a major updraft from the basement door (we use the basement which is partially finished but unconditioned), even though, yes, there is insulation in the floor joists below the 1st floor.