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Chapter 12 · HVAC · Section B · Installing Through-Wall HVAC EquipmentLPC Permit Guidebook · 12.8Installing Through-WallHVAC EquipmentInstalling Through-WallHVAC Equipment atPrimary FacadesStaff can only approve permanentinstallations of HVAC equipment,louvers, and vents through the wallon certain types of buildings.Small BuildingsIf the building is classified as asmall building (see Glossary inSection C), a manufacturing orloft building, or an individuallandmark, staff cannot approveinstallation of through-wall HVACequipment. Staff may suggestalternatives or your proposalmay be presented to the fullCommission for review at a publichearing. See Section A to verifywhether the building is considereda small building according to LPCRules.Large BuildingsIf the building is classified as alarge building (see Glossary inSection C), staff can approvepermanent installation of throughwall HVAC equipment if it meetsthe following criteria. See SectionA to verify whether the buildingis considered a large buildingaccording to LPC Rules.LocationThe location of the newinstallation must match theregular pattern of installationsat the building or the installationshould be centered beneaththe window opening. If thereis no pattern or it is not possibleto adhere to an existing pattern,the location can form the basisfor a new pattern that does notdetract from the facade or adjacentbuildings.If the window opening is wideenough to accommodate twoor more windows, placementmust match the predominantexisting pattern of throughwall installations, which can becentered beneath the opening or toone side.The installation must not occurthrough decorative masonrysuch as corbelled or patternedbrickwork.Design and InstallationThrough-wall HVAC equipmentmust be mounted as flushas possible with surroundingmasonry, typically no more than1/2 inch beyond the plane of thefacade. This type of installation istypically achieved with a rimlesstype architectural louver with flatmetal blades.FinishThe louver must be finished tomatch surrounding masonry.RequiredApplication Materials Photos of buildingfacades. Photos of the specificwall areas whereinstallations will occur. Existing and proposedannotated floor plans orelevations showing thelocation where installationswill occur, includingbuilding height and streetfrontage dimensions atprimary facades only. Comparative elevation foreach installation showingexisting and proposedconditions, includingalignment of the louver tothe associated window, ifany. Comparative verticalsection drawings showingexisting conditions andproposed louver, installedflush with the wall orminimally projecting. Manufacturer cut sheetsof the louver or vent. Color samples to matchthe surrounding masonryIf LPC requires additionalmaterials after yourapplication is reviewed,you will receive a MaterialsChecklist from LPC staff.

Chapter 12 · HVAC · Section B · Installing Through-Wall HVAC EquipmentLPC Permit Guidebook · 12.9New louverinstallationsshould followthe existingpattern of louverinstallations ormay establisha new pattern ifnecessary.Through-wall HVAC installations should not be installed atdecorative masonry (at left), but may be installed at plainmasonry (at right).New installations should match an established regularpattern of through-wall HVAC installations.

Chapter 12 · HVAC · Section B · Installing Through-Wall HVAC EquipmentA section drawing of a through-wall HVAC installation with a flush-mounted architecturallouver. The louver must be finished to match the surrounding masonry.A typical elevation drawing of a through-wall HVAC installation centered belowa window opening.LPC Permit Guidebook · 12.10

Chapter 12 · HVAC · Section B · Installing Through-Wall HVAC EquipmentInstalling Through-WallHVAC Equipment atSecondary FacadesStaff can approve throughwall HVAC and mechanicalinstallations at secondary facadesif they meet the following criteria:At secondary facades withoutwindows, the unit must beinstalled in a uniform pattern.Variations from the predominantexisting pattern may be permittedif interior space does not permitinstallation that conforms with thepattern.LocationAt visible secondary facades,FinishIf the vent or louver is 144 squareinches or less in surface area, itmust be below, above, or to theside of a window opening.At non-visible secondary facades,the installation does not needto be painted.if the vent or louver exceeds 144square inches in surface area,it must be centered beneath orabove a window opening.Design and InstallationAt visible and non-visiblesecondary facades, if thelouver is 144 square inches orless in surface area, a minimallyprojecting cap may be installed.Louvers that exceed 144 squareinches in surface area are onlypermitted through a masonryfacade. The exterior louver mustbe mounted as flush as possiblewith the exterior wall or facadecladding, and with the minimumfeasible projection.At visible secondary facades, theexterior louver must be finishedin a manner that approximates thecolor of the surrounding facadecladding.LPC Permit Guidebook · 12.11

Chapter 12 · HVAC · Section B · Installing Wall-Mounted HVACLPC Permit Guidebook · 12.12InstallingWall-Mounted HVACInstalling Wall-MountedHVAC at Primary FacadesStaff cannot approve wallmounted HVAC equipment atprimary facades on any building.These installations must bereviewed by the full Commissionat a public hearing.Installing Wall-MountedHVAC at SecondaryFacadesStaff can approve wall-mountedHVAC installations if they meetthe following criteria:LocationWall-mounted HVAC can be nomore than minimally visiblefrom a public thoroughfare. SeeSection C for more information onminimal visibility.Wall-mounted flues or ducts canbe minimally visible from apublic thoroughfare, or morethan minimally visible if requiredby building, fire. or health codes.If the duct or flue is more thanminimally visible, it must belocated in the least visiblelocation, not disrupt thecomposition of the facade, and notextend higher than required.Design and InstallationAny attachments, such asassociated platforms, brackets,and straps, must be reversible, ifpossible, and minimize damageto the historic building. Ifpenetrations through the facade arerequired for conduits or ducts, theymust be as small as possible toconform with the manufacturer’srecommended dimensions.FinishAt visible secondary facades,HVAC and other mechanicalequipment, flues, and ducts, plusassociated platforms, brackets,and straps, must have a finishthat matches the color of theunderlying material or is neutraland does not call attention to itself.RequiredApplication Materials Photos of buildingfacades. Photos of specific wallareas where installationswill occur. Existing and proposedannotated floor plansor elevations showinglocation of proposedinstallations. Comparative elevationsshowing existing andproposed conditions foreach installation. Comparative verticalsection drawings ofexisting and proposedHVAC equipment or flue,showing attachment to thewall, including platformsand brackets. Manufacturer cut sheetsof HVAC equipment. Color samples to matchor harmonize with thesurrounding masonry orwall cladding at visiblefacades only.If LPC requires additionalmaterials after yourapplication is reviewed,you will receive a MaterialsChecklist from LPC staff.

Chapter 12 · HVAC · Section B · Installing Wall-Mounted HVACWall-mounted flues at a secondary facade, as required by code. The flues havebeen finished to match the underlying material.A section drawing showing the attachment of a platformand brackets for a wall-mounted HVAC unit utilizing existingmortar joints.LPC Permit Guidebook · 12.13

LPC Permit Guidebook · 12.14Chapter 12 · HVAC · Section B · Installing HVAC Equipment in StorefrontsInstalling HVACEquipment in StorefrontsStaff can approve storefrontHVAC installation if it meets thefollowing criteria:RemovalThe installation must only involveremoving glazing, or modifyingor removing the transom windowsash and retaining the storefront ordoor frame.Transom Installationtime, the resulting installationmust comply with criteriain this section and Chapter 3(Storefronts) as well.FinishThe exterior louver and any solidfiller panel must be finished tomatch the storefront windowframe or bulkhead. At a recessedstorefront, the projecting windowunit does not need to be painted.The exterior louver must bemounted flush with or behindthe plane of the transomwindow frame and behind brickmold or panning.If the exterior louver replaces onlypart of the transom window sashbeing removed, the remainderof the space must be filled witha flat panel (glazed or solid) orpartial height transom windowsash that matches the finish andconfiguration (size permitting) ofthe overall transom window. Photos of buildingfacades. Photos of storefrontswhere installationswill occur. Existing and proposedannotated floorplans or elevationsshowing the location ofstorefront windows whereinstallations will occur. Comparative storefrontwindow elevationsshowing existing andproposed conditions. Comparative verticalThe glazing at one of these transomwindows has been replaced with aflush-mounted louver, finished tomatch the transom window frames.At recessed storefront entrancesonly, the window unit (projectingor flush) can be mounted withinthe transom window frame.section drawingsshowing existingconditions and proposedlouver installed within thestorefront window. Color samples to matchthe storefront at visiblefacades only.If LPC requires additionalmaterials after yourapplication is reviewed,you will receive a MaterialsChecklist from LPC staff.Bulkhead InstallationAt a non-historic storefrontbulkhead, a rimless architecturallouver can be integrated intothe design of the bulkhead andinstalled as flush as possible.If installation involves installingthe exterior louver and a newstorefront or door at the sameRequiredApplication MaterialsLouvers can be integrated into thedesign of a non-historic storefrontbulkhead.

Chapter 12 · HVAC · Section B · Installing Rooftop HVAC or Other Mechanical EquipmentLPC Permit Guidebook · 12.15Installing RooftopHVAC or Other MechanicalEquipmentStaff can approve rooftop HVACor other mechanical installations ifthey meet the following criteria:Staff may approve a minimallyvisible installation if it is notpossible to make the installationnon-visible, and visibility is notcaused by equipment being placedon a Commission-approvedaddition. See Section C for moreinformation on minimal visibility.If an existing grandfatheredor Commission-approvedinstallation is being replaced, staffcan approve work that slightlyincreases visibility over a primaryfacade if the increase is requiredby building or fire codes and thereis no feasible alternative.Otherwise, a grandfatheredor Commission-approvedinstallation can be replaced withmatching or smaller units, even ifit is more than minimally visible,provided that no other locationwould be less visible.At a secondary facade,the installation can be no morethan minimally visible.Required Application Materials Photos of building facadesand roof. Photos of areas ofinstallation at the roof. Existing and proposedannotated roof plan showinglocations where installationswill occur. Comparative elevationsexisting and proposedconditions for eachinstallation. Comparative buildingsection drawings of existingand proposed conditions,showing HVAC or mechanicalequipment installations on theroof, including dunnage andsurrounding parapets:–S ightline section takenat a 6-foot eye level fromdirectly across the streetat the property line andother points where HVAC ormechanical equipment maybe visible Manufacturer cut sheetsof HVAC or mechanicalequipment. Color specifications forvisible installations only. Two sets of DOB filingdrawings if proposed workrequires a DOB permit.A physical mock-up of theinstallation may be requiredto determine potentialvisibility of rooftop HVACand mechanical equipment(see Section C, TechnicalGuidance and Resources).If a mock-up is required,you must submit thefollowing applicationmaterials: Color photographs ofthe mock-up and rooffrom surrounding points onthe street to demonstratepotential visibility of theproposed installation. If the proposed installationis visible from a publicthoroughfare, colorphotographs from points ofvisibility noting the maximumpoint of visibility.If requested by staff, a photomontage for each view withthe installation drawn in.If LPC requires additionalmaterials after yourapplication is reviewed,you will receive a MaterialsChecklist from LPC staff.

Chapter 12 · HVAC · Section B · Installing Rooftop HVAC or Other Mechanical EquipmentRooftop HVAC installations, includingvents and condensing units, can beminimally visible if it is not possibleto make them non-visible from publicthoroughfares.LPC Permit Guidebook · 12.16Rooftop installations can includeother mechanical equipment like solarpanels, as seen here.Minimally visible rooftop HVAC units, as seen from a public thoroughfare.The orange box is a physical mockup of a proposed rooftop HVAC unit.Staff may require such a mock-up todetermine an installation’s potentialvisibility from public thoroughfares.

LPC Permit Guidebook · 12.17Chapter 12 · HVAC· Section B · Installing HVAC and Other Mechanical EquipmentInstalling HVAC and OtherMechanical Equipmentin Yards and AreawaysFinishStaff can approve HVAC and othermechanical installations in yardsand areaways if they meet thefollowing criteria:If there is any visibility of HVACand other mechanical equipment,conduit and ducts, and associatedplatforms, equipment must have afinish that matches the color of thefacade material or is neutral anddoes not call attention to itself.LocationEquipment should be placed in anon-visible location. Equipmentcan only be installed in frontof a primary facade or visiblesecondary facade if there is nopractical or feasible alternative.In front of a primary facade, theinstallation can be minimallyvisible only if at least partiallyscreened by architectural orhardscape features, e.g., behindan areaway wall, within a belowgrade light well. See Section Cfor more information on minimalvisibility.This HVAC unit was installed adjacentto a secondary facade. Evergreenplantings will further reduce theequipment’s visibility over time.Required Application Materials Photos of building facadesand areaway or yard. Photos of areas ofinstallation at areawayor yard.In front of a visible secondaryfacade, the installation must be setback as far as possible from theprimary facade. Visibility can bereduced or eliminated through theuse of permanent plantings. Existing and proposedInstallation Comparative elevationsPenetrations for associatedconduits or ducts through thefacade must be as small as possibleto conform with manufacturer’srecommended dimensions.annotated areaway orsite plan showing whereinstallations will occur; if inthe front areaway, includedetails on why it is not feasibleelsewhere.showing existing andproposed conditions for eachinstallation. Comparative verticalsection drawings of existingand proposed conditions,showing HVAC or mechanicalequipment and attachmentto paving, yard, or base ofthe wall, including platforms,conduits, and penetrations. Manufacturer cut sheetsof HVAC or mechanicalequipment. Color samples to match orharmonize with surroundingpaving or wall at visibleareaways and yards only.If LPC requires additionalmaterials after yourapplication is reviewed,you will receive a MaterialsChecklist from LPC staff.

Chapter 12 · HVAC · Section C · Technical Guidance and ResourcesSection CTechnical Guidanceand ResourcesThis section provides additional guidanceand resources to help you understandLPC’s rules and criteria in order to submitthe correct materials with your application.LPC Permit Guidebook · 12.18In This Section:GlossaryMaster PlansHow to Construct a Mock-Up

LPC Permit Guidebook · 12.19Chapter 12 · HVAC · Section C · GlossaryGlossaryDecorative Masonryis terra cotta, cast stone, naturalstone (such as limestone, marble,brownstone, or granite), and brickfacade areas; any ornamentalfeature that is a component ofthe facade such as belt courses,banding, water tables, cornices,corbelled brick work, medallions,enframements, and surrounds; andornamental bonding patterns, e.g.,tapestry or diaper brick patterns.The term does not include entirelyplain units of stone, masonry, orbrick laid up with simple, nondecorative coursing.HVAC Equipmentincludes through-window,through-wall, rooftop, areaway,and facade- and yard-mountedheating, ventilation, and airconditioning equipment, includinglouvers; wall-mounted louvers;and stove, restaurant, bathroom,and/or dryer vents.Large Buildingsare seven or more stories or havea street frontage of more than40 feet. Large buildings includelarge apartment buildings andhotels; large commercial and loftbuildings, including cast-ironfronted buildings, departmentstores, banks, office buildings; andother building types.See Chapter 6, Additions, for moreinformation about minimal visibility.Minimally Visibleis the amount of visibility ofHVAC and other mechanicalequipment that the staff canapprove over the primary andsecondary facades:Over a primary facade:If there is no feasible or practicalalternative, HVAC and othermechanical equipment can projectinto the maximum line of sightfrom a public thoroughfare nomore than 12 inches in height ifthe equipment is less than 60 feetabove the ground; project no morethan 18 inches if the equipment isbetween 61 and 80 feet above theground; project no more than 24inches if the equipment is between81 and 100 feet above the ground;and project no more than 36 inchesif the equipment is more than 100feet above the ground.Over a secondary facade:The visibility of HVAC and othermechanical equipment must notcall attention to itself or detractfrom significant architecturalfeatures of the building or otherbuildings if in a historic district. Indetermining whether equipmentdoes not call attention to itself ordetract, LPC staff considers thefollowing factors:Visibility at a significant distance.Mechanical Equipmentis equipment other than HVACequipment, such as solar and windpowered equipment, batteriesand emergency generators, andany associated elements such assafety railings and soundattenuation screens, baffles,and other structures.Visibility againstthe backdrop of another buildingor equipment.Visibility over other buildingsand not associated with significantfeatures of the building oradjacent buildings.Primary Facadeis:A facade fronting a street orpublic thoroughfare that is not astreet, such as a mews or court.A visible facade that possessesa level of design or significantarchitectural features that iscommensurate with the building’sstreet-fronting facades, and wheresuch facade:Faces but does not front a street,such as a setback facade, orIs part of

Installing Through-Wall HVAC Equipment - at Primary Facades - at Secondary Facades 12.8 Installing Wall-Mounted HVAC 12.12 - at Primary Facades - at Secondary Facades Installing HVAC Equipment in Storefronts 12.14 Installing Rooftop HVAC or Other Mechanical Equipment 12.15 Installing HVAC and Other Mechanical Equipment in Yards and .