Energy Recovery Ventilator (ERV) and Heat Recovery Ventilator (HRV) systems are mechanical ventilation that exhausts stale indoor air while capturing heat or cooling energy and transferring it to incoming fresh air. They reduce HVAC load and improve indoor air quality — but they're not cosmetic upgrades. Most jurisdictions require a permit for ERV/HRV installation because they tie into the home's HVAC and ductwork systems, which fall under the International Energy Conservation Code (IECC) and the International Mechanical Code (IMC). Whether you're integrating the unit into existing ductwork or running dedicated ducts changes the scope and permitting path. Most ERV/HRV installs require a mechanical permit; some jurisdictions bundle this with an electrical subpermit if the unit requires a dedicated circuit. The key question isn't whether you need a permit — you almost always do. The key question is whether your local building department processes this as a single mechanical permit or splits it into mechanical plus electrical. A quick call to your local building inspector clarifies this before you invest time in drawings.
When does an ERV or HRV system require a permit?
An ERV or HRV system requires a mechanical permit in nearly all jurisdictions because it's a permanently installed mechanical device that ties into the home's ventilation and ductwork. The International Mechanical Code (IMC), which most states and municipalities adopt with local amendments, requires permits for all mechanical systems including ventilation equipment. The IRC Section R105 establishes that work affecting the mechanical, electrical, plumbing, or HVAC systems requires a permit. An ERV or HRV, even when installed by a homeowner in a DIY-friendly jurisdiction, is a mechanical system and falls under this mandate.
The scope of work — whether you're tying the unit into existing ductwork or running dedicated supply and exhaust ducts — determines the complexity and inspection requirements, but not whether you need a permit. Both approaches require permitting. Tying into existing ductwork is simpler from a permitting standpoint because the existing ducts are already permitted; you're adding equipment to a permitted system. Running dedicated ducts means new ductwork paths, new penetrations through walls or the building envelope, and new sealing and insulation details — more inspection touch-points, but still a single mechanical permit in most jurisdictions.
Cosmetic or like-for-like work does not require a permit. Replacing an existing ERV or HRV unit with an identical model, keeping all ductwork and connections in place, is typically exempt. Cleaning, servicing, or filter replacement is never permitted work. But if you're upgrading to a different model with different specifications, adding ducting, changing duct routing, or installing a system where none existed before, you need a mechanical permit.
Some jurisdictions treat ERV/HRV systems as part of the HVAC permit, others as standalone mechanical permits, and a few require both a mechanical permit and an electrical subpermit if the unit requires a dedicated 120V or 240V circuit. The International Energy Conservation Code (IECC) sets efficiency standards for ventilation equipment in residential buildings, so energy compliance is often part of the review. Your local building department's permit matrix — usually available online or by phone — spells out which permit type applies to your scope.
Timeline and inspection scope depend on the jurisdiction and complexity. Plan check typically takes 1–3 weeks for routine residential mechanical permits. Once approved, inspectors focus on ductwork sealing, insulation, condensate drainage (critical for ERVs, which generate condensate), electrical connections, and duct pressure testing if your code edition requires it. Most jurisdictions inspect at rough-in (before drywall) and after completion. Expedited or over-the-counter permits are rare for mechanical work, but some departments offer same-day or next-day processing for straightforward like-for-like replacements.
Cost varies widely by jurisdiction, project valuation, and whether electrical work is bundled. Mechanical permits typically run $75–$400; adding an electrical subpermit adds $50–$150. A few jurisdictions use a flat fee for mechanical permits ($100–$200); others charge 1.5–2% of the project valuation. An ERV or HRV system with dedicated ductwork and installation labor typically valued at $3,000–$8,000 might trigger a $150–$250 mechanical permit plus a $75 electrical subpermit. Call your building department for the exact fee structure before you file.
How ERV and HRV permit requirements vary by state and climate zone
Cold-climate states have the most rigorous ERV/HRV permitting because ventilation heat recovery is essential to energy code compliance and home durability. Minnesota, Wisconsin, and the Upper Midwest require mechanical permits for all ERV/HRV installs and often mandate duct pressure testing to verify sealed, insulated ducts. The 2015 International Energy Conservation Code (IECC), adopted by most cold-climate states with amendments, requires ventilation systems to be sized, ductwork to be sealed with mastic and sealed seams (not duct tape), and insulation to meet R-6 minimum on supply and exhaust ducts in unconditioned spaces. Inspectors in these regions are familiar with ERV/HRV work and expect detailed ductwork plans showing duct sizing, insulation R-value, and condensate routing. Timeline is typically 2–3 weeks for plan review.
Warm and hot climates (Florida, Texas, Arizona) treat ERVs differently than HRVs. In high-humidity climates like Florida, ERVs (which transfer moisture as well as heat) must be designed carefully to avoid condensation problems; the Florida Building Code has specific moisture-management language for ventilation equipment. HRVs are less common in Florida because there's little heating season benefit. The 2023 Florida Building Code requires all mechanical ventilation to comply with the IMC, and ERV/HRV permits are processed like any other mechanical system — typically 1–2 weeks for review. In arid climates like Arizona, both ERVs and HRVs are permitted under the Arizona Residential Code (based on the IRC) with no special moisture requirements. Fees are generally lower in high-volume sunbelt jurisdictions ($50–$150 for routine mechanical permits).
California has the most stringent energy codes in the nation. Title 24 (the California Energy Code) mandates ventilation efficiency and sometimes requires ERVs or HRVs in new construction and major renovations. California jurisdictions process ERV/HRV permits under the California Mechanical Code (which mirrors the IMC) and require energy compliance documentation. The permit fee is often higher ($200–$400) because plan review includes both IMC and Title 24 compliance checks. Seismic bracing for ducting is also required in seismic zones, adding to the installation cost. Expect 2–4 weeks for plan review in California.
Mid-Atlantic and Midwest jurisdictions (New York, Pennsylvania, Ohio, Michigan) follow the IMC with state and local amendments. Most require mechanical permits for ERV/HRV systems; some have adopted the 2018 or 2021 IMC edition with more detailed ventilation equipment requirements. Permits typically cost $100–$250, and plan review takes 2–3 weeks. Condensate drainage is closely reviewed because of seasonal freeze-thaw cycles and foundation moisture concerns. A few jurisdictions in this region require a licensed HVAC contractor to design and install ventilation equipment, which can eliminate the DIY permitting path; check with your building department before hiring.
Common scenarios
Installing an HRV system with dedicated supply and exhaust ducts in a cold-climate home
You're running new ductwork from the HRV unit to the furnace return, new exhaust ducts to the exterior, and installing fresh-air intake ducts. This is a full mechanical system addition and requires a mechanical permit in all jurisdictions. You'll need a single-line duct layout showing duct sizing (diameter and length), insulation R-value, support locations, and exterior termination details. Most cold-climate jurisdictions also require duct pressure testing to verify ductwork is sealed. Expect a mechanical permit ($100–$250), plan review in 2–3 weeks, rough-in and final inspections, and duct pressure test on the final inspection. If the HRV requires a dedicated 120V outlet or hardwired connection, you'll also need an electrical subpermit ($50–$100) filed by an electrician or as a separate homeowner filing. Total cost: $150–$350 in permits plus $3,500–$6,000 in labor and materials. Typical timeline: permit approval + 2–4 weeks installation + 1–2 weeks for inspection scheduling. If condensate drainage requires running a drain line through a wall or foundation, the inspector will pay special attention to sealing and slope (minimum 1/8-inch drop per 12 inches of horizontal run).
Replacing an existing ERV unit with a newer model but keeping all existing ductwork in place
You're pulling out the old ERV core, installing a new unit in the same housing, and reusing all ductwork, connections, and electrical wiring. This is a like-for-like equipment swap with no change to system scope, ductwork routing, or code compliance. Most jurisdictions exempt this from permitting because you're not modifying the mechanical system itself, only replacing a component. This is comparable to replacing a furnace or air conditioner. However — call your local building department first. A few jurisdictions require a permit even for equipment replacement if the new unit has different specifications (higher CFM, different noise level, or different electrical draw). If you're upgrading the ductwork insulation, sealing, or routing during the swap, that changes the answer to yes. If you're adding a condensate pump or drain line that wasn't there before, that's a system modification and requires a permit. For a straightforward swap, you need no permit and no inspection — just verification that the new unit is installed per manufacturer specs and all connections are secure.
Adding an ERV system to an existing home by integrating it into the return side of the existing forced-air furnace ductwork
You're installing a new ERV unit, tying its fresh-air outlet into the furnace return plenum, and running new dedicated exhaust ducting to the exterior. This is a mechanical system modification — you're adding a ventilation component to the home's HVAC system. A mechanical permit is required. You'll need a scope drawing showing where the ERV unit is located, how it connects to the furnace return, duct sizing for supply and exhaust lines, insulation specifications, exterior penetrations, and condensate drainage routing. In a cold climate (Minnesota, Wisconsin, etc.), the inspector will verify that exhaust ducts are insulated to R-6 minimum and sealed with mastic, not duct tape. In warm climates, condensate management is critical — the inspector will check that condensate is routed to a proper drain or condensate pump, not into the foundation or crawlspace. Mechanical permit: $100–$250. Electrical subpermit if a dedicated outlet is added: $50–$100. Plan review: 2–3 weeks. Inspections: rough-in (before drywall) and final. Total permitting cost: $150–$350. Installation labor and materials: $3,000–$6,000 depending on ductwork distance and complexity. This scenario often comes with an additional challenge: existing furnace ductwork may be undersized or poorly sealed, so the inspector may require sealing and insulation upgrades to the existing return ductwork to meet current code. Clarify this with the inspector during plan review to avoid last-minute rework.
Homeowner installing a small ERV unit in a tight crawlspace with no ducting modification
You're squeezing a compact ERV unit into an existing crawlspace and using existing rim-joist vents for intake and exhaust (no new ductwork). This is a gray zone. Some jurisdictions see this as a minor equipment installation requiring no permit because no ductwork modifications are made. Others require a mechanical permit because any ventilation equipment installation is a permitted mechanical change. A few require a permit only if the unit draws more than a certain CFM threshold (e.g., over 50 CFM). Your local building code governs this, not the national IRC. The safest move: call your building department and describe the exact installation — unit model, CFM, location, intake and exhaust routing. Most inspectors will tell you yes or no over the phone. If yes, expect a simple mechanical permit ($75–$150) and a single final inspection. If no, confirm this in writing via email so you have documentation in case questions arise during a future home sale or renovation.
Installing an HRV in a multi-zone system that requires ducting to three separate bedrooms
You're adding a full-system ERV or HRV with dedicated supply ducts to three bedrooms, a common bathroom exhaust tying into the HRV exhaust plenum, and a main fresh-air intake on the exterior. This is a significant mechanical modification requiring a detailed mechanical permit and multi-point inspections. You'll need a floor-plan layout showing duct routing, duct sizing calculations for each zone, insulation R-value, condensate drainage path, and outdoor air intake and exhaust termination details. Inspectors will look for proper duct sealing, insulation in unconditioned spaces, support and vibration isolation, and compliance with the IMC Chapter 6 (ventilation). This is not a DIY-friendly permitting scope; most jurisdictions expect either a licensed HVAC designer to stamp the plans or a detailed homeowner drawing with specific code citations. Mechanical permit: $150–$300. Plan review: 2–4 weeks because of the complexity. Inspections: rough-in (before drywall), ductwork pressure test, and final. If the common bathroom exhaust is being rerouted, you may need to coordinate with plumbing permits if the vent path crosses plumbing lines. Total permitting cost: $150–$350 plus professional design ($300–$800 if you hire a designer). Installation: $4,500–$8,000 depending on duct runs and difficulty.
What documents you'll need and who can pull the permit
| Document | What it is | Where to get it |
|---|---|---|
| Mechanical permit application | The standard form your jurisdiction uses to request a permit for HVAC and ventilation work. Usually includes project address, scope of work description, contractor name (if applicable), and estimated project cost. | Your local building department website or in-person at the permit desk. Most jurisdictions post fillable PDFs online; some allow online permit filing through a portal (check your city or county website). |
| Scope drawing or site plan | A floor plan or elevation view showing where the ERV or HRV unit is installed, how ducts route to and from the unit, duct sizing, insulation R-value, exterior penetration details, condensate drainage routing, and fresh-air intake and exhaust termination locations. Does not need to be architect-quality, but must be legible and dimensioned. Single-line duct diagrams are acceptable for simple installs; complex systems may need isometric duct drawings. | You create this. For straightforward installs (integrating into existing ductwork), a hand-drawn floor plan with notes is usually sufficient. For dedicated ductwork, measure your duct runs, note insulation specs and duct diameters, and sketch the layout. If you're unsure about code-compliant detail, consult an HVAC designer ($300–$800) to stamp the plans; this speeds plan review and reduces the risk of rejection. |
| Equipment specifications | Manufacturer data sheet or cutsheet for the ERV or HRV unit showing model number, CFM rating, electrical requirements, condensate generation rate, and sound levels. Often available as a PDF from the manufacturer's website or retailer. | Equipment retailer or manufacturer website. Most plan reviewers expect this for any new mechanical equipment. |
| Electrical subpermit application (if applicable) | A separate permit form if the ERV or HRV requires a dedicated 120V or 240V circuit that doesn't exist. Most residential ERVs and HRVs run on 120V with a single 15-amp circuit, but some larger units need 240V or a dedicated circuit. If the home has an existing outlet or the electrician is pulling power from an existing circuit, an electrical subpermit may not be needed; clarify with the building department. | Your building department. Usually filed with the mechanical permit or immediately after, depending on your jurisdiction's workflow. An electrician must sign this form if the work requires a licensed electrician; homeowners can pull this permit in most states, but the electrician doing the work must be licensed. |
| Ductwork pressure test report (if required by code edition) | A document certifying that the new ductwork has been tested for leakage using a blower door or duct blaster per ASTM E1554 or the local code requirement. Cold-climate jurisdictions often require this; warm climates rarely do. This is ordered after ductwork is installed but before drywall. | An HVAC technician or duct tester performs this during construction. Some jurisdictions require the test to be performed by a third-party commissioning agent; others allow the installer. Cost: $300–$600 for a full ductwork test. Obtain a signed copy for the final inspection. |
Who can pull: In most states, homeowners can pull a mechanical permit for their own property, but the rules vary by jurisdiction. California, for example, restricts mechanical permit work to licensed contractors in most cases. Texas and many Midwest states allow homeowners to file mechanical permits themselves. A few jurisdictions require the installer (whether a contractor or the homeowner doing the work) to be licensed. Check your state's licensing board and your local building department's permit FAQ before assuming you can pull the permit yourself. If you hire a licensed HVAC contractor to design and install the system, the contractor typically pulls the permit on your behalf; you pay for it as part of the contract. If you're doing a DIY install or hybrid (contractor installs, you handle permitting), make sure you understand your jurisdiction's rules on who can sign off on mechanical work. An electrical subpermit, if required, must usually be signed by a licensed electrician in the state where the work occurs — homeowners cannot sign off on electrical work in most states.
Why ERV and HRV permits get rejected and how to fix them
- Application incomplete or filed under the wrong permit type
ERV/HRV systems are mechanical permits, not HVAC-only permits (in some jurisdictions) or plumbing permits. Verify the correct permit type with your building department before submitting. Check that the application form lists all required fields — project address, scope of work, estimated cost, equipment specifications, and contractor/designer name. Incomplete applications delay review by 1–2 weeks. Call the permit desk and ask, 'What permit type do you use for ERV/HRV installation?' and 'What fields are required on the application?' Most departments will tell you over the phone. - Scope drawing missing required detail (ductwork sizing, routing, insulation)
Plan reviewers reject drawings that lack duct diameters, insulation R-values, or condensate drainage path. Your drawing should show: (1) Duct sizing for each run (e.g., 6-inch round, 8-inch round), (2) Insulation specification (e.g., R-6 fiberglass wrap), (3) Ductwork routing from the unit to connection points, (4) Condensate drain line routing (downslope minimum 1/8 inch per 12 inches) to a floor drain, condensate pump, or exterior, and (5) Exterior intake and exhaust termination details (minimum distance apart, height above grade, rain caps). If you're uncertain about these details, have an HVAC designer or experienced HVAC contractor review your drawing before you submit. Many contractors will do a 30-minute phone consult for $50–$100. You'll save a plan-review rejection and delay. - Code citations referencing wrong code edition or missing code compliance language
Some jurisdictions require your application or drawing to cite specific code sections (e.g., 'Per IMC Chapter 6, all ventilation ductwork shall be sealed and insulated to R-6 minimum in unconditioned spaces'). If your plan does not cite code, the reviewer may not trust that it's code-compliant. Check your jurisdiction's website to find the current code edition being enforced (typically 2015, 2018, or 2021 IMC, depending on the state and when the jurisdiction last updated its building code). If unsure, call the building department and ask, 'What code edition applies to mechanical ventilation in my jurisdiction?' Then add relevant citations to your drawing or application. Most rejections on this point are easy fixes — just resubmit with the correct code reference. - Condensate drainage path not shown or non-compliant (especially in cold climates)
Reviewers in cold climates reject drawings that don't address condensate drainage because water in ducts and inadequate drainage cause freeze-thaw damage and mold. Your drawing must show: (1) Where condensate collects (typically a drain pan under the HRV core), (2) Ductwork slope if condensate is gravity-drained (minimum 1/8-inch drop per 12 inches of horizontal run in the drain line), and (3) Drain termination (floor drain, condensate pump, or exterior drain). If the exterior drain will freeze in winter, you must specify a condensate pump (typical cost: $100–$200) to safely dispose of condensate. If your drawing shows condensate draining to a crawlspace or foundation, the reviewer will reject it as non-compliant. Provide a compliant drainage detail and resubmit. - Trade-specific subpermit not applied for separately (electrical or plumbing)
Some jurisdictions require electrical subpermits and plumbing subpermits to be filed separately from the mechanical permit, not bundled. If your ERV or HRV requires a dedicated circuit, file an electrical subpermit with a licensed electrician's signature. If condensate must drain to a floor drain or sump (plumbing connection), coordinate with plumbing. Most building departments have a matrix showing which work requires separate permits; ask the permit desk, 'Do I need separate electrical and plumbing permits for this scope?' rather than guessing. Submitting all required permits at once speeds the overall timeline. - Equipment specifications or energy compliance documentation missing
Plan reviewers in energy-code-strict states (California, Massachusetts, etc.) require proof that the ERV or HRV meets the applicable energy efficiency standards. Submit the manufacturer's data sheet showing CFM rating, sensible and latent heat recovery efficiency (if applicable), and electrical specifications. In California, also confirm that the unit meets Title 24 efficiency requirements. Most manufacturers list efficiency ratings on their product spec sheet. If your chosen unit does not meet the required efficiency threshold, the reviewer will reject it. Check energy code compliance before you buy the unit to avoid a rejection and expense.
What does an ERV or HRV permit cost?
Permit costs are split into two categories: the permit itself and the inspections or testing that follow. The mechanical permit fee is typically a flat fee ($75–$250) or percentage-based (1–2% of project valuation). An electrical subpermit, if required, adds $50–$150. In cold-climate jurisdictions, duct pressure testing is often required at final inspection, which costs $300–$600 if you hire a third-party tester; some installers include this in their labor. A straightforward ERV or HRV system with dedicated ductwork usually costs $3,500–$7,000 in material and labor, which might trigger a $100–$250 mechanical permit in a flat-fee jurisdiction or $50–$140 in a percentage-based jurisdiction. Add the electrical subpermit and any testing costs, and total permitting is typically $150–$400. As with all permits, call your local building department for the exact fee breakdown before submitting; surprises are rare if you ask first.
| Line item | Amount | Notes |
|---|---|---|
| Mechanical permit (flat fee or percentage-based) | $75–$250 | Most jurisdictions use flat fees for routine residential work; some use 1–2% of project valuation. Example: $150 flat fee for a standard ERV install, or $100–$180 if charging 1.5% of a $6,000 project. |
| Electrical subpermit (if new circuit required) | $50–$150 | Only required if the ERV or HRV needs a dedicated 120V or 240V outlet that does not exist. If you're tapping into an existing circuit, this may not be needed; confirm with the building department. |
| Plan check or expedite fee | $0–$100 | Some jurisdictions charge an extra fee for expedited review; most include plan review in the base permit fee. Ask if expedite is available and what it costs if you're on a tight timeline. |
| Duct pressure test (if required) | $300–$600 | Cold-climate jurisdictions often require duct pressure testing per ASTM E1554 or the local code. This is performed after ductwork is installed; hire a licensed HVAC technician or commissioning agent. Some installers include this in their labor quote. |
| Inspections (included in permit fee) | Included | Mechanical permits include rough-in and final inspections. No separate fee per inspection in most jurisdictions; some larger cities charge $50–$100 per additional inspection if you fail and must be re-inspected. |
Common questions
Can I install an ERV or HRV myself and pull my own permit?
In most states, yes — homeowners can pull mechanical permits for their own property and install their own ERV or HRV. However, a few states (California, for example) restrict mechanical work to licensed contractors. Check your state's contractor licensing board and your local building department's website to confirm you're allowed to pull a mechanical permit. Even if the homeowner can pull the permit, the actual installation must comply with all code requirements. If the unit requires a dedicated electrical circuit, a licensed electrician must pull and sign off on the electrical subpermit in most states — the homeowner cannot do this. Hiring a licensed HVAC contractor handles both the mechanical permit and any necessary electrical work; the contractor typically pulls the permit and pays the fee, which you reimburse.
Do I need a permit if I'm just replacing my old ERV with a new one?
Usually no, if you're doing a like-for-like replacement in the same location with the same ductwork and electrical connections. Replacing an existing unit with identical specifications is typically an equipment swap and does not require a permit — it's treated the same as replacing a furnace or air conditioner. However, if the new unit has different dimensions, CFM rating, electrical requirements, or if you're modifying any ductwork or connections, you'll need a permit. The safest move: call your building department, describe the old unit and the new unit (include model numbers), and ask, 'Does this swap need a permit?' Most inspectors will tell you yes or no over the phone in 30 seconds.
What's the difference between an ERV and an HRV, and do they have different permit requirements?
An ERV (Energy Recovery Ventilator) transfers both sensible heat and latent heat (moisture) from exhausted air to incoming fresh air. An HRV (Heat Recovery Ventilator) transfers only sensible heat, not moisture. ERVs are better for cold, dry climates and tight, super-insulated homes where moisture control is important. HRVs are simpler and more common in cold climates where humidity is naturally low. From a permitting standpoint, both ERVs and HRVs are mechanical ventilation equipment and follow the same code requirements and permitting path. The main code difference is that ERVs in hot, humid climates (like Florida) require special attention to condensate and moisture routing to prevent mold; the building inspector may ask more detailed questions about the condensate path. But the permit process itself is identical — you file a mechanical permit, submit ductwork drawings, and get inspected. No different fee or timeline based on ERV vs. HRV.
Do I need both a mechanical permit and an electrical permit for an ERV or HRV?
Usually just a mechanical permit. However, if the ERV or HRV requires a dedicated 120V or 240V circuit that doesn't currently exist, you'll also need an electrical subpermit. Most residential ERVs and HRVs run on standard 120V and can use an existing outlet or a new outlet on an existing circuit — in those cases, no separate electrical permit is needed. Larger or commercial units sometimes require dedicated 240V circuits, which do require an electrical subpermit. The rule of thumb: if the unit is plugged into a standard 15-amp outlet, no electrical permit is needed. If it requires a 30-amp, 240V circuit or hardwired installation, you'll need an electrical subpermit. Call your building department or check the equipment specs before you commit to a purchase to understand the electrical path.
How long does plan review take for an ERV or HRV mechanical permit?
Typically 1–3 weeks for routine residential mechanical permits. Cold-climate jurisdictions like Minnesota or Wisconsin sometimes take 2–4 weeks because reviewers pay close attention to condensate drainage and duct sealing details. Urban jurisdictions with high permit volume (Los Angeles, New York) sometimes have longer queues; expect 3–4 weeks. If your drawings are incomplete or missing required detail, plan review will stall until you resubmit. The fastest way through: submit a complete application with detailed ductwork drawings, equipment specs, and code citations. Call your building department after submitting and ask, 'What's the current plan review queue? When should I expect preliminary comments?' Most departments will tell you a realistic timeline. Expedited or same-day review is rarely available for mechanical work unless it's a simple equipment replacement.
What happens if I install an ERV or HRV without a permit?
You risk a stop-work order, fines, and complications during a home sale or insurance claim. If a building inspector discovers unpermitted mechanical work during an inspection for another project (say, a roof replacement or addition), the city can order you to cease work, remove the system, or obtain a retroactive permit — all of which are expensive and disruptive. Some jurisdictions charge fines of $500–$2,000 for unpermitted mechanical work. If you ever sell the home and the new owner's inspector or appraiser finds unpermitted work, you may be liable for cost to bring it into compliance. Finally, if a problem arises (condensate damage, air-quality issues, electrical fault), your homeowner's insurance may deny a claim because the work was unpermitted. The permit cost ($150–$400) is trivial compared to these risks. Do the permit.
Can I use an online permit portal, or do I have to file in person?
It depends on your jurisdiction. Many large cities (Los Angeles, Chicago, Austin, Boston) offer online permit filing and payment through a portal. Many smaller cities and rural areas still require in-person filing at the building department desk. Your local building department's website will state whether online filing is available. If you don't see it on the website, call the permit desk and ask, 'Can I file a mechanical permit online, or do I need to come in person?' Most departments will tell you directly. Even if online filing is available, you may need to submit drawings as PDF scans or PDFs uploaded to the portal. If you file in person, bring multiple copies of your drawings and application (typically 2–3 copies) and your ID. Processing time is usually the same whether you file online or in person.
Do I need a licensed HVAC contractor or designer to stamp my plans?
Not always, but it speeds plan review. Simple plans (straightforward ductwork, clear dimensions, code citations) signed by the homeowner are acceptable in many jurisdictions. Complex systems or jurisdictions with strict code enforcement sometimes expect a licensed HVAC contractor or professional engineer to design and stamp the plans. If you're unsure, submit your drawing with a note, 'Homeowner-prepared design per [code edition],' and ask the building department, 'Do you require a licensed professional to design this scope?' If they say yes, hire an HVAC designer ($300–$800) or have the installing contractor stamp the design as part of the job. If they say no, your homeowner drawing is fine — proceed as-is.
What inspections will I need to pass?
Typically two: rough-in (after ductwork is run and tested but before drywall) and final (after the system is fully installed and operational). The rough-in inspection checks that ductwork is properly sealed (mastic, not duct tape), insulated to the required R-value, supported, and that penetrations through the building envelope are sealed. The final inspection verifies that the unit is properly connected, electrical connections are safe, condensate is draining correctly, and the system is operational. In cold-climate jurisdictions, a duct pressure test is often required at final inspection — hire a licensed tester if you don't have the equipment. Some jurisdictions also require a commissioning test or startup verification signed by the installer. Call your building department and ask, 'How many inspections will I need and what will they check?' Most inspectors will describe the process over the phone.
How do I schedule inspections?
After your permit is approved, the building department sends you a permit notice or approval email with instructions on how to request inspections. Many jurisdictions now use online portals where you submit an inspection request through the portal; others require a phone call to the inspection desk. When you're ready for rough-in inspection, call or submit the request at least 24–48 hours in advance (check your jurisdiction's notice period). The inspector will schedule a date and time and show up to verify the work. If the work fails (e.g., ductwork is not sealed properly), the inspector will issue a correction notice and schedule a re-inspection after you fix the issues. Final inspection follows the same process. Most building departments allow up to 30 days between permit approval and final inspection; if you exceed this timeline, the permit may expire and require renewal.
Ready to file for your ERV or HRV permit?
Call your local building department and confirm three things: (1) the correct permit type and application form, (2) the required drawings and detail level, and (3) the exact permit fee. Most building inspectors will answer these questions over the phone in a 5-minute call. Gather your equipment specifications, measure your ductwork routes, and sketch a simple floor plan showing where the unit is installed and how ducts connect. If you're uncertain about code compliance, hire an HVAC designer to review your plans ($300–$800 — money well spent to avoid plan-review rejections). Submit a complete application with all required drawings, get approved, and schedule your inspections. The permit process typically takes 3–5 weeks from application to final inspection; ERV and HRV systems are not complex from a permitting standpoint, but rushing the documentation invites rejections. Be thorough, ask questions, and the permit desk will guide you through.
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