Insulate all exterior walls, including (3A) walls between living spaces and unheated garages, shed roofs, or storage areas; (3B) foundation walls above ground level; (3C) foundation walls in heated basements. 4. Apply insulation to floors above unconditioned spaces, such as vented crawl spaces and unheated garages.
In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, cathedral ceilings, floors over unheated garages or porches, knee walls, and in between interior walls—especially bathrooms—as well as ceilings and floors.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
Attic. The attic is arguably the most important area in your home to insulate.
Missing insulation allows either heat or cold to infiltrate, which shows as hot or cold spots on your walls or ceiling when viewed by a thermal camera. You can easily detect areas of missing insulation by walking around your house with a thermal imager and looking for temperature differences.
Unlike exterior walls, which must meet local and state codes for insulation, interior wall insulation is rarely required. This is because interior insulation has much less impact on your home's energy efficiency – but it can still play a role.
Insulating your attic floor can create a vented attic, which is ideal for storage and not needing temperature control upstairs. Insulating the ceiling will make an unvented attic, which allows you to control the temperature for temperamental storage items, living space, and HVAC ductwork.
If you're looking to improve the energy efficiency of your home, installing ceiling insulation is one of the best things you can do.
External insulation maintains internal space, reduces thermal bridging, and improves thermal performance. However, it entails greater initial investment and external cosmetic considerations. Internal insulation is more cost-effective and enhances the comfort of a living space.
Cracks, holes, and gaps around the home can lead to a significant amount of heat loss. Especially around areas like your windows, it's estimated that poor air sealing can account for up to 30% of the air leaks in your home!
Moisture damage
This can occur due to leaks in the roof or foundation, inadequate ventilation, or high humidity levels inside a building. Moisture can cause the insulation material to become compressed and lose its effectiveness, leading to increased energy consumption and potential mold growth.
It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.
Besides safety concerns, installation inexperience can result in insulation mistakes that can affect both the quality of your insulation and installation. Improper placement can leave gaps and cause energy loss, lessening the insulation's lifespan.
Stapling insulation is the best way to ensure your underfloor insulation withstands the test of time.
Wiring – When wiring exists in the cavities that are being insulated, simply split the insulation so that it is placed around the wire on both sides, allowing the wire to be comfortably nested inside the insulation.
For example, if you need extra soundproofing or don't want to spend time installing a separate vapor barrier, then face may be the best option for you. However, if cost savings are more important than convenience, then unfaced may be the better choice in this case.
In finished attic rooms with or without dormers, insulate (2A) between the studs of "knee" walls, (2B) between the studs and rafters of the exterior walls and the roof, (2C) and ceilings with unconditioned spaces above. (2D) Extend insulation into joist space to reduce air flows.
External insulation boards are usually bulky and can add around 50mm to the exterior of your walls. This can create problems when installed around windows, doors or roof eaves. Addressing these issues can require costly adjustments and increase the overall cost of your insulation project.
Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).
Putting insulation in a ceiling between floors can help reduce noise to and from the residents above one's home. This can also be beneficial for decreasing your energy bills and carbon footprint.
Ceiling (attic) first. Door opening insulation (fill gaps). Then the walls, then double pane (or triple pane) windows, double-insulated doors, then cellar walls. If on a raised platform, the floors before double-pane windows.
Too much insulation will leave humidity and moisture to accumulate in your attic space. This can lead to mold growth on your walls and insulation. There might also be water damage to the support beams in your home's roof.
While both ceiling and roof insulation will increase your home's resistance to outside temperatures, insulating the ceiling should be your priority.
If a heating or cooling system is installed in an unfinished attic, insulate the rafters to convert the area into a conditioned space. In a finished attic room or dormer, insulate between the rafters and studs of your exterior wall for better temperature regulation.