How often is the insulation in the attic need to be changed? We have had the house for seven years and the insulation looks ratty. I really can't tell how old itis. Is it something that wouldn't hurt to change? It looks fairly old .
It should never need to be changed unless it's gotten wet or it's full of rodent poop.
If we had a picture and knew where you are I'm sure there would be some better suggestions.
Loose fiberglass can look a little ratty but as Joe points out it won't need to be replaced. It will compress over time and lose a little of its insulation value. You can beef it up, but there should be no reason to replace it. How much return on your investment you'd get by adding more greatly depends on where you are and how much you have there today. If your house 7 years old, or was it previously owned? A 7 year old house would likely be well insulated for your climate.
Any advice given here is general in nature and is not necessarily valid for your given area. If in doubt check with your local codes enforcement department for what is required when doing electrical, plumbing or structural work on your house. Permits may or may not be required in your area and home owners may not be able to DIY some tasks. I have no way of knowing if you have the skills needed to complete the tasks you are asking about, when in doubt seek professional assistance.
My advice may be worth exactly what you pay me for it. :-) For the record I did not stay in a Holiday Inn Express last night.
I am going to assume that although you have lived in the house for 7 years that the house is much older than that.
If so, everyone else is correct in that the insulation does not need to be replaced unless it has gotten wet and moldy or infested with animal droppings and urine. Insulation tends to pack down over time, especially older types like rockwool. The good news is that old insulation can be covered with new to up it's R-value.
You can either hire this out or do it yourself. Blown-in is the easiest to get to all places in your attic and most home stores will have a free rental of the blower unit with purchase of enough bagged blown-in insulation product. With the blower, it's a quick process - should only take a couple of hours to blow in an entire attic.
Insulation in the attic space can give you a fairly fast payback. Most heat loss is through the ceiling and even in summer, a hot attic with poor ceiling insulation will radiate a lot of heat into the house, causing the A/C to work harder. Old houses typically have anywhere from 3" to 5" of compressed insulation, good for maybe R-10 or so. Most areas of the country recommend R-38 in attic spaces - this would be about 15" of blown-in insulation.
In older homes the insulation does tend to compress itself overtime. My parents house ( 1965 circ) had R19 in the ceiling w/2X6 ceiling joist. The insulation had compressed itself to where it probably wouldn't have even rated a R12. I added R30 and it dramaticly incresed the heat retention in the house during the winter months and kept it cooler in the summer. Although insulation is basicly the same as that period date there have been technology advances in its manufacturing. Older insulation does not necessiarly holds it's shape as the newer kind.
just blow some new stuff in and be happy. dig a little bit out with your gloved hand and spread it out. if it's not full of crud, or if there is no vermiculite (boo! hiss! cancer!!!) at the bottom, have at it.
vermiculite is really, really nasty stuff, almost 100 percent liklihood it's from Zonolite or successor WR Grace, and that stuff flakes off short-fiber asbestos. that has to be professionally removed, and then you can go for broke reinsulating. lengthen the soffit vent pans up the roof if you have to, and go for it.
you don't have to get a blower for little spot fixups, there is insulation that flakes itself up to a nice fluff in bags now that works great for patches. just drag up the bags, slit them, and spread with a rake.
goggles, respirator, long sleeves and gloves, no matter what kind you get. rolling out unfaced batts works, but over time they shift and allow little gaps instead of settling, so the result is the same. and that costs more, too.
sig: if this is a new economy, how come they still want my old-fashioned money?
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