Affordable Housing Energy Performance Standards-WF2-14-22
Building and Sustainability Standards
Affordable Housing with Significant City Funding
The City of Northampton aims to support affordable housing, reduce on-going utility costs for
affordable housing providers and residents, and achieve community-wide net carbon neutrality by
2050 (city operations carbon neutrality by 2030).
As part of these efforts, the City has created minimum standards for affordable housing projects
which include significant City support. This support comes in the form of CDBG funding, CPA
funding, short term rental fee funding, Tax Increment Financing, donation or bargain sale of surplus
city land, conservation limited development projects, City obtaining state grants that support
affordable housing (e.g., MassWorks and Housing Choice), and new zoning density incentives.
These standards will not automatically apply for projects with small City contributions (e.g., housing
rehabilitation or soft second affordable housing mortgages). The standards will also be adjusted for
unique circumstances, such as rehabilitation of existing buildings where some of the performance
standards are not practical.
HERS ratings do not represent a linear relationship between energy savings and effort or expense. It
is much harder to go from HERS 50 to 45 than from 55 to 50. However the difference in energy
savings from 55 to 50 is larger than going from 50 to 45. On top of that, there is a small house
penalty that makes it harder to get a lower HERS rating that with a large house, and yet a smaller
house still inherently has a smaller carbon footprint than a larger home. DOE’s ZERH program has
a more lenient HERS rating requirement, but does end up with a house that, at least in theory, can
have energy bills that net out to zero dollars. For a lower income person, this is a big benefit. If the
least cost way to achieve this is a ZERH, then we think this should remain an option. One benefit to
using the ZERH standard is that we can count on DOE to revise it as technology and other
standards change.
-See detailed standards on the next page.
New Construction Standards
(will be adjusted for rehabilitation projects)
1 to 3-Family Homes Multi-Family Multi-family
≤1,500 sq ft >1,500 sq ft ≤600 sq ft >600 sq ft
For all Projects:
Minimum wall insulation R30 R30 R30 R30
Minimum attic insulation R60 R60 R60 R60
Minimum Foundation walls/slab, lowest floor 1 R20 R20 R20 R20
Minimum lowest floor if on piers R30 R40 R30 R40
No fossil fuels for heating and indoor appliances. YES YES YES YES
No fossil fuels for water heating YES YES See below See below
90th percentile DHW demand must be satisfied by
non-fossil fuel equipment. Fossil fuel equipment
may be used to meet the remaining peak demand
above the 90th percentile.
N/A N/A YES YES
IPMAO Water Demand Calculator may be used
for water demand sizing in lieu of sizing methods
from the Uniform Plumbing Code (UPC) and the
International Plumbing Code (IPC).
N/A N/A YES YES
Must meet Energy Star, Building Code, Energy
Stretch Code, Health Code in effect when built
YES YES YES
IF site is solar suitable then DOE Zero Energy
Ready Home
YES YES YES YES
IF site is not solar suitable (shading, roof,
orientation), then Maximum HERS rating
50 HERS 42 HERS 45 HERS 40 HERS
1. Where foundation walls and slab are insulated, insulation combined with interstitial materials should sum to R20 regardless
of orientation (see, for example, the sketch below).