HB 339 Maryland House of Delegates · 2025 Regular Session

Real Property - Residential Rental Apartments - Air-Conditioning Requirements

HB 339 requires landlords of non-historic residential rental apartments in Maryland to provide air-conditioning starting June 1, 2025 for new units and October 1, 2025 for units with qualifying HVAC system upgrades. Landlords must maintain temperatures within specific ranges during June-September: 90% of ASHRAE Standard 55 thresholds normally, and 80% thresholds if daily highs exceed 92.3°F. The law applies only to apartment buildings (excluding National Register historic properties) and distinguishes between landlord-controlled and tenant-controlled AC systems. It does not affect buildings with permits issued before the bill's effective date.

Issues: ✓ Housing

Bill status passed 3 of 5 stages cleared

Introduction

Jan 2025

Committee Review

Mar 2025

House of Delegates Passage

Mar 2025

Senate Passage

Governor

Introduced Jan 13, 2025 Last action Mar 19, 2025

Maddy AI version diff · 1 comparison

What changed between versions

First - Real Property - Residential Rental Apartments - Air-Conditioning Requirements → Third - Real Property - Residential Rental Apartments - Air-Conditioning Requirements · 4 edits

MODERATE

This bill was amended to clarify its applicability and strengthen air-conditioning requirements for residential rental units. The changes add a new requirement that the section only applies to apartment buildings with four or more units, and expands the definition of when air-conditioning must be provided to include specific HVAC system renovations. The bill also reorganizes the structure of the requirements and adds a new section specifying temperature limits for tenant-controlled systems.

Scope change

The bill now explicitly applies only to residential rental units in apartment buildings with four or more individual dwelling units, rather than all residential rental units in apartment buildings.

SCOPE

Added requirement that the section applies only to apartment buildings with four or more individual dwelling units.

REQUIREMENT

Expanded the definition of when air-conditioning must be provided to include HVAC upgrades or maintenance that meet the 'alteration' threshold under ASHRAE Standard 90.1, specifically including replacement or substantial upgrade of electrical or heating systems.

Added new requirement that landlords must maintain air-conditioning systems at not greater than 80 degrees Fahrenheit when the system is under tenant control.

TECHNICAL

Reorganized the bill structure by renumbering sections and subsections, and added formatting notes about amendments.

Floor votes · House of Delegates Feb 28, 2025

How they voted

99–39

Passed · 1 other

Total votes 139

Feb 28, 2025

D Democratic100

98 Yea 1 Nay 1

98% Yea

R Republican39

1 Yea 38 Nay

97% Nay

Vote distribution

All Yea All Nay Mixed No data

Full legislative history

Actions timeline

Total actions

Key actions

Committee

Amendments

Mar 12, 2025

Committee

Referred Judicial Proceedings

upper

Mar 11, 2025

Lower · Passed

Third Reading Passed

lower

Mar 5, 2025

Introduced

Floor Amendment {

lower

Mar 4, 2025

Lower · Passed

Motion Special Order until 03/05 (Delegate Schmidt) Adopted

lower

Mar 4, 2025

Lower · Passed

Favorable with Amendments {

lower

Mar 3, 2025

Lower · Passed

Favorable with Amendments Report by Environment and Transportation

lower

Feb 28, 2025

House Of Delegates · Passed

House of Delegates Vote: pass (99-39-1)

house of delegates

Jan 13, 2025

Committee

First Reading Environment and Transportation

lower

17 primary · 0 co-sponsors