ERV vs. HRV: Which Ventilator Fits Your NYC-Area Building
An HRV (heat recovery ventilator) moves only heat between outgoing stale air and incoming fresh air. An ERV (energy recovery ventilator) moves heat and a controlled amount of moisture. That one difference decides most of the choice. In the New York metro area, with cold, dry-air winters and sticky summers, both can be justified, and the right one depends on how your building is used, how tight it is and what your local code asks for.
This guide explains how each system works, where each one wins, and what owners, property managers and facility managers in NYC, Long Island, Westchester and northern New Jersey should check before a renovation locks in the ventilation plan.
TL;DR
An HRV transfers heat only. An ERV transfers heat and some moisture. Both are balanced systems with two fans that bring in fresh air while exhausting stale air.
HRVs are usually recommended for cold or dry climates and ERVs for humid ones. The NYC area has both extremes, so the building and how it is used matter more than the zip code.
An ERV is not a dehumidifier. Tight, well-insulated buildings in humid summers can still need separate dehumidification.
In NYC, the 2025 Energy Conservation Code requires new dwelling units to have an HRV, an ERV or an approved balanced system. Check which code edition your permit falls under.
Size the unit from airflow needs, not square footage alone, and plan for filter and core cleaning from day one.
Table of Contents
What an HRV and an ERV have in common
Both machines are balanced ventilation systems. According to Building Science Corporation, they use two fans to hold a building at roughly neutral pressure while energy passes between the incoming fresh air and the outgoing stale air. The two airstreams do not mix. They pass through a core, and the core moves energy from one stream to the other.
That design matters because modern buildings are tight. A new or fully renovated home leaks very little air on its own, so cooking fumes, moisture, odors and carbon dioxide stay inside unless something moves them out. Opening windows works in April, not in January or during a July heat wave. A balanced ventilator gives you steady fresh air without paying the full heating or cooling cost of bringing it in.
Both types also share the same practical footprint: ducts to the outdoors, a supply and an exhaust connection, a place to mount the unit, and a need for regular maintenance. The questions that separate them come down to moisture.
ERV vs. HRV: the difference in plain terms
Building Science Corporation describes the split simply: an HRV exchanges only heat, while an ERV exchanges both heat and moisture. In winter, that means:
HRV: warms the incoming cold air with heat from the outgoing air. Moisture leaves with the exhaust, so indoor humidity drops a little.
ERV: warms the incoming air and also returns part of the indoor moisture to the home, so the air stays somewhat less dry.
In summer the process reverses:
HRV: cools the incoming air with the cooler exhaust air, but humid outdoor moisture comes in with it.
ERV: cools the incoming air and holds back part of the outdoor moisture, so the air arrives less humid than it would through an HRV.
Side-by-side comparison
Factor | HRV | ERV |
What it transfers | Heat only | Heat and some moisture |
Winter effect on indoor humidity | Lowers it, because moisture leaves with exhaust | Helps retain it |
Summer effect | Brings in outdoor humidity with the fresh air | Reduces the humidity of incoming air |
Typical recommendation | Cold or dry (heating-dominated) climates | Humid climates |
Condensate drain | Usually needed | Often not required |
Maintenance | Filters and core cleaning | Filters and core cleaning |
The climate recommendation in the table comes from Building Science Corporation’s information sheet, which notes that manufacturers typically recommend HRVs for cold or dry climates and ERVs for humid ones. The drain point comes from CMHC’s guide to HRVs and ERVs, which says ERVs often do not need condensate drains, a real advantage in tight mechanical closets, though they can still generate condensation when outdoor air is very cold and indoor humidity is high.
Which is better for NYC, Long Island, Westchester and northern New Jersey?
No single answer fits the region. Winters here are cold and heating-dominated, which points toward an HRV on the standard rule. Summers are humid, which points toward an ERV. Most buildings in the region spend a large share of the year in both conditions.
So do not choose by region alone. Ask these questions about your own building instead.
Does the building run dry in winter or damp?
A home with many occupants, frequent cooking, an unvented dryer or a finished basement tends to carry high indoor humidity in winter. An HRV helps by sending that moisture outside. A small apartment with few occupants and strong heating often feels dry in January, and an ERV helps keep some moisture in.
How hard does summer humidity hit?
If your cooling system runs often, it removes moisture as a side effect, and an ERV takes a share of the humidity load off it. If the building is well insulated with low cooling loads, the air conditioner runs briefly and removes little moisture. That is where humidity can build up, and where an ERV alone will not be enough.
What does the building actually do?
A restaurant with a heavy kitchen exhaust, a gym, a classroom, a retail floor with constant door traffic and a quiet residential bedroom floor all have different moisture and occupancy patterns. For commercial and multifamily properties, ASHRAE’s chapter on air-to-air energy recovery argues that energy recovery should be considered for every building that uses conditioned air, since it keeps indoor air quality acceptable while cutting energy use and carbon dioxide emissions.
A practical rule of thumb
Choose an HRV when winter moisture is your main problem: crowded households, new tight construction with high moisture sources, basements prone to dampness, or spaces that stay cold for long periods.
Choose an ERV when you want to soften both seasons: dry winter air indoors, humid summer air outdoors, and a cooling system you want to relieve.
In either case, have a mechanical professional calculate the loads before you buy. A manufacturer’s general guidance is a starting point, not a design.
Does an ERV replace a dehumidifier?
No. This is the most common misunderstanding, and it is worth correcting before you spend money. An ERV reduces the moisture load of the air coming in, but it cannot effectively dehumidify a home. Building Science Corporation and the U.S. Department of Energy both note that in high-performance houses with low cooling loads, supplemental dehumidification is required.
The reason is simple. Air conditioning dehumidifies only while it runs. In a well-insulated building, it runs less. The U.S. Department of Energy’s measure guideline on supplemental dehumidification explains that low-sensible-gain homes can have long cooling-system off-times, allowing indoor moisture to build up, and that extra dehumidification may be needed to hold acceptable relative humidity.
If you see mugginess, musty smells or condensation on cool surfaces in July and August, ask for a humidity plan, not just a ventilator. The same DOE research program found, in a hot-humid climate study, that whole-house energy use was more sensitive to the indoor relative-humidity set point than to the dehumidification technology chosen. In practice, setting a sensible humidity target matters as much as the equipment.
Disadvantages and limits of each system
Neither system is a cure-all. Know the tradeoffs before you commit.
HRV limits
Does not return moisture, so a dry apartment can get drier in winter.
Brings humid outdoor moisture inside in summer.
Usually needs a condensate drain, which adds a plumbing connection.
ERV limits
Not a dehumidifier, as above.
Can still produce condensation when outdoor air is very cold and indoor humidity is high, per CMHC.
Moisture transfer is partial. It softens swings, it does not eliminate them.
Limits for both
Both need duct runs, a mounting location and electrical power.
Both are designed to run continuously, so maintenance is not optional. CMHC lists cleaning or replacing filters and servicing cores as routine work, typically handled by a property manager or contractor.
Poor duct design undermines either one. A top-rated unit connected to undersized, kinked or leaky ducts will underperform.
How to size an ERV or HRV
Floor area is a starting point, not the answer. A 2,000 square foot house with two occupants and one with six occupants need different airflow. The ventilation standards most designers work from, such as ASHRAE 62.2 for homes, build the target airflow from floor area and the number of bedrooms or occupants, then adjust for how airtight the building is and how the system will run.
What a mechanical designer looks at:
Floor area and bedroom count, which set the baseline airflow for a home.
Occupancy, which matters most in commercial spaces, where code ventilation rates are tied to use and the number of people. If you are not sure how many people a space is allowed to hold, our guide to calculating occupancy load walks through it.
Airtightness, since a tighter envelope leaves less natural leakage to count on.
Fan performance at the real duct resistance, not the number on the brochure.
Local code minimums, including the efficacy limit covered below.
Undersizing leaves stale air behind. Oversizing wastes energy and raises noise. Ask for a written airflow target and the duct layout before approving the work.
NYC code: what owners and managers should check
If your project is in New York City, ventilation is not just a comfort choice.
The 2025 NYC Energy Conservation Code, Chapter R4, requires dwelling units to be provided with an HRV or ERV installed per the manufacturer’s instructions, or an approved balanced ventilation system (Section R403.6.1).
The same chapter sets a minimum fan efficacy of 1.2 CFM per watt for balanced systems, HRVs and ERVs (Section R403.6.2, Table R403.6.2).
The Department of Buildings’ support document for the 2020 NYCECC states that each dwelling unit in a new building must be served by a listed, adequately sized HRV or ERV, and inspectors verify the unit is within the thermal enclosure and operates properly.
Which edition of the code applies to your job depends on when the work is filed. Our article on locking a NYC renovation under the 2020 energy code explains why the filing date matters. Outside the five boroughs, Long Island, Westchester and New Jersey follow their own state and municipal rules, so confirm with the local building department before ordering equipment.
Where ventilation fits into a renovation
The best time to plan an ERV or HRV is before the walls close. Ducts need paths through framing, the unit needs a mounting spot with access for service, and the outdoor intake and exhaust need locations that respect code spacing. Retrofitting later usually means opening finished surfaces.
Here is how it plays out in typical projects across the region:
Gut bathroom or kitchen renovation: exhaust and make-up air are rethought. A balanced system can take over general ventilation, while local exhaust still handles steam and cooking.
Basement finishing: new living space below grade brings moisture questions. Plan ventilation alongside waterproofing and, where needed, dehumidification.
Additions: more floor area and more bedrooms change the airflow target. The new space should be on the ventilation plan from the start.
Window replacement: tighter windows reduce leakage and raise the need for controlled ventilation. Our guide on vinyl versus wood windows and U-factor covers the envelope side of that decision.
Commercial build-outs: ventilation rates follow the use of the space, so the plan should be settled before layout is final.
Maintenance: what it takes to keep a unit working
A ventilator that nobody services quietly becomes a noisy box that does little. For either type, plan on:
Cleaning or replacing filters on a regular schedule set by the manufacturer.
Cleaning the core as the manual specifies.
Checking intake and exhaust hoods for debris, snow and ice.
Confirming drains are clear where the unit has one.
Listening for changes in fan noise and checking airflow if rooms feel stuffy.
For property and facility managers, this belongs in the preventive maintenance calendar next to boilers, rooftop units and fire systems. Our facility maintenance guide for managers shows how to build that kind of schedule.
Our perspective
We are a general contractor, not an equipment maker, so we do not sell a brand of ventilator. What we see on jobs across New York City, Long Island, Westchester and northern New Jersey is that the equipment is rarely the problem. The problem is timing. Owners decide on ventilation after the drywall is up, or they ask for an ERV because a website said “humid climate” without anyone checking how the building behaves in January.
Our advice is to treat ventilation as part of the scope, the same way you treat insulation, windows and waterproofing. Decide the airflow target early. Leave room for ducts and service access. Put the code requirements on the plans so inspection is routine. Then pick the type with the people who will design and maintain it: an HRV if winter moisture is the issue, an ERV if you want to soften both seasons, and a dehumidifier in addition if summer humidity is the real complaint.
Do not buy for the brochure. Buy for the building.
— DJ
Plan ventilation into your next project with us
DJ Custom Contracting LLC has served homeowners, business owners, property managers and facility managers since 2018, handling interior and exterior renovations, additions, alterations, basement finishing, kitchen and bathroom remodeling and building and facility maintenance. Our work follows applicable local laws, licensing requirements, building codes and insurance regulations, and we cover every phase of a project. If ventilation is part of your renovation or maintenance plan, see our services and tell us about your building.
FAQ
Is an ERV better than an HRV?
Neither is better in every case. An ERV suits buildings where summer humidity and dry winter air are both concerns, while an HRV suits buildings where winter moisture is the main issue. Match the type to the building’s moisture pattern and the local code.
Do I need a dehumidifier if I have an ERV?
Often, yes, especially in a tight, well-insulated building with a small cooling load. An ERV lowers the moisture in incoming air but cannot effectively dehumidify a home. If indoor humidity stays high in summer, plan supplemental dehumidification.
What are the disadvantages of an ERV system?
It moves only part of the moisture, so it does not replace a dehumidifier. It can still form condensation when outdoor air is very cold and indoor humidity is high. Like an HRV, it needs ducts, power and regular filter and core cleaning.
What size ERV do I need for a 2,000 square foot house?
There is no single number. Airflow targets come from floor area plus bedrooms or occupants, then adjust for airtightness and duct resistance. Ask a mechanical designer for a written airflow target, and check it against local code.
Does NYC require an HRV or ERV?
For dwelling units under the 2025 NYC Energy Conservation Code, yes: units must be provided with an HRV, an ERV or an approved balanced ventilation system. Which code edition applies depends on your filing, so confirm with your designer or the Department of Buildings.
Sources
Recommended
Comments