The Breakthroughs My Net Zero Home Is Missing

TL;DR

After 2 years in his net-zero home, Matt Frell identifies missed technologies and infrastructure decisions he wishes he'd made during construction.

Key Points

• 1.Sunamp's Thermino heat battery would have unlocked solar-powered hot water storage. Using phase-change materials that store 4x more heat than water, it allows charging during solar surplus; Edinburgh Napier University found it reduced backup heating from 4+ kWh/day to under 0.5 kWh/day, and it takes roughly 1/3 less floor space than a tank.
• 2.Skipping rainwater plumbing rough-ins was a missed low-cost opportunity. With 45 inches of annual rainfall and a 2,000 sq ft roof, 44,000+ gallons could be harvested yearly; installing just conduit, drain lines, and tank positioning during construction would have cost only $1,000–$2,000 versus far more expensive retrofits later.
• 3.A dedicated Zehnder ERV system would have delivered better air quality than his shared-duct setup. His current ERV must run the HVAC air handler fan at 35W constantly just to distribute fresh air; a separate small-diameter duct system uses 20–30W and delivers tuned fresh air directly to each bedroom, though retrofitting now costs $12,000 professionally.
• 4.Noble Carbon smart breakers offer a cheaper alternative to full SPAN panel replacement for retrofits. SPAN costs $13,000–$18,000 for both panels installed and requires full replacement, while Noble Carbon drops into existing panels circuit by circuit starting at ~$500, covering the 4 circuits (HVAC, water heater, EV charger, dryer) that account for 70% of electricity use.
• 5.Skipping the insulated roof panels and basement saved $35,000–$80,000 but created lasting space constraints. Without a conditioned basement or attic, all mechanical equipment competes for first-floor living space, duct runs require interior wall soffits, and future modifications like the ERV or solar upgrades become significantly harder and more expensive.
• 6.Franklin's APower S hybrid battery system — and pre-run conduit — represent the biggest future-proofing regrets. Launched in 2024, it supports AC- and DC-coupled solar simultaneously, allowing unlimited off-grid ground arrays without utility approval; burying 2-in PVC conduit from house to backyard during construction would have cost just $500–$600 when trenches were already open, unlocking all future expansion.