Quote Request — HVAC Replacement + Sound Room System
Property: 4000 Chamisa Dr, Austin, TX 78730 · Owner: Jeff Brabant · v3.2 — Sep 9, 2026 (supersedes v2)
How to read and answer this
This document is written as goals, each followed by what we believe the right answer is and a question for you. For every question, mark Agree or Alternate. Alternate means: say what you would do instead, why, and what it does to the price. You know your equipment and your crews; a well-argued alternate is welcome and may win the job. A blank is taken as Agree. Where we ask for a number — dimensions, CFM, static pressure, lineset length — the answer has to be a number; "per code" or "TBD" is not a response.
Use the response sheet — one line per question, printable, with a copy-to-email button — and return it with your quote. Drawings and equipment data are on the pad & site plan and equipment data pages; manufacturer submittals are linked from the overview.
What does not move: quiet is the top priority; every condenser goes on the ground pad northwest of the house at the location on the owner's site plan; nothing is mounted on the house or the sound room; and the sound room's airflow, fresh air, and static are measured at commissioning, not calculated.
1. Goals, in priority order
- Quiet. Outdoors at the pad and indoors in the sound room and the house. Every equipment and installation choice below serves this. Price is not the constraint; we will not take a lower bid that compromises this.
- A sound room that works as a room. Airflow at a target — and never above a ceiling — enough fresh air for the people sealed inside it, and a static-pressure budget that carries the owner-designed silencer path and a MERV 13 filter. All of it tested.
- Do it once. The 12×12 room is a prototype for a 20×20 room; the equipment moves there. Chases, pad, and controls are sized now for the second unit.
- Fixed, comparable pricing. Lump sum per scope line, exact models, written inclusions and exclusions, so three bids can be laid side by side.
- Documented commissioning and warranty. Numbers and photos, not "tested and working."
2. Scope lines to price
| Line | Scope | Notes |
|---|---|---|
| (a) | System 1 — Garage Attic (AHU-1 / HP-1): house system whose air handler is in the attic above the garage | Replace outdoor + indoor equipment, controls, condensate, electrical hookup, commissioning |
| (b) | System 2 — Master Attic (AHU-2 / HP-2): house system whose air handler is in the attic above the master bedroom | Same |
| (c) | Trench, chases, and conduits from the house to the pad | Sized for all systems plus the future second sound-room unit |
| (d) | System 3 — Sound Room (AHU-3 / HP-3) | Equipment, isolation mounting, duct terminations at the owner's silencer path, fresh-air provision, in-room sensor, commissioning tests |
| (e) | Optional: concrete pad and L walls per the pad plan, with a 6′ × 10′ allowance for pool equipment | Price it yourself, through a sub, or decline it — say which. If you decline, we build it with our concrete contractor and you still owe us the stub-up locations and pad requirements in writing (Q-P7). |
System names. Use these on your quote, drawings, equipment labels and the commissioning report: System 1 — Garage Attic (AHU-1 = the air handler in the attic above the garage, HP-1 = its heat pump on the pad), System 2 — Master Attic (AHU-2 above the master bedroom, HP-2), System 3 — Sound Room (AHU-3, HP-3), and System 4 for the reserved future sound-room unit (AHU-4, HP-4). HP = heat pump (outdoor unit), AHU = air handler (indoor unit).
3. Quote format, permits, warranty
Q-F1. Fixed lump-sum price per scope line (a)–(e), no separated materials/labor lines and no open-ended "will vary" amounts; exact model numbers for every piece of equipment, control, sensor, filter cabinet and accessory, no substitution without written approval; written inclusions/exclusions per line covering electrical circuits and disconnects, permits, refrigerant charge for actual lineset length, condensate routing, attic access, and coordination with the concrete work; and a change-order rate sheet (hourly rate, trip charge, materials markup) with every change order priced from it in writing before work proceeds. Quote valid 30 days minimum.
Q-F2. Permits: City of Austin requires a mechanical permit for the change-outs and an electrical permit for the new condenser circuits. You pull both, inspections are included, and the price says so. If you believe a permit is not required here, say why in writing.
Q-F3. Load calculations (ACCA Manual J) delivered with the quote for the zone served by System 1, the zone served by System 2, the current 12×12 sound room (System 3), and the planned 20×20 sound room (same equipment reused there). Sound-room loads must include occupants (see Q-V1), equipment heat (owner will state watts), and the ventilation air.
Q-F4. Warranty stated as parts years / labor years, and you register the equipment with the manufacturer in the owner's name within 30 days of start-up and send the confirmation.
4. Equipment
4.1 Main house — two systems, replacing everything
Our specification: System 1 — Garage Attic: HP-1 Carrier Infinity 27VNA348A003 heat pump + AHU-1 FE5 variable-speed air handler (FE5BNXC48L00 or the AHRI-matched FE5) + Infinity System Control; System 2 — Master Attic: HP-2 Carrier Infinity 27VNA360A003 + AHU-2 matched FE5 + Infinity System Control. System 1 serves the first floor (4-ton) and System 2 the second floor (5-ton) — owner-confirmed; verify on your site visit (Q-E3). Include Carrier's accumulator sound blanket accessory (KSASH2601COP / KSASH2701COP) on both units. Acceptable alternate for a Trane dealer: XV19 variable-speed equivalents, quoted as a separate alternate. Why: published sound floor of 55–58 dBA at minimum speed, 20–100 % compressor modulation, communicating variable-speed indoor fans — the house systems will spend most hours at low speed, which is where the quiet is.
Q-E1. Quote the Carrier equipment above with exact model numbers. If you would propose different premium variable-speed equipment (Trane XV19 or other), quote it as a separate alternate with its minimum-speed and maximum sound ratings (dBA, from the manufacturer's data) and its modulation range, and say why you prefer it.
Q-E2. Nominal sizes (System 1: 4-ton, System 2: 5-ton) are our estimate. Quote as specified, but if your Manual J disagrees by half a ton or more, say so in writing and price the Manual J size as an alternate. Auxiliary electric heat is sized from the Manual J heating load and balance point — not a default 10 kW kit.
Q-E3. Indoor units: confirm from your site visit that AHU-1 stays in the attic above the garage and AHU-2 in the attic above the master bedroom (or say where they move), which floor or rooms each one serves, that the cabinet fits with a 4″ media filter cabinet (MERV 13) and service clearance, and what plenum and duct transitions you include. State the target and expected total external static for each house system.
Q-E4. AHU-1 (garage attic) isolation: the garage-attic air handler transmits sound into the framing today and must not after replacement. Mount AHU-1 on spring isolation — high-deflection spring hangers if it is suspended, or a platform on spring (or spring-and-neoprene) isolators if it sits on the joists — with flexible fabric connectors at the supply and return plenums, lineset, drain and electrical on cushioned clamps, and no rigid contact between the cabinet or its platform and the framing. State the isolator product and its rated deflection. Price the same treatment for AHU-2 as a separate add.
4.2 System 3 — Sound Room: one ducted heat pump now, System 4 later
Our specification: AHU-3 Mitsubishi PVA-AA12NL multi-position air handler + HP-3 PUZ-AK12NL heat pump (P-series, R-454B). Heat pump required — no cooling-only outdoor unit. Why this pair: 4,500–12,400 BTU/h cooling modulation so it runs steady at the room's small load; 19,000 BTU/h heating at 47 °F; selectable 0.30 / 0.50 / 0.80″ WG external static — required, because the owner's silencer path, lined duct, and MERV 13 filter consume static that 0.2″-class low-static units cannot deliver against; 100 ft maximum refrigerant piping, which the NE pad needs (see Q-E6); and a 44/46 dBA outdoor unit. The M-series SVZ-AP12NL + SUZ-AA12NL is acceptable only if your measured lineset is 65 ft or less — its published limit. Owner's note: v2 of this document specified the SVZ/SUZ; the pad distance is what changed it.
Q-E5. Quote System 3 as AHU-3 PVA-AA12NL + HP-3 PUZ-AK12NL with exact accessory model numbers. If you would propose a different unit, it must be a heat pump, modulate to ≤ 5,000 BTU/h, deliver ≥ 0.8″ WG external static at 300–400 CFM, allow ≥ 100 ft of piping, and publish an outdoor sound rating ≤ 50 dBA — give the numbers.
Q-E6. Measure the actual refrigerant line route from the pad position on the site plan to your proposed sound-room air-handler location (horizontal + vertical + attic run, plus equivalent length of bends). State the number in feet in your quote. If it exceeds 100 ft, tell us which fix you recommend: move the pad toward the house, place the air handler at the end of the attic nearest the pad, or a different unit.
Q-E7. Controls: a wired remote temperature sensor inside the room (PAC-USSEN002-FM-1 flush-mount or PAC-SE41TS — confirm compatibility with the PVA) and the controller mounted outside the room (PAR-42MAAUB or equivalent wired controller — state which) configured for continuous fan while occupied and a fixed fan tap (Q-A3). The sensor's 22 AWG 2-conductor pair is the only HVAC wire that crosses the room shell, through the owner's sand-filled wire port; no line-voltage wiring through that port. Pull one spare sensor pair for System 4.
Q-E8. System 4 — the future second unit for the 20×20 room: the trench gets a chase and a conduit for it now (Q-T1), the pad has a slot for it (pad plan), and the duct design for the 20×20 will use a shared supply and shared return trunk with a motorized backdraft damper per unit interlocked to that unit's operation and a written control scheme (offset setpoints or grouped staging) so the two units never fight. Nothing you install now may preclude this.
5. Sound room — airflow, fresh air, static
5.1 Airflow: a target, and a ceiling
The PVA-AA12NL fan delivers 280 / 340 / 400 CFM (Lo / Mid / Hi). The room-side duct path is the owner's existing 10″ × 12″ (0.83 sq ft) per side, so those taps mean roughly 340 / 410 / 480 fpm in the duct. Grille faces are oversized (supply ≈ 24 × 12, return ≈ 24 × 14 or larger) so face velocity stays under 300 fpm supply / 250 fpm return at any tap. Design airflow: run continuously at the lowest tap that carries the Manual J load — we expect Lo or Mid, 280–340 CFM. Ceiling: 400 CFM, never exceeded in any mode. Lower velocity is quieter; the compressor, not the fan, does the modulating.
Q-A1. Design airflow of 280–340 CFM continuous (Lo or Mid tap), selected from your Manual J, with 400 CFM as the not-to-exceed. If your load calc says the Hi tap is needed for either the 12×12 or the 20×20 room, tell us — we would rather change the duct path than run at Hi.
Q-A2. Room-side terminations: each 10″ × 12″ duct ends in a lined plenum box expanding to the oversized grille face (supply ≈ 24 × 12, return ≈ 24 × 14 or larger), bar or perforated grilles, no dampers at the grille faces — balancing only at attic takeoffs — and no abrupt transitions downstream of the silencers.
Q-A3. Fan control: constant fan at the commissioned tap whenever the room is occupied; auto-fan and the Hi tap locked out or disabled at the controller so the ceiling cannot be exceeded by a setpoint change. State how you will configure this on the controller you propose.
5.2 Fresh air
The room is a sealed shell; nothing leaks in through the walls by design. Occupancy is up to 4 people (owner to confirm) in 144 sq ft. ASHRAE 62.1's music/theater rate (10 CFM per person + 0.06 CFM per sq ft) gives 49 CFM; holding CO₂ under about 1,000 ppm with four people needs closer to 75 CFM. Our target: 70 CFM of outdoor air, continuous while occupied, 60 CFM minimum as measured. It enters on the attic side — never through a new hole in the room shell — through a dedicated silenced intake path designed by the owner, into the return duct upstream of the filter.
Q-V1. Outdoor-air quantity: 70 CFM design, 60 CFM minimum measured, for 4 occupants. If you would size it differently, give your number and basis.
Q-V2. Method: we prefer balanced ventilation (a small ducted ERV, roughly 70–100 CFM class, on isolation mounts in the attic, with its outdoor-air and exhaust legs silenced) over a passive damper-controlled intake, because a passive intake pressurizes a sealed room and pushes air out through the door seals. Propose the ERV model and how it ties into the supply/return path (and its own static and sound), or make the case for a passive intake with a motorized damper interlocked to occupancy.
Q-V3. Relief: whatever you propose, state explicitly how ventilation air leaves the room and through what silenced path, and confirm no additional penetration of the room shell beyond the owner's supply and return.
Q-V4. Fresh air is verified at commissioning: outdoor-air CFM measured at the intake (flow hood or traverse) within ±15 % of design, and a CO₂ check with design occupancy for one hour that stays under 1,000 ppm (owner performs; pass/fail on the CFM, informational on the CO₂).
5.3 Static and humidity
Q-S1. Total external static at the commissioned fan tap, with the MERV 13 filter and the owner's silencer path installed, must be ≤ 0.80″ WG, measured and recorded. The owner will give you the silencer design's estimated pressure drop; state the drop you assumed and the ESP setting (0.30 / 0.50 / 0.80) you commissioned.
Q-S2. Humidity: with a modulating unit at low airflow we expect adequate latent removal and no standalone dehumidifier. State the indoor humidity you expect the system to hold in a Texas summer at the design airflow, and whether you would add a dehumidification control mode. No in-room standalone dehumidifier is acceptable.
6. Sound room — installation
Q-I1. Isolation: air handler hung from rafters on high-deflection spring hangers, no rigid contact with framing; flexible fabric duct connectors at both collars; lineset on cushioned clamps, no metal-to-wood contact anywhere; secondary drain pan. Unit positioned laterally offset from the room, not above it.
Q-I2. Filtration: MERV 13 at the unit in the attic — a 2″ or 4″ media cabinet (e.g., Mitsubishi FBM2-3-A filter box or an equivalent 4″ cabinet) rather than a 1″ filter, for lower pressure drop and longer change intervals. No filter grilles in the room. State the cabinet model and its clean pressure drop at the design airflow.
Q-I3. Condensate: gravity drain preferred; if a pump is required, specify it and locate it on isolation, not on the unit hangers. Route stated in the quote.
7. Outdoor units — pad, walls, orientation
All condensers — HP-1, HP-2, HP-3, and the reserved HP-4 slot — go on a common ground pad northwest of the house, at the location the owner has marked on the site plan, shielded on the house side and the pool side by two concrete walls in an L. The pad's long side runs parallel to the west property fence about 3 ft off it; the north end is open. The pad & site plan page gives the layout we derived from your equipment's clearances: a 20′ × 6′ condenser row (15′ × 6′ without the future slot), or a 20′ × 16′ envelope with the pool equipment.
Q-P1. Review the pad plan against the equipment you are quoting. Confirm the row layout, spacing (12″ to walls, 24″ between units, 24″ service apron, 60″ clear above) and dimensions work, or mark up your own dimensions and clearances on the plan.
Q-P2. Mounting: ground pad only, nothing on any structure — non-negotiable. Rubber anti-vibration feet or pads under every unit, anchored through the feet at the manufacturer's tie-down points; the Mitsubishi raised 3–4″ for defrost drainage. State the isolation product you will use.
Q-P3. Optional line (e): will you price the pad and walls (yourself or through a concrete sub)? Any objection to the existing pool equipment (pump, filter, heater) being relocated into the corral along the short wall?
Q-P4. Orientation and sound settings: Mitsubishi discharge faces the open side away from the house and pool; Carrier units are top-discharge and sit with their service side to the open side; no overhang over any unit. The west side faces the property fence about 3 ft away and the north end is open — say so if you see a recirculation or access problem with that (Carrier wants 24″ on the service side; the fence gap gives about 36″ beyond the pad edge). Confirm in writing what low-noise / quiet-mode settings each outdoor unit supports (Carrier Infinity control settings, Mitsubishi low-noise mode) and that you will enable them at commissioning.
Q-P5. Vibration: a vibration loop in each lineset at the unit, cushioned clamps along every run, and resilient, sealed wall penetrations at the house.
Q-P6. Electrical at the pad: circuits sized to the equipment (HP-1 Carrier 48: MCA 31 A / 40 A max; HP-2 Carrier 60: MCA 37.5 A / 40 A max; HP-3 PUZ-AK12NL: MCA 16 A / 27 A max), a disconnect at each unit, one spare conduit and panel space for the future unit. State whether the circuits, disconnects and electrical permit are included in your price or excluded (Q-F1).
Q-P7. Coordination with the concrete: before the pour you provide, on the pad plan, the exact stub-up locations and sleeve sizes for chases, control wiring and conduits at each unit, the anchor points, and the sequence you need (811 locate → trench + chases/conduits → pad with stub-ups → walls → set units → linesets/charge/electrical → commissioning).
8. Trench and chases
The site plan puts the trench at roughly 28 ft from the pad's house-side wall to the northwest corner of the house (the earlier 80-ft trench quote predates the pad location); size it for everything at once.
Q-T1. Chases with pulling room for all linesets and control wiring — two Carrier sets (3/8″ liquid + up to 1-1/8″ vapor, insulated), the Mitsubishi set (1/4″ + 1/2″), and the future unit's set — we suggest one 8″ chase for the two Carrier sets, one 6″ for the two Mitsubishi sets, one spare 4″ empty chase, and separate electrical conduit(s) sized for all condenser circuits plus one spare. All chases sloped and drained to the pad end, sealed at both ends, with pull strings. Say what you will install and why if different.
Q-T2. Lineset sizing and charge: state each system's vapor and liquid line size and actual length, and the capacity loss at that length from the manufacturer's table (Carrier's own table: a 4-ton on 100 ft of 7/8″ vapor loses 3.1 %, on 1-1/8″ loses 1.1 %). Runs over 80 ft follow Carrier's long-line guideline. Refrigerant trim charge weighed and documented per system.
Q-T3. Excavation: 811 locate before digging (owner arranges if you prefer — say which), hand-dig near located utilities, restore the trench line to grade with the spoil compacted; state what restoration is included.
9. Commissioning and acceptance
Sound room, at the commissioned fan tap, in final configuration (MERV 13 in, owner's silencer path installed). Owner may witness with 48 hours' notice; the report is part of the price.
Q-C1. Airflow is measured, not calculated: delivered airflow at the supply grille by flow hood, or by ≥ 9-point vane-anemometer traverse × free area, within ±10 % of the design value and not above the 400 CFM ceiling; supply face velocity ≤ 300 fpm and return ≤ 250 fpm, grid-averaged; outdoor-air CFM per Q-V4.
Q-C2. Static and settings recorded: total external static at the commissioned tap, the ESP setting, fan tap, controller configuration (constant fan, locked taps, sensor assignment), and the weighed refrigerant charge for the actual lineset.
Q-C3. Isolation photo checklist: spring hangers only, fabric connectors at both collars, cushioned lineset clamps, isolation feet under every outdoor unit, no rigid contact — one photo each. Plus an informational sound reading (dBA, slow, A-weighted) at 3 ft from the pad wall opening and at the nearest house wall with all units at low speed and again at high speed; this is a baseline, not an acceptance criterion.
Q-C4. Systems 1 and 2: documented commissioning per system — weighed charge, measured total external static, measured airflow at the commissioned settings, Infinity setup report — and duct sealing/verification at the new plenum connections.
10. By others
- Concrete pad and walls, unless you take optional line (e).
- Silencer path, sound-room ventilation silencer design, room-side grille/plenum boxes' acoustic design, and the shell wire port — owner.
- Pool equipment — owner's pool contractor.
- Electrical and permits — you state included or excluded (Q-F1, Q-F2, Q-P6).
Appendix: equipment numbers we rely on are on the equipment data page; drawings on the pad & site plan page; every question above in one table on the response sheet.