Maryland AC Requirement Law 2026: Effective Dates Explained
by Platuni | 30 Sep, 2026 | 5 mins read
Platuni
30 September, 2026
5 mins read
1. The building-size threshold this law actually uses
This requirement applies to residential rental units in apartment buildings with 10 or more individual dwelling units.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That threshold is worth confirming directly against the enrolled statute, since an earlier version of the companion House bill referenced a different, smaller unit count during the legislative process. The number that actually became law is 10 units, not a lower figure some earlier drafting language suggested.
2. The exact cooling standard the statute sets
Covered units must be maintained at a temperature not greater than 80 degrees Fahrenheit, measured 3 feet above the floor level, in each habitable space.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That's a specific, measurable standard, not a vague comfort requirement. A landlord verifying compliance needs a system capable of holding that 80-degree ceiling at that specific measurement height, not just a working air conditioner in a general sense.
3. Why this isn't one blanket requirement for every covered building
This is the detail most likely to get missed in a quick read of the law. Coverage isn't triggered the same way, or on the same date, for every unit in a qualifying building. The statute creates distinct categories with their own separate trigger dates.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
4. The first category, and its June 1, 2026 date
Newly constructed residential rental units are covered starting June 1, 2026. Separately, units where the lease required landlord-provided air conditioning, or where the landlord actually supplied air conditioning, at any point on or after January 1, 2025, are also covered starting that same June 1, 2026 date.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That second part matters beyond new construction. A landlord who voluntarily provided AC in an existing unit any time after January 1, 2025, even without a lease obligation to do so, triggered coverage for that unit under this category.
5. The second category, and its later October 1, 2026 date
Units undergoing a replacement or substantial upgrade of electrical systems or heating systems are covered starting October 1, 2026, a full four months after the first category's trigger date.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
A landlord planning a heating system replacement or a substantial electrical upgrade in a qualifying building needs to build AC installation into that renovation's scope with this October date in mind, rather than assuming the earlier June 1 date applies uniformly across the whole property.
6. Why the renovation trigger exists at all
Tying AC coverage to electrical and heating system upgrades specifically, rather than to every renovation of any kind, targets units where the infrastructure work happening anyway creates a natural opportunity to add cooling capacity. A landlord doing a heating system replacement in a covered building is, under this law, simultaneously taking on an AC installation obligation for that unit, whether or not AC was part of the original renovation plan.
[Cite: PK Law, "Beat the Heat: Maryland's New A/C Requirements for Certain Residential Rental Units"]
7. The requirement is seasonal, not year-round
This obligation runs specifically from June 1 through September 30 each year.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That seasonal framing matters for how a landlord should think about ongoing compliance. The temperature standard has to be met during those four months annually, not as a year-round mechanical requirement that happens to matter most in summer.
8. Who's responsible if the tenant controls the thermostat
Whether the tenant or the landlord controls the air conditioning system's operation, the landlord remains responsible for ensuring the system functions properly and can meet the required temperature standard.
[Cite: PK Law, "Beat the Heat: Maryland's New A/C Requirements for Certain Residential Rental Units"]
That allocation of responsibility means a landlord can't treat tenant control over day-to-day thermostat settings as a defense if the underlying system itself can't actually achieve the 80-degree standard when operated as designed.
9. The specific properties this law exempts
Properties listed on the National Register of Historic Places are exempt from this requirement.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
The statute also names specific exemptions tied to particular Baltimore public housing history: certain Baltimore Housing Authority developments built in the 1940s and 1950s, and specific Baltimore rowhouse public housing built between 1960 and 1997.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
Those named exemptions are specific to identified properties and development types rather than a general age-based or ownership-based exemption, so a landlord should confirm a given property actually matches one of these named categories rather than assuming an older building automatically qualifies.
10. Why there's no separate penalty section to plan around
Unlike some of Maryland's other recent housing legislation, this statute doesn't include an explicit enforcement mechanism or penalty provision of its own.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That doesn't mean noncompliance carries no consequence. A failure to provide required air conditioning in a covered unit would likely be addressed through Maryland's existing general habitability and code enforcement framework, the same avenues that already apply to other maintenance and repair obligations, rather than through a penalty structure unique to this specific law.
11. Why new construction and voluntary AC provision get treated the same way
It's worth noting that new construction and a landlord's voluntary decision to provide AC in an existing unit end up in the same coverage category with the same June 1, 2026 trigger date, even though those are very different situations.
[Cite: Maryland SB 12, Chapter 664, 2026 Regular Session, enrolled text]
That structure creates a practical incentive consideration: a landlord weighing whether to voluntarily add AC to an existing unit outside a renovation context should recognize that doing so on or after January 1, 2025 locks in the earlier June 1, 2026 compliance trigger for that unit, rather than the later October 1, 2026 date tied to electrical or heating system work.
12. What property managers should do now
The practical starting point is auditing a covered building's unit inventory against these two separate categories, new construction and existing voluntary or lease-required AC provision on one track, planned electrical or heating system upgrades on the other, rather than treating June 1, 2026 as a single portfolio-wide deadline.
For any unit scheduled for an electrical or heating system replacement or substantial upgrade, building AC installation into that renovation's budget and timeline now, ahead of the October 1, 2026 trigger date, avoids a late scramble once that later deadline arrives.
Frequently asked questions
What building size does this AC requirement apply to?
Apartment buildings with 10 or more individual dwelling units.
What's the required cooling temperature?
No greater than 80 degrees Fahrenheit, measured 3 feet above the floor level, in each habitable space.
Does this requirement apply year-round?
No. It applies specifically from June 1 through September 30 each year.
Are there two different effective dates?
Yes. New construction and units with existing or lease-required landlord-provided AC are covered starting June 1, 2026. Units undergoing electrical or heating system replacement or substantial upgrade are covered starting October 1, 2026.
Which properties are exempt?
Properties on the National Register of Historic Places, along with certain specific named Baltimore Housing Authority developments and Baltimore rowhouse public housing properties.
What happens if a landlord doesn't comply?
The statute doesn't set out its own specific penalty. Noncompliance would likely be addressed through Maryland's existing habitability and code enforcement framework.
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