How to Know How Much Insulation You Need for a House

How to Know How Much Insulation You Need for a House

June 3, 2024 Blog Financial Home 0

As a lot of women like myself do, I fell prey to the belief that my husband was handling all of the mechanic workings of our home when, in fact, he either one didn’t know how to, or two, didn’t care. Men can do the same when it comes to other gender-specific roles some of us tend to fall into when we get married or get domesticated. For example, today, being divorced, my ex-husband has had a challenging time learning.

It really doesn’t matter which one because I am now responsible for caring for my home, a home that needs some TLC and a little attention to detail. After getting divorced, I am now in charge of all the responsibilities, despite what gender category they might fall under. I am really okay with it all as since I grew up with a single mom, once I was old enough, she gave me what typical “boy jobs” to handle as well as some of the “girl jobs.” Needless to say, I am comfortable in handling a lot of the workload, and if I am physically unable (since I’m getting “old,” not because I am a woman), I have two big, strong sons to help me out.

An important project that needs to be done soon is my home insulation for Michigan’s extreme winter weather temperatures. According to Bob Vila, the nationally renowned television carpenter celebrity, the way to know how much insulation you need for a house he says, “For walls, measure the height and width of the wall and multiply the numbers together. Subtract the area of any windows or doors,”.

Here’s a quick breakdown in list form of how to know how much insulation you need for a house:

  • Measure height and length of each room’s walls
  • Determine amount of insulation needed
  • Write down spacing of studs
  • Multiply wall’s length by wall’s height
  • Determine what kind of house insulation will be needed

Below is a table demonstrating basic, average examples of how much one can expect to spend:

House SizeAverage Cost
1,200 sq. ft.$1,980 – $16,500
1,500 sq. ft.$2,475 – $18,000
2,000 sq. ft.$3,300 – $25,000
3,000 sq. ft.$4,950 – $35,000

*Note: All content within this article is meant for informational purposes only and is in no way a replacement for professional contractor advice or support. Seek appropriate advice from an insulation professional when necessary.

Should I insulate my attic or walls?

When I stumbled upon learning that what I really need is insulation, I was looking into getting new windows and a new HVAC (heating, ventilation, and air conditioning). Fortunately, I have many friends and family members who work in HVAC who have given me their honest opinion on what they thought. I told them how my energy costs were rising to amounts that I could not afford, how my windows were drafty, and that my current HVAC system is definitely not energy efficient as it was installed thirty years ago. They suggested I look into insulation first and then see what happens. But I was confused about whether I should do attic-only insulation or put it in the walls, too.

As for attic versus wall insulation, I was advised to always go for the attic. They told me that the most significant payback would be seen here. It will stop heat loss from natural convection and block solar gain (an increase in heat) in the attic, which can result in energy savings of thirty to fifty percent, which I could most certainly use.

According to Energy Saver, the U.S. Department of Energy’s (DOE) consumer resource on saving energy and using renewable energy technologies at home, “The illustration above shows all the areas of the home where there should be insulation. The numbered areas shown in the illustration are as follows:

  1. In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below. If the air distribution is in the attic space, then consider insulating the rafters to move the distribution into the conditioned space. (1A). Insulate the attic access door
  2. 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.
  3. 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. Also insulate (4A) any portion of the floor in a room that is cantilevered beyond the exterior wall below; (4B) slab floors built directly on the ground; (4C) as an alternative to floor insulation, foundation walls of unvented crawl spaces. (4D) Extend insulation into joist space to reduce air flows.
  5. Do not forget to insulate the band joists.
  6. Caulk and seal around all windows and doors,”.

Things to do before having insulation installed in house

As I mentioned earlier, I am lucky to have a lot of friends and family who work in the trades. Even my mom ran a general contracting outfit. We’re Italian, so naturally, a lot of us work in construction (haha). After asking around and doing my due diligence, I found the following list of things to do before having insulation installed in my house:

  • Check local building code for R-value (insulation level) recommendations and any vapor barrier requirements that apply to our area
  • Seal gaps that allow unconditioned air into the space we’re insulating
  • Pay attention to areas where plumbing, ductwork, or wiring enter the space
  • Ensure there is a clear pathway to the areas
  • Clean up said spaces
  • Ventilate areas being insulated
  • Search for and block air leaks
  • Check for water leaks
  • Box out light fixtures (to avoid fire hazards, keep at least a 3-5 inch gap between the insulating material and light fixtures. This can be done with hardware cloth, scrap plywood, or metal flashing)

How to know how much insulation you need for a house

In conclusion, even though I have a plethora of people to consult and have many years of experience in contracting businesses, I must always consult with a professional contractor for advice or support or from an insulation professional when doing this type of project.