What is the material cost difference between R-20 and R-24 fibreglass batt insulation for a 1,600 sq ft home in Dieppe NB?

The material cost difference between R-20 and R-24 fibreglass batts for a 1,600 sq ft home in Dieppe is approximately $200-$400, depending on the specific wall area and where you purchase the materials.

For a typical 1,600 sq ft bungalow or two-storey home in Dieppe, you're looking at roughly 1,200-1,400 square feet of exterior wall area (accounting for windows and doors). R-20 fibreglass batts cost approximately $0.75-$1.10 per square foot at NB building supply stores, while R-24 batts run $0.95-$1.35 per square foot. This puts your total material costs at roughly $900-$1,540 for R-20 versus $1,140-$1,890 for R-24.

However, there's an important consideration for your Dieppe location: R-24 batts are 6.25 inches thick and designed for 2x8 wall construction, while most homes in the Dieppe area built before 2010 have standard 2x6 walls that accommodate R-20 batts (5.5 inches thick). If your home has 2x6 framing, you cannot simply upgrade to R-24 batts — they won't fit without compression, which actually reduces their effective R-value below the R-20 you'd get from properly fitted R-20 batts.

For 2x6 walls in Dieppe's Maritime climate, focus on proper installation rather than higher R-values. A perfectly installed R-20 batt with no gaps, compression, or voids will outperform a compressed R-24 batt every time. More importantly, ensure you have a continuous 6-mil polyethylene vapour barrier on the warm (interior) side — this is critical in New Brunswick's cold, humid climate where condensation within wall cavities causes mould and rot.

If you're building new or doing a major renovation with 2x8 framing, the R-24 upgrade makes sense for Dieppe's 4,800+ heating degree days. The extra $200-$400 in material cost will save approximately $50-$100 annually in heating costs with oil or electric baseboard heating. For maximum performance in new construction, consider R-22 batts in 2x6 walls plus R-5 continuous exterior insulation — this eliminates thermal bridging through the studs and achieves true whole-wall performance that exceeds even R-24 batts in 2x8 framing.

Need help finding a professional insulation contractor to assess your wall framing and recommend the best approach? New Brunswick Insulation can match you with local professionals who understand Maritime climate requirements and proper vapour barrier installation.