When you turn on the furnace, your HVAC system is not the only thing keeping your house warm; proper insulation keeps this generated heat inside the home. Even though your walls, floors, and ceilings should all be equally padded, don't forget that your roof is also responsible for maintaining temperature control. Like wearing a stocking cap on a cold winter's day, the top of your house is what holds in the heat. And since heat always rises, it is critical that you have adequate roof insulation in order to keep your energy from escaping.
By adding roof insulation to your home, you will be able to save money because your furnace will no longer have to run as often, keeping your energy bills low. Alhough you may already have installed attic insulation, it doesn't hurt to occasionally inspect this area. The padding may have become packed due to moisture or aging, and therefore its R-value (a particular scale of thermal resistance: higher values equal more insulating power) may have decreased over time. So it never hurts to "bundle up" and add to your pre-existing padding so that it can maintain its proper strength.
First, measure the amount of attic insulation you already have installed and then convert that particular height into R-value. Most old homes have about a half-foot which would be an R-value of about 10-20, and should be then supplemented so that this value hits between 20-40. Much of this depends on your regional climate; colder areas of the country should shoot for higher R-values. As you measure, always make sure you wear proper protection (gloves, glasses, long sleeves) to guard against skin irritation. Also, for comfort, avoid hot days so that the task doesn't become a chore; and for safety, always make sure you watch your footing to avoid falling through unsupported areas of the attic.
So Many Choices
This material comes in many forms, so make sure you choose the best type for you and your particular roofing system:
Stay warm this winter! Use this link to addAttic Insulation
Fiberglass Batts: Arrives in long blankets that can be laid over rafters and is often used in sloped structures due to its ability to fit into tight corners. It usually has an R-value of 3 per square inch.
Fiberboard: Rigid squares of fiberglass great for flat roofs since they are easily able to fit next to one another on a level surface.
Loose Fill: Available in either fiberglass or cellulose form (cellulose has an R-value of 3 per square inch), these smaller fragments can be dropped by hand or blown-in. It's great for sloped roofs that have hard to reach areas. It can be a bit difficult to install, so this will probably need to done by a professional, but it is extremely efficient because it can cover any tiny space as it settles.
If you have an upstairs storage space, attic insulation can be added to it at any time and with minimal effort. However, for homes without an attic it may be difficult to add roof insulation without extensive re-construction, so consider all your options and always consult a professional for further advice. The installation itself may be somewhat expensive, but in the long run you'll actually save money. Remember: if you invest in the preparation now, you'll always reap the benefits later.