Estimating HVAC equipment from mechanical schedules
Equipment schedules hold most of the money in an HVAC bid. Reading every column, option and note, then turning them into complete quote requests and leveled quotes, is how estimators avoid the expensive misses. Since 2025, refrigerant rules have added one more column to check.
- Reading schedules
- Refrigerant rules
- Quote requests
- Rigging and startup
Reading the schedule
| Column | Why it matters |
|---|---|
| Tag and quantity | Count; check against plans |
| Capacity (tons, MBH, CFM) | Size and price |
| External static pressure | Fan and motor size; affects model selection |
| Efficiency (SEER2, IEER, EER) | Energy code compliance; higher efficiency costs more |
| Refrigerant | Post-2025 rules; A2L equipment and install requirements |
| Electrical (V/ph, MCA, MOCP) | Electrical coordination and circuit sizing |
| Operating weight | Rigging, crane and structure |
| Options and accessories | Curbs, economizers, coils, VFDs, disconnects, hail guards, controls |
| Basis of design | Manufacturer and model; "or equal" terms |
| Notes | Special requirements that override the row |
Check for typos
MBH = thousands of BTU/h → 120 MBH = 120,000 BTU/h = 10 tons
Rule of thumb: roughly 350–450 CFM per ton for comfort cooling
A schedule row showing 10 tons and 1,500 CFM, or 3 tons and 4,000 CFM, is probably a typo or a special application (DOAS, high latent). Ask.
Rules after 2025
Under EPA's Technology Transitions rule (AIM Act), new residential and light-commercial air conditioning and heat pump systems assembled from components made or imported on or after January 1, 2025 must use refrigerants with a GWP below 700, which in practice means A2L refrigerants such as R-454B or R-32. A 2026 EPA final rule, effective July 27, 2026, removed the federal installation deadline for qualifying legacy R-410A systems built entirely from components made or imported before January 1, 2025. VRF and other subsectors have their own dates; check EPA's sector table.
For the estimator:
- Confirm the scheduled refrigerant matches what manufacturers actually ship today.
- A2L refrigerants are mildly flammable. Equipment standards and codes can require leak detection or mitigation in some installations; ask suppliers what's included.
- Price A2L-rated tools, recovery equipment and technician training if your crews are new to it.
- Legacy R-410A equipment pricing and availability depend on remaining inventory.
Send the full schedule
- Send the full schedule, notes and relevant spec sections (Division 23) to each supplier.
- List every option and accessory explicitly.
- Ask for exceptions in writing.
- Ask what's excluded: startup, freight, warranty extensions, controls, curbs, refrigerant charge.
- Level quotes line by line against the schedule before choosing.
Reading one schedule line
Illustrative. RTU-1: nominal 25 tons, 10,000 CFM at 1.5 in ESP, gas heat 400 MBH input, 460V/3ph, MCA 62 A, MOCP 80 A, operating weight 4,800 lb, factory curb, economizer with fault detection, VFD supply fan, R-454B.
Weight 4,800 lb on roof → crane, structural check, curb coordination with roofer
MCA/MOCP → electrical contractor sizes feeder and disconnect
Economizer + VFD → confirm in quote; controls interface with BAS
R-454B → A2L; ask about leak detection requirements and lead time
What estimators get wrong
- Counting from the schedule only. Plans may show more or fewer units. Reconcile every tag both ways.
- Missing accessories. Curbs, adapters, economizers, disconnects and controls are separate costs.
- Ignoring weight. Heavy units need cranes, rigging, sometimes structural support.
- Assuming startup is included. Factory startup and warranty extensions may be extra.
- Missing connections. Flex, transitions, curb adapters and vibration isolation at equipment.
- Controls gaps. Who provides sensors, actuators and BAS integration.
Getting equipment in place
Quotes may or may not include freight, and rarely include unloading, hoisting or setting. Rooftop units and large air handlers can require cranes, street closures or after-hours work. Price rigging from each unit's operating weight and location, and confirm site access before bid day.
Equal products
If you propose substitute equipment, confirm dimensions, weight, electrical data, refrigerant and performance match, since changes ripple into structural, electrical, roofing and controls.
Pads, curbs and isolation
Count equipment pads, curbs, rails and vibration isolators, and confirm who furnishes them (mechanical, concrete, roofing).
Before you request quotes
- Tags reconciled between plans and schedules
- Notes reflected in the quote request
- Refrigerant and efficiency compliance confirmed
- Long-lead equipment identified, with lead times in the proposal
- Rigging paths and crane access checked
- Startup, warranty, freight and controls leveled across quotes
Equipment counts and duct runs, checked before pricing.
RenderDraw reads mechanical plans with schedules and specs, proposes equipment counts, duct and pipe runs with the source attached, and puts uncertain items in front of your estimator first.
- Equipment from schedules and plans. Traceable to the source sheet.
- Duct and pipe runs. Proposed lengths your estimator accepts or corrects.
- Addenda through the same review. Send the changed sheets back through takeoff and estimator review.
- Your labor and pricing. Applied to reviewed rows only.
Send one mechanical set
Files stay private while RenderDraw assesses the request. No obligation.
RenderDraw does not publish accuracy percentages or time-saved claims. Test it on your own plan set.
Questions estimators ask.
How do you estimate HVAC equipment?
Read every schedule column and note, send complete quote requests with options, level quotes line by line, reconcile tags with plans, and add rigging, startup, supports and controls.
What changed with refrigerants in 2025?
New residential and light-commercial AC and heat pump systems built from components made or imported on or after January 1, 2025 must use refrigerants with GWP below 700, typically A2Ls like R-454B or R-32. A 2026 EPA rule removed the installation deadline for qualifying legacy R-410A inventory.
What is MBH?
Thousands of BTU per hour. 12 MBH equals one ton of cooling.
Why check MCA and MOCP?
They define circuit size and overcurrent protection; errors affect electrical pricing and coordination.
Do equipment quotes include startup?
Sometimes. Read each quote for factory startup, warranty terms and training, and add what's missing.
Can RenderDraw check equipment counts?
RenderDraw's AI takeoff proposes equipment counts from plans and schedules with the source sheet on each row, for your estimator to review. Get a free sample takeoff.
Equipment counted against the schedule.
RenderDraw proposes equipment counts from plans and schedules and flags mismatches.
- Upload the plans, specs and schedules, plus an addendum if you have one.
- RenderDraw reviews the set and the scope you want tested.
- We follow up with extracted quantities, flagged items and next steps.
Where these numbers come from
We checked this guide against the standards, manufacturer documents and industry references below (last reviewed November 2026). Figures marked as rules of thumb are typical ranges, not requirements; your project documents, local code and your own cost history govern.