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ian finlayson



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MA new Stretch and Specialized (net-zero) Energy codes are out:…. 🧵

Stretch code currently in place in 299 cities and towns (90% of MA) so this update has an impact. Specialized code is a new local option for cities and towns to consider. There is also a 10 town/city pilot of all electric new construction and a base energy code in 51 small towns.

For what is in these updated codes, an explainer is here:… but if that’s too many words….

Residential new homes move from HERS 55 or Energy Star Home in today’s stretch code to HERS 42 or 45 or Passive House certified over next 2 years.

HERS 52 in 2023, HERS 42 after July 2024 for homes with any fossil fuel. All-electric homes meet HERS 55, then 45. Plus all-electric homes get $15k incentive or $25k for GSHP. Plus the Federal tax credits from IRA…

In the new top tier Specialized code res homes are Also HERS 45/42 up to 4,000sf. Homes >4,000sf with any fossil fuel use triggers net zero (HERS 0 or Phius zero). Above 12,000sf multi-family is Passivehouse (phius or PHI)

Commercial codes: Focus is on Envelope improvement, heat recovery ventilation and then electrification. New stuff includes the TEDI approach pioneered in Vancouver and Toronto. And real thermal bridge mitigation ( trust me that’s exciting for commercial energy code😂)

Specialized code for multi family is basically Passive House: Phius or PHI, plus solar ready and EV ready (20% wired spaces min)

Highly ventilated buildings like Labs can use ASHRAE 90.1 appG with min 25% electrification, curtain wall glass buildings must be 100% electric space heating ( unless also high vent Labs, etc)

In specialized code any fossil fuel use (except emergency generator) requires solar PV on site and electric service and wiring for future electric upgrade.

Net zero pathway is not required, you can choose all-electric or Passive House instead, but if used net-zero has to be on-site, no contracts for RECs or offsite renewable generation.

Could we do more? Yes in the future, but this is a meaningful step forwards that is mindful of GHG benefits and need to increase housing supply and affordability.

ian finlayson


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