The best way to ensure that you will fully benefit and get your money’s worth from your brand new air conditioning system or heating unit is to properly insulate your house. Failing to do proper home insulation would make you feel uncomfortably hot or extremely cold, waste precious energy, and even endanger the health and well-being of your family.
So, the next important question to address is, “What areas of your home need insulation?”
Which Parts of My Home Should I Insulate?
There are critical parts of the house that require adequate insulation if a homeowner wants optimum comfort and energy efficiency. These include the attic, ceilings, walls, floors, and foundation. Knowing the various types of these house sections and their specific insulation requirements can help you save time, money, and energy in your insulation project.
Most people are aware that insulation plays an important role in home comfort. Besides, it is quite easy to distinguish whether a place has excellent insulation or poor-to-none because of the presence of cold drafts or hot spots.
Since you want your home to be comfortable year-round, and yet not spend too much on cooling or heating costs, you know that you have to have adequate insulation in your home.
Let’s talk about critical areas in your home that require insulation.
Where Should You Insulate?
If you are to ask the Department of Energy, the authority on energy efficiency and saving, a place of residence “should be properly insulated from the roof down to its foundation.” But it is good to know which areas of your home to prioritize instead of just blindly doing the installation and hoping for the best.
Attic Insulation
The space or room right below the roof and just above your living space ceiling is called the attic. Before you start the insulation of the attic, it is crucial to identify what kind of attic you have.
Unfinished Attic
The type of attic that is primarily used for storage and does not necessarily conform to standard living codes is called an unfinished attic. It can either be a scuttle—accessible only by a pull-down ladder from a trapdoor—or space within reach via a permanent staircase.
In most cases, an unfinished attic has plywood installed as a floor covering with no level of insulation of any kind. Because of this, the attic is the perfect gateway for heat to escape.
If your intention is only to seal off your uninsulated attic from the rest of the house, you have to adequately insulate above and in between the floor joists.
Another important part of an unfinished attic that you need to prioritize insulating is the attic hatch or sometimes called the scuttle hole. This is a removable panel typically in your hallway or closet ceiling and provides access to your attic via a pulled-down ladder.
Since the attic hatch serves as a passageway that you need to shove to get up to the attic, it is usually constructed only with lighter materials or drywall. These materials cannot be expected to resist heat transfer very well, so the attic hatch is a common source of drafts and hot spots.
Insulating the attic hatch combined with air sealing would reduce heat movement through these access points. Meanwhile, radiant barriers are extremely helpful for residences in hotter climates as they reflect thermal radiation rather than absorb it.
Even if you already found a layer of insulation on the attic floor of your unfinished attic, consider measuring the thickness of the existing layer if it passes the recommended R-value in your area. In case you only measured less than 11 inches, then it came up short to the minimum R-value of R-30 and so more insulation is required.
Finished Attic
If your attic is in a state of being livable, this is characterized as a finished attic. This means that the walls and ceilings are at least covered and that no rafters are showing.
This category of the attic can even be further divided into two: partially-furnished and fully-furnished attics.
A partially-finished attic has at least 20% to 39% of its floor space area that is up to the standard living code. With enough headroom, these spaces can be used in part as a bedroom, study, or playroom but for the most part as a storage section of the house.
Meanwhile, a fully-finished attic has a percentage of 40% to 54% considered to be livable. The upgraded version of this is what they call in the construction industry as Full Fin Wall HGT which means “fully-finished wall height,” where 55% of the floor areas or more is fit for living.
Commonly, a finished attic has already basic insulation making it qualified as habitable. But if you want to increase your home’s energy efficiency and comfort, it is recommended that you increase its R-values by adding more insulation.
You can start with more accessible areas like the walls and the portion of the floor that is uninsulated. When you get to the ceiling, remove the drywall or whatever finishing material covering the ceiling first before you start the insulation process. Another way is to get through the sidewalls or knee walls.
This might be enough for some structures but if the attic still feels cold in the winter, you have to increase the insulation in the area behind the sidewalls.
Make sure that no insulation material will hinder the air from moving through the eave vents. If these openings are blocked, there will be no sufficient air circulation and it would, later on, lead to roof damage that requires an expensive repair.
Ceiling Area Insulation
The Department of Energy strongly recommends insulating the ceiling that has cold spaces above. If your house has a cathedral ceiling design—two equal, sloping sides that are parallel to the pitch of the roof—there are two ways to insulate your ceiling.
Vented Ceiling
This type of ceiling allows the circulation of air through vents. If your rafters, roof frames that support roof decks, and roof coverings, are measuring at least 2 x 12 inches, it would allow space for the standard insulation of 10 inches and still leave enough room for ventilation. The fiberglass type of batt insulation is ideal, which also leaves a 1.5″ gap for ventilation.
Unvented Ceiling
Also called the “sealed roof” or the “hot roof,” unvented ceilings allow no air to escape the roof space so no humid air can penetrate the roof. In this design, the temperature around the ceiling is closer to the temperature of the rest of the house, so even the attic space is already made to be livable.
Sources say that the best type of insulation for unvented ceilings is closed-cell insulation such as rigid foam or spray polyurethane foam. Otherwise, “air-permeable insulation such as fiberglass batts, dense-packed cellulose, or blown-in fiberglass…allow moist indoor air to reach the cold roof sheathing, leading to condensation or moisture accumulation in the sheathing,” according to Fine Home Building.
Wall Insulation
Say you already insulated the attic and ceiling, and yet you still feel there is much to improve on the comfort level inside your house temperature and humidity-wise. The answer may be quite expensive yet effective: insulate your exterior and interior walls next.
Exterior Walls
These walls that form the outside of your house are load-bearing walls, which means that they “support the weight of a building and distribute it effectively from the roof to the foundation.” Exterior walls are your first defense in keeping the heat out in summer seasons and keeping it in during winters.
The way to insulate depends on whether you are constructing a new home or in the process of remodeling or it is an existing home. If you are still constructing so the wall coverings are not yet put up, two-part spray foam or wet spray cellulose insulation is a good insulation method. But if you are only adding insulation to an existing home, you may consider blow-in insulation or injectable spray foam insulation.
Interior Walls
Most people view insulating the interior walls as unnecessary and costly, but it can pay for itself given the right circumstances. If you have unused rooms in the house such as a guest room or storage, insulating its interior walls would save the energy of cooling or heating these rooms. The monthly savings from utility costs or air conditioning or heating systems would be reduced so that it can cover the added initial expense of insulating an interior room.
Floor Areas Insulation
Insulating the floor can be quite beneficial, especially if it is above unheated spaces like the garage. However, added steps should be taken before the actual insulation. Air sealing all potential leakages is the first step, not only for keeping the heat movement under control but also for blocking unwanted toxins from the garage from mixing in with your breathing space.
Installing air barriers is another crucial step to ensuring the safety of your family. The cold air ensuing from the unheated garage has the danger of short-circuiting the insulation underneath the subfloor, according to DOE.
Foundation Insulation
Insulating your foundation such as basements and crawl spaces is a great way of preserving the comfortable indoor temperature. Additionally, it frees you from additional energy consumption that results in soaring monthly electric bills.
Basement
For newly constructed houses, it is best to install insulation materials to the exterior walls of the basement. If installed properly, insulation can minimize heat transfer, preserve the damp-proof coating, and protect your foundation from excessive moisture.
If the insulation is installed externally instead of the inside walls, you will also conserve whatever small space you have for your basement.
On the other hand, if the basement has long been built and you just want to add insulation, it is best to install it in the interior basement walls. It can cost you much less and it will offer protection against insect infestation.
Crawlspace
Judging from its name, a crawlspace is a hollow area, 1 foot to 3 feet high, between the ground and the first floor. It is relatively low which you can only crawl in. Insulating the crawl space will vary if it is ventilated or unventilated.
Ventilated
The preferred type of insulation for ventilated crawl spaces is fiberglass insulation, installed under the subfloor between the floor joists. Cover the insulation with a vapor barrier to prevent molds from developing.
Unventilated
If your crawlspace is not ventilated, it is more susceptible to excessive moisture as there are no vents to remove the humid air. In this case, it is better to insulate the walls of the crawl space instead of the subfloor of the room above.
The benefit of this manner of insulation is you will get the optimum comfort with minimal insulation and if there are ducts and pipes underneath they will be covered already by the wall insulation.