Best ways to add insulation inside existing walls

[DarkKnight]

Hi everyone! Many older homes weren’t built with much insulation, and tearing out walls isn’t always practical. Are methods like blown-in insulation through small holes effective? Or are there other reliable ways to improve energy efficiency from the inside? Thanks in advance for any advice!

[TinyTool]

Hello! Blown-in insulation through small holes can be quite effective, especially in walls that have no insulation or where removing drywall isn’t an option. It fills gaps and cavities well, improving thermal performance without major demolition. Just make sure the holes are properly patched and sealed afterward to maintain air tightness.

Other options to consider include:

• Adding rigid foam insulation panels on the interior walls before repainting or drywalling, which adds R-value and reduces drafts.
• Using insulating paint additives or thermal barrier coatings, though these usually offer only modest improvements.
• Sealing gaps and cracks around windows, doors, and outlets with caulk or spray foam to reduce air leaks.
• Upgrading to energy-efficient windows or storm windows if possible.

Blown-in insulation is often the best balance between effectiveness and minimal disruption for older homes. It’s a good idea to consult with a professional to assess existing wall cavities and ensure the insulation type matches the wall construction.

[DarkKnight]

Would adding insulation to just a few exterior walls make a noticeable difference in comfort?

[TinyTool]

Yes, adding insulation to just a few key exterior walls can make a noticeable difference in comfort, especially in rooms that tend to feel colder in winter or hotter in summer. Even partial upgrades help reduce drafts and heat transfer, which can improve both temperature stability and energy efficiency in those specific areas.

That said, the impact depends on factors like:

• Which walls you insulate (north-facing or wind-exposed walls often have the greatest effect)
• Room usage (living areas and bedrooms benefit most)
• Existing insulation levels elsewhere (like in the attic or basement)
• Air sealing (combining insulation with good sealing improves performance)

So even insulating just part of the home can still make a difference, and it’s a practical way to improve comfort.

[DarkKnight]

Besides insulation, are there any other underrated ways to make older houses more energy efficient without tearing out walls?

[TinyTool]

Definitely, there are actually quite a few underrated ways to boost energy efficiency in older homes without having to tear out walls. One of the most effective is thorough air sealing. It might not be as exciting as new insulation, but sealing gaps around windows, doors, baseboards, and outlets can drastically reduce drafts and heat loss. Another good option is upgrading window treatments. Things like thermal curtains or cellular shades can help insulate rooms without touching the walls. If the windows themselves are old but you're not ready to replace them, interior storm windows are surprisingly effective and easy to install. Don’t overlook the attic and basement either, since those areas are usually easier to access and insulating them can make a big difference throughout the house. Even something simple like adding a reflective barrier behind radiators on exterior walls can help retain heat. And of course, things like smart thermostats, energy-efficient lighting, and sealing unused chimneys with a flue plug can all chip away at energy loss bit by bit. When you're working with an older home, small improvements really do add up.