NORTHWEST HOUSTON Blog

How Insulation Impacts Energy Efficiency

Picture this: a sufficiently comfortable home, energy-efficient, warm in winter and cool in summer. It’s the dream, right? Let us let you in on a little secret... that is how air sealing and proper insulation works!

In Houston, air sealing and insulating your homes can save you 9% off your cooling/heating systems or an average of 6% off your total energy bills. 

Insulation works as a barrier that stops heat transfer into and out of your home. 

What is heat transfer and how does it affect my energy consumption?

According to the second law of thermodynamics, heat transfer occurs from higher- to lower-temperature bodies but never in the reverse direction. Heat can either transfer from conduction, convection, and/or radiation. 

Now, in buildings with no insulation and air sealing, heat transfer is more apparent.

During summer, heat gain transpires inside a building. The heat from the sun and the outer surroundings radiates from the roof and flows to the attic. Through conduction, the heat absorbed in the attic transfers into the ceiling and radiates down to the living spaces, which can then enter through walls and windows. 

The dense colder air inside the building speeds up heat gain. It pulls in warm air as it escapes due to the stack effect.

In the winter, the heat loss occurs as the heat from inside the house is pushed out by dense cold air forcing its way in. Through convection, heat rises upwards.

The constant heat transfer and air leaks in a home causes the HVAC systems to work harder. Just imagine the A/C blowing cool air to regulate the temperature but the room just takes too long to cool or won’t cool at all because the heat from the outside keeps entering! 

On cold days, energy is wasted as the heat from the furnace keeps on rising towards the attic and the roof (which causes ice dams during winter!). The wasted energy accounts for higher bills and reduced useful life of A/C and heating systems. Cooling/heating systems are designed for enclosed spaces, hence they wear out faster when exposed to work in a surrounding with constant heat transfer. 

To limit heat gain/heat loss, you need to block the potential entryways of air. 

Air leaks are commonly found in attic hatches, door/window frames and kitchen exhaust fans, chimney and flues, electrical outlets, light switches, recessed lights, plumbing, and rim joists.

Sealing air gaps save you energy on cooling/heating costs and it makes the indoor air quality better. It also prepares your building for more effective insulation!

How insulation prevents heat transfer

Even if you have sealed air gaps in your home, heat transfer is still imminent. Insulation reduces this by acting as a protective shield from the outer surroundings, allowing your home to retain its temperature without the substantial influence of outdoor temperature.

Insulation in walls

Heat radiating from the outside can enter through the interior walls through conduction. Similarly, heat can also escape from the same walls. There are different options of insulation for walls: blown-in, spray foam, batts, and rigid.

Blown-in insulation can be applied to unfinished walls but it is also suitable for drywalls and closed walls. Small holes are drilled on finished walls and insulating materials are blown inside, filling every nook and cranny of the wall cavities.

Like blown-in insulation, spray foam can be applied to both finished and unfinished walls. It is effective in sealing any gaps and cracks within interior walls.

Batts insulation is installed on unfinished interior walls while rigid foam boards are installed on unfinished exterior walls.
 

Attic Insulation

Of all the places in the house, the roof receives the most heat transfer. When insulating your home, the attic should be the top priority. The ceiling joists, rafters, and other structures must be insulated to limit heat entry.

Same with walls, you can choose from various types of insulation to suit your liking and your attic’s needs: batts, blown-in, rigid and spray foam.

If you have a small attic space, you can opt for a cellulose blown-in insulation. If you have a large space, open-cell spray foam is generally the best choice.
 

Payback Period of Insulation

Energy efficiency is best felt in a comfortable home and you will see the evidence in your bills.

The payback period of insulation refers to the amount of time it’ll take for your energy savings to break even with the initial cost of insulation installation. To calculate the payback period, first you have to know your:

• Insulation costs and installation costs
• Energy bill 

To have an idea on your payback period,

1. Determine the difference between the new insulation and old insulation cost. This will serve as your “costs”.
   
   New Insulation - Old Insulation = Cost

1. Then, deduct your annual old energy bill to your annual new energy bill to get your annual savings. (After a free insulation evaluation, we can help you estimate your energy savings)

          Old Energy Bill - New Energy Bill = Savings

1. Finally, divide your computed cost by your savings to get your payback period in years.
   
   Cost/Savings = Payback Period
    

Sometimes, it’s hard to determine the direct impact of insulation on your energy bills due to many factors. For every household, there are different variables that you have to take into account. Along with some energy payback calculators, we’ve listed out some of the things you may want to include in considering the computation for insulation’s energy savings here.

Air sealing and insulation work closely together to protect your home from heat and cold by serving as a thermal barrier and in the process, they save your money, too!  Koala Insulation of Northwest Houston can help you choose the best insulation tailored for your needs. What are you waiting for-- book your free insulation evaluation with us today!