single pane windows and heat/electric bills (rent, buying a house)

[windsorslp]

Have any of you moved from an older home with single pane windows to a newer home with double pane windows and did it make a big difference in your gas/electric bills?

Our average gas/electric bill is 500$ a month. We rent a house -built in 1995 about 3200 square feet with lots of windows and high ceilings - there are 3 systems in the house, one for each floor. It is poorly insulated,in our opinion and you can feel the cold or the heat escaping through the single pane windows. If we end up buying a house here, my husband won't even look at homes with single pane windows. I am thinking it might be better to buy a new home, even though they are more expensive, because we will be paying less in heating/AC and this may offset the cost. What do you think?

[ATLTJL]

You're right.

My house was built in 1993 and it leaks a lot. I have double pane windows with the gas between them, but they still leak (I think it's because there isn't enough insulation around the window itself where it placed into the wall, not the glass).

I also get drafts that come in through the actual wall. I asked my contractor about it, and he said that nowadays houses are wrapped in a plastic that keeps drafts out and it's part of the code, but it didn't come until a few years ago.

The bottom line is, the newer your house is, the newest codes it's going to have been constructed to. And they keep getting more efficient.

For your particular problem, you may be like me where the air isn't leaking through the glass itself, but from around the actual window box. And you can fix that. Or you can do what I do, just buy that plastic stuff that you tape to the window and shrink with a hair dryer. It helps a lot.

[BobKovacs]

There's more contributing to your utility bills than just the windows, though they do play a large part in the equation.

a) Back in the 90's you were lucky to get R-11 insulation in the walls, since that's all that was required by code. Most new homes have either R-15 batts in 2x4 walls, or R-21 batts in 2x6 walls.

b) You likely only have a few inches of insulation in the attic, unless someone has blown more in since the house was built.

c) Unless they've been replaced, your AC units are at or beyond their useful life, and if they're original to the home (or replaced a while ago) they're not as efficient as the new units.

d) You've got a lot of square footage and high ceilings, both of which require extra energy to heat/cool.

Only looking at houses with dual-pane windows will address the window issue, but won't address any of the other items I noted above. Even with a brand new house, if you're looking at 3,200sf, expect your power bills to be in the $300 range in the summer months, and gas/power combined to be about the same in the winter. Better than $500, but you'll get a bigger savings if you can go with a new, smaller house.

[ATLTJL]

Hey Bob, since you know construction, what do you think of foam in attics?

My energy auditors told me that foam in my attic would make a huge difference, but it seems like the jury is still out on just how good it is. I'm a little worried about sealing up my attic and unintended consequences it might have, including putting more heat on my asphalt shingles. I don't know enough about passive soffit ventilation, which I have, to know what the best solution is.

The professionals said go with foam. My parents said install an attic fan to aid the passive ventilation (some say that just causes negative pressure and sucks out your A/C). What do you think about foam?

I could have more of the loose stuff blown in, but I installed a lot of decking in my attic to create storage space, so there is a large area where I don't want loose fiberglass (I did leave a small amount of it uncompressed in the 4 inch space between the decking and the joists). Probably 1/4 to 1/3 of the area up there is decked, the rest has a pretty good amount of loose fill already, though it is old.

[BobKovacs]

Where is your AC unit located? Remember that when you foam the roof, you move the insulation barrier up, making the attic space part of the "conditioned space" of the house. This is good if the AC unit is in the attic, since a) it reduces the temp in the attic, allowing the unit to run better, and b) it keep all the conditioned air that's lost through leakage in the ductwork from escaping into the attic, and also keep hot attic air from getting drawn into the system through leaks on the return air side. If the unit and ductwork aren't in the attic, you're not likely to see as dramatic of a difference by insulating under the roof.

[ATLTJL]

Yes, my A/C unit and all of the ductwork is in the attic.

Can you explain what is meant by conditioned space? Even if the attic is foamed in, there still won't be climate control up there, it won't have vents and returns, so it would still be hotter than the rest of the house in summer and cooler in winter, right? Or do most systems have enough leakage to more or less make them climate controlled space?

I'm interested to know if I did have the attic foamed in, would it reduce the humidity up there, making it a more hospitable place to store some items that I wouldn't put up there now?

[arjay57]

Our house is old (1920s) but we changed out the windows and it make a huge difference. I'd recommend it.

[MaryleeII]

Originally Posted by ATLTJL

You're right.

My house was built in 1993 and it leaks a lot. I have double pane windows with the gas between them, but they still leak (I think it's because there isn't enough insulation around the window itself where it placed into the wall, not the glass).

I also get drafts that come in through the actual wall. I asked my contractor about it, and he said that nowadays houses are wrapped in a plastic that keeps drafts out and it's part of the code, but it didn't come until a few years ago.

The bottom line is, the newer your house is, the newest codes it's going to have been constructed to. And they keep getting more efficient.

For your particular problem, you may be like me where the air isn't leaking through the glass itself, but from around the actual window box. And you can fix that. Or you can do what I do, just buy that plastic stuff that you tape to the window and shrink with a hair dryer. It helps a lot.

Or, in a pinch, you can try "hillibilly insulation"Take Walmart type bags (the plastic type) and shove in through the cracks of door frames, etc, use a knife, like a butter knife.

Regardless of what you use, make sure you don't seal yourself in! Make sure the windows can open, and don't put plastic bags right around the door locks. In a fire, they cold melt, making the door stick!

[BobKovacs]

Originally Posted by ATLTJL

Yes, my A/C unit and all of the ductwork is in the attic.

Can you explain what is meant by conditioned space? Even if the attic is foamed in, there still won't be climate control up there, it won't have vents and returns, so it would still be hotter than the rest of the house in summer and cooler in winter, right? Or do most systems have enough leakage to more or less make them climate controlled space?

I'm interested to know if I did have the attic foamed in, would it reduce the humidity up there, making it a more hospitable place to store some items that I wouldn't put up there now?

When you move the insulation to the roof, the volume of the attic wants to have the same temperature/humidity characteristics as the house below, since it's a contiguous space. When they build new homes with insulated roofs, they do provide vents/returns in that space, and even though it seems counterintuitive, that extra volume being heated/cooled is offset by the HVAC equipment being located in conditioned space.

One thing you don't want to do is leave the existing insulation in the attic floor- that would create a fully sealed space that could possibly get more humid than it currently is.

[cittic10]

Originally Posted by BobKovacs

Where is your AC unit located? Remember that when you foam the roof, you move the insulation barrier up, making the attic space part of the "conditioned space" of the house. This is good if the AC unit is in the attic, since a) it reduces the temp in the attic, allowing the unit to run better, and b) it keep all the conditioned air that's lost through leakage in the ductwork from escaping into the attic, and also keep hot attic air from getting drawn into the system through leaks on the return air side. If the unit and ductwork aren't in the attic, you're not likely to see as dramatic of a difference by insulating under the roof.

From the sounds of it, we could actually have more efficient and comfortable homes if we didn't have ceilings in the uppermost floor. Is that right?

If there was no ceiling and all the HVAC ductwork was exposed and the a/c unit was out in the open, like you see in many commercial buildings and also in timber frame homes, and the insulation was instead in the roof itself, why praytell isn't every house built like that if it's more efficient?