Boiler sizing depends on your Newton home’s square footage, insulation level, and heating distribution system. A typical 1,500-square-foot Newton home needs a boiler rated between 60,000-80,000 BTUs, but this varies significantly based on your specific situation and Massachusetts climate demands.Older Newton homes, especially those built before 1950, often have less insulation and may need larger capacity boilers to handle heat loss through original windows and walls. However, oversizing wastes energy and money while undersizing leaves you cold during Newton’s harsh winters.We calculate the proper size using Manual J load calculations that account for your home’s actual heat loss, ceiling height, window efficiency, and insulation levels. Many Newton homeowners assume they need the same size as their old boiler, but heating needs change over time with improvements like new windows or added insulation.